JP2007064412A - Insert nut and work piece fastening structure using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insert nut which enables the fastening of two or more comparatively soft work pieces by combining with a screw member. <P>SOLUTION: The insert nut consists of an axial part 3 and a head 2 bigger than this, a prepared hole part 11 for making a female screw is formed in the top of the axial part 3 and a hollow hole part 12 having a diameter larger than the diameter of the prepared hole part 11 for making the female screw is formed in the part ranging from this to the head 2 to constitute a stepped hollow hole 10 consisting of the prepared hole part 11 for making the female screw and the hollow hole part 12. The hollow hole part 12 is caulked by screwing a screw member 20 while forming the female nut in the prepared hole part 11 for the female screw, and therefore, work efficiency is enhanced. Moreover, there is no loosening of tightening even if the time passes as the caulking part is in the condition where the caulking part is constantly raised to a head side. Furthermore, the female screw is not required to be formed in advance since it is formed by the screw member. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fastening part and a fastening structure for fastening a plurality of plate-like workpieces with a screw member and a nut screwed to the screw member, and in particular, an insert nut that enables fastening work from one direction. And a work fastening structure using the insert nut.

  Generally, when multiple workpieces are fastened, the screw member is directly screwed onto the workpiece and fastened, or a through hole is made in the workpiece, the screw member is inserted into the through hole, and the nut is inserted into the leg of the screw member from the other side. The members are screwed together, and the workpiece is sandwiched and fastened by the screw member and the nut member. In these fastening operations, in the operation of screwing the screw member into one workpiece and fixing the other workpiece, the workpiece to which the screw member is screwed must have a predetermined fastening strength because it is necessary to form a female screw. Therefore, a thickness greater than a certain level is required to screw the screw member, and if the workpiece is thin, the female screw is crushed, and the fastening with the screw member is insufficient, and the fastening strength is insufficient. .

  In addition, when fastening with a screw member and a nut member sandwiching each other's work, it is necessary to work from both sides of the work, so if there is no predetermined space on both sides, the fastening work by the screw member and the nut member There is a problem that cannot be done. In particular, recently, products have been downsized, parts used for the products have become thinner, and the fastening work of these products has become complicated.

  A fastening structure that is being used in recent years in view of the current situation is, for example, a fixing structure using a blind nut disclosed in JP-A-4-15309. This is mainly used for screwing parts to the frame of a motorcycle, and this blind nut is a nut member fixed to the back of a plate-like member. In addition, there is a caulking type that can be fixed from the outside. An improvement of such a fixing structure is shown in FIGS. This relates to a blind nut, and is a cylindrical female screw body having a head 102, and a blind nut material 101 having a thin-walled portion 112 whose inner diameter is cut off at the neck is used. The portion of the female screw 111 is inserted in the head direction by using a screw tool (not shown) screwed into the female screw 111 while being inserted into the pilot hole 106 of the member 105 and pressing the back surface of the head to the surface of the plate member 105. As a result, the thin-walled portion 112 bulges outwardly to form a caulking portion 113, and the plate-like member 105 is clamped and fixed between the caulking portion 113 and the head portion 102. It is a blind nut. Then, the pilot hole 106 of the plate-like member 105 is formed in a countersink that extends to the outer surface, while at least one bulging portion 125 that fills the inner peripheral root portion is formed on the back surface of the head of the blind nut material 101, The bulging portion 125 is configured to have a mountain shape in which the bulging amount gradually decreases in the circumferential direction on both sides around the top portion having a size matching the inclined surface of the countersink.

JP-A-4-15309

  However, in such a blind nut, a screw tool is screwed into a pre-formed female screw, and the female screw part is pulled up to the head side to form a caulked part, and then the screw is used to fix the work to this. With this blind nut, multiple workpieces cannot be clamped and fixed.For example, even if the workpiece can be clamped and fixed with this blind nut, the caulked portion will pass over time. If it returns even a little, there may be a gap between the workpieces and loosening may occur. Further, since this blind nut has a female screw formed in advance, it requires a large number of manufacturing steps and is expensive. Furthermore, in order to prevent rotation when the screw is screwed into the blind nut, a bulging portion is provided at the inner peripheral root portion of the rear surface of the head of the blind nut so as to sandwich the countersunk hole of the workpiece. Therefore, it is necessary to form a countersink in the prepared hole of the workpiece. In addition, since the bulging portion is required to be formed at the base portion of the back surface of the head as described above, there is a problem that a mold used when manufacturing the bulging portion by forging is complicated.

  A first object of the present invention is to obtain an insert nut that solves such problems and enables a plurality of relatively soft workpieces to be fastened by combination with a screw member. The object is to obtain a workpiece fastening structure using an insert nut that quickly fixes each other's workpieces with a simple configuration and enables all fastening operations from one side even when there is almost no space on the back surface.

  A first object of the present invention is composed of a shaft portion 3 and a head portion 2 having a larger outer peripheral shape than the shaft portion 3, and a female screw forming pilot hole portion 11 is formed at the tip of the shaft portion 3. A hollow hole portion 12 having a diameter larger than the diameter of the female screw forming pilot hole portion 11 is provided from the forming pilot hole portion 11 to the head 2, and a stepped hollow hole is formed from the female screw forming pilot hole portion 11 and the hollow hole portion 12. The insert nut 1 is formed with a screw member 20 inserted from the head side of the hollow hole portion 12, and the screw member 20 is screwed into the female screw forming pilot hole portion 11 while forming the female screw. This is achieved by providing an insert nut in which the hollow surface 12 is compressed and caulked by the seating surface 24 of the member 20 contacting the top surface of the head 2.

  In addition to this configuration, the outer periphery of the head has a rectangular or elliptical shape. The head is engaged with the engagement hole 7 of the workpiece 5 and the screw member 20 is screwed into the female screw forming pilot hole 11. By setting the insert nut so that it does not rotate when it is done, the idling action between the work and the insert nut is eliminated, and the work can be firmly fastened.

  Further, in addition to these configurations, the shaft portion is an insert nut having a plurality of thin-walled strips along the axial direction at equal intervals in the circumferential direction at the caulking position of the hollow hole portion 12, so that bulging by caulking Becomes even.

  The second object of the present invention is to form an insertion hole 6 into which a shaft portion 3 of the insert nut 1 can be inserted into a plurality of plate-like workpieces 5 fastened to each other. An engagement hole 7 in which the head 2 is engageably fitted is formed in the workpiece 5, while the insert nut 1 is longer than the interval (T) between the front surface and the back surface of the workpiece 5 to be fastened. 3 and a head 2 having a larger outer peripheral shape. A female screw forming pilot hole 11 is formed at the tip of the shaft 3, and the female screw forming pilot hole 11 extends from the female screw forming pilot hole 11 to the head 2. A hollow hole 12 having a diameter larger than the diameter of the pilot hole 11 is provided, and a stepped hollow hole 10 is formed from the female screw forming pilot hole 11 and the hollow hole 12, and the head of the insert nut 1 is formed. The screw member 20 is inserted from the side, and the female screw forming pilot hole 11, the screw member 20 is screwed in while forming a female screw, the seat surface 24 of the screw member 20 contacts the top surface of the head 2, and the hollow hole portion 12 is compressed and caulked at the end surface of the work 5. This is achieved by providing a workpiece fastening structure using an insert nut adapted to fasten a plurality of workpieces 5.

  Moreover, in addition to this configuration, at least the shaft 2 of the insert nut is fastened with a part of the hollow hole 12 and the female screw forming pilot hole 11 when at least the head 2 is fitted in the engagement hole 7 of the workpiece 5. By adopting a workpiece fastening structure using an insert nut protruding from the back surface of the workpiece 5, a caulking portion is reliably formed on the back surface of the workpiece.

  According to the present invention, as in the prior art, a screw tool is screwed into a previously formed female screw, the female screw part is pulled up to the head side to form a caulked portion, and then the screw is screwed together. Instead, the work efficiency is improved because the workpiece is directly caulked by the screw member. Also, a female screw forming pilot hole is provided at the tip of the insert nut, and a screw member is screwed into the female nut while forming a female screw therein, so that the workpiece is inserted between the head of the insert nut and the caulked portion of the shaft portion. It is possible to clamp and fasten, and the fastening work cost can be reduced. Further, since the caulking portion is always pulled up to the head side by the screw member, the caulking portion does not return even if time passes and the fastening is not loosened. Moreover, since the screw member is screwed in while forming the female screw in this way, it is not necessary to form the female screw in advance. In addition, since it can be manufactured only by forging, the manufacturing cost of the insert nut can be reduced and can be provided at a low cost. Also, the insert nut's outer periphery is formed in a rectangular or elliptical shape, and the engagement hole of the corresponding shape is formed on the surface of the work so that the head is engaged in the work's engagement hole. After that, if the screw member is screwed in, the insert nut rotates together with the screw member, so-called idling action due to the accompanying rotation does not occur, and firm fastening is ensured. Further, since the thin strip is formed in the axial direction on the shaft portion, when the caulking is performed, the thin strip is uniformly bulged outwardly so as to be torn, so that a predetermined caulking portion without variation is always obtained. In addition, the insert nut is inserted into the insertion hole formed in the workpiece, the screw member is screwed into the hollow hole of the insert nut, and the workpiece is clamped between the head and the caulking portion. It is possible to perform the work from one side, and there is a specific effect that a sufficiently reliable fastening work is possible even if the space on the back surface of the work is narrow.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. In FIGS. 1 and 2, reference numeral 1 denotes an insert nut member, and the nut member 1 is integrally formed from a head portion 2 and a shaft portion 3 having a smaller diameter. The head portion 2 and the shaft portion 3 are formed with a stepped hollow hole 10 penetrating the head portion 2 and the shaft portion 3, and the stepped hollow hole 10 is continuous with a female hole forming pilot hole portion 11 formed on the distal end side of the shaft portion. On the head side, a hollow hole 12 having a diameter larger than that of the female screw forming pilot hole 11 is formed. The diameter of the female screw forming pilot hole portion 11 is set to an effective diameter of the screw member 20 screwed into the female screw forming portion 11 or slightly smaller than the effective diameter, and is formed on the leg portion 21 of the screw member 20. The male screw 22 can be screwed in while forming a female screw.

  The screw member 20 is formed with a male screw 22 up to the middle of the leg portion 21, and a screwless portion 23 having a diameter larger than the diameter of the male screw 22 is formed on the head side. The unthreaded portion 23 has a cylindrical shape along the inner diameter of the hollow hole portion 12 of the insert nut 1. The boundary between the unthreaded portion 23 and the male screw 22 is appropriately set at a predetermined position, thereby being caulked as shown in FIG. The amount of caulking of the part 13 can be set. That is, if this boundary is formed on the distal end side of the leg portion of the screw member 20, the female screw forming pilot hole portion 11 abuts on the distal end of the non-threaded portion 23 during caulking, and the amount of caulking is inevitably reduced. If the boundary is formed on the head side, the amount of caulking can be increased, and the amount of caulking can be adjusted by the position of the boundary between the unthreaded portion 23 and the male screw 22.

  Further, since the unthreaded portion 23 of the screw member 20 has a shape along the hollow hole portion 12 of the insert nut 1, the screw member 20 is guided by this at the time of screwing, and the screw member 20 is inclined. Screwing in is avoided. Of course, the screw member 20 can sufficiently exert the caulking action on the insert nut 1 even when the male screw 22 is formed over the entire length of the leg portion 21. Moreover, as shown in FIG. If the screw portion 23 is made thinner than the diameter of the male screw 22 on the contrary, a part of the meat of the hollow hole portion 12 of the insert nut 1 bulges inward at the time of caulking. Therefore, the screw member 20 is prevented from loosening and coming out of the female screw.

  Furthermore, the outer shape of the head of the insert nut 1 shown in FIG. 1 and FIG. 2 is a rectangular shape larger than the diameter of the shaft portion 3 in this embodiment, but may be a rectangle instead. . That is, the head 2 may have a polygonal shape other than these, a rectangular shape such as a gear shape, or an elliptical shape, and the work 5 and the head 2 are prevented from spinning around the work 5 and causing an idling action. If it is a shape which can be engaged, the shape will not be specifically limited.

  On the other hand, a plurality of plate-like workpieces 5 fastened by the insert nut 1 are formed with insertion holes 6 having a diameter into which the shaft portion 3 of the insert nut 1 can be inserted. The work 5 on the contact side is formed with a bottomed rectangular engagement hole 7 having a shape along the rectangular shape that is the outer shape of the head 2. If the shape of the outer side of the head of the insert nut 1 is changed, the shape of the engagement hole 7 inevitably changes to a shape along the shape of the outer side of the head of the insert nut 1.

  Moreover, the length of the insert nut 1 is longer than the interval (T) between the front and back surfaces of the plurality of workpieces 5 to be fastened in a state where the head 2 is fitted in the engagement hole 7 of the workpiece 5. Particularly, the internal thread forming pilot hole portion 11 of the shaft portion 3 has a size sufficient to protrude from the back surface of the workpiece 5 together with a part of the hollow hole portion 12. Specifically, the length (L) of the insert nut 1 is approximately 1.5 to 3 times the thickness (T) of a plurality of workpieces, and the internal thread forming pilot hole 11 is completely formed. The structure protrudes from the back surface of the work 5.

  When fastening a plurality of workpieces 5 using such an insert nut 1, as shown in FIG. 1, the workpiece 5 having the engagement hole 7 formed on the surface side of the workpiece 5 is formed on the workpiece 5. Insert the insert nut 1 into the insertion hole 6. As a result, the head 2 of the insert nut 1 is fitted into the engagement hole 7 as shown in FIG. 2 and engaged, and then the stepped hollow hole 10 of the insert nut 1 is inserted into the head side as shown in FIG. Then, the screw member 20 is inserted. Thereby, the male screw 22 of the leg portion 21 of the screw member 20 is screwed into the female screw forming pilot hole portion 11 while forming the female screw, and the seat surface 24 of the head portion of the screw member 20 is inserted as shown in FIG. Abutting on the top surface of the head of the nut 1, the internal thread forming pilot hole 11 of the shaft portion 3 of the insert nut 1 is pulled up, so that the shaft portion 3 bulges outward, A caulking portion 13 is formed.

  As a result, the caulking portion 13 comes into contact with the back surface of the work 5, and the plural works 5 are sandwiched between the head 2 of the insert nut 1 and the caulking portion 13 and are fastened without generating a gap. At this time, since the friction force is acting between the insert nut 1 and the screw member 20 screwed into the insert nut 1, it is difficult for loosening to occur.

  5 and 6 show another embodiment of the present invention, which is an insert nut 1 in which a work 5 is fastened so as to form a predetermined space between the work 5. As shown in FIG. 5, the appearance of the shaft portion 3 of the insert nut 1 is a two-stage shape having a large diameter portion 3a and a small diameter portion 3b. Accordingly, as shown in FIG. 6, when the lower workpiece 5 is screwed into the screw member 20 and the small diameter portion 3b is caulked in the same manner as described above, the work 5 is interposed between the large diameter portion 3a and the caulking portion 13. The lower workpiece 5 can be suspended from the upper workpiece 5 at a predetermined interval.

  7 and 8 show another embodiment of the insert nut 1 according to the present invention. The insert nut 1 has a plurality of caulking positions of the shaft portion 3 along the axial direction and at equal intervals in the circumferential direction. A longitudinal groove 4 is formed. As a result, in the caulking operation, when a tensile force is generated in the circumferential direction of the hollow hole portion 12 when the shaft portion 3 is compressed, cracks are easily generated, and this facilitates swelling. This vertical groove 4 is effective when the shaft portion 3 of the insert nut 1 is cylindrical, but the outer periphery of the shaft portion 3 is not shown, but if the hexagon or higher polygonal shape is used, the shaft portion 3 A thin portion is inevitably formed in relation to the cylindrical stepped hollow hole 10, and a thin portion corresponding to the longitudinal groove 4 is obtained. By forming a plurality of such thin grooves made of the vertical grooves 4 or thin portions at equal intervals in the circumferential direction on the shaft portion 3, the caulking portion 13 that bulges outward evenly can be obtained.

  Further, since the periphery of the vertical groove 4 swells from the outer periphery of the shaft portion, it can come into contact with the insertion hole 6 of the workpiece 5, thereby making it possible to temporarily fix the insert nut 1. The insert nut 1 can be temporarily fixed in the same manner as described above by making the polygonal corners so as to contact the insertion hole 6 of the workpiece 5. Thereby, workability | operativity improves. In these embodiments, if an adsorbent that adsorbs and holds the molding powder is applied to the male screw 22 of the screw member 20, it is possible to prevent the molding powder from being scattered when the female screw is formed, and it is also used for assembling electronic equipment. it can.

It is a section front view showing an embodiment of the invention. It is a top view which shows the engagement state of the workpiece | work and insert nut of FIG. It is a cross-sectional front view which shows the crimping start state of this invention. It is a sectional front view showing the caulking state of the present invention. It is a cross-sectional front view which shows other embodiment of this invention. It is a cross-sectional front view which shows the crimping state in other embodiment of this invention. It is a principal part sectional front view which shows the other Example of the insert nut by this invention. It is the sectional view on the AA line of FIG. It is a cross-sectional front view which shows the crimping state which shows the other Example of this invention. It is a principal part cross-sectional front view which shows a prior art example. It is a cross-sectional front view which shows the crimping state of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insert nut 2 Head part 3 Shaft part 3a Large diameter part 3b Small diameter part 4 Longitudinal groove 5 Work piece 6 Insertion hole 7 Engagement hole 10 Stepped hollow hole 11 Female screw formation pilot hole part 12 Hollow hole part 13 Caulking part 20 Screw member 21 Leg part 22 Male screw 23 Unthreaded part 24 Bearing surface

Claims (5)

  The shaft portion (3) and a head portion (2) having a larger outer peripheral shape than the shaft portion are formed, and a female screw forming pilot hole portion (11) is formed at the tip of the shaft portion, and this female screw forming pilot hole portion An insert nut having a hollow hole (12) having a diameter larger than the diameter of the female screw forming pilot hole from the head to the head, and forming a stepped hollow hole (10) from the female screw forming pilot hole and the hollow hole (1) The screw member (20) is inserted from the head side of the hollow hole portion, and the screw member is screwed in while forming the female screw in the female screw forming lower hole portion. 24) The insert nut according to claim 24, wherein the hollow hole is compressed and caulked by contacting the top surface of the head.   The outer periphery of the head has a rectangular or elliptical shape, and is engaged with the engagement hole (7) of the work (5) so that the screw member does not rotate when screwed into the female screw forming pilot hole. The insert nut according to claim 1, wherein the insert nut is formed.   The insert nut according to claim 1 or 2, wherein the shaft portion has a plurality of thin strips along the axial direction at equal intervals in the circumferential direction at a caulking position of the hollow hole portion.   An insertion hole (6) into which the shaft portion (3) of the insert nut (1) can be inserted is formed in a plurality of plate-like workpieces (5) fastened to each other, and the head (2) of this insert nut is located. An engagement hole (7) is formed in the work so that the head can be engaged. The insert nut is longer than the interval (T) between the front surface and the back surface of the work to be fastened, and the outer periphery of the shaft portion. A female screw forming pilot hole (11) is formed at the tip of the shaft portion, and is larger than the diameter of the female screw forming pilot hole from the female screw forming pilot hole to the head. A hollow hole portion (12) having a diameter is provided, and a stepped hollow hole (10) is formed from the female screw forming pilot hole portion and the hollow hole portion, and the screw member (20) is formed from the head side of the insert nut. While forming the female screw in the female screw forming pilot hole The screw member is screwed in so that the seating surface (24) of the screw member is in contact with the top surface of the head, and the hollow hole portion is compressed and caulked at the end surface of the workpiece, thereby fastening the plurality of workpieces. Work fastening structure using an insert nut featuring The shaft portion of the insert nut protrudes from the back surface of the workpiece to which a part of the hollow hole portion and the female screw forming pilot hole portion are fastened when at least the head portion is fitted into the engagement hole of the workpiece. A workpiece fastening structure using the insert nut according to Item 4.

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