JP2019070422A - Structure of fastening screw - Google Patents

Abstract

To provide a structure of a fastening screw capable of enhancing friction force of a connection surface between a fastening screw and a member to be fastened without considerably changing a shape of the fastening screw, to prevent looseness of the fastening screw.SOLUTION: In a structure of a fastening screw 10, when a first member to be fastened 12 and a second member to be fastened 14 are fastened, a head part 10a has on a male screw part 10c side a pressing surface 20 pressing the first member to be fastened 12; onto the pressing surface 20, a friction material 18 is bonded; and the friction material 18 comprises fibers, a binder and a filler. Consequently, friction force between the fastening screw 10 and the first member to be fastened 12 can be increased without considerably changing the structure of the fastening screw 10. Accordingly, compared to a case where the friction material 18 is not bonded to the pressing surface 20, the fastening screw 10 can be prevented from loosening.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fastening screw, and in particular, to the prevention of loosening without significantly changing the shape and structure of the fastening screw.

  A structure of a fastening screw integrally including a head and an external thread portion smaller in diameter than the head is known. For example, the structure of the fastening screw described in Patent Documents 1 to 3 is that.

  In the structure of the fastening screw described in Patent Documents 1 to 3, for example, various slack suppressing members such as washers are interposed between the fastening screw and the fastened member, or a joint surface between the fastening screw and the fastened member By providing the loosening suppression structure, the frictional force of the joint surface between the fastening screw and the member to be fastened is increased, and the loosening of the fastening screw is suppressed.

JP 2003-156025 A JP-A-6-249221 JP-A-9-280237

  In the structure of the fastening screw described in Patent Document 1, a plurality of washers whose bending is applied to the outer peripheral portion and a coupling member for mutually coupling the plurality of washers are provided between the fastening screw and the member to be fastened. Have. Further, in the structure of the fastening screw described in Patent Document 2, a flange-like engaging portion which is provided with an engagement protrusion engaged with an engagement hole formed in the fastened member and which protrudes outward in the radial direction is It is formed in a fastening screw. Furthermore, in the structure of the fastening screw described in Patent Document 3, a washer having a sawtooth shape formed on the seat surface of the head of the fastening screw and a sawtooth shape meshing with the sawtooth shape is the fastening screw. And the to-be-fastened member. Thereby, in the structure of the fastening screw of the said patent documents 1 to 3, in order to raise the frictional force of the joint surface between a fastening screw and a to-be-fastened member, it is necessary to largely change the shape and structure of a fastening screw Therefore, there is a possibility that the versatility is poor and, for example, design changes may be required for the peripheral parts of the fastening screw.

  The present invention has been made against the background described above, and the object of the present invention is to increase the frictional force of the joint surface between the fastening screw and the member to be fastened without largely changing the shape of the fastening screw. An object of the present invention is to provide a structure of a fastening screw which suppresses the loosening of the fastening screw.

  The subject matter of the first invention is (a) a structure of a fastening screw integrally including a head and an external thread portion smaller in diameter than the head, and (b) the head is a member to be fastened (C) a friction material is adhered to the pressing surface, and (d) the friction material is bonded to a fiber. It has a composition containing an agent and a filler.

  According to a second aspect of the present invention, in the first aspect, the fiber contains one or more selected from steel fiber, brass fiber, copper fiber, aramid fiber, acrylic fiber and phenol fiber. It is in.

  According to the third aspect of the present invention, in the first aspect or the second aspect of the invention, the binder is one or two selected from a phenol resin, an epoxy resin, a melamine resin, a cashew resin and a rubber composition. It is to include the above.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third inventions, the friction material has 4 to 10% by weight of the fiber with respect to the entire friction material, The binder content is 20 to 32% by weight.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth inventions, the friction material is adhered to the pressing surface by a thermosetting resin adhesive.

  According to the structure of the fastening screw of the first aspect of the present invention, the head has a pressing surface for pressing the to-be-fastened member on the external thread portion side when fastening the to-be-fastened member. A friction material is adhered, and the friction material is composed of fibers, a binder and a filler. Thereby, the frictional force of the joint surface between the fastening screw and the member to be fastened can be increased without largely changing the structure of the fastening screw. Therefore, the loosening of the fastening screw can be suppressed as compared with the case where the friction material is not adhered to the pressing surface.

  According to the structure of the fastening screw of the second invention, the fiber contains one or more selected from steel fiber, brass fiber, copper fiber, aramid fiber, acrylic fiber and phenol fiber. Thereby, since the filler is made of a practical and inexpensive material, the inexpensive friction material can be provided.

  According to the third invention, the binder contains one or more selected from phenolic resin, epoxy resin, melamine resin, cashew resin and rubber composition. Thereby, since the binder is made of a practical and inexpensive material, it is possible to provide the friction material which is less expensive.

  According to the fourth invention, the friction material is 4 to 10% by weight of the fibers and 20 to 32% by weight of the binder, based on the entire friction material. Thereby, sufficient strength can be given to the said friction material.

  According to the fifth invention, the friction material is adhered to the pressing surface by a thermosetting resin adhesive. Thus, the friction material is bonded to the pressing surface by an adhesive that is resistant to impact and bending and has a strong resistance to peeling.

It is sectional drawing which shows the structure of the fastening screw of one Example to which this invention is applied. It is sectional drawing which shows the structure of the fastening screw of the other Example to which this invention is applied.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of the respective parts are not necessarily drawn accurately.

  FIG. 1 is a cross-sectional view showing a structure of a fastening screw 10 according to an embodiment of the present invention, and a cross-section showing a state in which a first fastening member 12 and a second fastening member 14 are fastened by the fastening screw 10. FIG. The fastening screw 10 includes a head portion 10a, a cylindrical portion 10b and an external thread portion 10c in series on an axial center C1 from a screw base end toward a screw tip and is integrally provided with each other with the axial center C1 as a central axis. ing. The cylindrical portion 10 b and the male screw portion 10 c are smaller in diameter than the head 10 a. The fastening screw 10 is inserted into the first insertion hole 12 a formed in the first member 12 to be fastened and the second insertion hole 14 a formed in the second member 14 to be fastened, and is tightened by the nut 16. As the fastening screw 10, for example, a fastening screw in accordance with the JIS standard is used.

  The head 10 a is an engaging portion with which a fastening tool (not shown) for fastening the first and second members 12 and 14 to be fastened by the fastening screw 10 is engaged. In the head 10a, a pressing surface 20 for pressing the first fastened member 12 is provided on the male screw 10c side. When the first to-be-fastened member 12 and the second to-be-fastened member 14 overlapping each other are fastened by the fastening screw 10, the pressing surface 20 is one of the first to-be-fastened member 12 and the second to-be-fastened 14. The joint surface 12 b of the first member 12 to be fastened positioned on the head 10 a side is pressed. As shown in FIG. 1, a friction material 18 is interposed between the pressing surface 20 and the first fastened member 12. The friction material 18 is adhered to the pressing surface 20 by an adhesive. As the adhesive, a thermosetting resin adhesive is suitably used. For example, a phenol resin-based adhesive containing a phenol resin as a main ingredient, an epoxy resin-based adhesive containing an epoxy resin as a main ingredient, or the like is used.

  The friction material 18 comprises a fiber, a binder and a filler. Specifically, the friction material 18 is an organic fiber containing one or more selected from steel fiber, brass fiber, copper fiber, aramid fiber, acrylic fiber and phenol fiber, filler such as metal powder, etc. The base material is bonded with a binder containing one or more selected from a thermosetting resin such as a phenol resin, an epoxy resin, a melamine resin, a cashew resin, and a rubber composition. The friction material 18 is 4 to 10% by weight of organic fibers, 20 to 32% by weight of a binder, and 58 to 76% by weight of other materials including a filler, based on the entire friction material 18 It is formulated to be The other material may include an abrasive material such as iron. Here, in the present embodiment, the fibers constituting the friction material 18 are organic fibers, but inorganic fibers such as glass fibers, alumina silica fibers, rock wool or potassium titanate fibers may be included. Further, in the present embodiment, the filler that constitutes the friction material 18 may contain an inorganic powder.

  The same friction material as the lining (not shown) provided on the brake shoe of the vehicle drum brake is used for the friction material 18. The friction coefficient of the friction material obtained based on the low speed friction test (JIS) is larger than, for example, the friction coefficient of the joint surface between the fastening screw and the fastened member in one fastening screw of bolt strength section 8.8. . That is, in the fastening screw 10 in which the friction material 18 is adhered to the pressing surface 20, compared with the fastening screw in which the friction material 18 is not adhered, the joint screw 12 and the first to-be-fastened member 12 have a joint surface 12b. The coefficient of friction increases.

  The adhesive is applied to the pressing surface 20 after removing the surface treatment of the pressing surface 20 for pressing the first fastened member 12, for example, the plating treatment by polishing. Thereafter, the friction material 18 is spread on the pressing surface 20 to which the adhesive is applied, and dried by heating, whereby the fastening screw 10 is manufactured.

  In the structure of the fastening screw 10 configured as described above, the friction material 18 bonded to the pressing surface 20 makes the pressing surface 20 and the joint surface 12 b of the first member 12 to be fastened compared with the case without the friction material 18. The coefficient of friction between them is increased. By increasing the coefficient of friction, the frictional force of the joint surface 12b between the fastening screw 10 and the first fastened member 12 is increased, so that the loosening of the fastening screw 10 is suppressed.

  As described above, in the structure of the fastening screw 10 of the present embodiment, the head 10 a presses the first fastened member 12 when the first fastened member 12 and the second fastened member 14 are fastened. The surface 20 is on the side of the male screw portion 10c, the friction material 18 is adhered to the pressing surface 20, and the friction material 18 is configured to include fibers, a binder, and a filler. Thereby, the frictional force of the joint surface 12b between the fastening screw 10 and the first fastened member 12 can be increased without largely changing the structure of the fastening screw 10. Therefore, as compared with the case where the friction material 18 is not adhered to the pressing surface 20, the loosening of the fastening screw 10 can be suppressed.

  Further, according to the structure of the fastening screw 10 of the present embodiment, the fibers include one or more selected from steel fibers, brass fibers, copper fibers, aramid fibers, acrylic fibers and phenol fibers. Thereby, since the filler is made of a practical and inexpensive material, the inexpensive friction material 18 can be provided.

  Moreover, according to the structure of the fastening screw 10 of a present Example, a binder contains 1 type (s) or 2 or more types chosen from a phenol resin, an epoxy resin, a melamine resin, cashew resin, and a rubber composition. Thereby, since the binder is made of a practical and inexpensive material, it is possible to provide the friction material 18 which is less expensive.

  Further, according to the structure of the fastening screw 10 of the present embodiment, the friction material 18 has 4 to 10% by weight of fibers and 20 to 32% by weight of the binder with respect to the entire friction material 18. Thereby, sufficient strength can be given to the friction material 18.

  Further, according to the structure of the fastening screw 10 of the present embodiment, the friction material 18 is adhered to the pressing surface 20 by a thermosetting resin adhesive. Thus, the friction material 18 is bonded to the pressing surface 20 by an adhesive that is resistant to impact and bending and has a strong resistance to peeling.

  Next, another embodiment of the present invention will be described. The same reference numerals as in the first embodiment denote the same parts as in the first embodiment, and a description thereof will be omitted.

  FIG. 2 is a cross-sectional view showing the structure of the fastening screw 100 in another embodiment, and is a cross-sectional view showing a state in which the first fastening member 12 and the second fastening member 14 are fastened by the fastening screw 100. is there. The fastening screw 100 is provided with a head portion 100a, a cylindrical portion 100b and an external thread portion 100c in series on an axial center C2 from the screw base end toward the screw tip, and integrally provided with each other with the axial center C2 as a central axis ing. The cylindrical portion 100 b and the male screw portion 100 c are smaller in diameter than the head portion 100 a. As shown in FIG. 2, in the present embodiment, an annular member, so-called washer 102 is disposed between the head 100 a of the fastening screw 100 and the first fastened member 12. The washer 102 has a washer pressing surface 102 a for pressing the first fastened member 12 on the male screw portion 100 b side. The washer pressing surface 102 a presses the joint surface 12 b of the first fastened member 12 when the first fastened member 12 and the second fastened member 14 are fastened by the fastening screw 100. As shown in FIG. 2, a friction material 18 is interposed between the washer 102 and the first fastened member 12, and the friction material 18 is adhered to the washer pressing surface 102a by an adhesive.

  As described above, according to the present embodiment, when the friction material 18 is adhered to the washer pressing surface 102 a, the first screwed member 12 and the second screwed member 14 are fastened by the fastening screw 100. The joint surface 12b of the first to-be-fastened member 12 positioned on the washer 102 side of the first to-be-fastened member 12 and the second to-be-fastened member 14 is pressed. Thereby, in the case of the structure of the fastening screw 100 in which the washer 102 is disposed between the head portion 100a and the first member 12 to be fastened, the fastening screw 100 and the first screw 100 are not changed significantly. The frictional force with the fastened member 12 can be increased. Therefore, the loosening of the fastening screw 100 can be suppressed as compared with the case where the friction material 18 is not adhered to the washer pressing surface 102a.

  Although the preferred embodiments of the present invention have been described in detail with reference to the drawings, the present invention is not limited thereto, and may be embodied in other aspects.

  For example, although the friction material 18 is adhered to the pressing surface 20 or the washer pressing surface 102a in the above-described embodiment, the present invention is not necessarily limited thereto. For example, the bearing surface of the nut 16 on the second fastened member 14 side The friction material 18 may be adhered to the nut pressing surface.

  Further, the friction material 18 in the above-described embodiment may be in the form of powder or in the form of a band plate.

  Although the above description is merely an embodiment and other examples are not illustrated, the present invention may be embodied in variously modified or improved modes based on the knowledge of those skilled in the art without departing from the spirit of the invention. Can.

10, 100: Fastening screw 10a, 100a: Head 10c, 100c: Male thread 12: first to-be-fastened member 14: second to-be-fastened member 18: friction material 20: pressing surface

Claims (5)

A structure of a fastening screw integrally including a head and an external thread portion smaller in diameter than the head,
The head portion has a pressing surface on the male screw portion side for pressing the to-be-fastened member when the to-be-fastened member is fastened,
A friction material is adhered to the pressing surface,
The structure of a fastening screw, wherein the friction material has a composition including a fiber, a binder and a filler.   The structure of a fastening screw according to claim 1, wherein the fiber comprises one or more selected from steel fiber, brass fiber, copper fiber, aramid fiber, acrylic fiber and phenol fiber.   The structure of the fastening screw according to claim 1 or 2, wherein the binder contains one or more selected from a phenol resin, an epoxy resin, a melamine resin, a cashew resin and a rubber composition. .   The said friction material is 4-10 weight% of the said fiber with respect to the whole friction material, The said binder is 20-32 weight%, Any one of Claim 1 to 3 characterized by the above-mentioned. Structure of the fastening screw described. The structure of a fastening screw according to any one of claims 1 to 4, wherein the friction material is adhered to the pressing surface by a thermosetting resin adhesive.

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