Fastening tool and method of fixing fastening tool

Abstract

To provide a fastening tool which can be fixed to a pore provided on a molding member consisting of not only a thermoplastic resin suitable for mass production but also a thermosetting resin, and a pore provided on carbon (carbon substrate), and to provide a method of fixing the fastening tool.SOLUTION: A fastening tool 1 is provided with a head part 3 provided with knurling (uneven strips) on an outer side circumferential surface having an edge surface (a) on a short columnar main body 2, a small diameter part 4, a cap body part 5 provided with knurling (uneven strips) of a rectangular mesh, on an outer side circumferential surface having an edge surface (a) and a rear end part 6. The head part 3 is processed in the same outer diameter with a pore diameter of molded article made of an after-described thermoplastic resin. The cap body part 5 has a truncated cone shape of which the side brought into contact with the small diameter part 4 is made to be the maximum outer diameter and reduces the outer diameter toward the rear end part 6. The truncated cone shape has an inclination angle of 4°.Further, a groove 7 is provided on the cap 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 synthetic resin molded parts suitable for mass production or 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. Therefore, the present inventors filed a patent application on July 10th of this year for a fastener and a fastener fixing method that can be fixed to holes in molded parts made of not only thermoplastic resins but also thermosetting resins as synthetic resins and holes in carbon (carbon substrates).

[0004] However, in the above-mentioned fastener, the thermoplastic resin is attached to the rear end of the fastener with an adhesive, etc. This poses a problem that it is time-consuming to attach the thermoplastic resin to the fastener and is not suitable for mass production. [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, the fastener applied for in Patent Application No. 2023-133165 had a problem that the thermoplastic resin was attached to the rear end of the fastener with adhesive or the like, which required time and effort to attach the thermoplastic resin to the fastener, making it unsuitable for mass production. 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 product members made of not only thermoplastic resin suitable for mass production but also thermosetting resin and holes provided in carbon (carbon substrate). [Means for solving the problem]

[0007] Therefore, the present invention is a nut-shaped metallic fastener which is fixed by applying heat and pressure into a hole in a raw material, and which comprises a cylindrical body, a head having an outer diameter the same as the diameter of the hole, and a plug body portion adjacent to the head which has a number of uneven stripes on the outer peripheral surface of the cylindrical body and whose outer diameter decreases at a predetermined gradient in a truncated cone shape from the side in contact with the head, and a groove provided in the center of the outer peripheral surface of the plug body portion. The present invention also relates to a method for fixing a nut-shaped metallic fastener which is heated and pressurized to be fixed in a hole provided in a molded thermoplastic resin member, the fastener having a cylindrical body, 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 uneven stripes on the outer circumferential surface of the cylindrical body, the plug body portion having a maximum outer diameter on the side in contact with the head and a predetermined gradient in outer diameter decreasing in a truncated cone shape, and a groove provided on the outer circumferential surface of the plug body portion, the thermoplastic resin molded member having a two-stage hole consisting of a first hole at the top and a second hole at the bottom having an inner diameter smaller than the inner diameter of the first hole, and when the fastener is inserted into the two-stage hole, the head of the fastener is heated and pressurized to fix the fastener in the two-stage hole. Effect of the Invention

[0008] The present invention makes it possible to provide a fastener that can be attached to holes provided in molded components made of not only thermoplastic resins suitable for mass production but also thermosetting resins and holes provided in carbon (carbon substrates), and a method for fixing the fastener. [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 cross-sectional view of a ring used in the second embodiment. [Figure 6] FIG. 11 is a cross-sectional view showing the shape of a molded member to which the second embodiment can be applied. [Figure 7] FIG. 11 is a cross-sectional view showing the shapes of a ring and 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 in a second embodiment is temporarily placed in a hole in a molded product member. [Figure 9]FIG. 11 is a diagram showing a state in which a fastener in a 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. 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 thermoplastic 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 product member described below. This maximum outer diameter may be set to be smaller than the hole diameter of the molded product member by a predetermined value depending on the size of the fastener. Furthermore, a groove 7 is provided in the plug body 5. The groove 7 is provided at approximately 1 / 2 the position of the truncated cone. However, the position of the groove is not limited to this and may be appropriately adjusted depending on the size of the fastener.

[0012] The body 2 is provided with a female screw 8 as a through screw from an end face a. The female thread may be machined with a closed end. Also, the small diameter portion 4 does not have to be provided.

[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 thermoplastic 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 hole 13 is formed in two stages, with the upper part having a hole diameter equal to the outer diameter of the head 3 of the fastener 1 and the lower part having a hole diameter smaller than the hole diameter by a predetermined value. For example, the hole 13 is formed to have an overall depth of 10.00 mm, with the upper part having a hole diameter of 6.00 mm and a depth of 4.00 mm from the end face b, and the lower part having a hole diameter of 5.40 mm and a depth of 6.00 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 fitting into hole 13 provided in molded member 11 of thermosetting resin. Furthermore, fastener 1 of the present invention does not scrape the peripheral surface of the hole of the molded member as in the past, but melts from the peripheral surface of hole 13 and hardens so as to wrap around groove 7 of plug body portion 5 at the center, as will be described in detail later. 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 Figure 3, the groove 7 of the plug body 5 rests on the hole at the bottom of the hole 13. In this state, the fastener 1 is heated and pressurized from above (top of the figure), and the peripheral surface of the hole 13 begins to melt, allowing the fastener 1 to enter the hole 13. That is, heat is concentrated in the heated fastener 1 at the contact point of the groove 7 of the plug body 5, and the melting of the peripheral surface of the hole is accelerated by the addition of pressure. The molten peripheral surface of the hole spreads vertically from the groove 7 of the plug body 5 as the center, and flows into the knurled peripheral surface of the plug body 5.

[0018] 4 shows the state of the fastener 1 after it has been heated and pressurized. The fastener 1 is fitted into 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 1 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 of the hole 13 (predetermined position), and therefore does not bite into the hole 13 beyond that depth.

[0019] The thermoplastic resin of the molded product member 11 which melts and flows into the hole surface centered on the groove 7 of the plug body portion 5 bites into the square mesh knurling and also flows into the groove 7, so that the fastener 1 is fixed in 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 of the boss 12 over time can also be avoided.

[0020] In addition, the head 3 of the fastener 1 of this embodiment may not have knurling (uneven stripes) on the outer peripheral surface in order to reduce the cost of the cutting process. The plug body 5 of the fastener 1 of this embodiment may be cut by cutting the upper part of the groove 7 as the first plug body and the lower part of the groove as the second plug body. For example, the gradient of the first plug body may be in the range of 0 degrees to 10 degrees, and the gradient of the second plug body may be in the range of 0 degrees to 10 degrees. Furthermore, the maximum outer diameter of the first plug body and the maximum outer diameter of the second plug body may be different. This may be appropriately handled according to the size and material of the fastener. Note that the gradient of the first plug body at 0 degrees and the gradient of the second plug body at 0 degrees result in a cylindrical shape rather than a truncated cone shape. The lengths of the first plug body and the second plug body may also be appropriately handled according to the size and material of the fastener, and in short, the upper and lower parts centered on the groove as shown in FIG. 4 may be melted.

[0021] Next, a second embodiment will be described. 5 is a cross-sectional view of the ring 20 molded from thermoplastic resin according to the second embodiment. The ring 20 is formed with an outer diameter of 6.00 mm, an inner diameter of 5.30 mm, and a length of 6.00 mm. The ring 20 may be made of a thermoplastic adhesive, which is simply required to melt when heated and harden at room temperature. 6 is a cross-sectional view showing an example of the configuration of a molded member 31 molded from a thermosetting resin. The molded member 31 is formed by providing a hole 33 in a boss 32 and providing an end face c on the upper surface of the boss 32. The inner diameter of the hole 33 is 6.00 mm and the depth is 10.00 mm. FIG. 7 is a cross-sectional view showing a state in which the ring 20 is inserted into the hole 33 of the molded product member 31. As shown in FIG.

[0022] Next, a method for fitting and fixing the fastener 1 shown in the first embodiment into the hole 33 of the molded member 31 in such a configuration will be described. As shown in Figure 8, the groove 7 of the plug body part 5 rests on the ring 20 at the bottom of the hole 33. In this state, the fastener 1 is heated and pressurized from above (top of the figure), and the peripheral surface of the hole of the ring 20 begins to melt, allowing the fastener 1 to enter the hole 33. That is, heat of the heated fastener 1 is concentrated at the contact point with the groove 7 of the plug body part 5, and the melting of the peripheral surface of the ring 20 is accelerated by the addition of pressure. The peripheral surface of the molten ring 20 spreads up and down around the groove 7 of the plug body part 5, and flows into the knurled peripheral surface of the plug body part 5.

[0023] 9 shows the state of the fastener 1 after it has been heated and pressurized. The fastener 1 is fitted and fixed in the hole 33 of the molded member 31. Since the overall length of the fastener 1 is the same as the depth from the end face c to the bottom of the hole 33 of the molded member 31, it is pressed to a predetermined position and stops. As a result, the end face a of the fastener 1 and the end face c of the molded member 31 are flush and aligned (predetermined position). This is because the fastener 1 is pressed to the bottom of the hole 33 (predetermined position), so it does not bite into the hole 33 beyond that depth. To begin with, the molded member 31 is made of a thermosetting resin and will not melt due to heat.

[0024] The thermoplastic resin which melts and flows into the ring 20 centered on the groove 7 of the plug body portion 5 bites into the square mesh knurling and also flows into the groove 7, and further melts and adheres to the circumferential surface of the hole 33 of the molded product member 31, so that the fastener 1 is fixed to the hole 33. This allows the fastener 1 to maintain the tensile strength (pull-out strength) of the hole 33 in the molded member 31, and also ensure torsional strength (rotational torque). Also, since there is no expansion pressure from inside the boss hole 33 due to the insertion of the fastener 1 described above, it is possible to avoid cracks that sometimes occur in the upper part of the boss 32. Furthermore, it is believed that cracks due to deterioration of the boss 32 over time can also be avoided. Although the hole in the molded product shown in the first embodiment was a two-stage hole, the fastener 1 of the present invention can be used even with holes in conventional thermoplastic resin that are not two-stage holes by using the ring shown in the second embodiment.

[0025] Next, a third embodiment will be described. 10 is a cross-sectional view showing an example of the configuration of a hole 53 formed in a carbon substrate 51 such as carbon according to the third embodiment. The hole 53 in this embodiment is formed with an inner diameter of 6.00 mm and a depth of 10.00 mm. Although the carbon substrate 51 has no viscosity and is brittle, the fastener 1 of the first embodiment described above can be easily fitted and fixed using the ring 20 shown in the second embodiment. This allows the fastener 1 to maintain the tensile strength (pull-out strength) of the hole 53 in the carbon substrate 51 and also ensure torsional strength (rotational torque).

[0026] 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 members through the above-mentioned embodiment. In other words, the fastener of the present invention can be used not only for molded members molded from conventional thermoplastic resins as materials, but also for molded members molded from thermosetting resins, and for carbon (carbon substrates) with poor viscosity. Furthermore, it was confirmed through prototypes that the fastener can be fixed to holes provided in wood, glass, and ceramics. 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.

[0027] As described above, according to the above-described embodiments 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 suitable for mass production but also thermosetting resin and holes provided in carbon (carbon substrate).

[0028] 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]

[0029] Reference Signs List 1...fixing device, 2...main body, 3...head, 4...small diameter portion, 5...plug portion, 6...rear end portion, 7...groove, 8...female thread, 11, 31...molded member, 12, 32...boss, 13, 33, 53...hole, 20...ring, 51...carbon.

Claims

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

4. 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 cylindrical body has a head having an outer diameter equal to the diameter of the hole, a first plug portion having a number of projections and recesses on an outer peripheral surface of the cylindrical body adjacent to the head portion, the first plug portion having a maximum outer diameter on the side in contact with the head portion and an outer diameter that decreases at a predetermined gradient in a truncated cone shape; a groove provided adjacent to the first plug portion; A second plug portion has a number of projections and recesses on an outer peripheral surface of the cylindrical body adjacent to the groove, and the outer diameter of the second plug portion decreases at a predetermined gradient in a truncated cone shape from the maximum outer diameter on the side in contact with the groove; A fastener comprising:

5. A method for fixing a nut-shaped metal fastener that is fixed by applying heat and pressure to a hole provided in a molded thermoplastic resin member, comprising the steps of: The fastener has a cylindrical body, a head having an outer diameter equal to the diameter of the hole, a plug portion having a number of ridges and grooves on the outer peripheral surface of the cylindrical body adjacent to the head, the plug portion having a maximum outer diameter on the side in contact with the head 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; The thermoplastic resin molded member has a two-stage hole consisting of a first hole at an upper portion and a second hole at a bottom portion, the second hole having an inner diameter smaller than the inner diameter of the first hole, A method for fixing a fastener, characterized in that when the fastener is inserted into the two-step hole, a head of the fastener is heated and pressurized so that the fastener is fixed to the two-step hole.

6. A nut-shaped metal fastener that is fixed to a hole in a synthetic resin molded member by applying heat and pressure, The fastener has a cylindrical body, a head having an outer diameter equal to the diameter of the hole, a plug portion having a number of ridges and grooves on the outer peripheral surface of the cylindrical body adjacent to the head, the plug portion having a maximum outer diameter on the side in contact with the head 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 method for fixing a fastener, characterized in that when a thermoplastic resin ring is placed in a hole provided in the synthetic resin molded member and the fastener is inserted into the hole, the head of the fastener is heated and pressurized, the ring is melted by the plug portion of the fastener, and the fastener is fixed in the hole.

7. A nut-shaped metal fastener that is fixed to a hole in a carbon substrate by applying heat and pressure, The fastener has a cylindrical body, a head having an outer diameter equal to the diameter of the hole, a plug portion having a number of ridges and grooves on the outer peripheral surface of the cylindrical body adjacent to the head, the plug portion having a maximum outer diameter on the side in contact with the head 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 ring of thermoplastic resin is placed in a hole provided in the carbon substrate, and when the fastener is inserted into the hole, a head of the fastener is heated and pressurized, causing the ring to melt by a plug portion of the fastener, thereby fixing the fastener in the hole.

8. 4. The fastener according to claim 1 or 3, wherein the material is one of thermoplastic resin, thermosetting resin, carbon-based material, polycarbonate, wood, glass, and ceramic.

9. 8. The fastener according to claim 6 or 7, wherein the ring is made of a thermoplastic resin or a thermoplastic adhesive and fixes the fastener at room temperature.

10. 3. The fastener according to claim 1, wherein the inclination of the plug portion is from 0.1 degrees to 10 degrees.

11. 3. The fastener according to claim 1, wherein the maximum outer diameter of the plug body is smaller than the diameter of the hole by a predetermined value.

Images