Contracted materials

Abstract

To provide a technology for suppressing creep deformation while reducing costs in fastened members fastened with screw members. [Solution] A fastened member (10) fixed to a vehicle body member (16) by a screw member (14) comprises a base (20) having a reference surface that receives the seating surface of the screw member (14), an insertion hole (26) formed in the base (20) for inserting the screw member (14), and a protrusion formed to protrude from the reference surface. The protrusion has an inclined surface that slopes upward in the rotation direction that fastens the screw member (14). When the screw member (14) is fastened, the protrusion and base (20) are sandwiched between the vehicle body member (16) and the seating surface, and undergo plastic and elastic deformation.

Description

[Technical Field]

[0001] The present invention relates to a fastened member that is fastened to a vehicle body member by a screw member. [Background technology]

[0002] Patent Document 1 discloses that a fiber-reinforced composite material formed in layers of thermosetting resin and carbon fiber is fastened to a metal material with a bolt. The fiber-reinforced composite material has a fastening through-hole for inserting the bolt and an iron coating layer on the inner periphery of the through-hole. The iron coating layer is formed by adhering powder. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-253697 Summary of the Invention [Problem to be solved by the invention]

[0004] The fiber reinforced composite material disclosed in Patent Document 1 is costly because iron must be attached to the through-holes for fastening, and a separate material must be prepared from the base material, and then a process for attaching the iron is performed.

[0005] An object of the present invention is to provide a technique for suppressing creep deformation while reducing costs in fastened members fastened with screw members. [Means for solving the problem]

[0006] In order to solve the above problems, one aspect of the present invention is a fastened member that is fixed to a vehicle body member by a screw member, and includes a base having a reference surface that receives the seating surface of the screw member, an insertion hole formed in the base for inserting the screw member, and a protrusion formed to protrude from the reference surface. The protrusion has an inclined surface that slopes upward in the rotation direction of fastening the screw member. When the screw member is fastened, the protrusion and the base are sandwiched between the vehicle body member and the seating surface and undergo plastic and elastic deformation. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a technique for suppressing creep deformation while reducing costs in fastened members fastened with screw members. [Brief explanation of the drawings]

[0008] [Figure 1] 10A and 10B are diagrams showing a fastened member fixed to a vehicle body member by a screw member according to an embodiment of the present invention; [Figure 2] 2(A) is a top view mainly showing the base of the workpiece, and FIG. 2(B) is a cross-sectional view of the base shown in FIG. 2(A) taken along line AA. [Figure 3] 2(A) is a cross-sectional view of the base portion taken along line BB shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view of the fastened members in a fastening completed state. [Figure 5] FIG. 10 is a cross-sectional view of a base portion of a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] 1 is a diagram showing a fastened member 10 fixed to a vehicle body member 16 by a screw member 14 of the embodiment. The fastened member 10 includes a base 20, a case 22, and an extension 24, which are integrally molded from the same resin material.

[0010] The case 22 accommodates and holds the electronic component 12. The electronic component 12 may be an electronic circuit board such as an on-board ECU (electronic control unit). The electronic circuit board may be arranged vertically or horizontally. The fastened member 10 functions as a component holder that holds the electronic component 12.

[0011] The extension portion 24 is formed in a columnar shape and extends from the case 22. The base portion 20 is fixed to the vehicle body member 16 by the screw member 14. When fastened, the base portion 20 is sandwiched between the screw member 14 and the vehicle body member 16, and is pressed against the vehicle body member 16 by the axial force of the screw member 14. The base portion 20 has an insertion hole portion 26 into which the screw member 14 can be inserted. A plurality of base portions 20 and extension portions 24 are provided for the case 22.

[0012] The vehicle body member 16 is, for example, a vehicle body panel, a vehicle body frame, or a metal bracket fixed to the vehicle body frame, and in any case is a member that constitutes the vehicle body. The vehicle body member 16 has a screw hole portion 16a that constitutes a female screw. The screw member 14 fastens the base portion 20 to the vehicle body member 16. The screw member 14 is, for example, a bolt.

[0013] The case 22 is positioned away from the surface of the vehicle body member 16. The shape, length, and angle of the extension 24 relative to the case 22 can be set according to the mounting position of the electronic component 12, and are not limited to the form shown in FIG. 1. In any case, the extension 24 extends toward the vehicle body member 16 to which it is to be mounted. The base 20 is connected to the extension 24.

[0014] Fig. 2(A) is a top view mainly showing the base 20 of the workpiece 10, and Fig. 2(B) is a cross-sectional view of the base 20 taken along line AA in Fig. 2(A). The base 20 has an insertion hole 26, a reference surface 28, and a protrusion 30.

[0015] The insertion hole 26 is formed through the center of the base 20, and the threaded portion of the screw member 14 can be inserted therein. The central axis direction of the insertion hole 26 is simply referred to as the axial direction. Note that the central axis direction of the insertion hole 26 is substantially the same as the axial direction of the screw member 14 in the attached state. The circumferential direction is the direction that is perpendicular to the axial direction and rotates around the axis. The radial direction is the direction that is perpendicular to the axial direction and extends radially.

[0016] The reference surface 28 is a flat surface of the base 20. The protrusions 30 are formed to protrude from the reference surface 28. A plurality of the protrusions 30 are formed spaced apart in the circumferential direction. By providing the protrusions 30 at intervals, they can be crushed more easily than if they were formed in an annular shape.

[0017] The protrusions 30 are formed so that their radial width is longer than their circumferential width. Alternatively, the plurality of protrusions 30 may include a protrusion 30 formed so that its radial width is longer than its circumferential width. The protrusions 30 are formed elongated along the radial direction. This allows the protrusions 30 to extend radially, which generates stress on both the inner diameter side and the outer diameter side during fastening, reducing stress bias.

[0018] The protrusions 30 are formed in a fan shape whose circumferential width increases along the radially outward direction. The multiple protrusions 30 may include protrusions 30 formed in a fan shape whose circumferential width increases along the radially outward direction. Since the circumferential width differs between the inner diameter side and the outer diameter side, the stress generated during fastening can be set to decrease from the inner diameter side toward the outer diameter side. This makes it possible to suppress creep deformation toward the outer diameter side, maintain the fastening force on the outer diameter side where the contact surface increases, and suppress rattle over time.

[0019] The multiple protrusions 30 are positioned away from the edge of the insertion hole 26. This prevents some of the multiple protrusions 30 from being crushed radially inward during fastening, causing the screw member 14 to tilt. The multiple protrusions 30 are positioned closer to the inner peripheral edge of the base 20 than to the outer peripheral edge.

[0020] 3 is a cross-sectional view of the base 20 taken along line BB in FIG. 2(A). The protrusion 30 has an inclined surface 30a that slopes upward along the rotation direction D in which the screw member 14 is tightened. While the rotation direction D in which the screw member 14 is tightened is counterclockwise in FIG. 3, it is not limited to this and may be clockwise. In either case, the rotation direction D is one of the two rotation directions and is along the circumferential direction around the central axis.

[0021] The inclined surface 30a rises from the reference surface 28 and extends to the highest point 30b. The protrusion 30 has a vertical surface 30c that hangs down from the point 30b toward the reference surface 28. By having the vertical surface 30c rise vertically from the reference surface 28, the point 30b can be formed to be sharp and easily crushed.

[0022] By forming the protrusion 30 so that it is higher along the rotation direction D in which the screw member 14 is tightened, it is less likely to get caught on the bearing surface 34 of the screw member 14 when the screw member 14 is being tightened. In addition, when the tightening of the screw member 14 is complete, the corner of the tip 30b will get caught on the screw member 14, preventing the screw member 14 from loosening. The inclined surface 30a may be flat along the inclination, or may be curved.

[0023] Figure 4 is a cross-sectional view of the workpieces 10 in a fastened state. Figure 4(A) shows a cross-section of the base 20 taken along line AA in Figure 2(A), and Figure 4(B) shows a cross-section of the base 20 taken along line CC in Figure 2(A). That is, Figure 4(A) shows a cross-section of a portion where the protrusion 30 is provided, and Figure 4(B) shows a cross-section of a portion where the protrusion 30 is not provided.

[0024] The screw member 14 has a head 32, a bearing surface 34, a cylindrical portion 36, and a threaded portion 38. The bearing surface 34 is located on the back surface of the head 32. The cylindrical portion 36 is located closer to the head 32 than the threaded portion 38 and hangs down from the back surface of the head 32. The threaded portion 38 forms a male screw. When the head 32 is rotated by a tool, the threaded portion 38 advances and retreats relative to the screw hole portion 16a.

[0025] With the base 20 placed on the vehicle body member 16, the insertion hole 26 is aligned with the screw hole 16a of the vehicle body member 16, and the screw member 14 is inserted into the insertion hole 26. The insertion hole 26 has a larger diameter than the cylindrical portion 36 and the screw portion 38.

[0026] The screw portion 38 is threaded into the screw hole 16a, and the seat surface 34 presses against the protrusion 30. The protrusion 30 is deformed so as to be crushed, and the reference surface 28 receives the seat surface 34. The screw member 14 is screwed in until it reaches the reference surface 28, deforming the protrusion 30 and its surrounding area.

[0027] The protrusion 30 constitutes a deformation portion that is deformed when pressed against the seat surface 34 during fastening. The protrusion 30 undergoes at least plastic deformation, and may partially undergo elastic deformation.

[0028] As shown in Figure 4(A), a protrusion 30 remains protruding from the head 32. The multiple protrusions 30 include a protrusion 30 formed to protrude radially outward from the seating surface 34. In other words, the protrusion 30 extends radially outward beyond the seating surface 34, and is formed at a position protruding radially outward from the seating surface 34. This allows the worker to visually check the degree of crushing of the protrusion 30, making it easier to check the degree of tightening of the screw member 14.

[0029] 4(A), the protruding portion 30 and a part of the base portion 20 located on the back side of the protruding portion 30 are pressed by the seating surface 34 and deform together to form a first deformation region 40. The first deformation region 40 is the part pressed by the seating surface 34, and refers to the protruding portion 30 and a region of the base portion 20 that overlaps with the protruding portion 30 in the axial direction.

[0030] 4(B), the base 20 without the protrusion 30 is pressed against the reference surface 28 by the seat surface 34 to form a second deformation region 42. The second deformation region 42 is a region of the base 20 that overlaps with the seat surface 34 but does not overlap with the protrusion 30.

[0031] The first deformation region 40 is longer in the axial direction by the height of the protrusion 30 than the second deformation region 42, and therefore experiences a greater stress. Therefore, the first deformation region 40 undergoes plastic and elastic deformation. The first deformation region 40 does not undergo plastic deformation only at the protrusion 30; rather, the entire first deformation region 40 is compressed, and although it may be difficult to distinguish the boundary between plastic deformation and elastic deformation, a larger volume fraction of the first deformation region 40 undergoes plastic deformation than the second deformation region 42. The second deformation region 42 undergoes elastic deformation and may also undergo plastic deformation depending on the axial force of the screw member 14.

[0032] Since the multiple protrusions 30 are spaced apart in the circumferential direction, the first deformation region 40, where stress is large, and the second deformation region 42, where stress is small, are located separately in the circumferential direction. Stress applied to the first deformation region 40 can be released to the second deformation region 42, and the occurrence of creep in the first deformation region 40 can be suppressed.

[0033] Fig. 5 is a cross-sectional view of a modified base 120. The modified base 120 has a different surface shape compared to the base 20 shown in Fig. 3. The base 120 has a recess 44 formed in the reference surface 28 and adjacent to the protrusion 30.

[0034] The recesses 44 are located on both circumferential sides of the protruding portion 30. The recesses 44 do not have to be located on the radially inner side and the radially outer side of the protruding portion 30. In other words, the recesses 44 may be located only on both circumferential sides of the protruding portion 30. This allows the recesses 44 to act as escape spaces when the protruding portion 30 is crushed, making it easier for the protruding portion 30 to be crushed.

[0035] The recess 44 is formed to be smaller than the circumferential width of the protrusion 30. The recess 44 is formed with a recess amount equal to or smaller than the protrusion height of the protrusion 30 from the reference plane 28. The volume of the recess 44 is smaller than the volume of the protrusion 30.

[0036] The recess 44 may be formed on only one side of the protrusion 30, or may be formed only along the vertical surface 30c. In other words, the recess 44 may be formed only on the tip 30b side. In either case, the recess 44 is formed along the protrusion 30.

[0037] The plurality of protrusions 30 may be formed so that the circumferential width is uniform throughout the radial direction. In other words, the protrusions 30 may be formed in a rectangular shape when viewed from above. This allows the protrusions 30 to have a uniform circumferential width, and creep deformation is uniform along the radial direction. The circumferential distance between the plurality of protrusions 30 is formed so as to expand radially outward, thereby suppressing creep deformation on the radially outer side.

[0038] The multiple protrusions 30 may be spaced apart not only in the circumferential direction but also in the radial direction. The distance at which the multiple protrusions 30 are spaced apart in the circumferential direction is not limited to being equal, and may be different. The multiple protrusions 30 may be circular or elliptical in top view. The multiple protrusions 30 may be a combination of these shapes.

[0039] The present disclosure has been described above based on examples. The present disclosure is not limited to the above examples, and various modifications such as design changes may be made based on the knowledge of those skilled in the art.

[0040] For example, the fastened member 10 may be integrally formed by the base portion 20 and the extension portion 24 and connected to a separate member such as a case 22. [Explanation of symbols]

[0041] 10 fastened member, 12 electronic component, 14 screw member, 16 vehicle body member, 16a screw hole portion, 20 base portion, 22 case, 24 extension portion, 26 insertion hole portion, 28 reference surface, 30 protrusion portion, 32 head portion, 34 seat surface, 36 cylindrical portion, 38 screw portion, 40 first deformation region, 42 second deformation region, 30a inclined surface, 30b tip, 30c vertical surface, 120 base portion, 44 recess portion.

Claims

1. A fastened member that is fixed to a vehicle body side member by a screw member, a base portion having a reference surface that receives the seat surface of the screw member; an insertion hole formed in the base portion for inserting the screw member; a protrusion formed to protrude from the reference surface, the protrusion has an inclined surface that is inclined so as to rise in a rotation direction in which the screw member is fastened, The fastened member is characterized in that the protrusion and the base are sandwiched between the vehicle body member and the seat surface and are plastically and elastically deformed when the screw member is fastened.

2. The fastened workpieces according to claim 1 , wherein the protrusions are formed in a plurality of positions spaced apart from one another in the circumferential direction.

3. 3. The fastened members according to claim 1, wherein the protrusion is formed so as to protrude radially outward from the seating surface.

4. 3. The fastened workpiece according to claim 1, wherein the base portion has a recess formed in the reference surface and adjacent to the protrusion.

5. a case for supporting electronic components; an extension extending from the case and connecting to the base, 3. The fastened workpiece according to claim 1, wherein the base portion, the case, and the extension portion are integrally formed from a resin material.

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