JP4204905B2 - Drilling tapping screw - Google Patents

Description

【００１９】
これらの実施例及び比較例について各３０本の打ち込み試験を行った結果を表１に示す。被締結物は、１．６mm厚の鋼板であり、ＪＩＳのＢ１１２５に準拠する試験装置によって、約１５２Ｎの荷重を加えて、ねじ込みを試験を行い、ねじ込み完了までの時間を測定し、各３０本のねじ込み時間の平均時間と、各３０本のねじ込み時間の標準偏差を表１に示した。
この試験から明らかなように、従来の尖端テーパのタッピングねじでは実質的に不可能とされた厚みの大きな鋼板に対しても、良好なねじ込み性能を示すことは勿論、ドリル先を有するドリリングタッピングねじに比しても、良好な結果を示したことは、発明者にとっても驚きであった。
また、表には示さないが、各実施例では、１．０mm以下の板厚の鋼板に対しても良好なねじ込み性能を示すことが確認されると共に、ねじの保持強度についても充分に使用可能な性能を示した。これは、本願発明では、初期貫通時において、尖端テーパによる突き破り作用とテーパ部ねじ山の良好な切削作用とが共に作用することによって、良好な初期の切削性能を示すと共に、突き破り作用により孔周辺に若干の鋼板片が生じるため、比較的薄い鋼板に対しても、良好なねじの保持強度を実現し得たものであると考えられる。
【００２０】
【発明の効果】
以上のように、本願発明は、被締結物に対する初期貫通時におけるねじ山の食い込み若しくは切削性能を改善し、比較的大きな板厚の被締結物に対しても、ねじ込み時間を短縮することができる尖端テーパのドリリングタッピングねじを提供することができたものである。特に、鋼板に使用した場合には、従来の１mm以下の板厚の鋼板はもちろんのこと、１．０〜１．６mmの板厚の鋼板に対して良好な穿孔性能と締付状態を実現することができたものである。
【図面の簡単な説明】
【図１】 本願発明の実施の形態に係るドリリングタッピングねじの要部拡大図である。
【図２】 同ねじの正面図である。
【図３】 同ねじを転造するための転造ダイスの正面図である。
【符号の説明】
１ 軸部
２ 頭部
３ テーパ部
４ 軸部ねじ山
５ テーパ部ねじ山
３１ 尖端箇所[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drilling tapping screw.
[0002]
[Prior art]
Conventionally, self-drilling tapping screws mainly used for steel plates are roughly classified into two types, those having a tapered tip and those having a drill blade at the tip. The one with a pointed taper is used for a relatively thin steel plate with a thickness of 1.0 mm or less, pierces the steel plate with a sharp tip, and tapping a thread on the steel plate around the hole caused by this initial penetration. However, it was screwed. Therefore, it is possible to form a thread even on a thin steel plate, and it has a pull-out holding force. On the other hand, a thick steel plate with a thickness of 1.6 mm requires a large force for initial penetration or a tightening time. It became long or a penetration failure occurred, and it was practically impossible to use. Therefore, at present, the taper tapping screw having a pointed tip is used for a thin steel plate having a thickness of 1.0 mm or less.
[0003]
On the other hand, a drilling tapping screw provided with a drill blade at the tip pierces a steel plate with the tip drill blade, taps the hole formed by drilling the drill portion, and is screwed. Therefore, while it can be used sufficiently for steel plates of 1.6 mm or more, it is not possible to form sufficient threads for thin steel plates, and the holding force becomes weak, and the drill part There is a problem that a process for forming the film is necessary and the production cost is higher than that of the former.
[0004]
As described above, both types of tapping screws have advantages and disadvantages. In particular, it is desired to provide an optimum screw for a steel plate having a thickness of 1.0 to 1.6 mm. In order to solve this type of problem, Patent Documents 1 to 3 have been proposed, but these are intended to cause the thread at the tip tapered portion to function as a cutting blade in a tapping screw having a tip tapered. In order to improve the cutting performance by making the shape of the thread near the tip and the shape of the shaft part special, the thread of the shaft part is formed during the manufacture of the rolling die. The groove for forming the thread and the groove for forming the thread of the tapered portion are set to substantially the same lead angle.
[0005]
[Patent Document 1]
Japanese Patent Publication No. 60-41243 [Patent Document 2]
Japanese Patent Publication No. 61-24566 [Patent Document 3]
Japanese Examined Patent Publication No. 62-15769 [0006]
[Problems to be solved by the invention]
The present invention provides a drilling tapping screw that improves the biting or cutting performance of a thread at the time of initial penetration of a fastened object, and can shorten the screwing time even for a fastened object having a relatively large thickness. With the goal. In particular, when steel plates are used as fasteners, provision of drilling tapping screws with a pointed taper that can achieve good drilling performance and tightening conditions for steel plates with a thickness of 0.8 to 1.6 mm With the goal.
[0007]
[Means for Solving the Problems]
In a conventional pointed taper tapping screw, a series of threads is formed from the shaft portion to the taper portion. When this thread is manufactured by a rolling die, it is rolled by a linear thread forming groove set to a constant lead angle. Basically, a screw having the same lead angle is formed in the shaft portion and the taper portion. A thread is formed by the thread forming groove. Even when different discontinuous screw threads are formed between the shaft portion and the taper portion, the lead angles of the screw thread forming grooves of both dies are designed to be equal. However, even in the case of a thread that is rolled by these conventional straight thread forming grooves, the taper is converged toward the tip at the tapered portion, so that the rolled thread is The lead angle is gradually increased and rolled at the tip portion. As a result, the lead angle of the screw thread that should have the function of first contacting the object to be fastened and penetrating becomes very large, and the function of cutting the tip as a blade has been weakened. Therefore, by forming a small lead angle thread in the middle of the taper part where the lead angle starts to increase with normal thread, the lead angle of the thread is made loose (small) at the tip, and the fastening object A drilling tapping screw with improved cutting capability has been developed, which makes it possible to apply it to thick steel plates that are difficult or impossible to penetrate with ordinary tapping screws.
[0008]
The invention which concerns on Claim 1 of this application is a shaft part, the engaging part with respect to the rotary tool provided in the base end side of the shaft part, the taper part provided in the front end side of the shaft part, the shaft part, and the taper part In the drilling tapping screw that is fastened while forming a screw hole in the object to be fastened at the tapered portion, the thread of the tapered portion is at least one thread, It is rolled by a rolling die having a thread forming groove with a lead angle of not less than 10 degrees and less than 10 degrees,
Threads of the tapered portion, the thread height at the tip portion of 0.3 mm from the tip of the tapered portion is from 0.03 to 0. A 2 mm, and, for the object to be fastened lead angle is no more than 70 degrees A drilling tapping screw characterized by being a screw thread having a cutting performance .
The invention according to claim 2 of the present application includes a shaft portion, an engaging portion for a rotary tool provided on the proximal end side of the shaft portion, a tapered portion provided on the distal end side of the shaft portion, and the shaft portion and the tapered portion. A drilling tapping screw that is fastened while forming a screw hole in an object to be fastened at the tapered portion, wherein the thread of the tapered portion is at least one thread, The thread is formed by a rolling die having a thread forming groove having a smaller lead angle than the thread of the part, and the lead angle of the thread forming groove is 4 degrees or more. mountains, thread height at the tip portion of 0.3 mm from the tip of the tapered portion is from 0.03 to 0. a 2 mm, and the lead angle has a cut performance against the fastened object is 40 to 70 degrees Doriringuta', characterized in that the screw thread To provide a ring screw.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an enlarged view of a main part of a drilling tapping screw according to an embodiment of the present invention. FIG. 2 is a front view of the screw, and FIG. 3 is a front view of a rolling die for rolling the screw.
[0010]
The drilling tapping screw includes a shaft portion 1, a head portion 2 having an engagement portion such as a cross hole, a slot or a hexagonal head with respect to a rotary tool provided on the base end side of the shaft portion 1, and a distal end of the shaft portion 1. And a tapered portion 3 provided on the side. In this drilling tapping screw, a thread is formed by a rolling die, and one (or two or more) shaft thread 4 is formed on the shaft, and one (or 2) is formed on the taper. Or more) is formed.
[0011]
The shaft portion 1 is a so-called parallel shaft portion having a constant diameter, and the taper portion 3 is a pointed taper portion whose diameter gradually decreases from the shaft portion 1 toward the tip. The taper angle t is 35 degrees, but is preferably about 25 to 45 degrees, and more preferably 30 to 40 degrees. In general, the taper portion 3 has a constant reduction rate of the above-mentioned diameter, and the outline thereof is generally a triangle when viewed from the front, but in some cases, the reduction rate of the diameter changes. For example, a substantially parabola may be drawn in front view. Note that the taper angle referred to here is a depression angle formed by two left and right line segments connecting a point 0.5 mm from the tip and the tip in a front view of the screw.
[0012]
The shaft portion thread 4 is formed around the shaft portion 1 mainly for fastening by a screw thread, like a conventional tapping screw, and the lead angle is preferably 10 to 30 in the case of a double thread. Degree, more preferably about 10 to 20 degrees, in the case of a single thread, preferably 5 to 15 degrees, more preferably about 5 to 10 degrees, It can be appropriately changed depending on various conditions such as the purpose of use and the type of the object to be fastened. The tip of the shaft portion thread 4 disappears near the base end of the taper portion 3 by gradually decreasing the height of the mountain, but it may disappear near the tip of the shaft portion 1. It may be eliminated at the boundary portion with the taper portion 3. Moreover, you may make it continue with the taper thread 5 mentioned below. The thread height is 0.45 to 0.75 mm, preferably about 0.5 to 0.65 mm, but this value can be changed as appropriate.
[0013]
The taper thread 5 is formed around the taper portion 3 and disappears at the tip 31 of the taper portion 3. The proximal end of the taper thread 5 is set closer to the proximal end of the tapered portion 3, but it may be provided closer to the distal end of the shaft portion 1, or may be provided from the boundary portion between the shaft portion 1 and the tapered portion 3. good. The shaft thread 4 may be brought into contact with each other, may be formed at an interval (provided with a screw-free part), or may be continuous. Moreover, if it is a short area, the axial part thread 4 and the taper thread 5 can also be provided overlappingly.
The taper thread 5 is set to have a lead angle smaller than the lead angle of the shaft thread 4 on a die described later. In this example, the thread height is also set lower than the shaft thread 4. The thread height of the taper thread 5 may be a constant height except for the incomplete thread part, but the base end side is made substantially the same height as the thread of the shaft part and gradually decreases toward the tip. Also good. Similarly, the lead angle may be gradually changed.
[0014]
Next, the taper thread 5 changes under the influence of taper convergence so that the lead angle gradually increases. Here, the taper screw thread 5 at the tip portion 31 of 0.3 mm from the forefront has a lead angle of 70 degrees or less. Preferably, it is 70 to 40 degrees, more preferably 65 to 45 degrees. The thread height of the taper thread 5 at the apex portion 31 is preferably 0.03 to 0.2 mm. If it is less than 0.03 mm, the drilling performance will be reduced. If it exceeds 0.2 mm, the thread may be deformed during drilling. In consideration of stability, it may be 0.1 mm or less. More preferred.
[0015]
Here, the relationship between the number of threads of the shaft thread 4 and the taper thread 5 will be described. The shaft thread 4 is implemented as a multi-thread such as 1, 3, or 3 threads. obtain. The same applies to the taper screw thread 5, and it can be implemented as a multi-thread screw such as one, two, three or the like. The shaft thread 4 and the taper thread 5 may have the same number of threads, but the former may be carried out with one or two more threads than the latter, and conversely, the former may be one thread than the latter. Or you may carry out by reducing 2 articles.
[0016]
Next, with reference to FIG. 3, the rolling flat die which manufactures the drilling tapping screw which concerns on said embodiment is demonstrated. A plurality of shaft thread forming grooves 4a and tapered thread forming grooves 5a are formed in the die. Each thread forming groove 4a, 5a is linearly formed with predetermined lead angles α, β. The lead angles α and β of the thread-forming grooves 4a and 5a are planes orthogonal to the thread-forming grooves 4a and 5a and the central axis of the threaded shaft portion 1 to be rolled thereby. Is the angle between The lead angle α of the groove 4a for forming the shaft thread is preferably 10 to 30 degrees, more preferably about 10 to 20 degrees in the case of a double thread, and in the case of a single thread, A half angle is preferable, and the angle appears as it is as the lead angle of the shaft thread 4 on the rolled screw shaft. The lead angle β of the groove 5a for forming the taper portion thread is preferably smaller than the lead angle α of the groove 4a for forming the shaft portion screw thread. Specifically, the lead angle β is 4 degrees or more and less than 10 degrees. Preferably, it is 6 degrees or more. The taper thread forming groove 5a is provided on the inclined surface 3a forming the pointed taper portion, and the taper screw whose lead angle is changed by the linear taper thread forming groove 5a. A mountain 5 is formed. In addition, since these grooves 4a and 5a are formed by cutting using a rotary cutting tool for dicing, they are linear when viewed from the front. For example, the grooves are formed using an electric discharge machine. Accordingly, the angle of the shaft thread forming groove 4a can be gradually changed to be formed continuously with the taper thread forming groove 5a. Further, the groove 5a for forming the taper thread may be provided in a curved shape to further emphasize the change in the lead angle.
[0017]
【Example】
As Examples 1 to 4, drilling tapping screws were manufactured under the conditions shown in Table 1. This linear taper thread forming groove 5a forms a taper thread whose lead angle changes at the taper portion. As shown in Table 1, at the tip (0.3 mm from the forefront). A thread having a lead angle of 43 to 57 degrees is formed. On the other hand, the comparative example 1 is a conventional pointed taper tapping screw (Dry Wall Modulus L25 manufactured by Yamahiro Co., Ltd.), and in a rolling die, a series of straight grooves for thread formation (on the die) As shown in Table 1, the lead angle is 79 degrees as a result of the formation of the shaft thread and the taper thread. A thread is formed. Comparative Example 2 is a drilling tapping screw (Jack Point Mod Truss MJ25 manufactured by Yamahiro Co., Ltd.) having a drill portion formed at the tip by forging.
[0018]
[Table 1]

[0019]
Table 1 shows the results of 30 implantation tests for each of these examples and comparative examples. The object to be fastened is a steel plate with a thickness of 1.6 mm, a load of about 152 N is applied by a test device conforming to JIS B1125, the screwing is tested, and the time until screwing is completed is measured, 30 pieces each. Table 1 shows the average time of the screwing times and the standard deviation of each of the 30 screwing times.
As is clear from this test, a drilling tapping screw having a drill tip as well as a good screwing performance even for a thick steel plate that is substantially impossible with a conventional pointed tapping screw. It was also surprising to the inventor that the good results were shown.
In addition, although not shown in the table, in each example, it is confirmed that the screwing performance is good even for a steel plate having a thickness of 1.0 mm or less, and the screw holding strength can be sufficiently used. Showed good performance. In the present invention, at the time of initial penetration, the piercing action by the tip taper and the good cutting action of the taper portion thread work together to show a good initial cutting performance, and by the piercing action, Therefore, it is considered that good screw holding strength can be realized even for a relatively thin steel plate.
[0020]
【The invention's effect】
As described above, the present invention can improve the bite or cutting performance of the screw thread at the time of initial penetration with respect to the fastened object, and can shorten the screwing time even for the fastened object having a relatively large plate thickness. A tip-tapered drilling tapping screw could be provided. In particular, when used for steel plates, it achieves good drilling performance and tightening condition for steel plates with a thickness of 1.0 to 1.6 mm as well as conventional steel plates with a thickness of 1 mm or less. Was able to.
[Brief description of the drawings]
FIG. 1 is an enlarged view of a main part of a drilling tapping screw according to an embodiment of the present invention.
FIG. 2 is a front view of the screw.
FIG. 3 is a front view of a rolling die for rolling the screw.
[Explanation of symbols]
1 Shaft 2 Head 3 Taper 4 Shaft Thread 5 Tapered Thread 31 Pointed Point

Claims (2)

A shaft portion, an engaging portion for the rotary tool provided on the proximal end side of the shaft portion, a tapered portion provided on the distal end side of the shaft portion, and a thread provided on the shaft portion and the tapered portion, In a drilling tapping screw in which fastening is performed while forming a screw hole in an object to be fastened at a tapered portion,
The thread of the taper portion is at least one thread, and is rolled by a rolling die having a thread forming groove with a lead angle of 4 degrees or more and less than 10 degrees,
Threads of the tapered portion, the thread height at the tip portion of 0.3 mm from the tip of the tapered portion is from 0.03 to 0. A 2 mm, and, for the object to be fastened lead angle is no more than 70 degrees A drilling tapping screw characterized by being a thread having a cutting performance . A shaft portion, an engaging portion for the rotary tool provided on the proximal end side of the shaft portion, a tapered portion provided on the distal end side of the shaft portion, and a thread provided on the shaft portion and the tapered portion, In a drilling tapping screw in which fastening is performed while forming a screw hole in an object to be fastened at a tapered portion,
The thread of the taper portion is at least one thread, and is rolled by a rolling die having a thread forming groove having a lead angle smaller than that of the shaft portion. The lead angle of the forming groove is 4 degrees or more,
Threads of the tapered portion, the thread height at the tip portion of 0.3 mm from the tip of the tapered portion from 0.03 to 0. A 2 mm, and, fastened object lead angle is 40 to 70 degrees A drilling tapping screw characterized by being a screw thread having a cutting performance with respect to .

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