JP2017214995A - Screw and structure including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screw capable of exhibiting a high looseness prevention effect and facilitating work for screwing.SOLUTION: A screw has a shaft part extending from a first end as a screw tip part to a second end along a central axis, according to one embodiment. The shaft part includes: a first region having a first thread with a first pitch; a second region positioned on the first end side with respect to the first region, and having a second thread with a second pitch different from the first pitch; and a third region positioned on the second end side with respect to the first region, and having a third tread with the second pitch. On a cross section along the central axis, a wall thickness of the third thread is made thinner than a wall thickness of the second thread in a direction along the central axis.SELECTED DRAWING: Figure 1

Description

  The present embodiment relates to a screw and a structure including the screw.

  A screw is used to fix two or more members. Examples of the material of the two members to be fixed include an inorganic material such as metal or ceramics, or an organic material such as resin. For example, a fastening member described in Patent Document 1 is known as a screw. In the screw described in Patent Document 1, each of the plurality of screw threads is pressed against the screw groove of the nut in a state of being elastically deformed. Therefore, the frictional force between the screw thread and the screw groove is increased, and a high locking effect can be exhibited.

International Publication No. 2010-092858

  In the screw described in Patent Document 1, since each of the plurality of screw threads is pressed against the thread groove of the nut, it is possible to exert a high locking effect, but a large force is also applied when attaching the screw. There is a need. For this reason, the screwing operation may become complicated.

  An object of the present aspect is to provide a screw that can be easily screwed and can exhibit a high locking effect.

  A screw according to an aspect includes a shaft portion extending from a first end that is a screw tip portion to a second end along a central axis, and the shaft portion includes a first thread having a first thread having a first pitch. And a second region having a second thread having a second pitch different from the first pitch, located closer to the first end than the first region, and the second end than the first region. And a third region having a third thread of the second pitch. And in the cross section along the said central axis, the thickness of the said 3rd thread is thinner than the thickness of the said 2nd thread.

  According to the screw of this aspect, it is possible to easily perform screwing and to exert a high locking effect.

It is a perspective view which shows the screw of an example of this embodiment. It is a side view in the screw shown in FIG. It is A1-A1 sectional drawing in the screw shown in FIG. It is an enlarged view in area | region B1 shown in FIG. It is an enlarged view which shows the same area | region as FIG. It is an enlarged view of the 1st modification of the screw shown in FIG. It is a perspective view which shows the screw of the other example of this embodiment. It is a side view in the screw shown in FIG. It is A2-A2 sectional drawing in the screw shown in FIG. FIG. 10 is an enlarged view of a region B2 shown in FIG. It is a perspective view which shows the structure of an example of this embodiment. It is A3-A3 sectional drawing in the structure shown in FIG.

<Screw>
Hereinafter, the screw of this embodiment will be described in detail with reference to the drawings. However, each drawing referred to below shows only a main member necessary for explaining the present embodiment in a simplified manner for convenience of explanation. Therefore, the screw of the present invention may include any constituent member that is not shown in the referenced drawings. Moreover, the dimension of the member in each figure does not faithfully represent an actual dimension, a dimension ratio, etc.

  A screw 1 in FIG. 1 showing an example of this embodiment is a rod-like body extending from a first end, which is a screw tip portion, to a second end along the central axis X, and is a tightening member called a so-called male screw. In FIG. 1, the lower right side is the first end, and the upper left side is the second end. Hereinafter, in the present embodiment, for convenience, the first end will be referred to as the front end, and the second end will be referred to as the rear end.

  The material of the screw 1 is not limited to a specific material, but for example, steel, cast iron or the like can be used. In particular, it is preferable to use steel having high toughness among these materials.

  The screw 1 in this embodiment includes a shaft portion 3 and a head portion 5. The shaft portion 3 is located on the distal end side with respect to the head portion 5. A spiral thread 7 is formed on the outer peripheral surface of the shaft portion 3 from the rear end side toward the front end side. The shaft portion 3 in the present embodiment has a single thread 7, but the shaft portion 3 may have a plurality of threads 7. For example, the shaft 3 may have two threads 7 having a double helix.

  The head 5 has an outer diameter larger than that of the shaft portion 3 and is located on the rear end side with respect to the shaft portion 3. The end face on the front end side of the head 5 has a flat shape. The male screw 1 as in the present embodiment is attached to a female screw having a thread groove having a shape corresponding to the screw thread 7. At this time, for example, two members can be fixed by engaging the male screw 1 and the female screw.

  Generally, the thread is formed in a spiral shape with a constant thickness and a pitch of the thread in the direction along the central axis. However, in the thread 7 in this embodiment, the thickness in the direction along the central axis X and the pitch of the thread 7 are not constant. Here, the pitch of the threads 7 is generally the distance between the threads 7, but in this embodiment, as shown in FIG. It means the interval of the bottom (valley bottom).

  The shaft portion 3 in this embodiment includes a first region 11 having a first thread 9, a second region 15 having a second thread 13, and a third region 19 having a third thread 17. Yes. The second region 15 is located on the front end side with respect to the first region 11, and the third region 19 is located on the rear end side with respect to the first region 11. That is, the above-mentioned areas are arranged in the order of the third area 19, the first area 11, and the second area 15 from the rear end side toward the front end side.

  When the pitch of the first thread 9 is the first pitch P1, the pitch of the second thread 13 is the second pitch P2, and the pitch of the third thread 17 is the third pitch, While the second pitch P2 and the third pitch are the same, the first pitch P1 is different from the second pitch P2 and the third pitch. Specifically, the first pitch P1 is shorter than the second pitch P2. In the case where the first pitch P1 is shorter than the second pitch P2, the first pitch P1 can be set to about 75 to 95% of the second pitch P2, for example.

  When the first pitch P1 is relatively short, the rear end portion of the second screw thread 13 and the front end portion of the third screw thread 17 are pressed against the thread groove of the female screw, respectively. At this time, even if a direction in which the screw 1 is removed, that is, a force from the front end side to the rear end side is temporarily applied to the screw 1, the second screw thread 13 is less likely to be elastically deformed than the third screw thread 17. Since it will be in the state pressed strongly by the screw groove, the screw 1 becomes difficult to remove.

  In the cross section along the central axis X, the screw 1 in the present embodiment has a shape in which the third screw thread 17 is more elastically deformed than the second screw thread 13. Specifically, in the cross section along the central axis X, the thickness of the third screw thread 17 is thinner than the thickness of the second screw thread 13. Therefore, the screw 1 of the present embodiment can be easily attached to the female screw and can be screwed, and can exhibit a high locking effect.

  Specifically, when attaching the screw 1 of the present embodiment to the female screw, the second region 15 is first inserted into the female screw among the first region 11, the second region 15, and the third region 19. At this time, since the second thread 13 is formed with a constant second pitch P2, the screw 1 can be rotated without applying a large force.

  When the first region 11 is inserted into the female screw subsequent to the second region 15, the pitch of the first screw thread 9 is different from the pitch of the second screw thread 13, so the second screw thread 13 is It becomes easier to be gradually pressed into the thread groove. In the present embodiment, since the first pitch P1 that is the pitch of the first thread 9 is shorter than the second pitch P2 that is the pitch of the second thread 13, the portion on the rear end side of the second thread 13 is It becomes easy to be pressed into the thread groove of the female screw.

  When the third region 19 is inserted into the female screw following the first region 11, the pitch of the first screw thread 9 is different from the pitch of the second screw thread 13 and the third screw thread 17. In addition to the thread 13, the third thread 17 is easily pressed against the thread groove of the female thread. In the present embodiment, since the first pitch P1 that is the pitch of the first thread 9 is shorter than the second pitch P2 that is the pitch of the second thread 13 and the third thread 17, in the third thread 17 The front end portion and the rear end side portion of the second screw thread 13 are easily pressed against the thread groove of the female screw. Therefore, the frictional force with respect to the thread groove in the second thread 13 and the third thread 17 can be increased.

  In the screw 1 of this embodiment, the thickness of the third screw thread 17 is thinner than the thickness of the second screw thread 13 in the cross section along the central axis X. Therefore, since the third thread 17 is more easily elastically deformed than the second thread 13, it is possible to avoid an excessively high frictional force at the second thread 13 and the third thread 17.

  As shown in FIG. 5, the thickness of the second thread 13 and the third thread 17 is the center axis X from the line connecting the bottom of the groove located between the threads 7 to the top of the thread 7. When the height in the direction orthogonal to H is H, it can be shown by the width W in the direction along the center axis X at the center in the height direction, that is, H / 2. By measuring the width W of each of the second thread 13 and the third thread 17, the thickness of the second thread 13 and the third thread 17 can be compared.

  In the screw 1 of the present embodiment, the length of the second region 15 in the direction along the central axis X is longer than the lengths of the first region 11 and the third region 19, and the second region 15 is in the shaft portion 3. It is structured as a main area. Therefore, the 2nd screw thread 13 in the 2nd field 15 serves as the standard composition in axis part 3 of screw 1 of this embodiment. Specifically, the second screw thread 13 in the present embodiment has a configuration along a reference thread shape shown in JIS B 0205.

  Since the second screw thread 13 is a reference configuration, when the screw 1 of this embodiment is attached to the female screw, the screw 1 can be rotated without applying a large force in most of the screwing process. it can. In other words, in the screw 1 of this embodiment, the second region 15 has a plurality of second screw threads 13 in order to easily rotate the screw 1 in screwing.

  The 3rd field 19 located in the back end side rather than the 1st field 11 has the 3rd thread 17, and the pitch of the 3rd thread 17 is the 2nd thread 13 in the 2nd field 15 as above-mentioned. The pitch is the same. Note that the fact that the pitch of the second thread 13 and the pitch of the third thread 17 are the same does not require that these pitches are exactly the same. These pitches may be shifted by about ± 1%.

  While the third screw thread 17 has the same pitch as the second screw thread 13, the shape of the third screw thread 17 is different from the shape of the second screw thread 13 in the cross section along the central axis X. Specifically, in the cross section along the central axis X, the thickness of the third screw thread 17 is thinner than the thickness of the second screw thread 13. In other words, in the cross section along the central axis X, the third screw thread 17 has a shape that is elongated more in the direction perpendicular to the central axis X than the second screw thread 13. When the thickness of the second thread 13 and the third thread 17 is evaluated by the above-described method, the thickness of the third thread 17 is about 60 to 80% with respect to the thickness of the second thread 13. Can be set. The third screw thread 17 is more easily elastically deformed than the second screw thread 13 due to the above configuration.

  When the third region 19 has a plurality of third threads 17 in the cross section along the central axis X, the second threads 13 are threaded while making the third threads 17 easy to deform. It is easy to ensure the force to press against the. In the present embodiment, as shown in FIG. 4, the third region 19 has two third screw threads 17 in the cross section along the central axis X.

  The first thread 9, the second thread 13, and the third thread 17 are respectively located on the front end side and inclined with respect to the central axis X, and on the rear end side, respectively, on the central axis X. And an inclined surface after inclining.

  Specifically, the first screw thread 9 is located on the front end side and inclined with respect to the central axis X, and the first front inclined surface 21 is positioned on the rear end side and inclined with respect to the central axis X. 1 and a rear inclined surface 23. The second thread 13 is located at the front end side and inclined with respect to the central axis X, and the second front inclined surface 27 is positioned at the rear end side and inclined with respect to the central axis X. And have. The third thread 17 is located on the front end side and is inclined with respect to the central axis X, and the third front inclined surface 31 is located on the rear end side and is inclined with respect to the central axis X. And have.

  When the screw 1 of the present embodiment is attached to the female screw, the second rear inclined surface 27 in the second screw thread 13 and the third front inclined surface 29 in the third screw thread 17 are respectively thread grooves. Pressed against.

  As already shown, the second thread 13 is the reference in the screw 1 of the present embodiment, and the second front inclined surface 25 and the second rear inclined surface 27 are respectively in relation to the central axis X. The structure is inclined at 60 °.

  In the screw 1 of the present embodiment, the inclination angle θ3 formed between the third front inclined surface 29 and the central axis X in the third screw thread 17 is the second rear inclined surface 27 and the central axis X in the second screw thread 13. It is larger than the inclination angle θ2. In such a configuration, the third screw thread 17 is easily brought into surface contact with the screw groove. In FIG. 5, the inclination angle θ <b> 2 and the inclination angle θ <b> 3 are illustrated using a virtual straight line X ′ parallel to the central axis X.

  Since the first pitch P1 is shorter than the second pitch P2 in the screw 1 of the present embodiment, the third thread 17 is elastically deformed toward the rear end side when attached to the female screw. At this time, the third front inclined surface 29 of the third screw thread 17 is set to a relatively large value in advance so that the third front inclined surface 29 of the third screw thread 17 is attached to the female screw. It becomes easy to make surface contact with the screw groove. Therefore, the third screw thread 17 can be stably brought into contact with the thread groove.

  In the present embodiment, the second region 15 has a concave groove-shaped first groove 33 located between the plurality of second screw threads 13, and the third region 19 includes a plurality of third screws. A concave groove-shaped second groove 35 located between the peaks 17 is provided. In the cross section including the central axis X, the curvature radius of the second groove 35 is larger than the curvature radius of the first groove 33.

  The screw 1 of the present embodiment is attached to the female screw in a state where the second screw thread 13 and the third screw thread 17 are pressed against the thread groove of the female screw. Therefore, when there are a plurality of second screw threads 13, the load may be concentrated between the adjacent second screw threads 13. For the same reason, when there are a plurality of third screw threads 17, the load may be concentrated between the adjacent third screw threads 17. At this time, when the first groove 33 and the second groove 35 are provided, it is possible to avoid a load from being concentrated on a part of the second region 15 and the third region 19. Therefore, the durability of the screw 1 can be improved.

  The third thread 17 is elastically deformed when attached to the female thread. At this time, when the second groove 35 is located between the adjacent third threads 17, the third thread 17 Becomes easily elastically deformed. Therefore, attachment to the female screw is further facilitated.

  In the present embodiment, the thickness from the central axis X to the second groove 35 is thinner than the thickness from the central axis X to the first groove 33. That is, the second groove 35 is formed larger than the first groove 33. Therefore, the third screw thread 17 is further easily deformed.

  The relationship between the first pitch P1 and the second pitch P2 is not limited to the relatively short first pitch P1, and the first pitch P1 is the second pitch P2 as shown in FIG. It may be longer. When the first pitch P1 is longer than the second pitch P2, the first pitch P1 can be set to about 105 to 125% of the second pitch P2, for example.

  Next, a screw 1 ′ as another example of the present embodiment will be described in detail with reference to FIGS. In the following, differences from the above-described screw 1 of the present embodiment will be mainly described. Therefore, about the same point, description is abbreviate | omitted using the same code | symbol.

  As shown in FIG. 7, the screw 1 ′ does not include the head 5, and has a so-called immo screw configuration.

  The screw 1 ′ has the same configuration as the screw 1 described above except that the head 5 is not provided. That is, the screw 1 ′ of the present embodiment also has the shaft portion 3 that extends from the first end that is the screw tip portion to the second end along the central axis X. As shown in FIG. 10, the shaft portion 3 has a first region 11 having a first thread 9 having a first pitch P1 and a first region 11 that is located on the tip side of the first region 11 and is different from the first pitch P1. The second region 15 having the second thread 13 with the second pitch P2 and the third region 19 having the third thread 17 with the second pitch P2 located on the rear end side of the first region 11 are provided. . In the cross section along the central axis X, the thickness of the third screw thread 17 is thinner than the thickness of the second screw thread 13.

  Therefore, the screw 1 ′ of the present embodiment can be easily screwed in the same manner as the screw 1 described above, and can exhibit a high locking effect.

<Structure>
Next, a structure according to an embodiment will be described with reference to FIGS.

  The structure 101 of this embodiment includes the screw 1 of this embodiment described above and the main body 103. The main body 103 includes a first member 103a and a second member 103b. Each of the first member 103a and the second member 103b has a flat plate shape and is overlapped. The main body 103 in the present embodiment has a hole formed from the first member 103a to the second member 103b. A thread groove is formed on the inner peripheral surface of the hole, and constitutes a female screw 105. The screw 1 is inserted into the female screw portion 105. The thread groove of the female thread portion 105 in the present embodiment has a configuration corresponding to the shape of the second thread. The first member 103a is not necessarily formed with a screw groove, and may be a simple through-hole, but from the viewpoint of fixation, it is better that the screw groove is formed.

  The first member 103a and the second member 103b constituting the main body 103 are fixed by the screw 1 inserted into the female screw 105. Since the structure 101 of the present embodiment has the screw 1 described above, the first member 103a and the second member 103b can be easily fixed, and the possibility that the screw 1 is loosened is reduced. Yes.

  In the structure 101 of the present embodiment, at least a part of the second region of the screw 1 is located in a region formed in the second member 103b in the female screw 105. Further, at least a part of the third region of the screw 1 is located in a region formed in the first member 103 a in the female screw 105. The first pitch P1 in the screw 1 is shorter than the second pitch P2.

  Therefore, when the third thread is elastically deformed, a force is applied to the first member 103a constituting the main body 103 in the direction toward the second member 103b, and the second member 103b constituting the main body 103 is applied to the second member 103b. A force is applied in the direction toward the first member 103a. Therefore, the second member 103b can be stably fixed to the first member 103a.

  As described above, the structure 101 including the screws 1 and 1 ′ and the screws 1 of the plurality of embodiments has been described with reference to the drawings. However, the screws and structures of the present invention are not limited to the configurations of the above-described embodiments. In addition, the scope of the present invention is within the scope of the present invention, and includes modifications not specifically described in detail. For example, in the structure 101, there is no problem even if the screw 1 'is used instead of the screw 1.

1 ... Screw (Male thread)
1 '... screw
3 ... shaft 5 ... head 7 ... thread 9 ... first thread 11 ... first area 13 ... second thread 15 ... second area 17 3rd thread 19 ... 3rd area 21 ... 1st front slope 23 ... 1st back slope 25 ... 2nd front slope 27 ... 2nd back slope 29 ... 3rd front inclined surface 31 ... 3rd back inclined surface 33 ... 1st groove | channel 35 ... 2nd groove | channel 101 ... Structure 103 ... Main body 103a ... 1st member 103b ... Second member 105 ... Female thread

Claims (8)

A shaft portion extending from the first end, which is the screw tip portion, to the second end along the central axis,
A first region having a first thread of a first pitch;
A second region that is located closer to the first end than the first region and has a second thread having a second pitch different from the first pitch;
A third region positioned on the second end side of the first region and having a third thread of the second pitch;
A screw in which the thickness of the third thread is thinner than the thickness of the second thread in a cross section along the central axis.   The screw according to claim 1, wherein the second region has a plurality of the second threads, and the third region has a plurality of the third threads. The second region has a concave groove-shaped first groove located between the plurality of second threads,
The third region has a concave groove-shaped second groove located between the plurality of third threads.
The screw according to claim 2, wherein a radius of curvature of the second groove is larger than a radius of curvature of the first groove in a cross section along the central axis.   The screw according to claim 3, wherein a thickness from the central axis to the second groove is thinner than a thickness from the central axis to the first groove.   The screw according to any one of claims 1 to 4, wherein the first pitch is shorter than the second pitch. In the cross section including the central axis, the second thread has a second front inclined surface on the first end side, and the third screw thread has a third front inclined surface on the first end side. And
The screw according to claim 5, wherein an inclination angle formed by the third front inclined surface and the central axis is larger than an inclination angle formed by the second front inclined surface and the central axis.   The screw according to claim 1, further comprising a head on the second end side. A male screw which is the screw according to any one of claims 1 to 7,
A first member having a through hole into which the male screw is inserted;
A second member having a female screw,
A structure in which the first member and the second member are fastened by the male screw and the female screw.

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