JP2007285440A - Nut assembly and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily manufacture a nut assembly which produces a locking effect. <P>SOLUTION: A nut assembly 1 comprises a metal nut 5, an annular elastic member 7, and a body part 8 for embedding and fixing a part of the elastic member 7 and the metal not 5. One end face 14 of the elastic member 7 surrounds the periphery of an opening 19 of a first end face 6 of the metal nut 5. The core pin of a mold for molding the body part is inserted in a non-threaded hole 16 of the elastic member 7, so that the outer peripheral surface of the core pin tightly contacts the inner peripheral surface of the non-threaded 16. So the elastic member 7 and the core pin cooperate with each other to seal the opening 19 of the first end face 6 of the metal nut 5. In this state, the body part 8 is injection-molded. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a nut assembly and a method of manufacturing a nut assembly.

A locking nut in which a metal nut is inserted into a resin member is known (for example, see Patent Document 1). The resin member is formed with a screwless hole having a smaller diameter than the screw hole of the metal nut. When the locking nut and the bolt are joined together, the bolt is screwed into the screw hole of the metal nut and inserted through the screwless hole of the resin member. Thus, the bolt is elastically tightened to the resin member so as not to loosen from the locking nut.
JP-A-6-308432

For example, a pin for forming a screwless hole is provided in a mold for molding the resin member of the locking nut as described above. When the resin member is molded, a nut is inserted into a part of the pin and the nut is held by the pin, and the resin member is molded in this state.
Here, the inner diameter of the screwless hole is smaller than the inner diameter (valley diameter) of the screw hole of the nut. That is, the outer diameter of the screwless hole forming pin is smaller than the inner diameter of the screw hole. Therefore, when the resin member is molded, even if the pin is inserted into the screw hole to close the screw hole, the resin flows into the gap between the pin and the screw hole and adheres to the inner peripheral surface of the screw hole. For this reason, after molding the resin member, it is necessary to remove the resin adhering to the inner peripheral surface of the screw hole, which is troublesome.

  The present invention has been made in view of such a background, and an object of the present invention is to provide a nut assembly and a method for manufacturing the nut assembly that can exhibit the effect of preventing the loosening of the screw shaft and are easy to manufacture.

  In order to achieve the above object, the invention according to claim 1 is a material including a screw hole for screwing onto a screw shaft, a nut having first and second end faces in which the screw hole is opened, and a thermoplastic elastomer. And an annular elastic member disposed adjacent to the first end surface of the nut, and a main body portion that embeds and fixes a part of the nut and the elastic member, and the elastic member is embedded in the main body portion. An annular embedded portion, an annular contact portion that contacts the first end surface of the nut and surrounds the periphery of the screw hole, and a screwless hole that is connected to the screw hole and through which the screw shaft is inserted. The nut assembly is characterized by being smaller than the root diameter of the screw hole of the nut.

  According to the present invention, the screwless hole of the elastic member can be elastically deformed into the screw hole that fits the outer shape of the screw shaft and can be engaged with the screw shaft, thereby reliably preventing the screw shaft from loosening. can do. In addition, for example, a pin is provided in a mold used for molding the main body portion, the pin is inserted into a screwless hole of the elastic member, and the outer periphery of the pin and the inner periphery of the screwless hole are brought into close contact with each other. And the pin can cooperate to seal the opening of the screw hole. Thereby, when a main part is shape | molded by inserting a nut and an elastic member, it can prevent that the material inject | poured in the metal mold | die for main part formation penetrate | invades into the screw hole of a nut. As a result, it is possible to prevent the material for molding the main body from adhering to the inner peripheral surface of the screw hole, so that the work of removing the material adhering to the inner peripheral surface of the screw hole becomes unnecessary, and the labor for manufacturing is greatly reduced. Can be reduced.

  According to a second aspect of the present invention, in the first aspect, the main body portion covers at least a part of the second end surface of the nut and receives a fastening target, and a screw hole of the nut formed in the seat portion. A large-diameter hole that is continuous with the inner diameter of the large-diameter hole is larger than the outer diameter of the screw shaft, and the nut is embedded in the seat portion of the main body portion and suppresses the expansion of the seat portion. The nut assembly further includes a protrusion.

  According to the present invention, for example, when a screw and a nut assembly are coupled and a fastening target such as a plate member is fastened, the nut is moved to the fastening target side by screwing with the screw shaft to compress the seat portion. Sometimes. In this case, the seat portion (large diameter hole) is expanded in diameter, and the nut is easily detached from the main body portion. However, since the diameter expansion of the seat portion can be suppressed by the diameter expansion suppression protrusion, it is possible to reliably suppress the nut from being detached from the main body portion.

  According to a third aspect of the present invention, there is provided a method of manufacturing the nut assembly according to the first or second aspect, wherein the nut and the elastic member are set in the cavity for molding the main body of the mold, In the above preparation step, the contact portion of the elastic member is the first part of the nut in a state where a part of the core pin holding the nut and the elastic member is fitted in the screwless hole of the elastic member. 1 is a method for manufacturing a nut assembly, wherein the nut assembly is in contact with an end surface of the nut.

  According to the present invention, the opening of the screw hole of the nut can be sealed by a simple preparatory work of fitting the core pin and the elastic member and bringing the elastic member into contact with the first end surface of the nut. Thereby, it can prevent that the material for main-body part shaping | molding penetrate | invades in the screw hole of a nut in a formation process. As a result, it is not necessary to provide a process for removing the material adhering to the inner periphery of the screw hole after the molding process, and the manufacturing process can be reduced and the manufacturing process can be greatly reduced.

Embodiments of the present invention will be specifically described below with reference to the drawings.
FIG. 1 is a schematic partial cross-sectional side view of a nut assembly according to an embodiment of the present invention. 2 and 3 are partial cross-sectional side views each showing a state in which a plate material to be fastened is fastened using a nut assembly, and FIG. 2 shows a state in the middle of fastening the plate material. FIG. 3 shows a state in which the fastening of the plate material is completed.

Referring to FIGS. 1 and 2, a nut assembly 1 is for coupling with a screw 2 to fasten plate members 3, 4 and the like as fastening objects, and includes a metal nut 5 as a nut, and a metal nut. 5 is provided with an annular elastic member 7 disposed adjacent to the first end surface 6 as one end surface, and a main body 8 for embedding and fixing a part of the metal nut 5 and the elastic member 7.
The metal nut 5 is for receiving an axial force by screwing with the screw shaft 9 of the screw 2 and is made of, for example, a square nut, and has a polygonal cross-sectional shape. Examples of the material of the metal nut 5 include brass, stainless steel (SUS) material, steel, and aluminum. The screw hole 10 of the metal nut 5 extends concentrically and parallel to the outer peripheral surface 11 of the metal nut 5 and penetrates the meat of the metal nut 5. The screw hole 10 is opened to the outside by openings 19 and 31 formed in the first end face 6 of the metal nut 5 and the second end face 12 as the other end face. The first and second end surfaces 6 and 12 are each formed as a flat surface and extend parallel to each other. The outer peripheral surface 11 of the metal nut 5 is a flat surface. In addition, the cross-sectional shape of the outer peripheral surface 11 may be circular, and the metal nut 5 may be a cylindrical nut.

The elastic member 7 is for elastically coupling with the screw shaft 9 of the screw 2 to prevent the screw shaft 9 from being loosened, and when the main body portion 8 is formed, the material for forming the main body portion is a metal nut 5. This is to prevent the screw hole 10 from entering.
The material constituting the elastic member 7 includes a thermoplastic elastomer. Examples of the thermoplastic elastomer include styrene elastomers, olefin elastomers, vinyl chloride elastomers, polyamide elastomers, and polyurethane elastomers. Examples of polyurethane elastomers include polyether elastomers and polyester elastomers.

Furthermore, as said thermoplastic elastomer, it is preferable to have 40-65 by D hardness of JIS (Japanese Industrial Standard). When D hardness is 40-45, it is preferable at the point which ensures the elasticity of the elastic member 7 fully, and exhibits a favorable sealing effect, and when D hardness is 45-65, at the point of heat resistance and durability. preferable.
The elastic member 7 has an outer peripheral surface 13 having a polygonal cross section, and is locked to the main body portion 8 in the circumferential direction of the elastic member 7. The cross-sectional shape of the outer peripheral surface 13 of the elastic member 7 may be a shape having a portion where the radius of curvature changes, such as an elliptical shape. Thereby, the rotation prevention of the elastic member 7 with respect to the main-body part 8 is achieved. For example, the outer peripheral surface 13 of the elastic member 7 has a substantially quadrangular cross section.

The elastic member 7 includes a pair of end surfaces 14 and 15 facing each other in the axial direction S, a screwless hole 16 formed between the pair of end surfaces 14 and 15, and an annular embedded portion 17 embedded in the main body portion 8. And an exposed portion 18 exposed from the main body portion 8.
The pair of end faces 14 and 15 are orthogonal to the axial direction S and extend parallel to each other. One end surface 14 as a contact portion has an annular shape surrounding the periphery of the opening 19 of the screw hole 10 of the metal nut 5, and is in liquid-tight contact with the first end surface 6 of the metal nut 5.

The unthreaded hole 16 is defined by a flat surface that does not include a thread, and communicates with the threaded hole 10 of the metal nut 5 through the elastic member 7. The screw shaft 9 is inserted into the screwless hole 16. The screwless hole 16 and the screw hole 10 are concentrically aligned in the axial direction S.
In a state where the screw shaft 9 is not inserted, the inner diameter A of the screwless hole 16 is set smaller than the valley diameter B of the screw hole 10 of the metal nut 5 (A <B). The upper limit of the inner diameter A of the screwless hole 16 may be the effective diameter C of the screw hole 10 or the crest diameter D of the screw hole 10. Further, the lower limit of the inner diameter A of the screwless hole 16 may be a crest diameter D or an effective diameter C.

  The embedded portion 17 is an annular portion embedded in the main body portion 8 when the main body portion 8 is molded, and corresponds to the outer peripheral portion of the elastic member 7. The other end surface 15 and the outer peripheral surface 13 of the elastic member 7 in the embedded portion 17 are received by the main body portion 8. The exposed portion 18 is an annular portion located radially inward of the embedded portion 17 and corresponds to the inner peripheral portion of the elastic member 7. The exposed portion 18 is provided with the above-described screwless hole 16.

The main body 8 integrally holds the metal nut 5 and the elastic member 7, protects the metal nut 5 from deterioration such as corrosion and electrolytic corrosion, and is in close contact with the plate material 3, This is to prevent foreign matter from entering the screw insertion holes 20 and 21.
The main body 8 is formed using the same material as the elastic member 7. The main body 8 is integrally formed of a single member as a whole, and includes a main body 22 that surrounds the metal nut 5 and the elastic member 7, and a seat 23 that is continuous with the lower end of the main body 22. .

The main body portion 22 is formed in, for example, a truncated cone shape, and is connected to a small diameter portion 24 surrounding the elastic member 7 and a lower end portion of the small diameter portion 24, and a large diameter portion 25 surrounding the outer peripheral surface 11 of the metal nut 5. Including.
The inner peripheral surface of the narrow-diameter portion 24 includes a first portion 26 that contacts the outer peripheral surface 13 of the elastic member 7, a second portion 27 located above the first portion 26, and the first and second portions. And a step portion 28 provided between the portions 26 and 27. The step portion 28 is in contact with a part of the outer peripheral side of the other end face 15 of the elastic member 7, and prevents the elastic member 7 from moving upward from the main body portion 8. The second portion 27 of the narrow-diameter portion 24 extends from the radially inner end of the step portion 28 along the axial direction S and is open to the upper end portion of the main body portion 8.

The inner diameter of the second portion 27 is smaller than the inner diameter of the first portion 26 and larger than the inner diameter A of the screwless hole 16 (the outer diameter F of the screw shaft 9). The second portion 27 and the screwless hole 16 are arranged concentrically and communicate with each other. The screw shaft 9 can be inserted into the elastic member 7 from the second portion 27.
The inner peripheral surface of the large diameter portion 25 is in contact with the outer peripheral surface 11 of the metal nut 5, and relative rotation of the metal nut 5 with respect to the main body portion 8 is restricted.

The seat portion 23 is for receiving the plate material 3 and covers at least a part of the second end surface 12 of the metal nut 5. The seat portion 23 is formed in a disk shape having a larger diameter than the lower end portion of the large diameter portion 25, and has a predetermined thickness in the axial direction S. In addition, you may make it receive the board | plate material 3 by the main-body part 22, without providing the seat part 23. FIG.
A large diameter hole 29 is formed in the seat portion 23 concentrically with the screw hole 10. The large-diameter hole 29 passes through the seat portion 23 in the axial direction, and is continuous with the screw hole 10 of the metal nut 5 and is open to the seat surface 30. The inner diameter E of the large-diameter hole 29 is larger (E> F) than the outer diameter F (valley diameter) of the screw shaft 9 and can be introduced into the screw hole 10 without hitting the screw shaft 9 against the large-diameter hole 29. It is like that.

Of the second end surface 12 of the metal nut 5, the peripheral edge of the opening 31 is exposed to the seat surface 30 side. Further, a part of the seat portion 23 that is radially outward of the large-diameter hole 29 receives a part of the second end face 12 of the metal nut 5. This prevents the metal nut 5 from coming off the main body portion 8.
A mortar-shaped recess 32 for increasing the frictional engagement force with the surface 33 of the plate member 3 is formed on substantially the entire surface 30 (lower end surface) of the seat portion 23. The depth of the recess 32 (the distance from the surface 33 of the plate member 3) increases as it goes from the outer periphery to the inner periphery of the seat surface 30. In addition, the dent 32 may be formed on the entire surface of the seating surface 30, or may be formed only on a part around the large-diameter hole 29.

A knob 34 is provided on the outer peripheral surface of the main body 22. A plurality (two in this embodiment) of knobs 34 are arranged at equal intervals along the circumferential direction of the nut assembly 1. Each knob 34 is formed in a plate shape, and the nut built-in body 1 can be turned by picking these knobs 34 by hand, for example.
In addition, the knob portion 34 may be eliminated, and a friction increasing means such as a knurled shape having a flat shape, an iris shape, or a demon shape may be formed on the outer peripheral surface of the main body portion 22. Further, the cross-sectional shape of the outer peripheral surface of the main body portion 22 may be a polygonal shape (for example, a hexagonal shape) having a two-surface width as a tool engaging portion.

FIG. 4 is a perspective view of the metal nut 5. Referring to FIGS. 2 and 4, the metal nut 5 is configured to suppress the diameter expansion of the seat portion 23 when the nut assembly 1 fastens the plate members 3, 4. 5 is prevented from being detached from the main body 8.
Specifically, the metal nut 5 has a protrusion 35 as a diameter expansion suppressing protrusion. For example, the protrusions 35 are formed by welding the outer peripheral corners of the second end surface 12 of the metal nut 5, and a plurality of protrusions 35 are arranged in the circumferential direction of the metal nut 5 (in this embodiment, 4 Pieces). Each protrusion 35 protrudes below the second end surface 12. Each projection 35 is disposed radially outward of the large-diameter hole 29 and is embedded in the seat portion 23, and restricts relative rotation between the main body portion 8 and the metal nut 5.

The above is the schematic configuration of the nut assembly 1. Next, a case where the plate members 3 and 4 are fastened using the nut assembly 1 will be described.
Referring to FIG. 2, when the screw 2 and the nut assembly 1 are coupled and the plate members 3 and 4 are fastened, first, the plate members 3 and 4 are overlapped, and the screw shaft 9 of the screw 2 is attached to the plate member 3. , 4 and the large diameter hole 29 of the nut assembly 1 are inserted. Next, the nut assembly 1 is rotated with respect to the screw shaft 9.

As a result, the screw shaft 9 is screwed into the metal nut 5 and is inserted through the screwless hole 16 (see FIG. 1) of the elastic member 7, and the inner peripheral surface of the screwless hole 16 is elastically deformed. As shown, a screw hole 33 is formed to be screwed into the screw thread of the screw shaft 9. As a result, the screw shaft 9 is coupled to the nut assembly 1 and the space between the screwless hole 16 and the screw shaft 9 is sealed.
Further, as the nut assembly 1 is rotated with respect to the screw shaft 9, the metal nut 5 and the elastic member 7 are screwed with the screw shaft 9 as shown in FIG. The metal nut 5 presses the meat of the seat portion 23 downward. As a result, the seat portion 23 is pressed between the metal nut 5 and the plate material 3, and the seat surface 30 is pressed against the periphery (surface 33) of the screw insertion hole 20 of the plate material 3. Thereby, the dent 32 of the seating surface 30 is deformed flat and comes into liquid-tight contact with the surface 33.

When the metal nut 5 moves to the plate member 3 side and each projection 35 is received by the surface 33 of the plate member 3, the downward movement of the metal nut 5 is restricted. As a result, the second end surface 12 of the metal nut 5 is prevented from reaching the seat surface 30, and the diameter of the seat portion 23 is prevented from being increased by each projection 35. As a result, the metal nut 5 is prevented from being detached from the main body portion 8.
FIG. 5 is a schematic partial cross-sectional side view of a mold 40 for molding the nut assembly 1. Referring to FIGS. 1 and 5, the mold 40 includes a cavity 41 for forming a main body part and a core pin 42 through which the cavity 41 is inserted.

The cavity 41 is partitioned by a cavity portion 43. The cavity portion 43 includes a first portion 44 for forming the shape of the outer surface of the main body portion 22 and the knob portion 34 of the main body portion 8, and a second portion for forming the shape of the outer surface of the seat portion 23. 45.
The first and second portions 44 and 45 are in contact with each other at their respective parting surfaces 46 and 47, and the cavity 43 can be divided at these parting surfaces 46 and 47. The bottom surface of the second portion 45 is formed in a shape corresponding to the shape of the seating surface 30 of the seat portion 23, and the core pin 42 that passes through the cavity 41 through the second portion 45 in the center portion of the bottom surface. Is erected.

The core pin 42 includes a large-diameter portion 48 for forming the large-diameter hole 29 of the seat portion 23, and a shaft portion 49 that is disposed above the large-diameter portion 48 and fits into the screw hole 10 of the metal nut 5. It has.
The shape of the outer peripheral surface of the large diameter portion 48 is a shape corresponding to the shape of the inner peripheral surface of the large diameter hole 29. The upper end of the large diameter portion 48 is an annular step portion 50. The annular step portion 50 extends in the horizontal direction (the left-right direction in FIG. 5) and can receive the second end surface 12 of the metal nut 5.

The shaft portion 49 has a smaller diameter than the annular step portion 50 and extends upward from the step portion 50. On the outer periphery of the shaft portion 49, a screw portion 51 similar to the screw shaft 9 (see FIG. 2) is formed. The outer diameter E of the shaft portion 49 is larger than the inner diameter A of the screwless hole 16.
1 and 5, when the inner diameter A of the screwless hole 16 is smaller than the crest diameter D of the screw hole 10 (A <D), the outer peripheral surface of the shaft portion 49 is You may make it a smooth surface without a thread part. In this case, the shaft portion 49 is inserted into the screw hole 10 of the metal nut 5 and is in close contact with the entire circumference of the inner peripheral surface of the screwless hole 16.

An engaging convex portion 52 is formed at the upper end of the shaft portion 49, and is engaged with the engaging concave portion 53 of the tip portion 55 of the pin 57 that passes through the first portion 44 and passes through the cavity 41. . Thereby, the core pin 42 can be accurately positioned with respect to the first portion 44.
The distal end portion 55 has a cylindrical shape extending from the first portion 44 toward the second portion 45 side, and the outer peripheral surface thereof has the shape of the second portion 27 of the inner peripheral surface of the small diameter portion 24. It has a corresponding shape. The end surface 54 of the tip 55 is parallel to the annular stepped portion 50 of the core pin 42, and the engagement recess 53 is formed on the end surface 54. The end face 54 comes into contact with the other end face 15 of the elastic member 7.

The above is the schematic configuration of the mold 40. Next, a method for manufacturing the nut assembly 1 will be described. The method for manufacturing the nut assembly 1 includes a preparation process for setting the metal nut 5 and the elastic member 7 in the cavity 41 of the mold 40, and a molding process for molding the main body 8 in the cavity 41.
Specifically, first, in the preparation step, the first and second portions 44 and 45 of the cavity portion 43 are separated from each other (see FIG. 6), and in this state, the thread portion of the shaft portion 49 of the core pin 42 is obtained. 51, the screw hole 10 of the metal nut 5 and the screwless hole 16 of the elastic member 7 are fitted (screwed together). The core nut 42 holds the metal nut 5 and the elastic member 7.

  At this time, the second end surface 12 of the metal nut 5 is brought into contact with the annular step portion 50 of the core pin 42, and the opening 31 of the second end surface 12 is sealed with the annular step portion 50. Further, the inner peripheral surface of the screwless hole 16 of the elastic member 7 and the outer peripheral surface of the screw portion 51 of the shaft portion 49 of the core pin 42 are brought into contact over the entire circumference, and one end surface 14 of the elastic member 7 and the metal The opening 19 is sealed by contacting the first end surface 6 of the nut 5.

  Next, as shown in FIG. 7, the parting surfaces 46 and 47 of the first and second portions 44 and 45 of the cavity portion 43 are overlapped with each other to partition the cavity 41. At this time, the engaging convex part 52 of the core pin 42 and the engaging concave part 53 of the front-end | tip part 55 are fitted, and positioning between both is made. Further, the end surface 54 of the distal end portion 55 is in contact with the other end surface 15 of the elastic member 7 over the entire circumference.

Then, as shown in FIG. 8, in the molding step, a main body portion forming material is injected into the cavity 41 from a gate (not shown) to mold the main body portion 8. Thereby, the nut assembly 1 is completed.
As described above, according to the present embodiment, the following operational effects can be achieved. That is, the screwless hole 16 of the elastic member 7 can be elastically deformed into the screw hole 33 that fits the outer shape of the screw shaft 9 and can be engaged with the screw shaft 9, thereby ensuring that the screw shaft 9 is loosened. Can be prevented.

  Further, by inserting the threaded portion 51 of the shaft portion 49 of the core pin 42 of the mold 40 into the screwless hole 16 of the elastic member 7, the outer peripheral surface of the core pin 42 and the inner peripheral surface of the screwless hole 16 are brought into close contact with each other. The elastic member 7 and the core pin 42 can cooperate to seal the opening 19 of the screw hole 10. The opening 31 can be sealed with the second end face 12 and the stepped portion 50. Thereby, when the metal nut 5 and the elastic member 7 are inserted and the main body portion 8 is formed, the material injected into the mold 40 can be prevented from entering the screw hole 10 of the metal nut 5. As a result, it is possible to prevent the material for molding the main body from adhering to the inner peripheral surface of the screw hole 10, so that the work of removing the material adhering to the inner peripheral surface of the screw hole 10 becomes unnecessary, which is troublesome in manufacturing. Can be significantly reduced.

  Further, when the screw 2 and the nut assembly 1 are coupled and the plate members 3 and 4 are fastened, the metal nut 5 is moved to the plate members 3 and 4 side by screwing with the screw shaft 9 to compress the seat portion 23. To do. Accordingly, the diameter of the seat portion 23 (large diameter hole 29) is increased, and the metal nut 5 tends to be easily detached from the main body portion 8. However, since the diameter of the seat portion 23 can be suppressed by the protrusions 35 provided on the metal nut 5, it is possible to reliably suppress the metal nut 5 from being detached from the main body portion 8.

  Furthermore, in the preparation process when manufacturing the nut assembly 1, the core pin 42 and the elastic member 7 are fitted together, and the elastic member 7 is brought into contact with the first end surface 6 of the metal nut 5. The opening 19 of the screw hole 10 of the metal nut 5 can be sealed. Further, the opening 31 of the screw hole 10 of the metal nut 5 can be sealed by a simple operation of placing the second end surface 12 of the metal nut 5 on the stepped portion 50 of the core pin 42. Thereby, it can prevent that the material for main-body part shaping | molding penetrate | invades into the screw hole 10 of the metal nut 5 in a shaping | molding process. As a result, it is not necessary to provide a process for removing the material adhering to the inner periphery of the screw hole 10 after the molding process, and the manufacturing process can be reduced and the manufacturing process can be greatly reduced.

  Further, the shaft portion 49 of the core pin 42 of the mold 40 is fitted into both the screw hole 10 of the metal nut 5 and the screwless hole 16 of the elastic member 7. As a result, by holding the metal nut 5 and the elastic member 7 on the core pin 42, the relative positions of the screw hole 10 and the screwless hole 16 can be accurately positioned, and a nut assembly with high dimensional accuracy. 1 can be molded.

In addition, in the small diameter part 24 of the main-body part 8, you may block | close the part which exists in the radial direction inside of the 2nd part 27 of an internal peripheral surface. In this case, the tip 55 of the first portion 44 of the mold 40 is eliminated.
FIG. 9 is a partial cross-sectional side view of a mold 40A according to another embodiment of the present invention. In the following, differences from the embodiment shown in FIG. 5 will be mainly described, and the same components are denoted by the same reference numerals and description thereof will be omitted.

In the present embodiment, a core pin 42A is used instead of the core pin 42 as shown in FIG. Referring to FIGS. 1 and 9, core pin 42A is formed separately from first and second portions 44A and 45A of cavity portion 43A and is held by first portion 44A.
The shaft portion 49A of the core pin 42A includes a screw portion 51A for screwing (fitting) into the screw hole 10 of the metal nut 5 and the screwless hole 16 of the elastic member 7, and a bulge disposed above the screw portion 51A. Part 55A.

The screw part 51A is opposed to the large diameter part 48A provided in the pin 57A penetrating the second part 45A of the cavity part 43 in the vertical direction. The upper end portion of the bulging portion 55A is fitted in a recess 58 formed in the first portion 44A. Thus, the core pin 42A is positioned on the core pin 42A while being held by the first portion 44A.
As shown in FIG. 10, in the preparation step, the threaded portion 51 </ b> A of the core pin 42 </ b> A is fitted into the screw hole 10 of the metal nut 5 and the unthreaded hole 16 of the elastic member 7. In this state, the core pin 42A is inserted into the cavity 41. At this time, the contact between the outer peripheral surface of the threaded portion 51 </ b> A and the inner peripheral surface of the screwless hole 16 and the contact between one end surface 14 of the elastic member 7 and the first end surface 6 of the metal nut 5 cause the first. The opening 19 of the end face 6 is sealed.

  According to the present embodiment, by holding the metal nut 5 and the elastic member 7 on the core pin 42A, the relative position between the screw hole 10 and the screwless hole 16 can be accurately determined, and the dimensional accuracy can be improved. A high nut assembly 1 can be formed. Further, since the core pin 42A is formed separately from the cavity portion 43A, the core pin 42A can be attached to another cavity portion, and the core pin 42A can have versatility.

  The present invention is not limited to the above embodiments. For example, a resin nut may be used instead of the metal nut 5. As the resin in this case, a thermoplastic resin may be used, or a thermosetting resin may be used. More specifically, as the resin, ABS (Acrylonitrile Butadiene Styrene) resin, polyethylene resin, polycarbonate, phenol resin, POM (PolyOxyMethylene, Duracon), polyamide resin (for example, nylon 6-6), polypropylene resin, butyl resin, Phenol formaldehyde (PF), melamine resin and urea resin can be exemplified.

  Further, the main body 8 may be molded with a resin similar to the above resin instead of the thermoplastic elastomer. When the main body 8 is molded from resin, the hardness of the main body 8 can be increased. In this case, by providing a tool engaging portion having a two-surface width on the outer peripheral portion of the main body portion 8, the main body portion 8 can be reliably rotated with a tool such as a spanner. In this case, the protrusion 35 is not formed on the nut, and one end surface of the nut directly faces the plate material (fastening target). Furthermore, an annular groove is formed on the outer peripheral surface of the nut in order to ensure an axial coupling force between the main body 8 and the nut. In this case, a knurling that has a flat shape, an iris shape, or a demon-like shape may be formed on the outer peripheral surface of the nut to further increase the binding force with the main body portion 8.

  Further, the number of the protrusions 35 may be any one of 1 to 3, and may be 5 or more. Further, the protrusion 35 may be eliminated. Moreover, you may shape | mold the elastic member 7 and the main-body part 8 by 2 color molding. Furthermore, when using a resin nut, in addition to the elastic member 7 and the main body 8, the resin nut may be formed by two-color molding (multicolor molding).

It is a typical partial cross section side view of the nut assembly concerning one embodiment of the present invention. It is a partial cross section side view which shows a mode that a board | plate material is fastened using a nut assembly, and has shown the state in the middle of fastening the board | plate material. It is a partial cross section side view which shows a mode that a board | plate material is fastened using a nut assembly, The state which completed the fastening of the board | plate material is shown. It is a perspective view of a metal nut. It is a typical partial cross section side view of the metal mold | die for shape | molding a nut embedding body. It is a figure for demonstrating a preparatory process, and has shown the state from which the 1st and 2nd part of the cavity part was mutually isolate | separated. It is a figure for demonstrating a preparatory process, and has shown the state by which the 1st and 2nd part of the cavity part was mutually engaged. It is a figure for demonstrating a formation process. It is a partial cross section side view of the metal mold | die concerning another embodiment of this invention. It is a figure for demonstrating a preparatory process.

Explanation of symbols

1 Nut assembly 3, 4 Plate material (to be fastened)
5 Metal nut (nut)
6 (first end surface of the metal nut) 7 elastic member 8 body portion 9 screw shaft 10 screw hole (of the nut) 12 second end surface (of the metal nut) 14 one end surface (contact portion)
16 Screwless hole 17 Buried part 23 Seat part 29 Large diameter hole 35 Protrusion (expansion suppression protrusion)
40, 40A Die 41 Cavity 42, 42A Core pin A Inner diameter B (of screwless hole) Valley diameter E (of screw hole) E Inner diameter F (of large diameter hole) Outer diameter (of screw shaft)

Claims (3)

A screw hole for screwing onto the screw shaft, and a nut having first and second end faces in which the screw hole opens;
An annular elastic member formed using a material comprising a thermoplastic elastomer and disposed adjacent to the first end face of the nut;
A main body portion for embedding and fixing a part of the nut and the elastic member,
The elastic member includes an annular embedded portion embedded in the main body, an annular contact portion that contacts the first end surface of the nut and surrounds the periphery of the screw hole, and a screwless hole that is connected to the screw hole and through which the screw shaft is inserted. Including
A nut assembly characterized in that the inner diameter of the screwless hole is smaller than the valley diameter of the screw hole of the nut. The main body according to claim 1, further comprising a seat for covering at least a part of the second end surface of the nut and receiving an object to be fastened, and a large-diameter hole formed in the seat and connected to the screw hole of the nut. Including
The inner diameter of the large hole is larger than the outer diameter of the screw shaft,
The nut assembly further includes a diameter expansion suppression protrusion embedded in the seat portion of the main body portion and suppressing the diameter expansion of the seat portion. A method of manufacturing a nut assembly according to claim 1 or 2,
A preparation step of setting a nut and an elastic member in a cavity for molding a main body of a mold;
A molding step of molding the main body in the cavity,
In the preparation step, the contact portion of the elastic member is in contact with the first end surface of the nut in a state in which a part of the core pin holding the nut and the elastic member is fitted in the screwless hole of the elastic member. A method of manufacturing a nut assembly.

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