JP3849793B2 - Drill and self-drilling screw - Google Patents

Description

  The present invention mainly includes a drill for drilling a structure such as a wall body such as mortar or concrete, a ceramic wall body such as tile or brick, and other wall bodies, and such a drill. It is related with the provided self-drilling screw.

  Conventionally, various drill tools are known, and metal structures such as metal walls (hereinafter referred to as “metal workpieces”), walls such as mortar or concrete, and ceramic-based walls such as tiles and bricks. It is used for drilling other inorganic structures (hereinafter collectively referred to as “inorganic work”). Such a drill tool is provided as a drill bit, and is driven and rotated by a rotary tool provided with an electric drive device to drill a structure as described above.

  Conventionally, a self-drilling screw in which a drill means is provided at the tip of the shank and a screw means having a thread is provided at the subsequent portion of the shank is known. In such a self-drilling screw, a pair of guide grooves are formed in the circumferential direction of the shank by pinching the tip of the shank with a pinching die, and a cutting blade is formed at the edge of the guide groove. Therefore, in the case of a normal screw, after drilling a pilot hole in the work in advance and then screwing the screw through the pilot hole, the self-drilling screw drills the pilot hole in advance in the work. There is an advantage that the following screw means can be screwed in while drilling with the drill means at the tip.

Various types of self-drilling screws are also known, and it has been proposed to form the drilling means with a high-hardness tip such as cemented carbide.
Japanese Patent Publication No. 63-33006 Japanese Patent No. 2968336 Japanese Patent No. 3334092

  Conventional drill tools are intended for repeated use and have excellent sharpness when drilling, but are expensive because they are formed of tool steel and are not suitable for use as a simple drill bit or the like.

  Also, among the conventional self-drilling screws, those with drilling means formed by cutting blades formed at the edge of the guide groove forged with pinching dies can drill well for metal workpieces, but are not practical for inorganic workpieces . This is because the cutting blade wears out early during the rotation of insertion into the inorganic workpiece.

  On the other hand, the self-drilling screw in which the drill means is formed with a high-hardness tip such as a cemented carbide has a high wear resistance of the cutting blade, and thus ensures a good sharpness. However, since the inorganic work produces powdery chips during drilling, the chips hinder driving rotation of the drill means. Therefore, a high torque is required to drive and rotate the self-drilling screw, and if the chips harden on the cutting blade, a non-rotatable state is often caused.

  If the present inventors provide an inexpensive drill, it can be used as a simple drill and can be used not only for a drill tool such as a drill bit but also for a disposable drill such as an anchor with a drill. I found out. It has been found that if such a drill is applied to a self-drilling screw, a practical self-drilling screw can be realized for an inorganic workpiece.

  Therefore, in order to provide an inexpensive drill, rather than using expensive tool steel as a conventional drill tool, Fe wire as a screw wire, carbon steel wire, SUS410 and other stainless steel It is preferable to form a shank with a wire. In order to guarantee the sharpness and wear resistance of the cutting blade, it is known that a blade means made of a high-hardness tip such as cemented carbide should be attached to the tip of the shank.

  By the way, even in a drill in which a blade means made of a high-hardness tip is provided at the tip of the shank, when drilling an inorganic workpiece as described above, resistance is caused by powdered chips, which is a problem of this point. If the problem is not solved, the practicality is poor. For example, it cannot be used with a relatively low output rotating tool such as a rechargeable electric screwdriver.

  It is known that such a problem can be solved by forming a guide groove for discharging chips on the peripheral surface of the shank following the blade means. In fact, the drill tool rotates the edge of the shank from the blade edge. A guide groove is formed between the blade edges by extending spirally along the direction. Therefore, it is understood that even in a drill provided with a high-hardness tip as described above, discharge of chips can be guided well if a guide groove is formed at the tip of the shank.

  However, in the case of a hybrid configuration in which the shank formed of threaded wire and the blade means made of a high-hardness tip are formed in separate processes and the blade means is attached to the tip of the shank, a guide groove is formed at the tip of the shank. After that, when attaching the blade means to the blade means, it is necessary to always position the cutting means of the blade means so as to be continuous with the guide groove, and high precision machining work is required. is there.

  The present invention solves such a problem, forms a guide groove at the tip of the shank, and forms a holding groove located on the diameter line of the tip of the shank, and a blade comprising a high hardness tip in the holding groove. In the hybrid configuration in which the means is attached, as long as the holding groove is positioned on the diameter line of the shank, the opening end of the guide groove is formed after the blade means is attached to the holding groove, regardless of the direction from which the blade is formed. Provided are a drill and a self-drilling screw that always perform a function for discharging chips as a guide groove without being blocked by means.

  Furthermore, the present invention provides a drill and a self-drilling screw with various new technical configurations for improving the chip discharging function by the guide groove and improving the centering of the drill during drilling. is there.

  Therefore, when the drill of the present invention is configured as means, it is formed at the tip of the shank continuous from the blade means and the blade means made of a high hardness tip fixed to the tip of the shank via the fixing means. In the drill means comprising the groove means, the fixing means includes a holding groove located on the diameter line of the tip of the shank and extending in the axial direction from the tip surface of the shank, and the blade means includes the A substrate portion inserted and held in the holding groove; and a mountain-shaped blade portion extending from the substrate portion and projecting from the front end surface of the shank; and a cutting blade is formed at the mountain-shaped edge of the blade portion. The maximum diameter D1 that defines the rotation trajectory of the blade means and the maximum diameter D2 of the tip of the shank having the groove means are formed so that D1 ≧ D2, and the groove means Spiral along the direction of rotation The guide groove has an opening end that extends and opens at the front end surface of the shank. By arranging at least three guide grooves at equal intervals in the circumferential direction of the shank, at least one guide groove opening is formed. The point is that the end is not blocked by the blade means.

  In the embodiment of the present invention, the opening end of the guide groove constituting the groove means forms a guide taper surface inclined toward the axial direction of the shank with respect to the front end surface of the shank.

  Further, the three or more guide grooves constituting the groove means are formed by rolling the tip portion of the shank with a rolling die, and the lead angle of the guide groove is set to 35 to 65 degrees.

  The guide groove constituting the groove means forms a spiral rib between adjacent guide grooves and forms a flat guide rib surface on the top of the spiral rib.

  Further, the blade means forms side blades on both side edges of the substrate portion, and the side blades are exposed through the guide grooves.

  The self-drilling screw of the present invention is configured as a means in which a drill having the above-described features is formed at the tip of the shank, and screw means having a thread is formed at the subsequent portion of the shank. It is in.

  In the embodiment of the present invention, the maximum diameter D1 that defines the rotation trajectory of the blade means, the maximum diameter D2 of the tip of the shank having the groove means, the crest diameter D3 and the trough diameter D4 of the screw means are D1 ≧ D2 and It is formed so that D3> D1> D4.

  In a further embodiment, the screw means constitutes a double thread having a large-diameter thread and a small-diameter thread, a maximum diameter D1 that defines the rotation trajectory of the blade means, and the tip of the shank having the groove means Are formed such that D3> D1 ≧ D2 ≧ D5. The maximum diameter D2, the crest diameter D3 of the large-diameter screw, and the crest diameter D5 of the small-diameter screw are formed.

  According to the drill of the present invention, a drill comprising a blade means made of a high-hardness tip fixed to the tip end of the shank via a fixing means, and a groove means formed at the tip of the shank continuous from the blade means. The maximum diameter D1 that defines the rotation trajectory of the blade means that forms the cutting edge at the edge of the mountain shape and the maximum diameter D2 of the tip of the shank having the groove means are such that D1 ≧ D2. Because it is formed, the shank is not expensive tool steel like conventional drill tools, but can be formed with wire rods for screws such as carbon steel wires and stainless steel wires, and other wire rods. Can be provided. And since the blade means is formed of a high-hardness tip, it is sharp when drilling and ensures wear resistance.

  Further, according to the present invention, the groove means formed at the tip of the shank is constituted by a guide groove having an open end that extends spirally along the direction of rotation of the shank and opens at the tip of the shank. Accordingly, the powdered chips generated when drilling the inorganic workpiece are suitably guided from the cutting blade to the guide groove and discharged, so that, for example, a relatively low output such as a rechargeable electric screwdriver is used. A rotary tool can be used, and a drill that can be easily used can be provided. Since the relationship between the maximum diameter D1 that defines the rotation trajectory of the blade means that forms the cutting blade and the maximum diameter D2 of the tip of the shank having the groove means is formed as D1 ≧ D2, drilling in the inorganic workpiece is performed. Inside, the chip discharging function is not lost due to wear of the groove means at the tip of the shank.

  In particular, according to the present invention, since at least three guide grooves having open ends on the front end face of the shank are arranged at equal intervals in the circumferential direction of the shank, the holding groove for attaching the blade means is formed in the shank. As long as the holding groove is located on the diameter line of the shank, the holding groove may be formed from any direction. That is, even if the holding groove is not formed in any position relative to the guide groove, after the blade means is attached to the holding groove, the opening end of at least one guide groove is always closed by the blade means. Since it opens to the cutting blade from the front end surface of the shank, the chip discharging function by the guide groove can always be suitably performed. For this reason, the shank made of screw wire and the blade means made of high hardness tip are formed in separate processes, and the blade means is attached to the tip of the shank. A product that is simple and easy and always guarantees a predetermined function of the guide groove can be provided.

  In addition, as described in claim 2, a guide taper surface which is located at the opening end of the guide groove constituting the groove means and is inclined toward the axial direction of the shank with respect to the front end surface of the shank is formed. According to the above, during drilling of the drill, the chips generated by cutting of the cutting blade can be suitably guided from the front end surface of the shank to the guide groove through the guide taper surface, so drilling due to good chip discharge function Improve performance.

Further, according to the third aspect of the present invention, according to the configuration in which three or more guide grooves constituting the groove means are rolled with a rolling die at the tip end portion of the shank, production by die wear like a conventional pinching die is performed. There is no problem of sex, and mass production is easy. Then, as a result of rolling with a rolling die, the guide groove is extended so as to be smoothly continuous, and the lead angle of the guide groove is greatly inclined so as to approach the shank axis as 35 to 65 degrees. In addition, since all the guide grooves can be opened at the front end surface of the shank, an excellent chip discharging function by the guide grooves as described above can be achieved.
The purpose and effect can be suitably achieved.

  And by designing the rolling die into a predetermined shape, as described in claim 4, according to the configuration in which a flat guide rib surface is formed at the top of the spiral rib formed between adjacent guide grooves. When the drill enters the workpiece during drilling, the tip of the shank extends along the axial center of the hole cut by the blade means while rotating with the guide rib surface approaching the inner peripheral surface of the hole. Since it guides, good centering is enabled.

  Furthermore, as described in claim 5, according to the configuration in which the side blades formed on both side edges of the substrate portion of the blade means are exposed through the guide grooves, the inorganic workpiece can be drilled extremely well. . That is, the drill means starts drilling with the cutting blade of the chevron-shaped blade portion, but due to the nature of the inorganic workpiece, the chips of the chips cut while collapsing do not always have a certain particle size. Accordingly, small-sized powdery particles are discharged through the guide groove from the opening end of the guide groove that opens to the front end surface of the shank. However, relatively large-diameter particles do not easily pass through the guide groove and are hardened. There is a fear that this causes a problem of increasing the rotational resistance of the shank. In addition, since it rotates and rubs against chips that do not easily pass through the guide groove, the guide groove at the tip of the shank may wear during entry of the inorganic workpiece, and the function as the guide groove may be lost. . In this regard, according to the present invention, such relatively large-sized particles are crushed by the side blades following the cutting blades, and the side blades face the guide grooves. The particles are preferably discharged through the guide groove.

  And according to this invention, the self drill screw provided with the above excellent drills is provided.

  That is, according to the self-drilling screw of the present invention, the effect of the drill described above can be exhibited at the time of drilling, and in particular, a screw capable of suitably attaching a member to be attached to an inorganic workpiece can be provided. For example, with regard to home renovation, recently, a method of covering a mortar wall with a decorative board such as siding has become widespread, and as a pretreatment operation for attaching a decorative board, a wooden trunk edge can be attached to the mortar wall with a self-drilling screw. However, in such a situation, the self-drilling screw of the present invention can be preferably used. In this regard, as described above, the self-drilling screw in which the drill means is formed by the conventional pinching die wears the cutting blade early during the approach to the mortar wall, resulting in a state in which the screw cannot be screwed during the approach, It can no longer move in either direction of retraction, making it a complaint for contractors. On the other hand, according to the self-drilling screw of the present invention, such a problem does not occur, and a good sharpness is ensured by a cutting blade having high wear resistance. Screw on the aggregate. In particular, powdered chips generated during drilling of the mortar wall are preferably discharged by the guide groove at the shank tip, so that they do not receive great resistance from the chips, such as a rechargeable electric screwdriver. The intended purpose is achieved with such a low power tool.

  At this time, as described in claim 7, the maximum diameter D1 that defines the rotation trajectory of the blade means, the maximum diameter D2 of the tip of the shank having the groove means, and the crest diameter D3 and the trough diameter D4 of the screw means. According to the configuration formed so that D1 ≧ D2 and D3> D1> D4, as a result of the configuration according to D1 ≧ D2, chipping is caused by wear of the groove means at the tip of the shank during drilling of the inorganic workpiece. The discharging function is not lost, and as a result of the configuration according to D3> D1> D4, the screw means is screwed on the inner peripheral surface of the perforation formed by the drill means while suitably tapping, Enables screw fastening force.

  By the way, although depending on the material of the inorganic workpiece, when the screw means is screwed while tapping the inner peripheral surface of the hole formed by the drill means, the thread of the screw means is worn. As shown in FIG. 8, the screw means is constituted by a double thread consisting of a large-diameter thread and a small-diameter thread, the maximum diameter D1 that defines the rotation trajectory of the blade part, and the maximum of the tip of the shank having the groove means The diameter D2, the crest diameter D3 of the large diameter thread, and the crest diameter D5 of the small diameter thread can be formed such that D3> D1 ≧ D2 ≧ D5. According to such a configuration, the screw thread of the large-diameter screw may be worn when the screw means is screwed through the perforation formed in the inorganic workpiece by the drill means. Does not wear. Therefore, when the thread means reaches the wooden aggregate after passing through the inorganic workpiece, in addition to the worn large diameter thread, the worn small diameter thread can exhibit a necessary and sufficient fastening force. it can. That is, when the wood aggregate is reached, a drill hole having a diameter D1 is formed in the aggregate by a drilling means, and a small diameter screw having a mountain diameter D5 enters the drill hole, and theoretically D1 ≧ D5. Although there is no fastening force on the thread of the small-diameter thread, the wooden aggregate actually has a contraction force (spring back) due to the fiber, and the thread is sharpened without being worn. Necessary and sufficient holding force can be given by the small-diameter screw.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

(One embodiment of self-drilling screw)
1 to 6 show an embodiment of a self-drilling screw according to the present invention. The self-drilling screw 1 is based on a shank blank material 3 formed with a head 2 as shown in FIG. As shown in FIG. 1 (B), a screw body 8 in which a fixing means 5 and a groove means 6 are formed at the tip portion 4a of the shank 4 and a screw means 7 having a thread is formed at the subsequent portion 4b of the shank 4 is formed. It is formed. Thereafter, as shown in FIGS. 1C and 1D, the drill means 10 is formed by fixing the blade means 9 to the fixing means 5. The shank blank 3 is formed of Fe wire, carbon steel wire, SUS410 or other stainless steel wire as a screw wire, and the blade means 9 is made of a cemented carbide tip made of a sintered alloy of tungsten carbide or powder high speed. It is formed of a high hardness chip, a high hardness chip made of ceramic, or a high hardness chip based on other high hardness materials. Moreover, the shank blank material 3 forms a tapered surface 3a chamfered at the tip.

  When the screw body 8 is formed based on the shank blank material 3, the screw means 7 is rolled by a rolling die as in the conventional case. Further, the groove means 6 is rolled by a rolling die, not a pinching forging by a pinching die as is carried out for a conventional self-drilling screw. The fixing means 5 is provided by forming a holding groove 11 extending in the axial direction from the tip surface with the tip portion 4a of the shank 4 positioned on the diameter line. In the case of the illustrated example, the front end 4 a of the shank 4 is divided in half by the holding groove 11. Further, in the case of the illustrated embodiment, a pair of thin blade-like reamers 9 a are formed between the groove means 6 and the screw means 7 and opposed to the peripheral surface of the tip portion 4 a of the shank 4. The holding groove 11 is formed after rolling the groove means 6.

  As shown in FIG. 2, the groove means 6 includes at least three or more guide grooves 12 a, 12 b that extend spirally along the rotational direction of the shank 4 (in the case of the example, six as shown in FIG. 3). The guide grooves 12 are arranged at equal intervals in the circumferential direction of the shank, and the open ends 13 of the three or more guide grooves 12 are opened on the front end surface 4c of the shank. The guide groove 12 is extended so as to be smoothly continuous by rolling the tip of the shank with a rolling die, and the lead angle θ1 of the guide groove 12 is set to 35 to 35 as shown in FIG. It is formed at 65 degrees, preferably 40 to 55 degrees, more preferably 45 degrees. This lead angle θ1 is an important condition for favorably discharging chips generated during drilling of an inorganic workpiece by the drill means 10 through the guide groove 12, and includes two movements due to rotation of the shank and advance in the thrust direction. On the other hand, it is set so that the chips generated by the blade means 10 can flow through the groove means 6. According to experiments, if the lead angle θ1 of the guide groove 12 is 35 degrees or more, there is no possibility of clogging by chips, and if it is 40 degrees or more, the flow of chips along the guide groove 12 becomes good. As for the discharge function by good flow of chips, 45 degrees is the best mode. However, if the lead angle θ1 exceeds 65 degrees, it becomes difficult for the chips to flow in the guide groove 12 following the rotation of the shank, and it is difficult to roll the guide groove 12 with a rolling die.

  The screw means 7 is composed of a double thread consisting of a large-diameter thread 14 and a small-diameter thread 15, and notches 16 are formed at equal intervals in the threads of both the threads 14, 15. . The lead angle of the threads 14 and 15 is the same as the lead angle of the threads in the conventional screw. In the illustrated embodiment, the lead angles of the threads 14 and 15 are as shown in FIG. The angle θ2 is 10 to 20 degrees.

  The blade means 9 is formed by the high hardness tip 17 as described above, and is inserted and held in the holding groove 11 of the fixing means 5, and extends from the substrate part 18 than the front end face 4 c of the shank 4. The cutting blade 20 is formed on the edge of the mountain shape of the blade portion 19, and the side blades 21 are formed on both side edges of the substrate portion 18. Each of the cutting blade 20 and the side blade 21 forms a knife edge that is secondly taken from the blade edge, and as shown in FIG. A maximum diameter D1 that defines nine rotation trajectories is formed.

  Therefore, as shown in FIGS. 2A and 2B, the maximum diameter D2 of the tip 4a of the shank 4 having the groove means 6, the peak diameter D3 of the large-diameter thread 14, the valley diameter D4, and the small diameter The crest diameter D5 of the screw thread 15 and the diameter D6 defined by the rotation locus of the reamer 9a are formed such that D6> D3 ≧ D1 ≧ D2 ≧ D5> D4.

  The relationship among the fixing means 5, the groove means 6 and the blade means 9 at the tip 4a of the shank 4 is shown in FIG. As shown in FIG. 3A, the tip 4a of the shank 4 is formed with groove means 6 by a rolling die, and the groove means 6 has at least three guide grooves arranged at equal intervals in the circumferential direction. 12a, 12b, 12c... 12n, and the open ends 13 of these guide grooves 12 are opened to the tip end surface 4c of the shank 4. The guide groove 12 is formed in an arc shape in cross section.

  And the spiral rib 6a is formed between the adjacent guide grooves 12 and 12, and the flat guide rib surface 6b is formed in the top part of each spiral rib 6a. Such a cross-sectional shape of the guide groove 12 and the guide rib surface 6b of the spiral rib are formed according to the shape of the rolling die.

  As described above, a tapered surface 3a by chamfering is formed in advance at the tip of the shank blank material 3, and a guide groove 12 is formed at the tip of the shank including the tapered surface 3a by rolling a rolling die. That is, as shown in FIG. 4 (A), the guide groove 12 is formed by rolling the shank blank material 3 having the tapered surface 3a formed at the tip, so as shown in FIG. The formed open end 13 of each guide groove 12 forms a guide taper surface 13a that inclines in the axial direction of the shank with respect to the tip surface 4c of the shank.

  As shown in FIG. 3B, the tip 4a of the shank in which the groove means 6 is formed by rolling is formed by cutting the fixing means 5 with a cutting device, and the fixing means 5 is the tip 4a of the shank 4. Is formed by a holding groove 11 that extends in the axial direction from the distal end surface 4c. As described above, the blade means 9 composed of the high hardness chip 17 includes the substrate portion 18 and the mountain-shaped blade portion 19, and forms the cutting blade 20 at the mountain-shaped edge portion of the blade portion 19, and the substrate portion 18. Side blades 21 are formed on both side edges.

  Therefore, as shown in FIG. 3C, the high hardness tip 17 constituting the blade means 9 is inserted and held in the holding groove 11 and fixed by brazing, welding or the like. At this time, the tip (vertex) of the mountain-shaped cutting blade 20 is positioned on the central axis of the shank 4. Thereby, the cutting blade 20 protrudes from the front end surface 4 c of the shank 4 together with the blade portion 19, and the side blade 21 of the substrate portion 18 faces one of the guide grooves 12 and is exposed through the guide groove 12.

  The self-drilling screw provided with the drill having the above-described configuration, when the drill means 10 is made to enter the inorganic workpiece W while rotating, as shown in FIG. The chips generated at this time suitably flow along the guide groove 12 and are discharged toward the subsequent portion 4b of the shank. That is, the chips generated by cutting with the cutting blade 20 easily enter the opening end 13 and flow along the guide groove 12 by being guided by the guide taper surface 13a that opens to the tip end surface 4c of the shank. The chips are caused to flow by the guide groove 12 in a state of being filled between the guide groove 12 and the inner peripheral wall of the hole H, and the spiral rib 6a rotates while approaching the inner peripheral wall of the hole H. When the top of the spiral rib 6a is formed thin and sharp like a screw thread, it wears early due to the friction of chips, but the spiral rib 6a is relatively relatively flat so that it has a flat guide rib surface 6b. Since it is formed thick, it is not easily worn away, and the flat guide rib surface 6b rotates in a state of facing the inner peripheral wall of the hole H, contributing to the centering of the shank. When the subsequent screw means 7 enters the hole H, the screw means 7 advances while being tapped with a screw (large-diameter screw 14 in the illustrated example).

  In order to explain the relationship between the guide groove 12 and the holding groove 11, which is one of the features of the present invention, FIG. 5A shows a cross section of the tip 4 a of the shank 4 before the blade means 9 is attached to the holding groove 11. FIG. 5B shows a cross section of the tip 4a of the shank 4 after the blade means 9 is attached to the holding groove 11. FIG. As can be understood from the figure, the present invention has at least three guide grooves 12 having open ends 13 on the front end surface 4c of the shank 4 and are arranged at equal intervals in the circumferential direction of the shank 4. When the holding groove 11 for attaching the means 9 is formed in the tip end portion 4a of the shank 4, as long as it is positioned on the diameter line XX of the shank 4, the holding groove 11 is held from any direction regardless of the position of the guide groove 12. Even if the groove 11 is formed, the opening end 13 of at least one or more guide grooves 12 (in the illustrated case, the guide grooves 12b, 12c, 12e, and 12f) is opened to the tip surface 4c of the shank 4. In other words, the holding groove 11 may be formed on a diameter line that is determined at random in the circumferential direction. For example, even when the holding groove 11 is formed on the diameter line X1-X1 as shown in the figure, Open ends 13 of one or more guide grooves 12 (in this case, guide grooves 12 a, 12 b, 12 d, 12 e) open to the front end surface 4 c of the shank 4. Therefore, in the state in which the blade means 9 is attached to the holding groove 11, at least one guide groove 12 does not have its opening end 13 blocked by the blade means 9, and the cutting blade 20 extends from the front end surface 4 c of the shank 4. Open to face.

  5A and 5B show an example in which six guide grooves 12 constituting the groove means 6 are provided. The feature of the present invention in this respect is that at least three guide grooves 12 are provided. This is achieved by providing. 5C and 5D show an example in which three guide grooves 12 (guide grooves 12a, 12b, and 12c) are provided, and the holding grooves 11 are formed at random on the diameter line of the shank 4. FIG. At this time, as shown in FIG. 5C, when the holding groove 11 is formed on the diameter line XX of the shank 4, the opening end 13 of the guide groove 12 c is formed on the tip surface 4 c of the shank 4. Open and not blocked by the blade means 9. On the other hand, when the holding groove 11 is formed on the diameter line X <b> 1-X <b> 1 of the shank 4, the opening ends 13 of the guide grooves 12 a and 12 b open to the tip surface 4 c of the shank 4. As shown in the figure, a small part of the holding groove 11 overlaps with the opening ends 13 of the guide grooves 12a and 12b, and only a small part is blocked by the blade means 9, but most of the opening ends 13 of the guide grooves 12a and 12b. Is open, the chip discharge function can be achieved from the opening end 13 through the guide grooves 12a and 12b. In this way, in the present invention, the meaning that the opening end 13 of at least one guide groove 12 opens to the front end surface 4c means that most of the opening end 13 is completely opened, as well as the case where the opening end 13 is completely opened. It should be understood that the meaning includes a case where it is understood that the opening is substantially open.

  In order to clarify the feature of this point of the present invention, comparative examples are shown in FIGS. In this comparative example, two guide grooves 12 g and 12 h facing the peripheral surface of the tip of the shank 4 are formed and opened at the tip of the shank 4. Therefore, when the holding groove 11 is formed on the diameter line XX as shown in FIG. 5 (E), the holding groove 11 overlaps the main part of the guide grooves 12g and 12h, and the holding groove 11 It is blocked by the blade means 9 to be attached. Therefore, only when the holding groove 11 is formed on the diameter line X1-X1 as shown in FIG. 5 (F), the holding groove 11 does not overlap the guide grooves 12g and 12h, and is blocked by the blade means 9. However, in the case of the comparative example as described above, when the holding groove 11 is formed at the tip of the shank 4, it must be positioned so as to be on the diameter line X1-X1. Work is required, the work becomes extremely complicated, and is not suitable for mass production.

(Self-drilling screw usage example)
FIG. 6 shows an example of use when the self-drilling screw 1 according to the embodiment of the present invention is implemented as a house remodeling screw, and a mortar wall 23 is provided outside an aggregate 22 such as a wooden pillar or rafter. Is formed. When renovation is performed to cover the mortar wall 23 with a decorative board (not shown) such as siding, a wooden trunk edge 24 is fixed to the mortar wall 23, and the self-drill screw 1 is used to fix the trunk edge 24. Is used.

  When the blade means 9 of the self-drilling screw 1 stands on the barrel edge 24 and the head 2 of the screw 1 is driven and rotated by a driving rotary tool such as an electric screwdriver, a drill is performed while drilling the barrel edge 24 by the cutting blade 20 of the blade portion 19. Means 10 penetrate the barrel edge 24. When the drill means 10 reaches the mortar wall 23, it drills by cutting the mortar wall 23 with the cutting blade 20. At this time, the powdered chips cut by the cutting blade 20 are guided to the guide groove 12 and discharged from the opening end 13 opened in the front end surface 4 c of the shank 4. The perforation is first formed by cutting with the cutting blade 20, and then the inner peripheral surface of the perforation is rubbed or cut by the side blade 21. Therefore, the chips having a large particle diameter generated by the cutting of the cutting blade 20 are crushed by the side blade 21 and guided to the guide groove 12 facing the side blade 21 and discharged. The operation at this point is as described above.

  When the drill means 10 penetrates the body edge 24, the tip part 4a of the shank 4 following the drill means 10 is provided with a reamer 9a, so that the perforation formed by the drill means 10 is enlarged by the reamer 9a, As a result, a large-diameter hole 25 as shown in FIG. Since the reamer 9 a is formed in a thin blade shape, the reamer 9 a is broken as soon as it reaches the mortar wall 23, and is separated from the tip 4 a of the shank 4. A large-diameter hole 25 is formed in the trunk edge 24 by the reamer 9a, and the inner diameter of the large-diameter hole 25 is formed larger than the crest diameter D3 of the screw 14 of the screw means 7. When penetrating the edge 24, the trunk edge 24 does not lift from the mortar wall 23 due to the rotation of the thread.

  Further, after the drill means 10 penetrates the mortar wall 23, the drill means 10 is entered while drilling the aggregate 22, and then the screw means 7 is screwed into the aggregate 22, as shown in FIG. 6 (B). With the portion 2 being substantially flush with the body edge 24, the driving rotation of the self-drilling screw 1 is finished. When the screw means 7 penetrates the mortar wall 23, the screw means 7 is screwed while tapping the inner peripheral surface of the drill hole formed by the drill means 10, and at this time, a peak larger than the maximum diameter D1 of the blade means 9 is reached. The thread of the large-diameter thread 14 having the diameter D3 is worn, but the thread of the small-diameter thread 15 having the diameter D5 smaller than the maximum diameter D1 of the blade means 9 is not worn. Accordingly, when the screw means 7 penetrates the mortar wall 23 and reaches the wooden aggregate 22, the screw means 7 exerts a fastening force on the aggregate 22 by both the worn large-diameter screw 14 and the non-wearing small-diameter screw 15. Arise. The operation at this point is as described above.

(Other embodiment of self-drilling screw)
FIG. 7 shows another embodiment of the self-drilling screw 1 according to the present invention. Since the structure of the drill means 10 provided in the front-end | tip part 4a of the shank 4 is the same as that of the drill means 10 demonstrated about the said embodiment, the above-mentioned description is used. In the embodiment shown in FIG. 7, the screw means 7 provided in the rear portion 4b of the shank 4 is formed as a single thread having a single thread 14a. Moreover, it has the head 2a made into the pot head at the tail end.

  In this embodiment provided with a single thread, the maximum diameter D1 that defines the rotation trajectory of the blade means 10, the maximum diameter D2 of the tip 4a of the shank having the groove means 6, and the crest of the thread 14a in the screw means 7 The diameter D3 and the valley diameter D4 are formed so that D1 ≧ D2 and D3> D1> D4.

(Drill embodiment)
FIG. 8 shows an embodiment of a drill according to the present invention, and illustrates a drill tool 26 as a drill bit.

  In the drill tool 26, the fixing means 5 and the groove means 6 are formed at the tip portion 4 a of the shank 4, and the tool mounting portion 28 is formed at the subsequent portion 4 b of the shank 4, and the blade means 9 is fixed to the fixing means 5. Thereby, the drill means 10 is comprised. The shank 4 is formed of a screw wire such as Fe wire, carbon steel wire, stainless steel wire, or other wire material, and the blade means 9 is formed of a high hardness tip. Since the specific configurations of the fixing means 5, the groove means 6, and the blade means 9 are the same as those described above for the self-drilling screw, the above description is incorporated.

1 shows one embodiment of a self-drilling screw according to the present invention, (A) is a front view showing a shank blank material, (B) is a front view showing a screw body formed based on the shank blank material, and (C) is a front view. The front view of the self-drilling screw which fixed the blade means to the screw body, (D) is a side view of the self-drilling screw. The enlarged view of one Embodiment of the self-drilling screw which concerns on this invention is shown, (A) is a side view, (B) is a front view. The relationship between the fixing means, the groove means and the blade means at the tip of the shank with respect to the drill means according to the present invention is shown, (A) is a perspective view showing the tip of the shank in which a guide groove is formed, and (B) is a guide. The perspective view which shows the front-end | tip part and blade means of the shank which formed the holding groove in addition to the groove | channel, (C) is a perspective view which shows the front-end | tip part of the shank in the state which fixed the blade means to the holding groove. The principal part of one Embodiment of the self-drilling screw which concerns on this invention is shown partially, (A) is a side view which shows a shank blank material partially, (B) shows a drill means and a screw means partially. Side view (C) is a side view partially showing the action of the drill means and screw means. The relationship between a guide groove, a holding groove, and a blade means is shown, (A) and (B) are sectional views showing the relationship in one embodiment of the self-drilling screw concerning the present invention, and (C) and (D) are three guide grooves. Sectional drawing which shows the relationship in embodiment made into a strip | line, (E) (F) is sectional drawing which shows the relationship in the comparative example which made two guide grooves. The usage example of the self-drilling screw which concerns on this invention is shown, (A) is explanatory drawing which shows the state in which the self-drilling screw is screwing, (B) is explanatory drawing which shows the fastening state of a self-drilling screw. It is a side view which shows other embodiment of the self-drilling screw which concerns on this invention. It is a side view showing a drill tool as an embodiment of a drill concerning the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Self-drill screw 4 Shank 4a Tip part 4b Trailing part 4c Tip surface 5 Adhering means 6 Groove means 6a Spiral rib 6b Guide rib surface 7 Screw means 8 Screw body 9 Blade means 10 Drill means 11 Holding groove 12 Guide groove 13 Open end 13a Guide Tapered surface 14 Large-diameter thread 15 Small-diameter thread 14a Screw 17 High-hardness tip 18 Substrate part 19 Blade part 20 Cutting blade 21 Side blade 26 Drill tool

Claims (8)

In what constitutes a drill means comprising a blade means made of a high hardness tip fixed to the tip of the shank via a fixing means, and a groove means formed in the tip of the shank continuous from the blade means,
The fixing means includes a holding groove that is positioned on the diameter line of the tip portion of the shank and extends in the axial direction from the tip surface of the shank;
The blade means includes a substrate portion that is inserted and held in the holding groove, and a mountain-shaped blade portion that extends from the substrate portion and protrudes beyond the tip end surface of the shank, and a mountain-shaped edge portion of the blade portion A cutting blade is formed, and a maximum diameter D1 that defines the rotation trajectory of the blade means and a maximum diameter D2 of the tip of the shank having the groove means are formed so that D1 ≧ D2.
The groove means is formed of a guide groove that extends spirally along the direction of rotation of the shank and has an open end that opens to the front end surface of the shank. At least three guide grooves are provided in the circumferential direction of the shank. A drill characterized in that the opening end of at least one guide groove is not blocked by the blade means by being arranged at intervals. The drill according to claim 1, wherein the opening end of the guide groove constituting the groove means forms a guide taper surface inclined toward the axial direction of the shank with respect to the front end surface of the shank. The three or more guide grooves constituting the groove means are formed by rolling the tip of the shank with a rolling die, and the lead angle of the guide groove is configured to be 35 to 65 degrees. The drill according to claim 1 or 2. The guide groove constituting the groove means comprises a spiral rib between adjacent guide grooves, and a flat guide rib surface is formed on the top of the spiral rib. Or the drill of 3. The drill according to claim 1, 2, 3, or 4, wherein the blade means has side blades formed on both side edges of the substrate portion, and the side blades are exposed through a guide groove. 6. A self-drilling screw comprising: the drill according to claim 1, 2, 3, 4 or 5 formed at a tip portion of a shank; and screw means having a thread at a rear portion of the shank. The maximum diameter D1 that defines the rotation trajectory of the blade means, the maximum diameter D2 of the tip of the shank having the groove means, and the crest diameter D3 and valley diameter D4 of the screw means are D1 ≧ D2 and D3> D1> D4. The self-drilling screw according to claim 6, wherein the self-drilling screw is formed as described above. The screw means comprises a double thread having a large-diameter thread and a small-diameter thread, a maximum diameter D1 that defines the rotation trajectory of the blade means, a maximum diameter D2 of the tip of the shank having the groove means, and a large diameter 7. The self-drilling screw according to claim 6, wherein the thread crest diameter D3 and the crest diameter D5 of the small diameter thread are formed such that D3> D1 ≧ D2 ≧ D5.

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