JP2022042404A - Drill screw for thin metal plate, structure using the same and fixing device - Google Patents

Abstract

To improve fastening rigidity and a retention effect while simplifying a structure, in a drill screw for fixing a workpiece to a thin metal plate member (structure material) such as a deck plate.SOLUTION: A drill screw is composed of a shaft 1, a drill part 2 and a head 3. A first thread 4 is entirely or partially split by a notched groove 14. A screw part has a band-shaped trough face 11, and a trough diameter D1 is larger than a drill diameter D2. Also, a plate thickness of a mating member 10 is thicker than a trough width E. At construction, since an internal peripheral edge part 21 of the mating member 10 receives a diameter-expansion action, a part of the internal peripheral edge part 21 exhibits a bite-in part 21b, and a region at an opposite side becomes a heavy thickness part 21a. Therefore, the thread 4 can be made to firmly bite into the heavy thickness part 21a. By this constitution, high fastening rigidity and a retention effect can be obtained, and a stripping effect for making the screw part idle due to the crush of a female screw can be also prevented.SELECTED DRAWING: Figure 2

Description

There is an application for exception of loss of novelty

The present invention relates to a self-drilling screw for a thin metal plate, a structure constructed using the self-drilling screw, and a fixing device. Here, the thin metal plate means a metal plate (mainly a steel plate or a stainless steel plate) having a size of about 2 mm or less (usually 1.6 mm or less), and the structure is a roof, ceiling, wall, etc. of a building. Is included.

There are many buildings that use steel plate base materials with a plate thickness of about 1 to 2 mm, and it is widely practiced to fix heat insulating materials, control panel materials, etc. to these base materials with self-drilling screws such as drill screws. It has been. For example, waterproof sheets and heat insulating materials are fixed to the upper surface of deck plates (folded plates) that make up the roof of buildings with drill screws and tapping, and heat insulating materials and interior materials are used for columns and beams made of shaped steel such as C type. It is widely practiced to fix the roof with a drill screw.

Then, in the drill screw, it has been proposed or implemented to form a notch groove such as a V shape extending in the axial direction by dividing the thread completely or partially in the thread portion. As an example, Patent Document 1 discloses that a plurality of recesses (notch grooves) parallel to the axis are formed in a tapered threaded portion closer to a drill portion among the threaded portions. It is described that the screwing torque can be reduced by the dent. Therefore, in Patent Document 1, it is understood that the dent is provided for the effect of improving the machinability of the thin metal plate.

On the other hand, Patent Document 2 also discloses that a V-shaped notch line is formed. In this Patent Document 1, the presence of the notch line improves the discharge of chips and the base material. It is stated that a smooth cut can be realized. Therefore, in Patent Document 2, as in Patent Document 1, it can be said that the notch line is provided for the effect of improving the machinability of the thin metal plate. It should be noted that also in the wood screw, a notch groove is formed in order to improve the machinability and the chip discharge property.

Japanese Unexamined Patent Publication No. 2006-177436 Japanese Unexamined Patent Publication No. 2017-67179

In buildings and structures, it is widely practiced to fix a work such as a heat insulating material to a structural material made of a thin metal plate such as a deck plate with a drill screw. One of the problems in this case is a screw to the structural material. Since the catching allowance of the ridge is small, if the screwing torque is too strong, a stripping phenomenon may occur in which the female screw of the structural material is crushed and the drill screw spins idle, making it meaningless as a screw.

Another problem is loosening of the drill screw after fastening. There are many causes of looseness. For example, the wind may push the work away from the structural material. When vibration acts on the drill screw by repeating the movement that the work is elastically deformed by the wind pressure and returned by the elastic restoring force, the drill screw tends to loosen at an accelerating rate. Loosening may also occur when the vibration of the air conditioner travels through the structural material and acts on the drill screw. It should be noted that the looseness and the idling at the time of construction are inextricably linked to each other, and both of them are caused by the weak catching of the thread on the structural material.

Regarding this point, Patent Document 1 states that the inner peripheral portion of the prepared hole is 2.5 times the plate thickness by pressing the prepared hole with a protruding angle portion (rib) provided on the valley surface of the tapered threaded portion. It is explained that it can be expanded to a certain thickness.

As described in Patent Document 1, if the inner peripheral edge of the prepared hole can be partially thickened, the catching allowance between the screw thread and the thin metal plate can be remarkably increased, so that high fastening strength can be ensured. It can be said that the phenomenon that the threaded portion spins idle can be avoided.

The present invention has been made against the background of such a situation, and secures high fastening strength while suppressing screwing resistance, and secures a high loosening prevention effect, and prevents idle rotation of the threaded portion during construction. This is an attempt to easily realize this with a technique from a viewpoint different from that of Patent Document 1.

The invention of the present application includes various configurations, and a typical example thereof is specified in each claim. Of these, the invention of claim 1 relates to a self-perforated screw for a thin metal plate, and the self-perforated screw is a self-perforated screw.
"A shaft having a threaded portion, a self-perforated portion provided at the tip thereof, and a head provided at the base end of the shaft are provided, and the threaded portion is completely or partially divided into threads. A group of notched grooves is divided in the circumferential direction to form multiple rows. "
It has a basic structure.

And in the above basic configuration
"In the threaded portion, a band-shaped valley surface is formed between adjacent threads, and the valley diameter of the threaded portion is larger than or substantially the same as the inner diameter of the prepared hole formed by the self-perforated portion. While it has a diameter,
When the width dimension of the valley surface is E, the pitch of the thread is P, and the thickness of the thin metal plate to which the threaded portion is screwed and used to fasten the work is t, the relationship of E <t <P. It has become
In addition, at least one notch groove is set so as to overlap the inner peripheral surface of the thin metal plate with the threaded portion screwed into the thin metal plate. "
It is configured as.

The notch groove may be positioned up to the valley surface and the thread may be completely divided by the notch groove, or the notch groove may be located at the middle height of the thread.

The invention of claim 2 is an example of development of claim 1.
"The angle formed by the plane orthogonal to the axis and the flank on the advancing side of the thread is θ1, and the angle formed by the plane orthogonal to the axis and the flank on the trailing side of the thread is θ2, and θ1> θ2. In relation to this, θ1 + θ2 is set to about 35 to 45 °.
Further, when the axial distance between the bottoms of the notch grooves in the adjacent threads is L, L and the t are set to about the same degree or t> L. "
It is configured as.

The invention of claim 3 embodies claim 1 or 2.
"The thin metal plate and the thread have a plurality of notched grooves within the thickness range of the thin metal plate within a range of approximately half a circumference in a state where the threaded portion is screwed into the thin metal plate. It will be set in the relationship "
It is configured as.

The present invention also includes a structure, and as claimed in claim 4, this structure is:
"It is provided with a structural material made of a thin metal plate, a work overlapping the structural material, and a self-drilling screw that presses and fixes the work to the thin metal plate.
The self-drilled screw includes a shaft having a threaded portion made of a thread, a self-drilled portion provided at the tip thereof, and a head provided at the base end of the shaft, and the threaded portion has a thread. A group of notched grooves that divides completely or partially is divided in the circumferential direction to form multiple rows. "
It is a basic configuration.

And in the above basic configuration
"In the threaded portion, a band-shaped valley surface is formed between adjacent threads, and the valley diameter of the threaded portion is larger than or substantially the same as the inner diameter of the prepared hole formed by the self-perforated portion. While it has a diameter,
When the width dimension of the valley surface is E, the pitch of the thread is P, and the thickness of the thin metal plate to which the threaded portion is screwed and used to fasten the work is t, the relationship of E <t <P. It has become
Further, each of the notch grooves is formed to a depth up to the middle height of the thread, and at least one notch groove is formed in the thin metal plate with the threaded portion screwed into the thin metal plate. It is set to overlap the inner peripheral surface. "
It is configured as.

In many cases, the thread has a triangular cross section, and a grooved thread (or a two-hump type thread) in which one thread has two ridges and a spiral groove is formed in the thread is also assumed. However, the present invention also includes such a grooved thread. In the case of this grooved thread, it is also possible to form a notch groove only in the part of the trailing side flank or only in the part of the advancing side flank.

The present invention also includes a fixing device relating to a combination of a self-drilling screw and a washer, and this fixing device is as described in claim 5.
"It is composed of the self-drilling screw and the washer according to any one of claims 1 to 3, and the bearing surface of the head of the screw is formed in a tapered shape with a downward constriction and a polygonal flat cross section. On the other hand, the washer is formed with a flat cross-section polygonal lower constricted tapered receiving seat in which the seating surface of the screw head is in close contact, and the receiving seat is not divided by a slit and is in the circumferential direction. It is continuous in a series. "
It is configured as.

In this case, it is preferable that the number of angles of the seat surface of the screw head and the receiving seat of the washer is the same as the number of threads of the notch groove of the screw. The fixing device of claim 5 is used for fixing a work that is compressed and deformed against elasticity. In this case, the work may be a single layer or a plurality of layers, but in the case of a plurality of layers, it is sufficient if at least one layer is elastically deformed.

When the threaded portion is screwed into the thin metal plate, an external force is applied to the thin metal plate in the front and back directions due to the screw thread, so that the inner peripheral portion of the thin metal plate tends to bend and deform in the front and back directions. If the thickness of the thin metal plate is smaller than the valley width of the threaded portion, or the valley diameter of the threaded portion is larger than the inner diameter of the prepared hole due to the self-drilled portion, the inner peripheral portion of the thin metal plate is oriented in the front and back directions. Since the thread easily escapes and deforms, the thread bites into the inner peripheral edge of the prepared hole only slightly, a stripping phenomenon occurs, the threaded portion tends to run idle, and the fastening strength and the loosening prevention effect tend to be insufficient.

On the other hand, in the present invention, first, the valley diameter of the threaded portion is larger than or substantially the same as the prepared hole, so that the prepared hole can be expanded by the valley portion of the shaft, and therefore, it is thin. It is possible to tightly mesh the inner peripheral edge of the metal plate with the threaded portion in a state where bending and deformation in the front and back directions are restricted.

Further, since the width dimension E of the valley surface, the pitch P of the screw thread, and the plate thickness t of the thin metal plate have an E <t <P relationship, the inner peripheral edge of the pilot hole of the thin metal plate is formed. The flesh loses its refuge and escapes to the outside of the radius, and the inner peripheral portion of the prepared hole can be thickened at least partially.
Specifically, since the resistance to the pilot hole is usually non-uniform in the circumferential direction, the inner peripheral portion of the thin metal plate fits firmly into the valley portion of the threaded portion on one side of the axial center. On the other side of the axis, the inner peripheral edge tends to be thickened about half a circumference, and one or more threads bite into the thickened portion. Depending on the size of the plate thickness t with respect to the valley width, a thick portion may be formed over the entire circumference.

In other words, at the inner peripheral edge of the thin metal plate, the escape deformation in the front and back directions is restricted, so that at least a part of the inner peripheral edge in the circumferential direction becomes thicker and the screw thread firmly bites into it. As a result, it is possible to improve the catching property of the thread on the prepared hole, prevent the female screw on the inner peripheral part of the prepared hole from being crushed and the threaded part from spinning (stripping phenomenon), as well as high fastening strength and anti-loosening. You can get the effect.

Since at least one notch groove formed in the threaded portion overlaps the inner peripheral surface of the prepared hole, screwing resistance is caused by the cutting edge action of the advancing side end portion of the notch groove portion facing the screwing direction. Can be suppressed, and the force required for screwing can be reduced accordingly. Therefore, it is possible to reduce the burden on the operator while ensuring high fastening strength. Further, since the chasing end face of the notch groove facing the screw return direction acts as a resistance to screwing back, the notch groove can improve the effect of preventing loosening.

In this case, as in the embodiment, the notch groove is tilted from the start end to the end in the direction opposite to the screwing direction (that is, the spiral direction of the notch groove and the spiral direction of the thread are in the same direction). When tilted to, the inner peripheral portion of the prepared hole is pushed downward (in the direction of the tip) by the chasing end surface of the notch groove, so that there is an advantage that the resistance to screwing back can be increased and the loosening prevention effect can be promoted.

If the angle of the screw thread is about 60 ° like a normal machine screw, the thin metal plate must be widely spread in both front and back directions in order to bite into the thin metal plate. The biting property may deteriorate or the screwing resistance may increase. However, if the thread angle is set to about 35 to 45 ° as in claim 2 of the present application, the biting property to the thin metal plate is improved. , The function of forming female threads in the prepared holes in the thin metal plate is improved.

In addition, since the tilt angle of the trailing flank is smaller than the tilting angle of the leading flank, the screwing resistance can be reduced and vice versa as compared with the case where the angle of the leading flank and the angle of the chasing flank are the same. Resistance to rotation can be increased. Therefore, it is possible to achieve both ease of screwing and improvement of the loosening prevention function.

Further, as described as the effect of claim 1, in the present invention, the inner peripheral portion of the thin metal plate is partially thickened, which ensures that the screw thread bites into the prepared hole. If the distance L between the edges of the adjacent notch grooves is the same as or t> L as the plate thickness t of the thin metal plate as in claim 2, the thin metal plate fits into the valley of the threaded portion. When it is inserted, it is possible to make it easier for the adjacent notch grooves to bite into the thin metal plate. As a result, the effect of preventing loosening due to catching of the notch groove can be improved.

As described above, in the notch groove, when screwing, the advancing side end face facing the screwing direction acts as a cutting edge, so that the biting property to the thin metal plate can be improved and the screwing resistance can be suppressed, while the screwing resistance can be suppressed. With respect to reverse rotation, the trailing side surface of the notch groove acts as a resistance to exert a locking effect, but if the configuration of claim 3 is adopted, the threaded portion of the inner peripheral edge portion of the thin metal plate can be screwed in. Since there are a plurality of notch grooves in the thickened portion, the effect of the notch grooves can be promoted. The number of notched grooves is preferably about 3 or 4 in about half a circumference. Therefore, it can be said that it is preferable that the number of notched grooves is at least 5 in the circumferential direction.

As a means for preventing screws from loosening, it has been proposed to form a protrusion on the seat surface of the screw head, while forming an engagement groove on the washer receiving seat to fit the protrusion into the engagement groove. However, in this case, the loosening prevention function is carried only by the receiving seat of the washer, and the receiving seat is divided by the engaging groove and easily deformed, so that the loosening prevention effect is limited.

On the other hand, when the configuration of claim 5 of the present application is adopted, when the screw tries to loosen, the entire washer must be pushed into the work to greatly elastically deform the work, so that the resistance to the loosening of the screw becomes significantly high. That is, the elastic resistance of the work can be used to prevent the screws from loosening. Therefore, the anti-loosening effect can be significantly improved.

In claim 5, when the number of angles of the seat surface and the seat is made to match the number of notch grooves as in the embodiment, the synergistic action of the notch groove loosening prevention function and the square receiving seat loosening prevention function is achieved. , There is an advantage that the loosening prevention effect can be further improved.

In the figure showing an embodiment, (A) is a front view in which most of the notched grooves are omitted, (B) is an overall side view (photograph), (C) is a plan view, and (D) is a partially enlarged view. The figure, (E) is a sectional view taken along the line EE of (D), and (F) is a partial perspective view (photograph). (A) is a schematic vertical sectional view of the structure, (B) is a vertical sectional view of a main part of the structure, (C) is a vertical sectional view at the initial stage of fastening work, and (D) is a vertical sectional view of the main part in a screwed state. A plan view, (E) is an enlarged view of a notched groove portion, and (F) is an enlarged view of another notched groove in which the posture is changed. (A) is a perspective view in a screwed state, (B) is a perspective view in a state where the screw portion is removed, and (C) is a perspective view seen from the back side. (A) is a front view of a drill screw of another form, (B) is a perspective view of a threaded portion, and (C) is a view showing another example of a thread and a notch groove. It is a figure which shows the fixing device combined with the washer, (A) is the perspective view which looked at the screw from the bottom, (B) is the figure which looked at the washer from the top, (C) is the figure which looked at the washer from the bottom, ( D) is a partial cross-sectional view in a used state, and (E) is a sectional view taken along the line EE of (D).

(1). Structure of drill screw Next, an embodiment of the present invention will be described with reference to the drawings. This embodiment is applied to a drill screw. The drill screw is made of metal such as steel or stainless steel, and as shown in FIGS. 1 (A) and 1 (B), the shaft 1 and the drill portion 2 (self-drilled portion) provided at the tip (one end) thereof and the shaft 1 It is composed of a head 3 provided at the base end (the other end), and a threaded portion composed of one thread 4 is formed on the shaft 1. In the following, the upper and lower words are used for convenience to specify the direction, but it is defined that the drill portion 2 is located at the bottom and the head 3 is located at the top. Therefore, the top surface of the head 3 appears in a plan view.

The drill portion 2 has a conventionally known shape, and a pair of vertical grooves 5 are formed to form a pair of cutting edges 6, and a chisel edge is formed at the tip of the drill portion 2. The vertical groove 5 hangs on the tip of the threaded portion, and the starting end of the thread 4 is divided by the vertical groove 5.

The head 3 is a dish type having a downwardly narrowed tapered seat surface, and a quadrangular engaging groove (recess) 7 with which a driver bit (not shown) is engaged is formed on the top surface. The engaging groove 7 may have another form such as a cross shape. Further, the head 3 can be set to an arbitrary shape depending on the application, such as a hexagonal head, a pan head, or a flat plate type.

As shown in FIG. 1 (D), the thread 4 has a ridge line formed on the thread surface, but is basically a triangular cross section (to be exact, the cross section is trapezoidal), and the shaft. The angle θ1 formed by the plane orthogonal to the center O and the advancing flank 8 is larger than the angle θ2 formed by the plane orthogonal to the axial center O and the trailing flank 9. For example, θ1 can be set to about 30 to 35 °, and θ2 can be set to about 0 to 10 °. θ1 + θ2 is the angle of the thread 4, and the angle of the thread 4 is set to about 35 to 45 °.

FIG. 1 (D) shows the width dimension (mountain thickness) W of the base of the thread 4 and the height H of the thread 4, but the relationship is W <H (both are). It may be almost the same.). Therefore, the thread 4 has a shape that easily bites into the thin metal plate 10 that is the mating material to be screwed.

A band-shaped valley surface 11 exists between the adjacent threads 4. The groove width E of the valley surface 11 is smaller than the maximum width W of the thread 4. The outer diameter D1 of the valley surface 11 (see FIG. 2D) is set to be slightly larger than the rotational outer diameter D2 of the drill portion 2 (see FIG. 2B). Therefore, the prepared hole formed in the mating material 10 is expanded and expanded by the valley surface 11. The groove width E of the valley surface 11 is smaller than the plate thickness t of the mating material 10. For example, when the plate thickness t of the mating material 10 is 1.0 mm, the groove width E is set to about 0.8 mm.

Although the plate thickness t of the mating material 10 varies, in the present invention, the groove width E and the like are set corresponding to the plate thickness t of the mating material 10. That is, the structural materials of buildings are usually standardized by each manufacturer, and it is also normal that the plate thickness is common in the standards of each company. Therefore, in the present invention, the numerical value is selected according to the standard, which can be applied to many structural materials.

The thread 4 is gradually increased in height from its starting end. Therefore, as shown in FIG. 1A, the threaded portion has a tapered portion 12 in which the height of the thread 4 changes, and the outer diameter of the portion following the tapered portion 12 is constant. It is a straight part.

There is a screwless portion 13 in which the thread 4 is not formed in the lower part of the neck of the shaft 1, but in FIG. 1B, the screwless portion 13 is slightly longer than that in FIG. 1A. Therefore, strictly speaking, (A) and (B) in FIG. 1 cannot be said to be the same, but the presence or absence of the screwless portion 13 and its length are selected according to the intended use, and the essence of the invention is Since it is an element that does not affect, the embodiment of FIG. 1 (A) and the embodiment of FIG. 1 (B) can be regarded as the same embodiment. As shown by another example in FIG. 4A, there is also a drill screw having a considerably long screwless portion 13 (the notch groove 14 is not specified in FIG. 4A, but the threaded portion is shown in FIG. 1 (A) It has the same form as (B).) In FIG. 4B, the entire notch groove 14 is displayed.

The screw thread 4 is formed with a plurality of V-shaped notch grooves 14 extending (spotted) in the axial direction in a state of dividing the threads (notch grooves 14 in FIGS. 2C and 2D). 14 is omitted.). In the illustrated form, the depth of the notch groove 14 is lower than the height of the thread 4. Therefore, as shown in FIG. 1 (E), the bottom 14a of the notch groove 14 is located at the mid-height of the thread 4 without reaching the valley surface 11, but the bottom 14a of the notch groove 14 is the valley surface. You may reach 11. The distance L between the edges of the bottoms 14a of the adjacent notch grooves 14 is set to be substantially the same as or larger than the plate thickness t of the mating material 10.

The start end of the notch groove 14 starts from the end portion of the tapered portion 12. Therefore, the notch groove 14 is not formed in most of the threads 4 at the tapered portion 12. Further, the notch groove 14 has a posture twisted around the axis (spiral posture) so as to incline in the same direction as the thread 4, and the lead angle with respect to the axis is very small (about half a circumference). It is designed to pass 10 or more threads with a twist of.).

When the plate thickness t of the mating material 10 is 1.0 mm, the outer diameter of the thread 4 is about 7 mm, the valley diameter D1 is about 4.2 mm, the pitch P is about 1.8 mm, and the drill. The rotation outer diameter D2 of the portion 2 can be set to about 3.4 mm. The length is set arbitrarily.

(2). Construction condition The drill screw of this embodiment can be used at various sites (structures). For example, as shown in FIGS. 2A and 2B, the heat insulating material 17 can be used to hold and fix the heat insulating material 17 to the deck plate 18 (the mating material 10). A circular washer 19 is used for construction, and the washer 19 is provided with a lower constricted tapered receiving seat 19a that overlaps the seat surface of the head 3 in the drill screw. The screw head 3 and the heat insulating material 17 are covered with a waterproof sheet 16.

In construction, the drill screw enters the heat insulating material 17 by the drilling action of the drilling portion 2 and the screwing action of the threaded portion, and then, as shown in FIG. 2C, the drilling portion 2 enters the deck plate 18. The pilot hole 20 is drilled, and then, as the screw thread 4 is screwed in, the pilot hole 20 is expanded by the valley surface 11 to expand the diameter, and the screw thread 4 bites into the inner peripheral edge portion 21 of the pilot hole 20. Eventually, the head 3 strongly abuts on the washer 19 and the screwing is stopped.

Since D1 <D2 and E <T, as shown in FIG. 2, first, the inner peripheral edge portion 21 of the deck plate 18 is crushed and deformed while being tightly fitted to the valley surface 11 of the threaded portion. As a result, the movement in the vertical direction (bending deformation) is restricted, and a part of the inner peripheral edge portion 21 becomes a thick wall portion 21a due to the movement of the meat due to the forced expansion (diameter expansion).

Further, when the screw portion is screwed in, the inner peripheral edge portion 21 is deformed in the vertical direction at the initial stage of screwing to become a bite portion 21b in which a part of the screw portion has entered the valley of the screw portion, and in that state, the diameter is expanded. It can be said that a strong pressing force acts on a portion located on the opposite side of the biting portion 21b with the axis O sandwiched between them to form a thick portion 21a. That is, when about half of the prepared hole 20 becomes the biting portion 21b that strongly stretches against the valley of the threaded portion, the inner peripheral edge portion 21 escapes to the opposite side to the biting portion 21b and the thick portion 21a is formed. I can say.

This point can be understood from the photographs of FIGS. 3 (B) and 3 (C). In addition, in FIG. 3, the upper surface of the deck plate 18 appears in (A) and (B), the lower surface of the prepared hole 20 appears, and the lower surface appears in (C), but the upper and lower surfaces are viewed from the axial direction. Marks 22 are placed at the same positions to clarify the positional relationship.

By firmly biting the thread 4 into the thick portion 21a, a high fastening force and a loosening prevention effect are exhibited, and a stripping phenomenon in which the female screw of the prepared hole 20 is crushed and the thread portion is idle is prevented. can.

Further, in the present embodiment, the advancing side end surface 14b of the notch groove 14 facing the screwing direction acts as a cutting edge, so that the force required for screwing can be reduced and the thick portion 21a of the inner peripheral edge portion 21 is provided. The bite of the thread 4 can be made good, and the female thread forming function can be improved. In this case, eight notch grooves 14 are formed, and the height of the adjacent notch grooves 14 in the axial direction is P / 8, so that at least three or four notches are cut within a range of about half a circumference. The notch groove 14 overlaps the inner circumference of the prepared hole 20 in the deck plate 18.

Therefore, the notch groove 14 frequently overlaps with the inner peripheral surface of the prepared hole 20, and the cutting function by the advancing side end surface 14b of the notch groove 14 can be ensured. Although the burr 23 can be seen in FIG. 3, it can be said that the occurrence of the burr 23 in this way is proof that the advancing side end surface 14b of the notch groove 14 functions as a cutting edge. Further, the chasing end surface 14c of the notch groove 14 acts as a resistance against loosening, but the chasing end surface 14c of the plurality of notch grooves 14 is particularly stretched into the pilot hole 20 at the thick portion 21a. , Can exert a high anti-loosening effect.

In addition, the thick portion 21a is elastically deformed to form a female screw, and when the screwing is completed, an elastic restoring force (spring back) acts, but the thick portion 21a bites into the notch groove 14 due to the elastic restoring force. Then, the advancing side end surface 14b of the notch groove 14 acts as a strong resistance against screwing back.

The notch groove 14 can be formed in a posture parallel to the axis, but if it is formed in a twisted posture as in the present embodiment, it will come into contact with the blade of the die in processing with a rolling die or a flat die. Has the advantage of being smooth and easy to process. That is, since the notch groove 14 can be formed while pressurizing the die with a constant pressure, the processing accuracy can be improved and the durability of the die is also excellent. In particular, if the spiral direction of the notch groove is formed in the same direction as the spiral direction of the thread 4 as in the embodiment, the resistance to the die can be made constant, which is preferable.

As shown in FIG. 2F, the notch groove 14 can be inclined in the direction opposite to the inclination direction of the thread 4, but the notch groove 14 is in the same direction as the thread 4 as in the embodiment. As shown by the arrow X24 in FIG. 2E, when the drill screw is unscrewed (when it is raised), the trailing side surface 14c of the notch groove 14 pushes the deck plate 18 downward. Therefore, it is understood that a resistance action against loosening of the drill screw is exerted. Therefore, it can be said that it is also excellent in the anti-loosening effect.

As shown in FIGS. 4C and 4D, the thread 4 can be formed in a grooved manner having two ridges 4a and 4b, and in the illustrated example, the notch groove 14 is a follow-up. It is formed only at the side flank. The notch groove 14 reaches the valley surface 11 in the segmentation diagram (C), and ends at the mid-height of the thread 4 in the segmentation diagram (D) (that is, only the ridge on the trailing side is cut off). It has been formed.).

The notch groove 14 can be formed so as to divide the entire thread 4, but if it is formed only at the part of the trailing flank as shown in the figure, the function of pushing the mating materials 10 and 18 into the valley portion is available. Since it is high, the loosening prevention effect can be improved. Further, the notch groove 14 can be formed only at the portion of the leading flank, but when formed at the portion of the trailing flank as shown in the illustrated example, the notch groove 14 resists screwing back. Since the function of acting as a screw is enhanced, there is an advantage that the anti-loosening effect can be further improved. When the notch groove 14 is formed at the portion of the trailing flank, the angle θ2 of the chasing flank may be about 5 to 10 °.

FIG. 5 shows an example of a fixing device related to a combination of a drill screw and a washer 19. The drill screw is basically the same as that of the above-described embodiment, and the only difference is that the seat surface 3a of the head 3 has a polygonal flat cross section (octagonal shape). Then, corresponding to the polygonal shape of the seating surface 3a of the head 3 in the drill screw, the receiving seat 19a of the washer 19 also has a flat cross-section polygonal shape (octagonal shape) similar to the seating surface 3a. There is.

In this example, the washer 19 is pushed into the heat insulating material 17 at the end of fastening. Therefore, although the screwing resistance is large, as described above, since the drill screw of the present embodiment has a high fastening force to the deck plate, the washer 19 does not cause the phenomenon that the female screw formed on the deck plate 18 is crushed. Can be strongly pressed against the heat insulating material 17 and screwed firmly.

On the other hand, if the drill screw loosens and tries to rotate after fixing, the ridgeline of the seat surface 3a must get over the plane of the receiving seat 19a, and therefore, when the screw loosens, the washer 19 must compress and deform the heat insulating material 17. However, since the washer 19 has a large area, a large resistance is generated in pushing the washer 19 into the heat insulating material 17, so that a remarkably high anti-loosening effect can be obtained.

When the number of rows of the notch groove 14 and the number of angles of the seat surface 3a and the receiving seat 19a are matched as in the embodiment, the effect of preventing the notch groove 14 from being caught and the square seat surface 3a and the receiving seat 19a are obtained. Since the loosening prevention effect due to the fitting is exhibited at the same time, the loosening prevention effect can be significantly improved, which is preferable.

In the present embodiment, when the receiving seat 19a is pushed by the ridgeline of the seating surface 3a, the meshing between the seating surface 3a and the receiving seat 19a changes. Therefore, the screwing resistance and the loosening prevention effect become higher as the number of angles of the seat surface 3a and the receiving seat 19a is smaller. On the other hand, the screwing resistance and the loosening prevention effect also depend on the elastic deformation rate of the work such as the heat insulating material 17. Therefore, the number of angles of the seat surface 3a of the head 3 and the receiving seat 19a of the washer 19 may be set in consideration of the elastic deformation rate of the work such as the heat insulating material 17. Generally, it can be said that the number of angles is preferably about 5 to 10.

Although the embodiments of the present invention have been described above, the present invention can be embodied in various ways. For example, the shape of the thread may be an ordinary triangle, and each dimension can be set according to the application. The drill screw may be pyramidal. In addition, even if the self-perforated part is a pointed kneading method like a wood screw, it pierces the cutting edge into the mating material and then pushes it into the mating material as the screw thread is screwed in. good. It is also possible to form a thread into a multi-threaded screw (in this case, it is also possible to arrange threads having different heights side by side).

Further, the invention of the present application has an excellent design in terms of the relationship between the thread and the notch groove. Therefore, it can also be a target for design registration. In this case, it is possible not only to be registered as a whole design but also to be registered as a partial design. An arbitrary range can be specified as the partial design. For example, as shown by K1 in FIG. 1A, the range sandwiching the tapered portion 12, and as shown by K2, the tapered portion 12 and the straight portion of the threaded portion. As shown by K3, it is possible to specify an appropriate range of only the straight portion of the threaded portion. The notch groove does not have to be V-shaped when viewed from the axial direction, and may be rectangular or trapezoidal.

The present invention can be embodied in a self-drilling screw such as a drill screw, a structure using the self-drilling screw, and a fixing device. Therefore, it can be used industrially.

1 axis 2 drill part (self-drilling part)
3 head 4 thread 8 thread leading side flank 9 thread trailing side flank 10 mating material 11 valley surface 14 notch groove 14a bottom 14b leading side end face 14c chasing side end face 17 heat insulating material as work 18 structural material (counterpart) Deck plate as an example of material) 19 Washer 19a Receiving seat 20 Pilot hole 21 Inner peripheral edge 21a Thick part 21b Biting part

The present invention relates to a drill screw for a thin metal plate, a structure constructed by using the drill screw, and a fixing device. Here, the thin metal plate means a metal plate (mainly a steel plate or a stainless plate) of 1.6 mm or less, and the structure includes a roof portion, a ceiling portion, a wall portion, and the like of a building.

There are many buildings that use steel plate base materials with a plate thickness of about 1 to 2 mm, and it is widely practiced to fix heat insulating materials, control panel materials, etc. to these base materials with self-drilling screws such as drill screws. It has been. For example, the waterproof sheet and heat insulating material are fixed to the upper surface of the deck plate (folded plate) that constitutes the roof of the building with drill screws and tapping screws , and the heat insulating material and interior are attached to the columns and beams made of shaped steel such as C type. It is widely practiced to fix the material with a drill screw.

Then, in the drill screw, it has been proposed or implemented to form a notch groove such as a V shape extending in the axial direction by dividing the thread completely or partially in the thread portion. As an example, Patent Document 1 discloses that a plurality of recesses (notch grooves) parallel to the axis are formed in a tapered threaded portion closer to a drill portion among the threaded portions. It is described that the screwing torque can be reduced by the dent. Therefore, in Patent Document 1, it is understood that the dent is provided for the effect of improving the machinability of the thin metal plate.

On the other hand, Patent Document 2 also discloses that a V-shaped notch line is formed. In this Patent Document 1, the presence of the notch line improves the discharge of chips and the base material. It is stated that a smooth cut can be realized. Therefore, in Patent Document 2, as in Patent Document 1, it can be said that the notch line is provided for the effect of improving the machinability of the thin metal plate. It should be noted that also in the wood screw, a notch groove is formed in order to improve the machinability and the chip discharge property.

Japanese Unexamined Patent Publication No. 2006-177436 Japanese Unexamined Patent Publication No. 2017-67179

In buildings and structures, it is widely practiced to fix a work such as a heat insulating material to a structural material made of a thin metal plate such as a deck plate with a drill screw. One of the problems in this case is a screw to the structural material. Since the catching allowance of the ridge is small, if the screwing torque is too strong, a stripping phenomenon may occur in which the female screw of the structural material is crushed and the drill screw spins idle, making it meaningless as a screw.

Another problem is the loosening of the drill screw that occurs after fastening. There are many causes of looseness. For example, the wind may push the work away from the structural material. When vibration acts on the drill screw by repeating the movement that the work is elastically deformed by the wind pressure and returned by the elastic restoring force, the drill screw tends to loosen at an accelerating rate. Loosening may also occur when the vibration of the air conditioner travels through the structural material and acts on the drill screw. It should be noted that the looseness and the idling at the time of construction are inextricably linked to each other, and both of them are caused by the weak catching of the thread on the structural material.

Regarding this point, Patent Document 1 states that the inner peripheral portion of the prepared hole is 2.5 times the plate thickness by pressing the prepared hole with a protruding angle portion (rib) provided on the valley surface of the tapered threaded portion. It is explained that it can be expanded to a certain thickness.

As described in Patent Document 1, if the inner peripheral portion of the prepared hole can be partially thickened, the catching allowance between the screw thread and the thin metal plate can be significantly increased, so that high fastening strength can be ensured. At the same time, it can be said that the phenomenon that the threaded portion spins idle can be avoided.

The present invention has been made against the background of such a situation, and secures high fastening strength while suppressing screwing resistance, and secures a high loosening prevention effect, and prevents idle rotation of the threaded portion during construction. This is an attempt to easily realize this with a technique from a viewpoint different from that of Patent Document 1.

The invention of the present application includes various configurations, and a typical example thereof is specified in each claim. Of these, the invention of claim 1 relates to a self-perforated screw for a thin metal plate, and the self-perforated screw is a self-perforated screw.
" A drill screw for fixing a work to a thin metal plate with a thickness of 1.6 mm or less.
It is provided with a shaft having a threaded portion made of a thread, a drill portion provided at the tip of the shaft , and a head provided at the base end of the shaft.
A group of notch grooves that divide the thread completely or partially is formed in the thread portion in the circumferential direction, and a plurality of notch grooves are formed in the notch groove across the valley bottom in the screwing direction. The located chasing end face functions as a cutting edge for the thin metal plate. "
It has a basic structure.

And in the above basic configuration
"In the threaded portion, a band-shaped valley surface is formed in the valley portion between adjacent threads, and the valley diameter of the threaded portion is larger than the inner diameter of the prepared hole formed in the thin metal plate by the drill portion. While having a large diameter or the same diameter,
When the width dimension of the valley surface is E, the pitch of the threads is P, and the plate thickness of the thin metal plate is t, the relationship of E <t <P allows the metal plate to be screwed into the thin metal plate. In this state, the inner circumference of the thin metal plate fits tightly into the valley on one side of the axis, and the inner circumference of the pilot hole in the thin metal plate on the other side of the axis. The screw thread is set to bite into the surface, and
By making the axial distance between the notch grooves adjacent to each other in the circumferential direction smaller than the plate thickness of the thin metal plate, the thread portion is screwed into the thin metal plate and the thread is threaded . At least one of the notch grooves is set to overlap the inner peripheral surface of the prepared hole in the thin metal plate. "
It is configured as.

The notch groove may be positioned up to the valley surface and the thread may be completely divided by the notch groove, or the notch groove may be located at the middle height of the thread.

The invention of claim 2 is an example of development of claim 1.
"The angle formed by the plane orthogonal to the axis and the flank on the advancing side of the thread is θ1, and the angle formed by the plane orthogonal to the axis and the flank on the trailing side of the thread is θ2, and θ1> θ2. In relation to each other, θ1 + θ2 is set to 35 to 45 °.
Further, when the axial distance between the bottoms of the notch grooves in the adjacent threads is L, L and the t are the same or set to t> L. "
It is configured as.

The invention of claim 3 embodies claim 1 or 2.
"The thin metal plate and the thread have a plurality of notched grooves within the thickness range of the thin metal plate within a half circumference in a state where the threaded portion is screwed into the thin metal plate. Set to relationship "
It is configured as.

The present invention also includes a structure, and as claimed in claim 4, this structure is:
"It is provided with a structural material made of a thin metal plate having a thickness of 1.6 mm or less, a work overlapping the structural material , and a drill screw for pressing and fixing the work to the thin metal plate.
The drill screw includes a shaft having a screw portion made of a screw thread, a drill portion provided at the tip of the shaft , and a head provided at the base end of the shaft, and the screw portion has a screw thread. A group of notch grooves that completely or partially divides the groove is divided in the circumferential direction to form a plurality of rows , and the trailing end surface of the notch grooves located behind the valley bottom in the screwing direction is thin. It functions as a cutting edge for metal plates. "
It is a basic configuration.

And in the above basic configuration
"In the threaded portion, a band-shaped valley surface is formed in the valley portion between adjacent threads, and the valley diameter of the threaded portion is larger than the inner diameter of the prepared hole formed in the thin metal plate by the drill portion. While having a large diameter or the same diameter,
When the width dimension of the valley surface is E, the pitch of the threads is P, and the plate thickness of the thin metal plate is t, the relationship of E <t <P allows the metal plate to be screwed into the thin metal plate. In this state, the inner circumference of the thin metal plate fits tightly into the valley on one side of the axis, and the inner circumference of the pilot hole in the thin metal plate on the other side of the axis. The screw thread is set to bite into the surface, and
By making the axial distance between the notch grooves adjacent to each other in the circumferential direction smaller than the plate thickness of the thin metal plate, the thread portion is screwed into the thin metal plate and the thread is threaded . At least one of the notch grooves is set to overlap the inner peripheral surface of the prepared hole in the thin metal plate. "
It is configured as.

In many cases, the thread has a triangular cross section, and a grooved thread (or a two-hump type thread) in which one thread has two ridges and a spiral groove is formed in the thread is also assumed. However, the present invention also includes such a grooved thread. In the case of this grooved thread, it is also possible to form a notch groove only in the part of the trailing side flank or only in the part of the advancing side flank.

The present invention also includes a fixing device relating to a combination of a self-drilling screw and a washer, and this fixing device is as described in claim 5.
"It is composed of the drill screw and the washer according to any one of claims 1 to 3, and the bearing surface of the head of the drill screw is formed in a tapered shape with a downward constriction and a polygonal flat cross section. On the other hand, the washer is formed with a flat cross-sectional polygonal lower narrowing tapered receiving seat in which the seating surface of the head of the drill screw is in close contact, and the receiving seat is not divided by a slit. It is continuous in a series in the circumferential direction. "
It is configured as.

In this case, it is preferable that the number of angles of the seat surface of the screw head and the receiving seat of the washer is the same as the number of threads of the notch groove of the screw. The fixing device of claim 5 is used for fixing a work that is compressed and deformed against elasticity. In this case, the work may be a single layer or a plurality of layers, but in the case of a plurality of layers, it is sufficient if at least one layer is elastically deformed.

When the threaded portion is screwed into the thin metal plate, an external force is applied to the thin metal plate in the front and back directions due to the screw thread, so that the inner peripheral portion of the thin metal plate tends to bend and deform in the front and back directions. If the thickness of the thin metal plate is smaller than the valley width of the threaded portion, or the valley diameter of the threaded portion is larger than the inner diameter of the prepared hole due to the self-drilled portion, the inner peripheral portion of the thin metal plate is oriented in the front and back directions. Since the thread easily escapes and deforms, the thread bites only slightly into the inner peripheral portion of the prepared hole, a stripping phenomenon occurs, the thread portion tends to run idle, and the fastening strength and the loosening prevention effect tend to be insufficient. ..

On the other hand, in the present invention, first, the valley diameter of the threaded portion is larger than or the same as that of the prepared hole, so that the prepared hole can be expanded by the valley portion of the shaft, and therefore, it is thin. It is possible to tightly mesh the inner peripheral portion of the metal plate with the threaded portion in a state where bending and deformation in the front and back directions are restricted.

Further, since the width dimension E of the valley surface, the pitch P of the screw thread, and the plate thickness t of the thin metal plate have an E <t <P relationship, the inner circumference of the pilot hole of the thin metal plate is formed. The flesh of the portion loses a refuge and escapes to the outside of the radius, and the inner peripheral portion of the prepared hole can be thickened at least partially. Specifically, since the resistance to the pilot hole is usually non-uniform in the circumferential direction, the inner peripheral portion of the thin metal plate fits firmly into the valley portion of the threaded portion on one side of the axial center. On the other side of the axis, the inner peripheral part tends to thicken about half a circumference, and one or more threads bite into this thickened part. .. Depending on the size of the plate thickness t with respect to the valley width, a thick portion may be formed over the entire circumference.

In other words, in the inner peripheral part of the thin metal plate, the escape deformation in the front and back directions is restricted, so that at least a part of the inner peripheral part in the circumferential direction becomes thicker and the thread bites firmly. This makes it possible to improve the catching property of the thread on the prepared hole, prevent the female screw on the inner peripheral part of the prepared hole from being crushed and the threaded part from spinning (stripping phenomenon), and also have high fastening strength and looseness. A stopping effect can be obtained.

Since at least one notch groove formed in the threaded portion overlaps the inner peripheral surface of the prepared hole, the notch groove is screwed in by the cutting edge action of the trailing end surface facing the screwing direction. The resistance can be suppressed, and the force required for screwing can be reduced accordingly. Therefore, it is possible to reduce the burden on the operator while ensuring high fastening strength. Further, since the advancing side end face of the notch groove facing the screw return direction becomes a resistance to screwing back, the effect of preventing loosening can be improved by the notch groove.

In this case, as in the embodiment, the notch groove is tilted from the start end to the end in the direction opposite to the screwing direction (that is, the spiral direction of the notch groove and the spiral direction of the thread are in the same direction). When tilted to, the inner peripheral portion of the prepared hole is pushed downward (in the direction of the tip) by the advancing side end surface of the notch groove, so that there is an advantage that the resistance to screwing back can be increased and the loosening prevention effect can be promoted.

If the angle of the screw thread is about 60 ° like a normal machine screw, the thin metal plate must be widely spread in both front and back directions in order to bite into the thin metal plate. The biting property may deteriorate or the screwing resistance may increase. However, if the thread angle is set to about 35 to 45 ° as in claim 2 of the present application, the biting property to the thin metal plate is improved. , The function of forming female threads in the pilot holes of thin metal plates is improved.

In addition, since the tilt angle of the trailing flank is smaller than the tilting angle of the leading flank, the screwing resistance can be reduced and vice versa as compared with the case where the angle of the leading flank and the angle of the chasing flank are the same. The resistance to rotation can be increased. Therefore, it is possible to achieve both ease of screwing and improvement of the loosening prevention function.

Further, as described as the effect of claim 1, in the present invention, the phenomenon that the inner peripheral portion of the thin metal plate is partially thickened occurs , and the bite of the screw thread into the prepared hole is ensured. If the distance L between the edges of the adjacent notch grooves is the same as or t> L as the plate thickness t of the thin metal plate as in claim 2, the thin metal plate fits into the valley of the threaded portion. When it is inserted, it is possible to make it easier for the adjacent notch grooves to bite into the thin metal plate. As a result, the effect of preventing loosening due to catching of the notch groove can be improved.

As described above, in the notch groove, when screwing, the trailing side end face facing the screwing direction acts as a cutting edge, so that the biting property to the thin metal plate can be improved and the screwing resistance can be suppressed, while the screwing resistance can be suppressed. With respect to reverse rotation, the end face on the advancing side of the notch groove acts as a resistance to exert a loosening prevention effect, but if the configuration of claim 3 is adopted, the threaded portion of the inner peripheral portion of the thin metal plate is screwed in. Since there are a plurality of notch grooves in the thickened portion, the effect of the notch grooves can be promoted. The number of notched grooves is preferably about 3 or 4 in about half a circumference. Therefore, it can be said that it is preferable that the number of notched grooves is at least 5 in the circumferential direction.

As a means for preventing screws from loosening, it has been proposed to form a protrusion on the seat surface of the screw head, while forming an engagement groove on the washer receiving seat to fit the protrusion into the engagement groove. However, in this case, the loosening prevention function is carried only by the receiving seat of the washer, and the receiving seat is divided by the engaging groove and easily deformed, so that the loosening prevention effect is limited.

On the other hand, when the configuration of claim 5 of the present application is adopted, when the screw tries to loosen, the entire washer must be pushed into the work to greatly elastically deform the work, so that the resistance to the loosening of the screw becomes significantly high. That is, the elastic resistance of the work can be used to prevent the screws from loosening. Therefore, the anti-loosening effect can be significantly improved.

In claim 5, when the number of angles of the seat surface and the seat is made to match the number of notch grooves as in the embodiment, the synergistic action of the notch groove loosening prevention function and the square receiving seat loosening prevention function is achieved. , There is an advantage that the loosening prevention effect can be further improved.

In the figure showing an embodiment, (A) is a front view in which most of the notched grooves are omitted, (B) is an overall side view (photograph), (C) is a plan view, and (D) is a partially enlarged view. The figure, (E) is a sectional view taken along the line EE of (D), and (F) is a partial perspective view (photograph). (A) is a schematic vertical sectional view of the structure, (B) is a vertical sectional view of a main part of the structure, (C) is a vertical sectional view at the initial stage of fastening work, and (D) is a vertical sectional view of the main part in a fully screwed state. A plan view, (E) is an enlarged view of a notched groove portion, and (F) is an enlarged view of another notched groove in which the posture is changed. (A) is a perspective view in a screwed state, (B) is a perspective view in a state where the screw portion is removed, and (C) is a perspective view seen from the back side. (A) is a front view of a drill screw of another form, (B) is a perspective view of a threaded portion, and (C) is a view showing another example of a thread and a notch groove. It is a figure which shows the fixing device combined with the washer, (A) is the perspective view which looked at the screw from the bottom, (B) is the figure which looked at the washer from the top, (C) is the figure which looked at the washer from the bottom, ( D) is a partial cross-sectional view in a used state, and (E) is a sectional view taken along the line EE of (D).

(1). Structure of drill screw Next, an embodiment of the present invention will be described with reference to the drawings. This embodiment is applied to a drill screw. The drill screw is made of metal such as steel or stainless steel, and as shown in FIGS. 1 (A) and 1 (B), the shaft 1 and the drill portion 2 (self-drilled portion) provided at the tip (one end) thereof and the shaft 1 It is composed of a head 3 provided at the base end (the other end), and a threaded portion composed of one thread 4 is formed on the shaft 1. In the following, the upper and lower words are used for convenience to specify the direction, but it is defined that the drill portion 2 is located at the bottom and the head 3 is located at the top. Therefore, the top surface of the head 3 appears in a plan view.

The drill portion 2 has a conventionally known shape, and a pair of vertical grooves 5 are formed to form a pair of cutting edges 6, and a chisel edge is formed at the tip of the drill portion 2. The vertical groove 5 hangs on the tip of the threaded portion, and the starting end of the thread 4 is divided by the vertical groove 5.

The head 3 is a dish type having a downwardly narrowed tapered seat surface, and a quadrangular engaging groove (recess) 7 with which a driver bit (not shown) is engaged is formed on the top surface. The engaging groove 7 may have another form such as a cross shape. Further, the head 3 can be set to an arbitrary shape depending on the application, such as a hexagonal head, a pan head, or a flat plate type.

As shown in FIG. 1 (D), the thread 4 has a ridge line formed on the thread surface, but is basically a triangular cross section (to be exact, the cross section is trapezoidal), and the shaft. The angle θ1 formed by the plane orthogonal to the center O and the advancing flank 8 is larger than the angle θ2 formed by the plane orthogonal to the axial center O and the trailing flank 9. For example, θ1 can be set to about 30 to 35 °, and θ2 can be set to about 0 to 10 °. θ1 + θ2 is the angle of the thread 4, and the angle of the thread 4 is set to about 35 to 45 °.

FIG. 1 (D) shows the width dimension (mountain thickness) W of the base of the thread 4 and the height H of the thread 4, but the relationship is W <H (both are). It may be almost the same.). Therefore, the thread 4 has a shape that easily bites into the thin metal plate 10 that is the mating material to be screwed.

A band-shaped valley surface 11 exists in the valley portion between the adjacent threads 4. The groove width E of the valley surface 11 is smaller than the maximum width W of the thread 4. The outer diameter D1 of the valley surface 11 (see FIG. 2D) is set to be slightly larger than the rotational outer diameter D2 of the drill portion 2 (see FIG. 2B). Therefore, the prepared hole formed in the mating material 10 is expanded and expanded by the valley surface 11. The groove width E of the valley surface 11 is smaller than the plate thickness t of the mating material 10. For example, when the plate thickness t of the mating material 10 is 1.0 mm, the groove width E is set to about 0.8 mm.

It should be noted that the structural materials of buildings are usually standardized by each manufacturer, and it is also normal that the plate thickness is common in the standards of each company. Therefore, in the present invention, the numerical value is selected according to the standard, which can be applied to many structural materials.

The thread 4 is gradually increased in height from its starting end. Therefore, as shown in FIG. 1A, the threaded portion has a tapered portion 12 in which the height of the thread 4 changes, and the outer diameter of the portion following the tapered portion 12 is constant. It is a straight part.

There is a screwless portion 13 in which the thread 4 is not formed in the lower part of the neck of the shaft 1, but in FIG. 1B, the screwless portion 13 is slightly longer than that in FIG. 1A. Therefore, strictly speaking, (A) and (B) in FIG. 1 cannot be said to be the same, but the presence or absence of the screwless portion 13 and its length are selected according to the intended use, and the essence of the invention is Since it is an element that does not affect, the embodiment of FIG. 1 (A) and the embodiment of FIG. 1 (B) can be regarded as the same embodiment. As shown by another example in FIG. 4A, there is also a drill screw having a considerably long screwless portion 13 (the notch groove 14 is not specified in FIG. 4A, but the threaded portion is shown in FIG. 1 (A) It has the same form as (B).) In FIG. 4B, the entire notch groove 14 is displayed.

The screw thread 4 is formed with a plurality of V-shaped notch grooves 14 extending (spotted) in the axial direction in a state of dividing the threads (notch grooves 14 in FIGS. 2C and 2D). 14 is omitted.). In the illustrated form, the depth of the notch groove 14 is lower than the height of the thread 4. Therefore, as shown in FIG. 1 (E), the bottom 14a of the notch groove 14 is located at the mid-height of the thread 4 without reaching the valley surface 11, but the bottom 14a of the notch groove 14 is the valley surface. You may reach 11. The distance L between the edges of the bottoms 14a of the adjacent notch grooves 14 is set to be substantially the same as or larger than the plate thickness t of the mating material 10.

The start end of the notch groove 14 starts from the end portion of the tapered portion 12. Therefore, the notch groove 14 is not formed in most of the threads 4 at the tapered portion 12. Further, the notch groove 14 has a posture twisted around the axis (spiral posture) so as to incline in the same direction as the thread 4, and the lead angle with respect to the axis is very small (about half a circumference). It is designed to pass 10 or more threads with a twist of.).

When the plate thickness t of the mating material 10 is 1.0 mm, the outer diameter of the thread 4 is about 7 mm, the valley diameter D1 is about 4.2 mm, the pitch P is about 1.8 mm, and the drill. The rotation outer diameter D2 of the portion 2 can be set to about 3.4 mm. The length is set arbitrarily.

(2). Construction condition The drill screw of this embodiment can be used at various sites (structures). For example, as shown in FIGS. 2A and 2B, the heat insulating material 17 can be used to hold and fix the heat insulating material 17 to the deck plate 18 (the mating material 10). A circular washer 19 is used for construction, and the washer 19 is provided with a lower constricted tapered receiving seat 19a that overlaps the seat surface of the head 3 in the drill screw. The screw head 3 and the heat insulating material 17 are covered with a waterproof sheet 16.

In construction, the drill screw enters the heat insulating material 17 by the drilling action of the drilling portion 2 and the screwing action of the threaded portion, and then, as shown in FIG. 2C, the drilling portion 2 enters the deck plate 18. The pilot hole 20 is drilled, and then, as the screw thread 4 is screwed in, the pilot hole 20 is expanded by the valley surface 11 to expand the diameter, and the screw thread 4 bites into the inner peripheral portion 21 of the pilot hole 20. Eventually, the head 3 strongly abuts on the washer 19 and the screwing is stopped.

Since D1 <D2 and E <T, as shown in FIG. 2, first, the inner peripheral portion 21 of the deck plate 18 is crushed and deformed while being tightly fitted to the valley surface 11 of the threaded portion. As a result, the movement in the vertical direction (bending deformation) is restricted, and the inner peripheral portion 21 becomes a part of the thick portion 21a due to the movement of the meat due to the forced expansion (diameter expansion).

Further, when the screw portion is screwed in, the inner peripheral portion 21 is deformed in the vertical direction at the initial stage of screwing to become a bite portion 21b in which a part of the screw portion has entered (fitted) into the valley portion of the screw portion, and the diameter is expanded in that state. It can be said that by receiving the action, a strong pressing force acts on the portion located on the opposite side of the biting portion 21b across the axial center O to form the thick portion 21a. That is, when about half of the prepared hole 20 becomes the biting portion 21b that strongly stretches against the valley of the threaded portion, the inner peripheral portion 21 escapes to the opposite side to the biting portion 21b and the thick portion 21a is formed. I can say.

This point can be understood from the photographs of FIGS. 3 (B) and 3 (C). In addition, in FIG. 3, the upper surface of the deck plate 18 appears in (A) and (B), the lower surface of the prepared hole 20 appears, and the lower surface appears in (C), but the upper and lower surfaces are viewed from the axial direction. Marks 22 are placed at the same positions to clarify the positional relationship.

Then, by firmly biting the notched groove 14 of the thread 4 into the thick portion 21a, a high fastening force and a locking effect are exhibited, and the female screw of the prepared hole 20 is crushed and the threaded portion spins idle. It is also possible to prevent the stripping phenomenon that occurs.

Further, in the present embodiment, the follow-up end surface 14b located behind the valley bottom 14a in the notch groove 14 in the screwing direction acts as a cutting edge, so that the force required for screwing can be reduced and the inner peripheral portion can be reduced. The bite of the thread 4 into the thick portion 21a of 21 can be made good, and the female thread forming function can be improved. In this case, eight notch grooves 14 are formed, and the height of the adjacent notch grooves 14 in the axial direction is P / 8, so that at least three or four notches are cut within a range of about half a circumference. The notch groove 14 overlaps the inner circumference of the prepared hole 20 in the deck plate 18.

Therefore, the notch groove 14 frequently overlaps with the inner peripheral surface of the prepared hole 20, and the cutting function of the notch groove 14 on the follow-up side end surface 14b can be ensured. Although the burr 23 can be seen in FIG. 3, it can be said that the occurrence of the burr 23 in this way is proof that the trailing end surface 14b of the notch groove 14 functions as a cutting edge. Further, among the notch grooves 14, the advancing side end surface 14c located on the front side in the screwing direction across the valley bottom 14a acts as a resistance against loosening, but the advancing side end surface 14c of the plurality of notch grooves 14 is particularly thick. Since the pilot hole 20 is stretched at the position 21a, a high anti-loosening effect can be exhibited.

In addition, the thick portion 21a is elastically deformed to form a female screw, and when the screwing is completed, an elastic restoring force (spring back) acts, but the thick portion 21a bites into the notch groove 14 due to the elastic restoring force. Then, the advancing side end surface 14c of the notch groove 14 acts as a strong resistance against screwing back.

The notch groove 14 can be formed in a posture parallel to the axis, but if it is formed in a twisted posture as in the present embodiment, it will come into contact with the blade of the die in processing with a rolling die or a flat die. Has the advantage of being smooth and easy to process. That is, since the notch groove 14 can be formed while pressurizing the die with a constant pressure, the processing accuracy can be improved and the durability of the die is also excellent. In particular, if the spiral direction of the notch groove is formed in the same direction as the spiral direction of the thread 4 as in the embodiment, the resistance to the die can be made constant, which is preferable.

As shown in FIG. 2F, the notch groove 14 can be inclined in the direction opposite to the inclination direction of the thread 4, but the notch groove 14 is in the same direction as the thread 4 as in the embodiment. As shown by the arrow 24 in FIG. 2E, when the drill screw is unscrewed (when it is raised), the advancing side end surface 14c of the notch groove 14 causes the deck plate 18 to face downward. It is understood that the action of pushing is promoted by the resistance action against the loosening of the drill screw. Therefore, it can be said that it is also excellent in the anti-loosening effect.

As shown in FIG. 4C , the thread 4 can be formed in a grooved manner having two ridges 4a and 4b, and in the illustrated example, the notch groove 14 is the follower flank. It is formed only in the place. Although the notch groove 14 reaches the valley surface 11 in the division diagram (C), it may be formed in a state where only the ridge portion on the follow -up side is excised.

The notch groove 14 can be formed so as to divide the entire thread 4, but if it is formed only at the part of the trailing flank as shown in the figure, the function of pushing the mating materials 10 and 18 into the valley portion is available. Since it is high, the loosening prevention effect can be improved. Further, the notch groove 14 can be formed only at the portion of the leading flank, but when formed at the portion of the trailing flank as shown in the illustrated example, the notch groove 14 resists screwing back. Since the function of acting as a screw is enhanced, there is an advantage that the anti-loosening effect can be further improved. When the notch groove 14 is formed at the portion of the trailing flank, the angle θ2 of the chasing flank may be about 5 to 10 °.

FIG. 5 shows an example of a fixing device related to a combination of a drill screw and a washer 19. The drill screw is basically the same as that of the above-described embodiment, and the only difference is that the seat surface 3a of the head 3 has a polygonal flat cross section (octagon). Then, corresponding to the polygonal shape of the seating surface 3a of the head 3 in the drill screw, the receiving seat 19a of the washer 19 also has a flat cross-section polygonal shape (octagonal shape) similar to the seating surface 3a. There is.

In this example, the washer 19 is pushed into the heat insulating material 17 at the end of fastening. Therefore, although the screwing resistance is large, as described above, since the drill screw of the present embodiment has a high fastening force to the deck plate, the washer 19 does not cause the phenomenon that the female screw formed on the deck plate 18 is crushed. Can be strongly pressed against the heat insulating material 17 and screwed firmly.

On the other hand, if the drill screw loosens and tries to rotate after fixing, the ridgeline of the seat surface 3a must get over the plane of the receiving seat 19a, and therefore, when the screw loosens, the washer 19 must compress and deform the heat insulating material 17. However, since the washer 19 has a large area, a large resistance is generated in pushing the washer 19 into the heat insulating material 17, so that a remarkably high anti-loosening effect can be obtained.

When the number of rows of the notch groove 14 and the number of angles of the seat surface 3a and the receiving seat 19a are matched as in the embodiment, the effect of preventing the notch groove 14 from being caught and the square seat surface 3a and the receiving seat 19a are obtained. Since the loosening prevention effect due to the fitting is exhibited at the same time, the loosening prevention effect can be significantly improved, which is preferable.

In the present embodiment, when the receiving seat 19a is pushed by the ridgeline of the seating surface 3a, the meshing between the seating surface 3a and the receiving seat 19a changes. Therefore, the screwing resistance and the loosening prevention effect become higher as the number of angles of the seat surface 3a and the receiving seat 19a is smaller. On the other hand, the screwing resistance and the loosening prevention effect also depend on the elastic deformation rate of the work such as the heat insulating material 17. Therefore, the number of angles of the seat surface 3a of the head 3 and the receiving seat 19a of the washer 19 may be set in consideration of the elastic deformation rate of the work such as the heat insulating material 17. Generally, it can be said that the number of angles is preferably about 5 to 10.

Although the embodiments of the present invention have been described above, the present invention can be embodied in various ways. For example, the shape of the thread may be an ordinary triangle, and each dimension can be set according to the application. The drill screw may be pyramidal. It is also possible to form a thread into a multi- threaded screw (in this case, it is also possible to arrange threads having different heights side by side).

Further, the invention of the present application has an excellent design in terms of the relationship between the thread and the notch groove. Therefore, it can also be a target for design registration. In this case, it is possible not only to be registered as a whole design but also to be registered as a partial design. An arbitrary range can be specified as the partial design. For example, as shown by K1 in FIG. 1A, the range sandwiching the tapered portion 12, and as shown by K2, the tapered portion 12 and the straight portion of the threaded portion. As shown by K3, it is possible to specify an appropriate range of only the straight portion of the threaded portion. The notch groove does not have to be V-shaped when viewed from the axial direction, and may be rectangular or trapezoidal.

The present invention can be embodied in a drill screw, a structure using the drill screw, and a fixing device. Therefore, it can be used industrially.

1 axis 2 drill part (self-drilling part)
3 head 4 thread 8 thread leading side flank 9 thread trailing side flank 10 mating material 11 valley surface 14 notch groove 14a bottom 14b chasing side end face
14c advancing side end face
17 Insulation material as work 18 Deck plate as an example of structural material (counterpart material) 19 Washer 19a Receiving seat 20 Pilot hole 21 Inner circumference
21a Thick part 21b Biting part

Claims (5)

It is provided with a shaft having a threaded portion, a self-perforated portion provided at the tip thereof, and a head provided at the base end of the shaft, and the threaded portion is completely or partially divided into threads. A self-drilling screw for thin metal plates in which a group of notched grooves is divided in the circumferential direction and formed in multiple rows.
In the threaded portion, a band-shaped valley surface is formed between adjacent threads, and the valley diameter of the threaded portion is larger than or substantially the same as the inner diameter of the prepared hole formed by the self-perforated portion. On the other hand,
When the width dimension of the valley surface is E, the pitch of the thread is P, and the thickness of the thin metal plate to which the threaded portion is screwed and used to fasten the work is t, the relationship of E <t <P. It has become
Moreover, at least one notch groove is set so as to overlap the inner peripheral surface of the thin metal plate in a state where the threaded portion is screwed into the thin metal plate.
Self-drilling screw for thin metal plates. Let θ1 be the angle between the plane orthogonal to the axis and the flank on the advancing side of the thread, and θ2 be the angle between the plane orthogonal to the axis and the flank on the trailing side of the thread, and the relationship θ1> θ2. And θ1 + θ2 is set to about 35 to 45 °.
Further, when the axial distance between the bottoms of the notch grooves in the adjacent threads is L, L and t are set to approximately the same degree or t> L.
The self-perforated screw for a thin metal plate according to claim 1. The thin metal plate and the thread have a relationship in which a plurality of notched grooves exist within a range of the thickness of the thin metal plate within a range of approximately half a circumference in a state where the threaded portion is screwed into the thin metal plate. Is set to,
The self-perforated screw for a thin metal plate according to claim 1 or 2. It is equipped with a structural material made of a thin metal plate, a work overlapping the structural material, and a self-drilling screw that presses and fixes the work to the thin metal plate.
The self-perforated screw includes a shaft having a thread portion made of a thread, a self-perforated portion provided at the tip thereof, and a head provided at the base end of the shaft, and the thread portion is provided with a thread. A group of notched grooves that are totally or partially divided is divided in the circumferential direction to form a plurality of rows.
In the threaded portion, a band-shaped valley surface is formed between adjacent threads, and the valley diameter of the threaded portion is larger than or substantially the same as the inner diameter of the prepared hole formed by the self-perforated portion. On the other hand,
When the width dimension of the valley surface is E, the pitch of the thread is P, and the thickness of the thin metal plate to which the threaded portion is screwed and used to fasten the work is t, the relationship of E <t <P. It has become
Further, each of the notch grooves is formed to a depth up to the middle height of the thread, and at least one notch groove is formed in the thin metal plate with the threaded portion screwed into the thin metal plate. It is set to overlap the inner peripheral surface,
Structure. It is composed of the self-drilling screw and the washer according to any one of claims 1 to 3, and the bearing surface of the head of the screw is formed in a tapered shape with a narrowed lower portion and a polygonal flat cross section. The washer is formed with a flat cross-sectional polygonal lower constricted tapered receiving seat in which the seating surface of the screw head is in close contact, and the receiving seats are serially arranged in the circumferential direction without being divided by a slit. Continuous,
Fixing device for thin metal plates.

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