Fastening tool and fixing method of the same

Abstract

To provide a fastening tool which can be fixed to a hole provided at not only a molded member made of a thermoplastic resin used as a synthetic resin, but also a molded member made of a thermosetting resin or a hole provided at a carbon material (a carbon base material), and to provide a fixing method of the fastening tool.SOLUTION: A fastening tool 1 is provided having, in a short columnar body 2, a head 3 which is provided on an outer peripheral surface having an end surface a and has a knurled part (irregularities), a small diameter part 4, a plug body part 5 provided on the outer peripheral surface and having a knurled part (irregularities) having a square-shaped mesh form, and a rear end part 6. The head 3 is processed so as to have the same outer diameter as a hole diameter of a molded member made of a thermosetting resin. Further, the plug body part 5 is formed in a circular truncated cone shape having a maximum outer diameter at the side contacting with the small diameter part 4 and its outer diameter is reduced toward the rear end part 6. An angle of an inclination of the circular truncated cone shape is set to 4 degrees. Further, a groove 7 is provided at the plug body part 5.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fastener suitable for use by being fitted and fixed to a variety of synthetic resin molded members and carbon (carbon substrate), and a method for fixing the fastener. [Background technology]

[0002] Conventionally, when a screw hole is formed in a component made of a synthetic resin molded product and a bolt or the like is screwed in to fix the component, the screw hole becomes deformed or destroyed and becomes unusable when the component is subjected to tension, torsion, vibration or other external forces, or when the bolt or the like is repeatedly attached and removed. Therefore, nut-shaped metal fasteners (inserts) have been put to practical use, which can be fitted into holes in molded members such as synthetic resins to stably fix bolts and the like and can withstand repeated fastening and unfastening. Furthermore, a method has been proposed in which the outer peripheral surface of such fasteners is provided with knurled or other irregularities so that the fasteners bite into the holes in the molded members and are fixed with sufficient strength (e.g., Patent Documents 1 and 2).

[0003] When fitting such fasteners into molded components, the fasteners are heated (to around 200°C) and pressurized into boss holes provided in the molded components to fit them in. This is possible because synthetic resin molded components like this are thermoplastic resins. The synthetic resin used is not a thermoplastic resin, and molded components made of thermosetting resins and carbon (carbon substrates) do not melt even when heated (to around 200°C), so it is impossible to fit and secure fasteners in this configuration.

[0004] However, in recent years, there has been a strong demand for application to a variety of synthetic resin molded components and carbon (carbon substrates), and there was a challenge to develop a fastener that could be used not only for thermoplastic resins but also for thermosetting resin molded components and carbon (carbon substrates). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 50-85756 [Patent Document 2] Japanese Unexamined Patent Publication No. 58-124809 Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, there is a strong demand for application to diversified synthetic resin molded members and carbon (carbon substrates), and there was a need to develop a fastener that can be used not only for thermoplastic resin molded members but also for thermosetting resin molded members and carbon (carbon substrates).The object of the present invention is to provide a fastener and a fastener fixing method that can be fixed to holes provided in molded members made of not only thermoplastic resin as synthetic resin but also thermosetting resin and holes provided in carbon (carbon substrates). [Means for solving the problem]

[0007] Therefore, the present invention is a nut-shaped metal fastener which is fixed by applying heat and pressure into a hole in a raw material, and which comprises a head which has a number of ridges on the outer peripheral surface of a cylindrical body and has an outer diameter the same as the diameter of the hole, a plug part which is adjacent to the head and has a number of ridges on the outer peripheral surface of the cylindrical body and has a maximum outer diameter on the side in contact with the head, and whose outer diameter decreases at a predetermined gradient in a truncated cone shape, and a groove which is provided on the outer peripheral surface of the plug part. The present invention also relates to a method for fixing a nut-shaped metal fastener which is fixed in a hole provided in a synthetic resin molded member or a hole provided in a carbon base material by applying heat and pressure, the fastener having a cylindrical body having a number of ridges on the outer peripheral surface thereof and a head having an outer diameter the same as the diameter of the hole, a plug body portion adjacent to the head and having a number of ridges on the outer peripheral surface of the cylindrical body and having an outer diameter which decreases at a predetermined gradient in a truncated cone shape with the outer diameter being maximum on the side in contact with the head, and a groove provided on the outer peripheral surface of the plug body portion, a metal fitting consisting of an insertion portion which is inserted into the rear end portion of the plug body portion with the reduced outer diameter and a sealing portion to which thermoplastic resin or a thermoplastic adhesive is adhered is placed at the bottom of the hole with the sealing portion facing down, the fastener is placed in the hole so that the rear end portion with the reduced outer diameter is inserted into the insertion portion, and the head of the fastener is fixed in the hole by applying heat and pressure. Effect of the Invention

[0008] The present invention makes it possible to provide a fastener and a method for fastening the fastener that can be fixed to holes provided in molded components made of not only thermoplastic resins but also thermosetting resins as synthetic resins, and to holes provided in carbon (carbon substrates). [Brief description of the drawings]

[0009] [Figure 1] 1 is a half-sectional view showing an example of a fastener to which a first embodiment according to the present invention can be applied. [Diagram 2] FIG. 2 is a cross-sectional view showing the shape of a molded member to which the first embodiment can be applied. [Diagram 3] FIG. 13 is a diagram showing the state in which the fastener is temporarily placed in the hole of the molded product member. [Figure 4] FIG. 4 is a diagram showing the state in which the fastener is fixed in a hole in the molded product member. [Diagram 5] FIG. 11 is a half-sectional view showing an example of a fastener to which the second embodiment can be applied. [Figure 6] FIG. 11 is a cross-sectional view of a metal fitting used in the second embodiment. [Figure 7] FIG. 11 is a cross-sectional view showing the shape of a molded member to which the second embodiment can be applied. [Figure 8] FIG. 11 is a diagram showing a state in which a fastener according to a second embodiment is temporarily placed in a hole in a molded product member. [Figure 9] FIG. 11 is a diagram showing the state in which the fastener of the second embodiment is fixed in a hole in a molded product member. [Figure 10] FIG. 11 is a cross-sectional view showing the shape of carbon (carbon substrate) to which the third embodiment can be applied. [Figure 11] FIG. 13 is a cross-sectional view showing the shape of carbon (carbon substrate) to which the fourth embodiment can be applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. 1 is a half-sectional view showing a fastener 1 called an insert according to a first embodiment of the present invention. That is, this fastener 1 is provided with a short cylindrical body 2 having an end face a, a head portion 3 having a knurl (uneven stripes) on the outer peripheral surface, a small diameter portion 4, a plug portion 5 having a square-mesh knurl (uneven stripes) on the outer peripheral surface, and a rear end portion 6. The head 3 is machined to have the same outer diameter as the hole diameter of the molded member made of a thermosetting resin, which will be described later. This head may be made smaller than the hole diameter of the molded member by a predetermined value depending on the size of the fastener. The plug portion 5 has a truncated cone shape with the maximum outer diameter on the side in contact with the small diameter portion 4, and the outer diameter decreases toward the rear end portion 6. Therefore, in this embodiment, the gradient angle is 4 degrees. This gradient angle is machined in the range of 0.1 degrees to 10 degrees depending on the size and material of the fastener.

[0011] The maximum outer diameter of the plug body 5 is machined to be the same as the hole diameter of the molded member described below. This maximum outer diameter may be a predetermined value smaller than the hole diameter of the molded member depending on the size of the fastener. Furthermore, a groove 7 is provided in the plug body 5. It is effective to provide the groove 7 at the tip of the cone, more than halfway through the truncated cone. Although there is one groove in this embodiment, there may be two, three, or more grooves.

[0012] In addition, the rear end 6 of the plug body 5 is rounded to have a pot bottom shape. This rounding is done to make it easier for the molten thermoplastic resin, which will be described later, to flow around the circumferential surface of the plug body 5. The rear end may be hemispherical rather than pot bottom shaped, as long as it allows the thermoplastic resin to flow easily. The body 2 is provided with a female screw 8 at a closed end from an end face a. A predetermined amount of thermoplastic resin 9 with a thickness of 2 mm is attached to the rear end 6 of the plug body 5 with adhesive or the like. The thermoplastic resin 9 may be a thermoplastic adhesive. The point is that it is easy to melt when heated and pressurized as described below, and hardens with a certain strength at room temperature.

[0013] The fastener 1 of this embodiment is machined to an accuracy of 1 / 100 mm. For example, the dimensions of fastener 1 are as follows: total length (from end face a to rear end 6) is 10.00 mm, head 3 has an outer diameter of 6.00 mm and a length of 2.00 mm, small diameter portion 4 has an outer diameter of 5.80 mm and a length of 0.50 mm, and plug body portion 5 has a maximum outer diameter of 6.00 mm on the side in contact with small diameter portion 4 and a length of 7.50 mm, all of which are machined. Female thread 8 is machined with M4. Although the fastener 1 is made of brass in this embodiment, metals such as stainless steel, carbon steel, aluminum, and zinc may also be used.

[0014] 2 is a cross-sectional view showing an example of the configuration of a molded member 11 molded from a thermosetting resin. The molded member 11 is formed by providing a hole 13 in a boss 12 and providing an end face b on the upper surface of the boss 12. The inner diameter of the hole 13 is 6.00 mm and the depth is 10.00 mm.

[0015] Next, the configuration of the fastener 1 will be described in more detail. As described above, fastener 1 is provided with plug body portion 5, which serves as a guide when fastener 1 is fitted into hole 13 provided in molded member 11 of thermosetting resin. Furthermore, fastener 1 of the present invention has plug body portion 5 that does not scrape the peripheral surface of the hole of the molded member as in the past, but rather, as will be described in detail later, thermoplastic resin 9 molten from the bottom surface of hole 13 hardens so as to envelop plug body portion 5. This is a novel idea that is completely different from the conventional idea of ​​forcibly fitting a fastener with an outer diameter larger than the inner diameter of a hole.

[0016] Next, a method for fitting and fixing the fastener 1 into the hole 13 of the molded product member 11 in such a configuration will be described. That is, in this fitting and fixing method, the fastener 1 is heated and pressurized to be fitted into the hole 13 of the molded product member 11. First, the fastener 1 is fed into the hole 13 of the molded product member 11 by a parts feeder or the like. At that time, the fastener 1 is temporarily placed in the hole 13 of the molded product member 11 with the plug body portion 5 acting as a guide.

[0017] As shown in FIG. 3, the head 3 protrudes from the end face b of the hole 13. The amount of protrusion depends on the thickness of the thermoplastic resin 9. In this state, the fastener 1 is heated and pressurized from above (top of the figure), melting the thermoplastic resin 9 and enabling it to enter the hole 13 of the fastener 1. That is, the heat of the heated fastener 1 is concentrated at the rear end 6 of the plug body 5, and the melting of the thermoplastic resin 9 is accelerated by the addition of pressure. The molten thermoplastic resin 9 is pushed upward from the bottom of the hole 13 and the rear end 6 of the fastener 1 through the R part of the plug body 5, and flows into the knurled peripheral surface and groove 7 of the plug body 5. At this time, the head 3 and the small diameter part 4 act to release the air in the hole 13 upward, creating a state in which the molten thermoplastic resin 9 can be easily pushed upward. The head 3 has a knurl for this purpose, but if the air in the hole 13 can be released upward only by the head 3, the small diameter part 4 does not need to be provided. This can be appropriately designed according to the size of the fastener.

[0018] FIG. 4 shows the state of the fastener 1 after it has been heated and pressurized. The fastener 1 is fitted and fixed in the hole 13 of the molded member 11. Since the overall length of the fastener 1 and the depth from the end face b to the bottom of the hole 13 of the molded member 11 are the same, the fastener is pressed to a predetermined position and stops. As a result, the end face a of the fastener 1 and the end face b of the molded member 11 are flush and aligned (predetermined position). This is because the fastener 1 is pressed to the bottom (predetermined position) of the hole 13, so it does not bite into the hole 13 beyond that depth. However, a small amount of thermoplastic resin 9 remains between the bottom face of the hole 13 and the rear end 6 of the fastener 1. If the end face a and the end face b do not become flat enough that this remaining amount cannot be ignored, it is necessary to design the overall length of the fastener 1 to be shorter than the depth of the hole 13 by a predetermined value. This can also be designed appropriately according to the size of the fastener.

[0019] In addition, the thermoplastic resin 9 melts and flows, and cools and solidifies at approximately the middle of the plug body 5. Therefore, the thermoplastic resin 9 does not overflow from the hole 13. This is determined as a predetermined amount based on the volume of the thermoplastic resin 9 that is melted in advance and the amount that flows onto the peripheral surface of the plug body 25, which will be described later. The thermoplastic resin 9 that has flowed onto the peripheral surface of the plug body 5 bites into the knurling of the square mesh and also flows into the grooves 7, so that the fastener 1 is fixed to the hole 13. This allows the fastener 1 to maintain the tensile strength (pull-out strength) of the hole 13 in the molded member 11, and also ensure torsional strength (rotational torque). Also, since there is no expansion pressure from inside the boss hole 13 due to the insertion of the fastener 1 as described above, it is possible to avoid cracks that sometimes occur in the upper part of the boss 12. Furthermore, it is believed that cracks due to deterioration over time can also be avoided. In the above embodiment, the thermoplastic resin 9 is bonded to the fastener 1, but it may be provided at the bottom of the hole 13 in the molded member 11.

[0020] Next, a second embodiment will be described. 5 is a half-side cross-sectional view showing a fastener 21 called an insert according to a second embodiment. That is, this fastener 21 is provided with a head 23 having a knurl (uneven stripes) on the outer peripheral surface having an end face c at the head of a short cylindrical body 22, a small diameter portion 24, a plug body portion 25 having a square-mesh knurl (uneven stripes) on the outer peripheral surface, and a rear end portion 26. The head 23 is machined to have the same outer diameter as the hole diameter of the molded product member 11 molded from a thermosetting resin. This head may be made smaller by a predetermined value than the hole diameter of the molded product member according to the size of the fastener. Plug body portion 25 has a truncated cone shape with the maximum outer diameter on the side in contact with small diameter portion 24, and the outer diameter decreases toward rear end portion 26. Therefore, in this embodiment, the gradient angle is 4 degrees. This gradient angle is machined in the range of 0.1 degrees to 10 degrees depending on the size and material of the fastener.

[0021] The maximum outer diameter of the plug body portion 25 is machined to be the same as the hole diameter of the molded product member 11. Furthermore, a groove 27 is provided in the plug body portion 25. The groove 27 is machined toward the tip of the plug body portion 25, which has a truncated cone shape. Generally, it is effective to provide the groove at a point between 1 / 2 and the tip of the truncated cone. Although there is one groove in this embodiment, there may be two, three, or more grooves. In addition, a rounded edge is formed along the rear end surface 26 of the plug body 25. This rounded edge is formed so that the molten thermoplastic resin described below can easily flow onto the peripheral surface of the plug body 25. Further, the main body 22 is provided with a female screw 28 as a through screw from the end face c.

[0022] The fastener 1 of this embodiment is machined to an accuracy of 1 / 100 mm. For example, the dimensions of fastener 21 are machined to have a total length (from end face c to rear end 26) of 9.50 mm, head 23 with an outer diameter of 6.00 mm and a length of 2.00 mm, small diameter portion 24 with an outer diameter of 5.80 mm and a length of 0.50 mm, and plug portion 25 with a maximum outer diameter of 6.00 mm on the side in contact with small diameter portion 24 and a length of 7.00 mm. Female thread 28 is machined with M4. Although the fastener 21 is made of brass in this embodiment, metals such as stainless steel, carbon steel, aluminum, and zinc may also be used.

[0023] 6 is a cross-sectional view of a metal fitting 31 made of brass used in this embodiment. The metal fitting 31 is composed of an inlay portion 32 and a sealing portion 33. This metal fitting 31 is machined to 1 / 100 mm units, with the inlay portion 32 having an outer diameter of 3.80 mm and a length of 1.20 mm, and the sealing portion 33 having an outer diameter of 4.10 mm and a length of 0.50 mm. The sealing portion 33 is machined so as to close the through thread of the female thread 28. A predetermined amount of thermoplastic resin 34 is attached to the sealing portion 33 of the metal fitting 31 with adhesive or the like. The "predetermined amount" here is determined by the melted volume and the amount that flows onto the peripheral surface of the plug portion 25, which will be described later. The thermoplastic resin 34 may be a thermoplastic adhesive. The point is that it melts and flows when heated, and cools and hardens at room temperature.

[0024] 7 is a cross-sectional view showing an example of the configuration of a molded member 41 molded from a thermosetting resin. The molded member 41 is formed by providing a hole 43 in a boss 42 and providing an end face d on the upper surface of the boss 42. The inner diameter of the hole 43 is 6.00 mm and the depth is 9.50 mm.

[0025] 8 is a diagram showing the state in which the fastener 21 and metal fitting 31 are temporarily placed in the hole 43 of the molded member 41. The metal fitting 31 is placed at the bottom of the hole 43 with the thermoplastic resin 34 of the sealing portion 33 facing the bottom, and the rear end portion 26 of the plug portion 25 of the fastener 21 is placed on top of the metal fitting 31. The fitting portion 32 of the metal fitting 31 may be processed so as to be fitted into the female thread 28, and may be supplied to the hole 43 integrally with the fastener 21. In this state, the fastener 21 is heated and pressurized from above (top of the figure), allowing the head 23 of the fastener 21 to enter the hole 43, and at the same time, the thermoplastic resin 34 of the metal fitting 31 placed below the fastener 41 (top of the figure) is melted. When the thermoplastic resin 34 melts, the molten thermoplastic resin is pushed upward from the bottom of the hole 23 and the sealing part 33 of the metal fitting 31 via the R processing of the plug body part 25, and flows into the knurled peripheral surface and groove 27 of the plug body part 25. At this time, the head 23 and the small diameter part 24 act to allow the air in the hole 43 to escape upward, creating a state in which the molten thermoplastic resin 34 can be easily pushed upward. The head 23 has a knurl for this purpose, but if the air in the hole 43 can be allowed to escape upward only by the head 23, the small diameter part 24 does not need to be provided. This can be designed appropriately according to the size of the fastener.

[0026] FIG. 9 shows the state of the fastener 21 after it has been heated and pressurized. The fastener 21 is fitted into the hole 43 of the molded member 41. Since the overall length of the fastener 21 and the depth of the hole 43 of the molded member 41 are the same, the fastener 21 is pressed to the bottom of the hole 43 (predetermined position) and stops there. As a result, the end face c of the fastener 21 and the end face d of the molded member 21 are flush and aligned (predetermined position). This is because the fastener 21 is pressed to the bottom of the hole 43 (predetermined position), so it does not bite into the hole 43 beyond that depth. However, a small amount of thermoplastic resin 34 remains between the bottom of the hole 43 and the sealing portion 33. If the end face c and the end face d are not flat enough to be negligible, it is necessary to design the fastener 21 so that its overall length is shorter than the depth of the hole 43 by a predetermined value.

[0027] In addition, the thermoplastic resin 34 melts and flows, and cools and solidifies at approximately the middle of the plug body portion 25. Therefore, the thermoplastic resin 34 does not overflow from the hole 43. The thermoplastic resin 34 that has flowed onto the peripheral surface of the plug body portion 45 bites into the knurling of the square mesh and also flows into the grooves 27, so that the fastener 21 is fixed to the hole 43.

[0028] This allows the fastener 21 to maintain the tensile strength (pulling strength) of the molded member 41 toward the hole 23, and also ensure the torsional strength (rotational torque). Also, since there is no expansion pressure from inside the boss hole 43 due to the insertion of the above-mentioned fastener 21, it is possible to prevent cracks that sometimes occur in the upper part of the boss 42. Furthermore, it is believed that cracks due to deterioration over time can also be avoided. In the above embodiment, the thermoplastic resin 34 is bonded to the sealing portion 33, but it may be provided at the bottom of the hole 43 of the molded member 41.

[0029] Next, a third embodiment will be described. 10 is a cross-sectional view showing an example of the structure of a hole 51 formed in a carbon substrate 50 such as carbon. The hole 51 in this embodiment is formed with an inner diameter of 6.00 mm and a depth of 10.00 mm. The carbon substrate 50 is not viscous and is brittle, but the fastener 1 of the first embodiment described above can be easily fitted and fixed therein. As a result, the fastener 1 can maintain the tensile strength (pull-out strength) of the hole 51 in the carbon substrate 50 and also ensure torsional strength (rotational torque). In the above embodiment, the thermoplastic resin 9 is bonded to the fastener 1, but it may be provided at the bottom of the hole 51 in the carbon substrate 50.

[0030] Next, a fourth embodiment will be described. 11 is a cross-sectional view showing an example of the structure of a hole 61 formed in a carbon substrate 60 such as carbon. The hole 61 in this embodiment is formed with an inner diameter of 6.00 mm and a depth of 9.50 mm. The carbon substrate 60 is not viscous and is brittle, but the fastener 21 of the second embodiment described above can be easily fitted and fixed therein. As a result, the fastener 21 can maintain the tensile strength (pull-out strength) of the hole 61 in the carbon substrate 60 and also ensure torsional strength (rotational torque). In the above embodiment, the thermoplastic resin 34 is bonded to the sealing portion 33 , but it may be provided on the bottom of the hole 61 of the carbon substrate 60 .

[0031] The present inventor has repeatedly produced prototypes of fasteners based on a completely new concept, and has succeeded in putting the fastener to practical use, which was previously impossible, not only for the above-mentioned thermosetting resin molded member, but also for holes opened in a carbon (carbon substrate) plate, through the above-mentioned embodiment. Similarly, the fastener has also been successfully put to practical use for conventional thermoplastic resin molded member through the above-mentioned embodiment. In other words, the fastener of the present invention can be used not only for molded member molded from conventional thermoplastic resin as a material, but also for molded member molded from thermosetting resin, and carbon (carbon substrate) which has poor viscosity. Furthermore, it was confirmed through prototypes that the fastener can be fixed to holes provided in wood and glass. Furthermore, the fastener of the present embodiment can be put to practical use in polycarbonate, which is prone to cracking due to stress, because it does not generate stress (expansion pressure) from inside the hole.

[0032] As described above, according to the above-described embodiment of the invention, it is possible to provide a fastener and a fastener fixing method that can be fixed to holes provided in molded members made of not only thermoplastic resin as synthetic resin but also thermosetting resin and holes provided in carbon (carbon substrate).

[0033] The present invention is not limited to the above embodiment, and can be modified in various ways in the implementation stage without departing from the gist of the invention. The embodiments may be implemented in combination as appropriate as possible, and in that case, the combined effects can be obtained. Furthermore, the above embodiment includes inventions at various stages, and various inventions can be extracted by appropriate combinations of the disclosed multiple constituent elements. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiment, if the problem described in the "Problem to be Solved by the Invention" column can be solved and the effect described in the "Effect of the Invention" column can be obtained, the configuration from which the constituent elements are deleted can be extracted as the invention. [Explanation of symbols]

[0034] 1,21...fixing device, 2,22...main body, 3,23...head, 4,24...small diameter portion, 5,25...plug body portion, 6,26...rear end portion, 7,27...bottom hole, 8,48...female thread, 9,34...thermoplastic resin, 11,41,50,60...molded member, 12,42...boss, 13,43,51,61...hole, 31...metal fitting, 32...fitting portion, 33...sealing portion.

Claims

1. A nut-shaped metal fastener that is fixed to a hole in a material by applying heat and pressure, a head portion having a number of projections and recesses on an outer peripheral surface of a cylindrical body and an outer diameter equal to the diameter of the hole; a plug portion having a number of projections and recesses on an outer peripheral surface of the cylindrical body adjacent to the head portion, the outer diameter of which is maximum on the side in contact with the head portion and decreases at a predetermined gradient in a truncated cone shape; A groove is provided on the outer peripheral surface of the plug body. A fastener comprising:

2. A nut-shaped metal fastener that is fixed to a hole in a synthetic resin molded member or a hole in a carbon substrate by applying heat and pressure, a head portion having a number of projections and recesses on an outer peripheral surface of a cylindrical body and an outer diameter equal to the diameter of the hole; a plug portion having a number of projections and recesses on an outer peripheral surface of the cylindrical body adjacent to the head portion, the outer diameter of which is maximum on the side in contact with the head portion and decreases at a predetermined gradient in a truncated cone shape; A groove is provided on the outer peripheral surface of the plug body. A fastener comprising:

3. A nut-shaped metal fastener that is fixed to a hole in a synthetic resin molded member or a hole in a carbon substrate by applying heat and pressure, a head portion having a number of projections and recesses on an outer peripheral surface of a cylindrical body and an outer diameter equal to the diameter of the hole; a small diameter portion provided on an outer peripheral surface of the cylindrical body adjacent to the head portion and having an outer diameter smaller than an outer diameter of the head portion; a plug portion having a number of ridges and grooves on an outer peripheral surface of the cylindrical body adjacent to the small diameter portion, the plug portion having a maximum outer diameter on the side in contact with the small diameter portion and an outer diameter that decreases at a predetermined gradient in a truncated cone shape; A groove is provided on the outer peripheral surface of the plug body. A fastener comprising:

4. A method for fixing a nut-shaped metal fastener that is fixed by applying heat and pressure to a hole provided in a synthetic resin molded member or a hole provided in a carbon substrate, comprising the steps of: The fastener has a head portion having a large number of ridges on the outer peripheral surface of a cylindrical body and an outer diameter equal to the diameter of the hole, a plug portion having a large number of ridges on the outer peripheral surface of the cylindrical body adjacent to the head portion and having a maximum outer diameter on the side in contact with the head portion and an outer diameter which decreases at a predetermined gradient in a truncated cone shape, and a groove provided on the outer peripheral surface of the plug portion, a metal fitting comprising an insertion portion which is inserted into the rear end portion of the plug body portion, the rear end having a reduced outer diameter, and a sealing portion to which a thermoplastic resin or a thermoplastic adhesive is attached, is placed at the bottom of the hole with the sealing portion facing down, the rear end portion of the fastener, the rear end having a reduced outer diameter, is placed in the hole so that it is inserted into the insertion portion, and the head of the fastener is heated and pressurized to fix it in the hole.

5. A method for fixing a nut-shaped metal fastener that is fixed by applying heat and pressure to a hole provided in a synthetic resin molded member or a hole provided in a carbon substrate, comprising the steps of: The fastener has a cylindrical body having a large number of ridges on its outer peripheral surface, a head having an outer diameter equal to the diameter of the hole, a small diameter portion provided on the outer peripheral surface of the cylindrical body adjacent to the head and having an outer diameter smaller than the outer diameter of the head, a plug portion having a large number of ridges on its outer peripheral surface of the cylindrical body adjacent to the small diameter portion, the plug portion having a maximum outer diameter on the side in contact with the small diameter portion and a predetermined gradient in outer diameter in a truncated cone shape, and a groove provided on the outer peripheral surface of the plug portion, a metal fitting comprising an insertion portion which is inserted into the rear end portion of the plug body portion, the rear end having a reduced outer diameter, and a sealing portion to which a thermoplastic resin or a thermoplastic adhesive is attached, is placed at the bottom of the hole with the sealing portion facing down, the rear end portion of the fastener, the rear end having a reduced outer diameter, is placed in the hole so that it is inserted into the insertion portion, and the head of the fastener is heated and pressurized to fix it in the hole.

6. 2. The fastener of claim 1, wherein the material is one of a thermoplastic resin, a thermosetting resin, a carbon-based material, a polycarbonate, wood, and glass.

7. 4. The fastener according to claim 1, 2 or 3, wherein a thermoplastic resin or a thermoplastic adhesive is bonded to a rear end portion of the plug portion where the outside diameter is reduced.

8. 6. The fastener according to claim 1, 2, 3, 4 or 5, wherein an outer diameter of the head is smaller than a diameter of the hole by a predetermined value.

9. 6. The fastener according to claim 1, 2, 3, 4 or 5, wherein the inclination of the plug portion is from 0.1 degrees to 10 degrees.

10. 6. The fastener according to claim 1, 2, 3, 4 or 5, wherein the maximum outer diameter of the plug body portion is smaller than the diameter of the hole by a predetermined value.

11. 6. The fastener according to claim 1, 2, 3, 4 or 5, characterized in that the groove is one or more.

12. 6. A fastener according to claim 1, 2, 3, 4 or 5, wherein the length of the fastener body is equal to or shorter than the depth of the hole by a predetermined value.

Images