Fastening component

Abstract

To provide a fastening member which can secure fastening while inhibiting increase of the weight.SOLUTION: A fastening member 10, 50 includes: a screw formation part 11, 51; and a seating surface formation part 12, 52 forming a seating surface 12a, 52a which contacts with a member to be fastened (a fastened member) 40. At a seating surface 12a, 52a side portion of the seating surface formation part 12, 52, a flange part 122, 522 which has a shape expanding to the radial outer side and exerts a compression force on the fastened member 40 is formed. A surface, which is opposite to the seating surface 12a, 52a, of the flange part 122, 522 forms an inclined surface 122c, 122d which inclines toward the seating surface 12a, 52a in a direction from the radial inner side to the radial outer side. The inclined surface 122c, 122d has: an inner inclined surface 122c located close to the radial inner side; and an outer inclined surface 122d which is located at the radial outer side relative to the inner inclined surface 122c and has an inclined angle relative to the seating surface 12a, 52a which is larger than that of the inner inclined surface 122c.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to fastening components.

Background Art

[0002] Conventionally, Patent Document 1 describes a technique for improving the driving stability of a vehicle by strengthening fastening by providing an annular groove in a washer used for a fastening portion between a vehicle component and a vehicle structure.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to the above prior art, since a washer is added to the fastening portion, the vehicle weight increases. As a means for strengthening fastening without using a washer, it is conceivable to use a fastening member with a flange (for example, a bolt with a flange or a nut with a flange). However, if the rigidity of the bolt with a flange is increased to strengthen the fastening, it is necessary to increase the wall thickness of the flange portion, so the weight of the bolt with a flange increases.

[0005] The present invention has been made in view of such a background, and an object thereof is to provide a fastening member capable of strengthening fastening while suppressing an increase in weight.

Means for Solving the Problems

[0006] One aspect of the present invention includes a threaded portion formed with a male thread or a female thread, and a seat surface forming portion that forms a seat surface that abuts against a member to be fastened. In a part of the seat surface forming portion on the seat surface side, a flange portion is formed which has a shape that expands radially outward and applies a compressive force to the fastened member. On the surface of the flange portion opposite to the seat surface, an inclined surface is formed which inclines so as to approach the seat surface side as it goes from the radially inner side to the radially outer side. The inclined surface has an inner inclined surface located closer to the radially inner side, and an outer inclined surface located radially outside the inner inclined surface and having a larger inclination angle with respect to the seat surface than the inner inclined surface. This is in the fastening member.

[0007] Another aspect of the present invention includes a threaded portion formed with a male thread or a female thread, and a seat surface forming portion that forms a seat surface that abuts against the fastened member. In a part of the seat surface forming portion on the seat surface side, a flange portion is formed which has a shape that expands radially outward and applies a compressive force to the fastened member. The flange portion has a recess formed in a concave shape on the surface opposite to the seat surface. The recess has a shape that is closest to the seat surface at the outermost diameter side portion. This is in the fastening member.

Advantages of the Invention

[0008] According to one aspect of the present invention, since the outer inclined surface having an inclination angle larger than that of the inner inclined surface is provided radially outside the inner inclined surface, while increasing the thickness of the radially inner portion of the flange portion that contributes greatly to rigidity to enhance the rigidity of the flange portion, an increase in the thickness of the radially outer portion of the flange portion where the axial stress is small can be suppressed, and an increase in the weight of the fastening member can be suppressed.

[0009] According to another aspect of the present invention, since a concave portion is formed on the surface of the flange portion opposite to the seating surface, the starting point of the internal stress of the flange portion when fastened can be created in the concave portion. Therefore, fastening can be made stronger compared to the case where the starting point of the internal stress of the flange portion is only at the innermost diameter portion of the flange portion. Moreover, since the concave portion has a shape that is closest to the seating surface at the outermost diameter side portion, a decrease in the rigidity of the flange portion due to the formation of the concave portion can be suppressed as much as possible.

[0010] As described above, according to the above aspect, it is possible to provide a fastening member that can firmly fasten while suppressing an increase in weight.

[0011] Note that the reference signs in parentheses described in the claims indicate the correspondence with the specific means described in the embodiments described later, and do not limit the technical scope of the present invention.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0013] The fastening member includes a threaded portion and a seat surface forming portion. Among the portions of the seat surface forming portion on the seat surface side, it has a shape that expands radially outward more than the portion on the side opposite to the seat surface, and a flange portion that applies a compressive force to the fastened member is formed. Among the flange portions, the surface on the side opposite to the seat surface forms an inclined surface that inclines so as to approach the seat surface side as it goes from the radially inner side to the radially outer side. The inclined surface has an inner inclined surface located closer to the radially inner side and an outer inclined surface located radially outside the inner inclined surface and having a larger inclination angle with respect to the seat surface than the inner inclined surface.

[0014] In the fastening member, the portion where the inclination angle changes between the inner inclined surface and the outer inclined surface is located radially inside the outermost contact portion, which is the portion of the seat surface that contacts the fastened member at the outermost position in the radial direction. Thereby, an increase in the thickness of the radially outer portion of the flange portion where the axial stress is small can be effectively suppressed.

[0015] In the fastening member, the inclination angle of the inner inclined surface is 20° to 30°, and the inclination angle of the outer inclined surface is 35° to 50°. Thereby, the thickness of the portion on the radially inner side of the flange portion, which contributes greatly to the rigidity, can be effectively increased, and an increase in the thickness of the radially outer portion of the flange portion where the axial stress is small can be effectively suppressed.

[0016] In the fastening member, the flange portion has a concave portion formed in a concave shape between the inner inclined surface and the outer inclined surface on the surface on the side opposite to the seat surface. Thereby, the starting point of the internal stress of the flange portion at the time of fastening can be created in the concave portion, so that the fastening can be made stronger compared to the case where the starting point of the internal stress of the flange portion is only the innermost diameter portion of the flange portion.

[0017] In the fastening member, the concave portion is located radially inside the outermost contact portion, which is the portion of the seat surface that contacts the fastened member at the outermost position in the radial direction. Thereby, the axial stress can be effectively applied to the fastened member by the starting point of the internal stress created by the concave portion, so that the fastening can be made stronger.

[0018] In the fastening member, the recess forms a step and has a shape in which the surface of the flange portion on the side opposite to the seating surface is cut out in an L-shaped cross section. Thereby, it is possible to suppress a decrease in the rigidity of the flange portion due to the recess, and it is possible to effectively create a starting point of the internal stress of the flange portion at the time of fastening in the recess.

[0019] In the fastening member, the recess has a shape that is closest to the seating surface at the outermost diameter side portion. Thereby, it is possible to suppress a decrease in the rigidity of the flange portion due to the recess.

[0020] In the fastening member, the recess is located between the innermost diameter portion, which is the innermost diameter side portion of the flange portion in the radial direction, and the outermost contact portion, which is the portion of the contact surface that contacts the member to be fastened at the outermost side in the radial direction, and in the axial direction, it is located between the outermost diameter portion, which is the outermost diameter side portion of the flange portion, and the innermost diameter portion, which is the innermost diameter side portion of the flange portion. Thereby, it is possible to suppress a decrease in the rigidity of the flange portion due to the recess, and it is possible to effectively create a starting point of the internal stress of the flange portion at the time of fastening in the recess.

[0021] In the fastening member, the recess is arranged at a position that bisects the radial distance between the innermost diameter portion and the outermost contact portion and coincides with a virtual line parallel to the axial direction. Thereby, it is possible to suppress a decrease in the rigidity of the flange portion due to the recess, and it is possible to effectively create a starting point of the internal stress of the flange portion at the time of fastening in the recess.

[0022] In the fastening member, the inner inclined surface and the outer inclined surface are formed in a tapered shape that is linear in the axial cross section. Thereby, it is possible to effectively increase the wall thickness of the portion on the inner side in the radial direction of the flange portion, which contributes greatly to the rigidity, and it is possible to effectively suppress an increase in the wall thickness of the portion on the outer side in the radial direction of the flange portion, where the axial stress is small.

[0023] (Embodiment 1) 1. Configuration of the fastening structure 1 The fastening structure 1 in Embodiment 1 will be described with reference to FIGS. 1 to 3. The fastening structure 1 is a structure for fastening a rear absorber that constitutes a chassis part of an automobile to the vehicle body of the automobile using a first fastening member 10.

[0024] As shown in FIG. 1, the fastening structure 1 in the present embodiment includes a first fastening member 10, a second fastening member 20, a first fastened member 30, and a second fastened member 40. The fastening structure 1 fastens the first fastened member 30 and the second fastened member 40 using the first fastening member 10 and the second fastening member 20. In the present embodiment, the first fastened member 30 is a steel plate that constitutes the vehicle body of the automobile, and the second fastened member 40 is a bracket for fixing the rear absorber of the automobile to the vehicle body.

[0025] As shown in FIG. 1, the first fastening member 10 is a bolt having a threaded portion 11 and a seat surface forming portion 12. In the present embodiment, the first fastening member 10 is a bolt having a screw diameter (nominal diameter) of 10 mm. The threaded portion 11 is a shaft-like shaft portion on which a male thread 11a is formed. The seat surface forming portion 12 is the head of the bolt and has a seat surface 12a that abuts against the second fastened member 40. The seat surface forming portion 12 is arranged coaxially with the threaded portion 11 and has a larger radial dimension than the threaded portion 11. The male thread 11a of the threaded portion 11 may be formed only in the middle portion of the threaded portion 11 as shown in FIG. 1, or may be formed over the entire length of the threaded portion 11 (not shown).

[0026] The first fastening member 10 is a bolt with a flange. That is, the seating surface forming portion 12 of the first fastening member 10 is a head with a flange. Specifically, the seating surface forming portion 12 includes a head body 121 and a flange portion 122. In the present embodiment, the head body 121 constitutes a hexagonal head, but the head body 121 may have a shape other than a hexagon or may constitute a headed head with a hole. The flange portion 122 has a shape that extends radially outward over the entire circumference from the portion on the seating surface 12a side of the seating surface forming portion 12, and applies a compressive force to the second fastened member 40. The seating surface 12a of the seating surface forming portion 12 is continuously formed by the bottom surface of the head body 121 and the bottom surface of the flange portion 122.

[0027] In the present embodiment, the two-sided width (the diameter of the inscribed circle of the head body 121) of the head body 121 of the seating surface forming portion 12 is larger than the diameter of the threaded portion 11. Also, the diameter of the flange portion 122 of the seating surface forming portion 12 is larger than the diameter of the threaded portion 11 and the two-sided width of the head body 121.

[0028] The second fastening member 20 is a nut formed with an internal thread that is screwed onto the male thread 11a of the first fastening member 10. In the present embodiment, the second fastening member 20 is a weld nut that is fixed to the first fastened member 30 in advance by welding. As the second fastening member 20, a flanged nut separate from the first fastened member 30, a nut without a flange separate from the first fastened member 30, or the like may be used.

[0029] 2. Detailed configuration of the seating surface forming portion 12 of the first fastening member 10 Hereinafter, the portion of the seating surface 12a of the seating surface forming portion 12 that abuts the second fastened member 40 at the outermost radial position is referred to as the outermost abutting portion 122a. As shown in FIG. 2, the portion of the flange portion 122 on the seating surface 12a side and radially outside the outermost abutting portion 122a is a chamfered portion 122b formed when the first fastening member 10 is cast and formed.

[0030] The surface of the flange portion 122 on the side opposite to the seating surface 12a is inclined so as to approach the seating surface 12a side as a whole from the radially inner side toward the radially outer side. Hereinafter, the surface of the flange portion 122 on the side opposite to the seating surface 12a is referred to as an inclined surface.

[0031] An inner inclined surface 122c, an outer inclined surface 122d, and a concave portion 122e are formed on the inclined surface of the flange portion 122. The inner inclined surface 122c is connected to the head body 121. The outer inclined surface 122d is located radially outside the inner inclined surface 122c. That is, the inner inclined surface 122c constitutes a radially inner part of the inclined surface of the flange portion 122, and the outer inclined surface 122d constitutes a radially outer part of the inclined surface of the flange portion 122.

[0032] Hereinafter, an angle that is an acute angle with respect to the inclination angle with respect to the seating surface 12a is simply referred to as an inclination angle. The inclination angle of the outer inclined surface 122d is larger than the inclination angle of the inner inclined surface 122c. The inclination angle of the inner inclined surface 122c is preferably 20° to 30°, and the inclination angle of the outer inclined surface 122d is preferably 35° to 50°. In the present embodiment, the inclination angle of the inner inclined surface 122c is 25°, and the inclination angle of the outer inclined surface 122d is 40°.

[0033] In the present embodiment, the outer inclined surface 122d is formed up to the outermost diameter portion 122f of the flange portion 122. A predetermined thickness t1 is provided between the outermost diameter portion 122f of the flange portion 122 and the seating surface 12a.

[0034] By making the inclination angle of the outer inclined surface 122d larger than the inclination angle of the inner inclined surface 122c, while increasing the thickness of the portion on the head body 121 side of the flange portion 122, which contributes greatly to rigidity, to increase the rigidity of the flange portion 122, an increase in the thickness of the radially outer portion of the flange portion 122, where the axial stress is small, can be suppressed, and an increase in the weight of the first fastening member 10 can be suppressed.

[0035] The recess 122e is formed in a concave shape on the inclined surface of the flange portion 122. The recess 122e is formed in an annular shape over the entire circumference of the flange portion 122. In the present embodiment, the recess 122e is disposed at the boundary between the inner inclined surface 122c and the outer inclined surface 122d. In other words, the recess 122e is connected to the inner inclined surface 122c on the radially inner side and is connected to the outer inclined surface 122d on the radially outer side.

[0036] In the present embodiment, the recess 122e is formed in a stepped shape on the inclined surface of the flange portion 122. The recess 122e has a shape in which the inclined surface of the flange portion 122 is notched in an L-shaped cross section. Specifically, the recess 122e is composed of a wall surface extending substantially parallel to the axial direction Y of the first fastening member 10 from the connecting portion 122g with the inner inclined surface 122c and a bottom surface extending in a direction substantially orthogonal to the axial direction Y of the first fastening member 10 from the connecting portion 122h with the outer inclined surface 122d. Thereby, the recess 122e approaches the seating surface 12a as it goes from the radially inner side to the radially outer side, and is closest to the seating surface 12a at the portion on the outermost diameter side.

[0037] The recess 122e is disposed in the region inside the virtual rectangle S1 indicated by the two-dot chain line in FIG. 2. Specifically, in the radial direction of the first fastening member 10, the recess 122e is disposed between the innermost diameter portion 122i and the outermost contact portion 122a of the flange portion 122, and in the axial direction Y of the first fastening member 10, the recess 122e is disposed between the innermost diameter portion 122i and the outermost diameter portion 122f of the flange portion 122.

[0038] In the present embodiment, the recess 122e is disposed at a position that bisects the radial distance between the innermost diameter portion 122i and the outermost contact portion 122a of the flange portion 122 and coincides with the virtual line L1 parallel to the axial direction Y.

[0039] By forming the concave portion 122e in the flange portion 122, it is possible to create the origin of the internal stress of the flange portion 122 when the first fastening member 10 and the second fastening member 20 fasten the first fastened member 30 and the second fastened member 40 at the concave portion 122e. Thereby, compared with the case where the origin of the internal stress of the flange portion 122 is only at the innermost diameter portion 122i of the flange portion 122, the moment when an external force that tries to peel the second fastened member 40 from the first fastened member 30 acts on the outermost diameter portion of the second fastened member 40 can be reduced. Therefore, the fastening of the first fastened member 30 and the second fastened member 40 by the first fastening member 10 and the second fastening member 20 can be strengthened.

[0040] 3. Analysis of the fastening structure 1 Regarding the analysis of the fastening structure 1, it will be described with reference to FIG. 3. The analysis results of Analysis Example 1 corresponding to the present embodiment are shown in FIG. 3(a), the analysis results of Analysis Example 2 are shown in FIG. 3(b), and the analysis results of Analysis Example 3 are shown in FIG. 3(c).

[0041] The analysis models used in Analysis Examples 1 to 3 are three-dimensional models including the first fastening member 10, the first fastened member 30, and the second fastened member 40.

[0042] In Analysis Example 1 shown in FIG. 3(a), the inclination angle of the inner inclined surface 122c is 25°, the inclination angle of the outer inclined surface 122d is 40°, and an analysis model in which the concave portion 122e is formed is used.

[0043] In Analysis Example 2 shown in FIG. 3(b), the inclination angle of the inclined surface of the flange portion 122 is constant at 25° without changing, and an analysis model in which the concave portion 122e of the present embodiment is not formed in the flange portion 122 is used.

[0044] In Analysis Example 3 shown in FIG. 3(c), the inclination angle of the inclined surface of the flange portion 122 is constant at 25° without changing, and an analysis model in which a concave portion 122e similar to the present embodiment is formed in the flange portion 122 is used.

[0045] In the analysis models used in Analysis Examples 1 to 3, the first fastened member 30 is made of structural steel, the second fastened member 40 is made of an aluminum alloy, and for the first fastening member 10, the Young's modulus is 206 GPa, the Poisson's ratio is 0.3, and the yield stress is 1017 MPa.

[0046] The analysis results of Analysis Examples 1 to 3 shown in FIGS. 3(a) to 3(c) are contour diagrams of the axial stress in these analysis models when the axial force generated by the first fastening member 10 is 38.6 kN and a load of 8.4 kN in the direction of trying to peel the second fastened member 40 from the first fastened member 30 is applied to the outermost diameter part of the second fastened member 40, and the greater the stress, the darker the color.

[0047] By comparing Analysis Example 2 shown in FIG. 3(b) with Analysis Example 3 shown in FIG. 3(c), the effect of the concave portion 122e on the axial stress can be understood. By comparing Analysis Example 3 shown in FIG. 3(c) with Analysis Example 1 shown in FIG. 3(a), the effect of making the inclination angle of the outer inclined surface 122d larger than the inclination angle of the inner inclined surface 122c can be understood.

[0048] In Analysis Example 2 shown in FIG. 3(b), the starting point of the axial stress in the flange portion 122 is formed at the innermost diameter portion 122i of the flange portion 122, but the axial stress transmitted to the radially outer portion of the flange portion 122 is small.

[0049] On the other hand, in Analysis Example 3 shown in FIG. 3(c), due to the formation of the concave portion 122e, the starting point of the axial stress in the flange portion 122 is formed not only at the innermost diameter portion 122i of the flange portion 122 but also at the concave portion 122e. Therefore, the axial stress transmitted to the radially outer portion of the flange portion 122 is larger compared to Analysis Example 2. However, in Analysis Example 3 shown in FIG. 3(c), outside the concave portion 122e in the radial direction, the axial stress transmitted to the vicinity of the inclined surface of the flange portion 122 is almost unchanged and remains small compared to Analysis Example 2.

[0050] Therefore, in Analysis Example 1 shown in Fig. 3(a), by making the inclination angle of the outer inclined surface 122d larger than the inclination angle of the inner inclined surface 122c, the portion where the axial stress is small is removed radially outside the concave portion 122e to reduce the weight. From the above, according to Analysis Example 1 corresponding to the present embodiment, it can be seen that the fastening between the first fastened member 30 and the second fastened member 40 can be strengthened without increasing the weight as much as possible.

[0051] 4. Operational Effects According to the first fastening member 10 in the present embodiment, since the inclination angle of the outer inclined surface 122d of the flange portion 122 of the first fastening member 10 is larger than that of the inner inclined surface 122c, while increasing the wall thickness of the portion on the head body 121 side of the flange portion 122 that contributes greatly to rigidity to enhance the rigidity of the flange portion 122, the increase in the wall thickness of the radially outer portion of the flange portion 122 where the axial stress is small is suppressed, and the weight increase of the first fastening member 10 can be suppressed. Therefore, the fastening by the first fastening member 10 can be strengthened while suppressing the increase in the weight of the first fastening member 10.

[0052] According to the first fastening member 10 in the present embodiment, the portion where the inclination angle changes between the inner inclined surface 122c and the outer inclined surface 122d is located radially inside the outermost contact portion 122a. Thereby, the increase in the wall thickness of the radially outer portion of the flange portion 122 where the axial stress is small can be effectively suppressed.

[0053] According to the first fastening member 10 in the present embodiment, the inclination angle of the inner inclined surface 122c is 20° to 30°, and the inclination angle of the outer inclined surface 122d is 35° to 50°. Thereby, the wall thickness of the portion on the head body 121 side of the flange portion 122 that contributes greatly to rigidity can be effectively increased, and the increase in the wall thickness of the radially outer portion of the flange portion 122 where the axial stress is small can be effectively suppressed.

[0054] According to the first fastening member 10 in the present embodiment, since the concave portion 122e is formed on the inclined surface of the flange portion 122, the starting point of the internal stress of the flange portion 122 at the time of fastening can be created in the concave portion 122e. Therefore, the fastening can be made stronger as compared with the case where the starting point of the internal stress of the flange portion 122 is only the innermost diameter portion 122i of the flange portion 122.

[0055] According to the first fastening member 10 in the present embodiment, the concave portion 122e is located radially inward of the outermost contact portion 122a of the flange portion 122. Thereby, since the axial stress can be effectively applied to the second fastened member 40 by the starting point of the internal stress created by the concave portion 122e, the fastening can be made stronger.

[0056] According to the first fastening member 10 in the present embodiment, the concave portion 122e forms a step and has a shape in which the inclined surface of the flange portion 122 is cut out in an L-shaped cross section. Thereby, it is possible to suppress a decrease in the rigidity of the flange portion 122 due to the concave portion 122e, and it is possible to effectively create the starting point of the internal stress of the flange portion 122 at the time of fastening in the concave portion 122e.

[0057] According to the first fastening member 10 in the present embodiment, the concave portion 122e has a shape that is closest to the seating surface 12a at the outermost diameter side portion. Thereby, a decrease in the rigidity of the flange portion 122 due to the concave portion 122e can be suppressed.

[0058] According to the first fastening member 10 in the present embodiment, the concave portion 122e is located between the innermost diameter portion 122i and the outermost contact portion 122a of the flange portion 122 in the radial direction, and is located between the outermost diameter portion 122f and the innermost diameter portion 122i of the flange portion 122 in the axial direction. Thereby, it is possible to suppress a decrease in the rigidity of the flange portion 122 due to the concave portion 122e, and it is possible to effectively create the starting point of the internal stress of the flange portion 122 at the time of fastening in the concave portion 122e.

[0059] According to the first fastening member 10 in the present embodiment, the concave portion 122e is disposed at a position that bisects the radial distance between the innermost diameter portion 122i and the outermost contact portion 122a and coincides with the virtual line L1 parallel to the axial direction. Thereby, it is possible to suppress a decrease in the rigidity of the flange portion 122 due to the concave portion 122e, and it is possible to effectively create a starting point of the internal stress of the flange portion 122 when fastened at the concave portion 122e.

[0060] According to the first fastening member 10 in the present embodiment, the inner inclined surface 122c and the outer inclined surface 122d are formed in a tapered shape that is linear in the axial cross section. Thereby, it is possible to effectively increase the thickness of the radially inner portion of the flange portion 122 that contributes greatly to the rigidity, and it is possible to effectively suppress an increase in the thickness of the radially outer portion of the flange portion 122 where the axial stress is small.

[0061] (Embodiment 2) In the above-described Embodiment 1, the concave portion 122e has a shape in which the inclined surface of the flange portion 122 is cut out in an L-shaped cross section. However, in the present Embodiment 2, as shown in FIG. 4, the concave portion 122k formed on the inclined surface of the flange portion 122 has a shape in which the inclined surface of the flange portion 122 is cut out in an arc shape.

[0062] In the axial cross section of the flange portion 122, a tangent line (not shown) of the concave portion 122k at the connecting portion 122h with the outer inclined surface 122d is parallel to the seating surface 12a. Thereby, the concave portion 122k approaches the seating surface 12a as it goes from the radially inner side to the radially outer side, and is closest to the seating surface 12a at the outermost diameter side portion.

[0063] Also in the present Embodiment 2, similarly to the above-described Embodiment 1, since the concave portion 122k is formed on the inclined surface of the flange portion 122, it is possible to create a starting point of the internal stress of the flange portion 122 when fastened at the concave portion 122k. Therefore, fastening can be made stronger as compared with the case where the starting point of the internal stress of the flange portion 122 is only the innermost diameter portion 122i of the flange portion 122.

[0064] (Embodiment 3) In the above Embodiments 1 and 2, the inner inclined surface 122c, the outer inclined surface 122d, and the recesses 122e and 122k are formed on the inclined surface of the flange portion 122. However, in this Embodiment 3, as shown in FIG. 5, the recesses 122e and 122k are not formed on the inclined surface of the flange portion 122, and only the inner inclined surface 122c and the outer inclined surface 122d are formed.

[0065] Also in this embodiment, similar to the above embodiments, the inner inclined surface 122c and the outer inclined surface 122d can exhibit the same effects. That is, since the outer inclined surface 122d of the flange portion 122 has a larger inclination angle than the inner inclined surface 122c, while increasing the thickness of the portion of the flange portion 122 on the head body 121 side that contributes greatly to rigidity to enhance the rigidity of the flange portion 122, an increase in the thickness of the radially outer portion of the flange portion 122 where the axial stress is small can be suppressed, thereby suppressing an increase in the weight of the first fastening member 10. Therefore, while suppressing an increase in the weight of the first fastening member 10, the fastening by the first fastening member 10 can be strengthened.

[0066] (Embodiment 4) In the above Embodiment 1, the first fastening member 10 is a bolt with a flange, the second fastening member 20 is a nut, and the inner inclined surface 122c, the outer inclined surface 122d, and the recess 122e are formed on the inclined surface of the flange portion 122 of the first fastening member 10. In contrast, in this Embodiment 4, as shown in FIG. 6, the first fastening member 50 is a nut with a flange, the second fastening member 60 is a bolt, and an inner inclined surface, an outer inclined surface, and a recess similar to those in Embodiment 1 are formed on the inclined surface of the flange portion 522 of the first fastening member 50.

[0067] The second fastening member 60 may be a weld bolt that is fixed to the first fastened member 30 by welding in advance, or a bolt with a flange separate from the first fastened member 30, a bolt without a flange separate from the first fastened member 30, etc. may be used.

[0068] The first fastening member 50 has a threaded portion 51 and a seating surface portion 52. The threaded portion 51 constitutes the portion on the central axis side of the first fastening member 50. A female thread 51a is formed on the threaded portion 51. The seating surface portion 52 constitutes the portion on the outer peripheral side of the first fastening member 50. A seating surface 52a that abuts against the second fastened member 40 is formed on the seating surface portion 52. The seating surface portion 52 includes a nut body 521 and a flange portion 522. In the present embodiment, the nut body 521 has a hexagonal prism shape.

[0069] The flange portion 522 has a shape that extends radially outward over the entire circumference from the portion on the seating surface 52a side of the seating surface portion 52, and applies a compressive force to the second fastened member 40. The seating surface 52a of the seating surface portion 52 is continuously formed by the bottom surface of the nut body 521 and the bottom surface of the flange portion 522.

[0070] On the surface of the flange portion 522 opposite to the seating surface 52a, an inner inclined surface, an outer inclined surface, and a concave portion are formed in the same manner as in the first embodiment. Since the specific configurations of the inner inclined surface, the outer inclined surface, and the concave portion are the same as those in the first embodiment, detailed description thereof is omitted.

[0071] Also in the fourth embodiment, since the inner inclined surface, the outer inclined surface, and the concave portion similar to those in the first embodiment are formed on the flange portion 522 of the first fastening member 50, the same operational effects as those in the first embodiment can be achieved.

[0072] (Other embodiments) In the above embodiment, the inner inclined surface, the outer inclined surface, and the concave portion are formed only on the first fastening member among the first fastening member and the second fastening member, but the inner inclined surface, the outer inclined surface, and the concave portion may be formed on both the first fastening member and the second fastening member.

[0073] In the above-described embodiment, the inner inclined surface and the outer inclined surface are formed on the inclined surface of the flange portion, and the inclination angle of the inclined surface of the flange portion changes in two stages from the radially inner side to the radially outer side. However, the inclination angle of the inclined surface of the flange portion may change in three or more stages. When the inclination angle of the inclined surface of the flange portion is three or more stages, the inclination angles of the two inclined surfaces located on both sides of the concave portion do not necessarily have to be different from each other, and the inclination angles of the two inclined surfaces located on both sides of the concave portion may be the same as each other.

[0074] In the above-described embodiment, the inclination angles of the inner inclined surface and the outer inclined surface of the flange portion are each constant, and the inner inclined surface and the outer inclined surface are linear when viewed in the axial cross-section. However, at least one of the inclination angles of the inner inclined surface and the outer inclined surface may not be constant and may change. That is, at least one of the inner inclined surface and the outer inclined surface may be curved when viewed in the axial cross-section.

Explanation of Signs

[0075] 10, 50 First fastening member 11, 51 Thread forming portion 12, 52 Seat surface forming portion 12a, 52a Seat surface 122, 522 Flange portion 122a Outermost contact portion 122c Inner inclined surface 122d Outer inclined surface 122e, 122k Concave portion 122f Outermost diameter portion 122i Innermost diameter portion 40 Second fastened member (fastened member) L1 Virtual line

Claims

1. A threaded portion (11, 51) formed with a male thread (11a) or a female thread (51a), and a seating surface forming portion (12, 52) that forms a seating surface (12a, 52a) that abuts against the member to be fastened (40), A flange portion (122, 522) having a shape that expands radially outward is formed at a portion on the seating surface side of the seating surface forming portion, and a compressive force is applied to the member to be fastened, A surface of the flange portion opposite to the seating surface forms an inclined surface (122c, 122d) that inclines so as to approach the seating surface side as it goes from the radially inner side to the radially outer side, The inclined surface An inner inclined surface (122c) located closer to the radially inner side, and An outer inclined surface (122d) located radially outside the inner inclined surface and having a larger inclination angle with respect to the seating surface than the inner inclined surface, a fastening member (10, 50).

2. A portion where the inclination angle changes between the inner inclined surface and the outer inclined surface is located radially inside the outermost contact portion (122a), which is the portion of the seating surface that abuts against the member to be fastened at the outermost in the radial direction, the fastening member according to claim 1.

3. The inclination angle of the inner inclined surface is 20° to 30°, The inclination angle of the outer inclined surface is 35° to 50°, the fastening member according to claim 1.

4. The flange portion has a concave portion (122e, 122k) formed in a concave shape between the inner inclined surface and the outer inclined surface on the surface opposite to the seating surface, The concave portion is located radially inside the outermost contact portion (122a), which is the portion of the seating surface that abuts against the member to be fastened at the outermost in the radial direction, the fastening member according to claim 1.

5. The recess forms a step and has a shape in which a surface of the flange portion opposite to the seating surface is cut out in an L-shaped cross section. The fastening member according to claim 4.

6. The recess has a shape that is closest to the seating surface at the outermost diameter side portion. The fastening member according to claim 4.

7. The recess is located between the innermost diameter portion (122i), which is the innermost diameter side portion of the flange portion in the radial direction, and the outermost contact portion, and is located between the outermost diameter portion (122f), which is the outermost diameter side portion of the flange portion in the axial direction, and the innermost diameter portion. The fastening member according to claim 4.

8. The recess is disposed at a position that bisects the radial distance between the innermost diameter portion and the outermost contact portion and coincides with a virtual line (L1) parallel to the axial direction. The fastening member according to claim 7.

9. The inner inclined surface and the outer inclined surface are formed in a tapered shape that is linear in the axial cross section. The fastening member according to any one of claims 1 to 8.

10. A threaded portion (11, 51) formed with a male thread (11a) or a female thread (51a), A seating surface forming portion (12, 52) that forms a seating surface (12a, 52a) that abuts against the member to be fastened (40), A flange portion (122, 522) having a shape that expands radially outward is formed at a portion of the seating surface forming portion on the seating surface side, and a compressive force is applied to the member to be fastened. The flange portion has a recess (122e, 122k) formed in a concave shape on a surface opposite to the seating surface, The recess has a shape that is closest to the seating surface at the outermost diameter side portion. The fastening member (10, 50).

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