JP4553324B1 - Multi-threaded screw - Google Patents

Abstract

An object of the present invention is to reduce the rotational force of a multi-thread screw and prevent loosening after tightening.
A screw thread of a male screw 13 or a female screw is a multi-threaded screw 12 having a high screw thread 13a and a low screw thread 13b, and the high screw thread 13a is connected to a pressure contact side in a fastening state among flanks on both sides. A multi-threaded screw characterized in that a flat flank portion and a pressure flank portion following the flat flank portion are formed on the top portion 25a side of the high thread 13a.
[Selection] Figure 1

Description

  The present invention relates to a multi-threaded screw configured to be engaged with one touch and complete tightening with a small number of rotations.

  Conventionally, there is a tapping screw as a fastening screw that can be tapped with the screw itself, and this tapping screw is called a single thread, a double thread, or a multiple thread depending on the number of spirals that constitute the thread. However, a double thread or more is called a multi-thread, and the multi-thread includes a double thread, and is configured to complete or disengage with one-touch sense of a small number of rotations (Patent Document 1). ).

  For example, as a tapping screw, the bottom part of the valley formed between the threads has an arc shape, and the top part of the screw thread also has an arc shape, and the valley bottom part and the top part are directly connected to each other. No straight part is provided on the bottom part, or a straight part having a length of 20% or less of the height h of the thread is provided between the valley bottom part and the summit part, and screwed into the mating material. When twisting, there is a material in which the plastic flow of the counterpart material is performed smoothly and the internal structure of the counterpart material is not cut or destroyed (Patent Document 2).

Japanese Patent Laid-Open No. 11-247818 JP 2009-191930 A

  In this way, when multiple threads are used for fastening and screwed into the mating material and tapped into the mating material, the plastic flow of the mating material is performed smoothly, and the internal structure of the mating material is not cut or destroyed Although there is something to do, since the bottom side part of the valley formed between the threads is arcuate, and the crest side part of the thread is also arcuate, there is a risk that the screw will gradually loosen after tightening .

  The present invention has been made in view of such circumstances, and provides a multi-threaded screw that can reduce the rotational force of the multi-threaded screw and prevent loosening after tightening. Objective.

  In order to solve the above-described problems and achieve the object, the present invention is configured as follows.

The invention according to claim 1 is a multi-threaded screw in which the thread of the male thread has a high thread and a low thread,
The high thread, of both sides of the flanks, chromatic for pressure side flank of the pressing side in a fastening state, and the flat flank portion on the top side of the high thread, and a pressure-side flank portion following the flat flank portion And
The low thread has a flat flank on the tip side of the low thread and a pressure flank following the flat flank. And
The top of the low thread is located within the heightwise width of the flat flank of the high thread;
And the height of the base of the flat flank portion of the high screw thread and the base of the flat flank of the low screw thread,
The low thread height is a multi-thread thread characterized by being 12% -13% lower than the high thread height .

  With the above configuration, the present invention has the following effects.

In the first aspect of the present invention, the thread of the male screw is a multi-threaded screw having a high thread and a low thread, and by having a high thread and a low thread, at the time of screwing, The plastic flow can be smoothly performed, and the internal structure of the counterpart material can be easily screwed in without being cut or destroyed. In addition, when tightening the screw that is finally screwed in, a high screw thread bites into the mating material, or generates a large frictional force by performing elastic deformation or plastic deformation, and secures sufficient locking by a sufficiently large frictional force. It can be carried out. In addition, the low thread can secure a sufficient thickness at the part between the pitches of the high thread and the high thread, and the low thread generates a frictional force without cracking. To prevent loosening. Also, the low thread has the same configuration as the high thread, and even with the low thread, the top of the low thread is positioned within the height of the flat flank of the high thread when fastened. Therefore, it is possible to sufficiently secure the thickness of the portion between the pitches of the high screw thread and the high screw thread, and to bite into the counterpart material without causing cracks due to the low screw thread, or to perform elastic deformation or plastic deformation Thus, a frictional force is generated, and the frictional force can surely prevent loosening.

It is a side view of a double thread screw of an embodiment of this invention . It is sectional drawing which shows the whole structure of the fastening state of a double thread screw. It is a figure which shows the effect | action of the fastening state of a double thread screw. It is a figure which shows the double thread screw of embodiment of a reference example . It is a figure which shows the double thread screw of embodiment of a reference example .

Hereinafter, embodiments of the multi-thread screw of the present invention will be described. The embodiment of the present invention shows the most preferable mode of the present invention, and the present invention is not limited to this. In this embodiment, a two-thread screw will be described as a multi-thread screw, but it is not limited to a two-thread screw including a two-thread screw.
(First embodiment)
The first embodiment will be described with reference to FIGS. FIG. 1 is a side view of a double thread screw, FIG. 2 is a cross-sectional view showing the overall configuration of the double thread screw, and FIG. 3 is a diagram showing the action of the double thread thread. As shown in FIG. 2A, the double thread 12 of this embodiment is inserted into the through hole 11 formed in the fixed member 10 and the male thread 13 of the double thread 12 is inserted into the support member 14. In this example, the fixed member 10 is sandwiched and fixed between the support member 14 and the back surface 17 of the head 16 of the double thread screw 12 by tightening.

  As the double thread 12 used here, a normal screw having a circular section as shown in the AA sectional view of FIG. 2A of FIG. 2B is used, and in particular, the fixed member 10 is made of resin. When the material is relatively soft, such as a screw having a cross section as shown in the AA sectional view of FIG. 2 (a) in FIG. 2 (c) may be used. The present invention is not only effectively used for such a cross-sectional screw, but also can be used for various other types of screws.

  The double thread 12 of this embodiment is a multiple thread having a high thread 13 a and a low thread 13 b of the male thread 13. First, the configuration of the high screw thread 13a will be described. As shown in FIG. 3, a flat flange portion 26a is formed on the male screw pressure contact side flank side at the top portion 25a of the high screw thread 13a of the male screw 13, and the flat screw crank portion 26a is formed. The male screw pressure contact side flank 28a is formed by raising the male screw pressure contact side flank portion 23a from the screw inner direction end portion 27a.

  The male screw pressure contact side flank 28a composed of the male screw pressure contact side flank portion 23a and the flat flank portion 26a is an example in which the flat flank portion 26a is formed in a plane perpendicular to the male screw axial direction in the illustrated embodiment. However, this surface does not necessarily have to be a right-angled surface, and even if it is configured to have an appropriate gentle inclination, the following operation can be performed.

  Next, the configuration of the low screw thread 13b will be described. As shown in FIG. 3, a flat crank part 26b is formed on the male screw pressure contact side flank side at the top 25b of the low screw thread 13b of the male screw 13, and the flat screw crank part 26b. The male screw pressure contact side flank 28b is formed by raising the male screw pressure contact side flank portion 23b from the screw inner direction end portion 27b.

Further, as shown in FIG. 1, the top 25b of the low thread 13b is positioned within the width W in the height direction of the flat flank 26a of the high thread 13a. The height H1 of the low thread 13b is 12% to 13% lower than the height H2 of the high thread 13a. Thus, the top portion 25b of the low screw thread 13b is positioned within the width W in the height direction of the flat flank portion 26b of the high screw thread 13a, so that the pitch between the high screw thread 13a and the high screw thread 13a can be reduced. A sufficient thickness can be ensured in this portion, and a frictional force can be generated without cracking by the low screw thread 13b, and this frictional force can surely prevent loosening.

  The male screw pressure contact side flank 28b comprising the male screw pressure contact side flank portion 23b and the flat flank portion 26b is an example in which the flat flank portion 26b is formed in a plane perpendicular to the male screw axial direction in the illustrated embodiment. However, this surface does not necessarily have to be a right-angled surface, and if it has a gentler inclination than the female thread pressure contact side flank 24b, it will be described later even if it is configured to have an appropriate gentle inclination. Can also be performed.

  When the double thread 12 having the high thread 13a and the low thread 13b of the male screw 13 is screwed into the support member 14 as shown in FIG. 3A, the force applied to the screw-side flank. Since the contact is made possible with a sufficiently smaller force, the two flank sides are screwed in without causing any particularly large friction. At this time, the plastic flow of the support member 14 can be smoothly performed on the counterpart support member 14, and the internal structure of the support member 14 can be easily screwed in without being cut or destroyed.

  When the rear surface 17 of the head 16 of the male screw 13 comes into contact with the surface of the fixed member 10 by subsequent screwing, as shown in FIG. 3B, the top portion 25a of the high thread 13a of the male screw 13 and the flat crank portion 26a, the tip corner 30a of the flat crank portion 26a, which is the intersection of the flat screw crank 26b, and the tip corner 30b of the flat crank portion 26b, which is the intersection of the low thread 13b of the male screw 13 and the flat crank portion 26b. When 14 is a resin article, it bites into the support member 14, or when the support member 14 is made of metal having the same degree of hardness as the male screw 13, it generates frictional force by elastic deformation or plastic deformation. In addition, this frictional force can surely prevent loosening.

  The biting state of the tip corner portions 30a, 30b and the base end corner portions 31a, 31b, or the state of elastic deformation and plastic deformation at the time of such screw fastening, is determined by the female screw pressure contact side flank 24a, 24b and the male screw pressure contact side flank portion 23a. , 23b, and the difference between the materials of the two members and the like.

( Reference embodiment)
Next, an embodiment of a reference example will be described with reference to FIG. The double thread 12 of this embodiment is a multiple thread having a high thread 13a and a low thread 13c of the male thread 13, and the configuration of the high thread 13a is the same as that of the first embodiment. Therefore, the same reference numerals are given and the description is omitted.

  The low thread 13c is formed symmetrically at the same angle as the inclination of the pressure-contact side flank 50c that is the pressure-contact side in the fastened state and the inclinations α1 and α2 of the non-pressure-contact side flank 51c that is the non-pressure-contact side. ing.

  Also in this embodiment, the top 25c of the low thread 13c is configured in the same manner as in the first embodiment, such as being positioned within the width W in the height direction of the flat flank 26a of the high thread 13a. Even with the low thread 13c, at the time of fastening, a frictional force is generated by biting into the support member 14 or by elastic deformation or plastic deformation, and reliable loosening can be prevented by this frictional force.

( Reference embodiment)
Next, an embodiment of a reference example will be described with reference to FIG. The double thread 12 of this embodiment is a multiple thread having a high thread 13a and a low thread 13d of the male thread 13, and the structure of the high thread 13a is the same as that of the first embodiment. Therefore, the same reference numerals are given and the description is omitted.

  The lower thread 13d is formed asymmetrically by changing the angle of the inclination of the pressure contact side flank 60d which is the pressure contact side in the fastening state and the inclinations α3 and α4 of the non-pressure contact side flank 61d which is the non-pressure contact side among the flanks on both sides. is doing. In this embodiment, the inclination of the non-pressure contact side flank 61d as the non-pressure contact side is formed larger than the inclination of the pressure contact side flank 60d as the pressure contact side, but the inclination of the non-pressure contact side flank 61d as the non-pressure contact side is formed. May be formed small.

  Also in this embodiment, the top 25d of the low thread 13d is configured within the width W in the height direction of the flat flank 26a of the high thread 13a. Even with the low screw thread 13d, at the time of fastening, a frictional force can be generated by biting into the support member 14, or by elastic deformation or plastic deformation, and reliable loosening can be prevented by this frictional force.

  The present invention can be applied to a multi-thread screw that is configured to be engaged and tightened with a one-touch feeling with a small number of rotations, after the rotational force of the multi-thread screw is reduced and tightened. Can be prevented.

DESCRIPTION OF SYMBOLS 10 Fixed member 12 Double screw 13 Male screw 13a High screw thread 13b Low screw screw 14 Support member 16 Head of double screw screw 17 Back surface of double screw screw 23a Male screw pressure contact side flank portion 24a Female screw pressure contact side flank 25a Top portion of mountain 13a 25b Top portion of low screw thread 13a 26a, 26b Flat crank portion

Claims (1)

The thread of the male thread is a multi-thread with a high thread and a low thread,
The high thread, of both sides of the flanks, chromatic for pressure side flank of the pressing side in a fastening state, and the flat flank portion on the top side of the high thread, and a pressure-side flank portion following the flat flank portion And
The low thread has a flat flank on the tip side of the low thread and a pressure flank following the flat flank. And
The top of the lower thread is located within the heightwise width of the flat flank of the higher thread;
And the height of the base of the flat flank portion of the high screw thread and the base of the flat flank of the low screw thread,
A multi-threaded screw characterized in that the low thread height is 12% to 13% lower than the high thread height .