Fastener and method of fixing fastener

Abstract

To provide a fixing tool capable of being fixed to a hole provided to a thermoplastic resin molded product member suitable for mass production, and a fixing method of the fixing tool.SOLUTION: The fastener 1 of the present invention includes a short cylindrical body 2, a head 3 provided on an outer peripheral surface of the body 2 and having an end face a, a small-diameter portion 4, a plug portion 5 provided on the outer peripheral surface and having square-mesh knurls, a rear end portion 6, and an anchor 7 including a shank 7a and an anchor head 7b. The 7a of the anchor head of the anchor 7 is cut into a conical shape with a sloped surface curved and recessed toward the core. The plug portion 5 has a truncated cone shape having a 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. The truncated cone shape has a slope angle of 10 degrees.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 molded thermoplastic resin member in response to mass production, and to a method for fixing the fastener. [Background technology]

[0002] Conventionally, when a screw hole is formed in a component made of a molded thermoplastic resin and a bolt or the like is screwed into the screw hole to fix it, the screw hole becomes deformed or destroyed, making it unusable, when the component is subjected to tension, twisting, vibration, or other external forces, or when the bolt or the like is repeatedly attached and detached. Therefore, nut-shaped metal fasteners (inserts) have been put to practical use, which can be fitted into holes in molded members to stably fix bolts and the like and can withstand repeated attachment and detachment. Furthermore, methods have been proposed in which the outer peripheral surface of such fasteners is provided with knurling or other irregularities so that the fasteners can bite into holes in molded members and be fixed with sufficient strength (for example, Patent Documents 1 and 2).

[0003] When such fasteners are fitted into molded components, they are pressed into boss holes provided in the molded components while being heated (to around 200°C), which is possible because such synthetic resin molded components are made of thermoplastic resin. Therefore, the 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). Patent application No. 2023-133165

[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 filed in Japanese Patent Application No. 2023-133165 has a problem in that the thermoplastic resin is attached to the rear end of the fastener with an adhesive or the like, which makes it difficult to attach the thermoplastic resin to the fastener and makes it unsuitable for mass production. The object of this invention is to provide a fastener and a fastener fixing method that can be fixed to a hole provided in a molded thermoplastic resin member suitable for mass production. [Means for solving the problem]

[0007] Therefore, the present invention provides a nut-shaped metal fastener that is heated and pressurized to be fixed into a hole in a molded thermoplastic resin member, and includes 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 surfaces on the outer peripheral surface of the cylindrical body, the plug body portion having a maximum outer diameter on the side in contact with the head and having an outer diameter that decreases at a predetermined gradient in a truncated cone shape, and an anchor portion provided adjacent to the plug body portion. The present invention also provides a method for fixing a nut-shaped metal fastener that is heated and pressurized to be fixed in a hole provided in a molded thermoplastic resin member, the fastener having a cylindrical body and a head having the same outer diameter as the diameter of the hole, a plug body portion adjacent to the head and having a number of uneven ridges on the outer peripheral surface of the cylindrical body, the plug body portion having a maximum outer diameter on the side in contact with the head and having a truncated cone shape whose outer diameter decreases at a predetermined gradient, and an anchor portion provided adjacent to the plug body portion, such that when the fastener is inserted into a hole provided in the molded thermoplastic resin member and the head of the fastener is heated and pressurized, the anchor portion of the fastener melts the bottom of the hole and is fixed. [Effects of the Invention]

[0008] The present invention can provide a fastener that can be fixed to a hole provided in a molded member made of thermoplastic resin, which is suitable for mass production, and a method for fixing the fastener. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a half-sectional view showing an example of a fastener to which a first example according to an embodiment of the present invention can be applied. [Figure 2] 1 is a cross-sectional view showing the shape of a molded member to which the first embodiment can be applied. [Figure 3] FIG. 10 is a diagram showing a state in which the fastener is temporarily placed in a hole in the molded product member. [Figure 4] FIG. 10 is a diagram showing the state in which the fastener is fixed to the hole in the molded product member. DETAILED DESCRIPTION OF THE INVENTION

[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. This fastener 1 comprises a short, cylindrical body 2, a head 3 provided on the outer peripheral surface having an end face a, a small-diameter portion 4, a plug body portion 5 provided on the outer peripheral surface with a square-mesh knurling pattern (uneven stripes), a rear end portion 6, and an anchor (anchor portion) 7 consisting of a shank (anchor handle) 7a and an anchor head (anchor crown) 7b that also serves as a claw. The anchor head 7a of the anchor 7 is machined into a conical shape with a sloped surface that curves concavely toward the core. The head 3 is machined with an outer diameter equal to the hole diameter of the molded thermoplastic resin member described below. The head is designed according to the size of the fastener, with the "hole diameter of the molded member ≧ the outer diameter of the head." This is done to change the design dimensions if necessary to remove air from the hole when the fastener is heated and pressurized into the hole. Therefore, the head may be made smaller than the hole diameter of the molded member by a predetermined value depending on the size of the fastener.

[0011] The plug body 5 has a truncated cone shape with the largest outer diameter on the side adjacent to the small-diameter portion 4, and the outer diameter decreases toward the rear end 6. Therefore, in this embodiment, the gradient angle is 10 degrees. The gradient angle of this plug body is machined within the range of 0 to 20 degrees depending on the size and material of the fastener. A 0-degree gradient for the plug body would be cylindrical, but if necessary for design purposes, a cylindrical shape may be used instead of a truncated cone. Furthermore, 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. The plug body is designed according to the size of the fastener, such that "the hole diameter of the molded product member ≥ the maximum outer diameter of the plug body." Therefore, this maximum outer diameter may be set to a predetermined value smaller than the hole diameter of the molded product member depending on the size of the fastener.

[0012] The main body 2 is provided with a closed-end internal thread 8 extending from the end face a. The small diameter portion 4 need not be provided. The key point is to design it so that the molten thermoplastic resin does not flow from the plug body portion 5 into the head portion 3, as will be described in detail later. The anchor is used to provide the strength for the fastener to be pulled out of the hole, and can be made into various shapes depending on the size of the fastener.

[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 anchor 7) is 11.00 mm, head 3 has an outer diameter of 6.00 mm and a length of 5.50 mm, small diameter portion 4 has an outer diameter of 5.80 mm and a length of 0.50 mm, plug body 5 has a maximum outer diameter of 6.00 mm and a length of 4.00 mm on the side that contacts small diameter portion 4, shank 7a has an outer diameter of 2.00 mm and a length of 0.50 mm, and anchor head 7b has a maximum outer diameter of 3.00 mm and a length of 0.50 mm. Female thread 8 is machined with an M4 thread. Although the fastener 1 is made of brass in this embodiment, other 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 has a boss 12 with a hole 13 formed in it, and an end face b on the top surface of the boss 12. The hole 13 has an inner diameter of 6.00 mm and a depth of 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 acts as a guide when fitting into hole 13 formed in thermosetting resin molded member 11. Furthermore, fastener 1 of the present invention does not have plug body portion 5 that scrapes the circumferential surface of the hole in the molded member as in the past, but rather, as will be described in detail later, anchor 7 melts the bottom of hole 13 and embeds itself in the hole bottom and hardens. This is a novel concept that is completely different from the conventional idea of ​​forcibly fitting a fastener with an outer diameter larger than the inner diameter of the 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, this fitting and fixing method involves applying pressure to the fastener 1 while heating it, thereby fitting it 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 this time, the fastener 1 is temporarily placed in the hole 13 of the molded product member 11, with the plug portion 5 acting as a guide.

[0017] As shown in Figure 3, the tip of anchor 7 of fastener 1 rests on the bottom of hole 13. In this state, fastener 1 is heated and pressurized from above (top of the figure), causing the anchor 7 to melt the bottom of hole 13, allowing fastener 1 to enter hole 13. That is, as fastener 1 is heated, melting of the resin at the bottom of the hole begins from anchor head 7b of anchor 7, and the application of pressure accelerates the melting. The molten resin at the bottom of the hole flows from anchor 7 through rear end 6 onto the knurled surface of plug body 5.

[0018] FIG. 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 product member 11. The fastener 1 is pressed until the entire length of 1.00 mm of the anchor 7 is embedded in the bottom of the hole 13 (predetermined position), and stops there. As a result, the end face a of the fastener 1 and the end face b of the molded product member 11 are flush and coincident (predetermined position). Conversely, by applying heat and pressure until the end face a of the fastener 1 and the end face b of the molded product member 11 are flush and coincident (1.00 mm, the entire length of the anchor 7 in this embodiment), the anchor 7 is embedded in the bottom of the hole 13.

[0019] In this way, the resin at the bottom of the hole 13 melted by the anchor 7 bites into the knurling of the square mesh of the plug body portion 5, and the anchor 7 is buried in the bottom of the hole 13. The fastener 1 maintains tensile strength (pull-out strength) to the hole 13 of the molded member 11 through the anchor 7, and the square mesh knurling on the plug body portion 5 ensures 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 at the top of the boss 12. Furthermore, it is thought that cracks due to deterioration of the boss 12 over time can also be avoided.

[0020] As described above, according to the above-described embodiments of the present invention, it is possible to provide a fastener that can be fixed to a hole provided in a molded thermoplastic resin member suitable for mass production, and a method for fixing the fastener.

[0021] The present invention is not limited to the above-described embodiments and may be modified in various ways without departing from the spirit of the invention. Furthermore, the embodiments may be combined as appropriate to the extent possible, and the combined effects may be obtained. Furthermore, the above-described embodiments include inventions at various stages, and various inventions may be extracted by appropriately combining the disclosed multiple constituent elements. For example, if some constituent elements are deleted from all constituent elements shown in the embodiments, and the problem stated in the "Problem to be Solved by the Invention" section can be solved and the effects stated in the "Effects of the Invention" section can be obtained, the configuration from which these constituent elements are deleted can be extracted as an invention. The present invention applies to fasteners with an outer diameter of 30 mm or less. [Explanation of symbols]

[0022] 1...fixing device, 2...main body, 3...head, 4...small diameter portion, 5...plug body portion, 6...rear end portion, 7...anchor, 8...female thread, 11...molded member, 12...boss, 13...hole

Claims

1. A nut-shaped metal fastener that is fixed by applying heat and pressure to a hole having a hole bottom provided in a molded thermoplastic resin member, a head provided on a cylindrical body; a plug portion having a plurality of ridges and grooves on the outer peripheral surface of the cylindrical body adjacent to the head portion, the outer diameter of which decreases at a predetermined gradient in a truncated cone shape from a maximum outer diameter equal to or smaller than the inner diameter of the hole by a predetermined value; an anchor portion comprising an anchor handle adjacent to the plug body portion and having an outer diameter smaller than the outer diameter of the plug body portion, and an anchor crown adjacent to the anchor handle and having an outer diameter larger than the outer diameter of the anchor handle; A fastener characterized by comprising:

2. A method for fixing a nut-shaped metal fastener that is fixed by applying heat and pressure to a hole having a hole bottom provided in a thermoplastic resin molded member, comprising: The fastener has an anchor portion comprising a head portion provided on a cylindrical body, a plug portion adjacent to the head portion having a number of ridges and grooves on the outer peripheral surface of the cylindrical body, the plug portion having a maximum outer diameter equal to or smaller by a predetermined value than the inner diameter of the hole and having an outer diameter decreasing at a predetermined gradient in a truncated cone shape, an anchor handle adjacent to the plug portion and having an outer diameter smaller than the outer diameter of the plug portion, and an anchor crown adjacent to the anchor handle and having an outer diameter larger than the outer diameter of the anchor handle, a method for fixing a fastener, characterized in that when the fastener is inserted into a hole provided in the thermoplastic resin molded product member and the fastener is heated and pressurized, the anchor portion of the fastener melts and fills the bottom of the hole, the resin that is melted and extruded from the bottom of the hole by the anchor portion flows onto the peripheral surfaces of the numerous concave-convex strips of the plug body portion, and the molten resin solidifies around the anchor portion and the peripheral surfaces of the numerous concave-convex strips of the plug body portion, thereby fixing the fastener in the hole.

3. A nut-shaped metal fastener that is fixed by applying heat and pressure to a hole having a hole bottom provided in a molded thermoplastic resin member, a plug portion having a cylindrical body with a number of ridges and grooves on the outer peripheral surface thereof, the plug portion having a maximum outer diameter equal to or smaller than the inner diameter of the hole by a predetermined value, and a truncated cone shape with an outer diameter that decreases at a predetermined gradient; an anchor portion comprising an anchor handle adjacent to the plug body portion and having an outer diameter smaller than the outer diameter of the plug body portion, and an anchor crown adjacent to the anchor handle and having an outer diameter larger than the outer diameter of the anchor handle; A fastener characterized by comprising:

4. A method for fixing a nut-shaped metal fastener that is fixed by applying heat and pressure to a hole having a hole bottom provided in a thermoplastic resin molded member, comprising: The fastener has an anchor portion having a cylindrical body with a number of ridges and grooves on the outer peripheral surface thereof, the anchor portion being a truncated cone-shaped plug portion whose maximum outer diameter is equal to or smaller by a predetermined value than the inner diameter of the hole, and whose outer diameter decreases at a predetermined gradient; an anchor handle adjacent to the plug portion and having an outer diameter smaller than the outer diameter of the plug portion; and an anchor crown adjacent to the anchor handle and having an outer diameter larger than the outer diameter of the anchor handle. a method for fixing a fastener, characterized in that when the fastener is inserted into a hole provided in the thermoplastic resin molded product member and the fastener is heated and pressurized, the anchor portion of the fastener melts and fills the bottom of the hole, the resin that is melted and extruded from the bottom of the hole by the anchor portion flows onto the peripheral surfaces of the numerous concave-convex strips of the plug body portion, and the molten resin solidifies around the anchor portion and the peripheral surfaces of the numerous concave-convex strips of the plug body portion, thereby fixing the fastener in the hole.

5. A nut-shaped metal fastener that is fixed by applying heat and pressure to a hole having a hole bottom provided in a molded thermoplastic resin member, a head provided on a cylindrical body; a cylindrical plug portion having a number of ridges and grooves on the outer peripheral surface of the cylindrical body adjacent to the head portion and an outer diameter equal to or smaller by a predetermined value than the inner diameter of the hole; an anchor portion comprising an anchor handle adjacent to the plug body portion and having an outer diameter smaller than the outer diameter of the plug body portion, and an anchor crown adjacent to the anchor handle and having an outer diameter larger than the outer diameter of the anchor handle; A fastener characterized by comprising:

6. A method for fixing a nut-shaped metal fastener that is fixed by applying heat and pressure to a hole having a hole bottom provided in a thermoplastic resin molded member, comprising: The fastener has an anchor portion comprising a head portion provided on a cylindrical body, a cylindrical plug portion adjacent to the head portion having a number of uneven portions on the outer peripheral surface of the cylindrical body and an outer diameter the same as or smaller by a predetermined value than the inner diameter of the hole, an anchor handle adjacent to the plug portion and having an outer diameter smaller than the outer diameter of the plug portion, and an anchor crown adjacent to the anchor handle and having an outer diameter larger than the outer diameter of the anchor handle, a method for fixing a fastener, characterized in that when the fastener is inserted into a hole provided in the thermoplastic resin molded product member and the fastener is heated and pressurized, the anchor portion of the fastener melts and fills the bottom of the hole, the resin that is melted and extruded from the bottom of the hole by the anchor portion flows onto the peripheral surfaces of the numerous concave-convex strips of the plug body portion, and the molten resin solidifies around the anchor portion and the peripheral surfaces of the numerous concave-convex strips of the plug body portion, thereby fixing the fastener in the hole.

7. A nut-shaped metal fastener that is fixed by applying heat and pressure to a hole having a hole bottom provided in a molded thermoplastic resin member, a cylindrical plug portion having a large number of ridges and grooves on the outer peripheral surface of the cylindrical body and an outer diameter that is the same as or smaller by a predetermined value than the inner diameter of the hole; an anchor portion comprising an anchor handle adjacent to the plug body portion and having an outer diameter smaller than the outer diameter of the plug body portion, and an anchor crown adjacent to the anchor handle and having an outer diameter larger than the outer diameter of the anchor handle; A fastener characterized by comprising:

8. A method for fixing a nut-shaped metal fastener that is fixed by applying heat and pressure to a hole having a hole bottom provided in a thermoplastic resin molded member, comprising: The fastener has a cylindrical body having a large number of ridges on the outer peripheral surface thereof, and comprises an anchor portion consisting of a cylindrical plug portion having an outer diameter equal to or smaller than the inner diameter of the hole by a predetermined value, an anchor handle adjacent to the plug portion and having an outer diameter smaller than the outer diameter of the plug portion, and an anchor crown adjacent to the anchor handle and having an outer diameter larger than the outer diameter of the anchor handle, a method for fixing a fastener, characterized in that when the fastener is inserted into a hole provided in the thermoplastic resin molded product member and the fastener is heated and pressurized, the anchor portion of the fastener melts and fills the bottom of the hole, the resin that is melted and extruded from the bottom of the hole by the anchor portion flows onto the peripheral surfaces of the numerous concave-convex strips of the plug body portion, and the molten resin solidifies around the anchor portion and the peripheral surfaces of the numerous concave-convex strips of the plug body portion, thereby fixing the fastener in the hole.

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