fasteners

Abstract

The present invention provides a fastener that improves the withdrawal force from the fixing hole while suppressing the insertion resistance from the fixing hole. [Solution] The fastener 10 has a head portion 20 and a leg portion 30, the leg portion 30 having a columnar portion 31, a pair of side portions 35, 35 and a plurality of locking pieces 40, a first groove portion 60 extending in the axial direction of the columnar portion 31 is formed between the locking piece 40 and the side portion 35, and ribs 50, 50 extending from the base portion 41 of the locking piece 40 are provided on both sides of the locking piece 40 in the circumferential direction.

Description

Technical Field

[0001] The present invention relates to a fastener that is inserted into and fixed in a fixing hole.

Background Art

[0002] For example, fixing holes are formed in a vehicle body panel or the like of an automobile, and a trim board or the like is attached to the vehicle body panel or the like, or a long member such as a pipe or a tube is arranged through a fastener that is inserted into and fixed in the fixing hole.

[0003] Patent Document 1 below describes a fastener in which a head, a connection part provided to project downward from this head, a leg part provided to project downward from this connection part, and an engaging part provided to project laterally from this leg part are integrally formed.

[0004] The leg part has a pair of parallel outer surfaces and a pair of arc-shaped surfaces arranged orthogonally to the pair of outer surfaces (see FIG. 1 of Patent Document 1). Further, the engaging part is formed of a thin plate-like part that projects from the arc-shaped surface of the leg part toward the head side, and a plurality of the engaging parts are provided in the axial direction of the pair of arc-shaped surfaces.

[0005] When the leg part is inserted into the mounting hole, the tip parts of the respective engaging parts are pushed in while being pressed against the inner circumference of the mounting hole, and by pushing in the fastener until the head abuts against the flange part provided on the periphery of the mounting hole, the tip parts of the respective engaging parts engage with the inner circumference of the mounting hole, and the fastener is fixed in the mounting hole (see FIG. 15 of Patent Document 1).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] By the way, when the thickness of the material (such as a metal panel) in which the mounting holes are formed is thick, there may be large variations in the inner diameter of the mounting holes, or burrs may frequently form on the inner circumference of the mounting holes when the panel is punched out to form the mounting holes.

[0008] In such cases, when inserting the legs of the fastener described in Patent Document 1 into the mounting hole, variations in the inner diameter of the mounting hole and the influence of burrs can cause the engaging portion to easily get caught inside the mounting hole, affecting the ease of insertion. Furthermore, if the engaged portion gets caught, it may bend and deform significantly, resulting in a concentration of load on the base of the engaging portion, which can adversely affect the engaging portion.

[0009] Furthermore, when a fastener is fixed in the mounting hole, if a pulling or twisting force is applied in a direction along the axis of the mounting hole or at an angle to the axis, the engaging portion may be pressed against the inner circumference of the mounting hole and deform excessively. In this case, too, the load may concentrate at the base of the engaging portion, which can adversely affect the entire engaging portion.

[0010] Therefore, the object of the present invention is to provide a fastener that can improve the force required to remove the leg from the fixing hole while suppressing the resistance to inserting the leg into the fixing hole. [Means for solving the problem]

[0011] To achieve the above objective, the present invention provides a fastener that is inserted into and fixed in a fixing hole, comprising a head and a leg connected to the head and inserted into the fixing hole, wherein the leg comprises a columnar portion extending from the back side of the head, a pair of side portions connected to the columnar portion, and a plurality of locking pieces between the pair of side portions, protruding from the outer surface of the columnar portion and arranged at predetermined intervals in the axial direction of the columnar portion, and engaging with the fixing hole, wherein a first groove portion extending in the axial direction of the columnar portion is formed between the locking pieces and the side portions, and ribs extending from the base of the locking pieces are provided on both sides of the locking pieces. [Effects of the Invention]

[0012] According to the fastener of the present invention, since ribs extending from the base of each locking piece are provided on both sides of the locking piece, both sides of the base of each locking piece are firmly supported by the columnar part via the ribs. Using this firmly supported base as a fulcrum, the bending deformation performance of the portion of each locking piece that extends beyond the tip of the rib in the protruding direction (hereinafter referred to as the "portion beyond the rib") can be appropriately exercised, and when inserting the leg into the fixing hole, each locking piece is less likely to get caught on the inner circumference of the fixing hole, making insertion easier and smoother.

[0013] Furthermore, since ribs extending from the base of the locking piece are provided on both sides of the locking piece in the circumferential direction, the strength and rigidity of the base, which is the root portion of each locking piece, can be increased, and the length of the portion of each locking piece that extends beyond the ribs can be shortened, thereby increasing the strength and rigidity of the portion that extends beyond the ribs, and ultimately improving the overall strength and rigidity of the locking piece.

[0014] Therefore, when the fixed member is thick and there are variations in the inner diameter or burrs in the fixing hole, or when these are absent, the force that pulls out the fastener from the fixing hole can be increased when a pulling force or prying force is applied to the fastener fixed in the fixing hole.

[0015] Furthermore, since ribs are provided on both sides of the locking piece in the circumferential direction, when inserting the leg into the fixing hole, or when pulling or twisting forces are applied to the fastener fixed in the fixing hole, even if the pair of sides collapse radially inward due to the inner circumference of the fixing hole and come into contact with the circumferential side surface of the locking piece, the strength and rigidity of the base portion of the locking piece are increased by the ribs, thus suppressing damage to the locking piece.

[0016] Furthermore, the first groove ensures that the side of the leg portion is securely separated from the circumferential side of each locking piece, thereby allowing the desired values ​​(design values) for the aforementioned deflection deformation performance, strength, and rigidity of each locking piece to be obtained.

[0017] Therefore, it is possible to provide a fastener that can improve the removal force with respect to the fixing hole while suppressing the insertion resistance of the leg portion with respect to the fixing hole by the first groove portion, the portion of the locking piece that exceeds the rib, and the rib.

Brief Description of the Drawings

[0018] [Figure 1] Fig. 8 shows a perspective view of an embodiment of a fastener according to the present invention. [Figure 2] Fig. 11 is an enlarged cross-sectional perspective view of the main part of the fastener. [Figure 3] Fig. 14 is a cross-sectional view taken along the line A-A of Fig. 1. [Figure 4] Fig. 17 is a cross-sectional view taken along the line B-B of Fig. 1. [Figure 5] Fig. 20 is a cross-sectional view taken along the line E-E of Fig. 1. [Figure 6] Fig. 23 is an enlarged cross-sectional view of the main part of Fig. 5. [Figure 7] Fig. 26 is a schematic explanatory view of a mold for molding the fastener. [Figure 8] Fig. 29 is a cross-sectional view showing a modified example of the fastener according to the present invention. [Figure 9] Fig. 32 is a cross-sectional view of a fastener of a comparative example. [Figure 10] Fig. 35 is a view showing the measurement result of the insertion force of the leg portion with respect to the fixing hole. [Figure 11] Fig. 38 is a view showing the removal force of the leg portion from the fixing hole of the fastener fixed to the fixing hole.

Embodiments for Carrying Out the Invention

[0019] (An Embodiment of the Fastener) Hereinafter, an embodiment of a fastener according to the present invention will be described with reference to the drawings.

[0020] As shown in Figures 1 and 6, the fastener 10 is inserted into a fixing hole 3 formed in a predetermined member to be fixed 1 and is fixed in place. It has a head portion 20 and a leg portion 30 connected to the head portion 20 and inserted into the fixing hole 3. In this embodiment, the fastener 10 holds a long member 5 (see Figure 6) to the member to be fixed 1. The fixing hole 3 in this embodiment is circular in shape.

[0021] The fixed member 1 is, for example, a vehicle body panel or a vehicle body frame. The long member 5 is, for example, a linear, tubular, or rod-shaped member such as a pipe, tube, hose, rod, wire, cable, harness, or cord.

[0022] However, the fasteners are not particularly limited and may be used to fix components such as body panels or body frames to a vehicle, for example, to secure trim boards, covers, garnishes, assist grips, bumpers, lamps, insulators (soundproofing materials), or to close off fixing holes when they are used as maintenance holes, etc. (used as so-called hole plugs).

[0023] The head portion 20 is roughly rectangular in shape (here roughly square in shape), and has a bottom portion 21 positioned on the front side of the fixed member 1, a pair of side wall portions 22, 22 that extend diagonally outward from both sides of the bottom portion 21 and are bent so as to be somewhat close to each other, and an intermediate wall portion 23 provided between the pair of side wall portions 22, 22 that defines two holding spaces R, R capable of holding two long members 5, and has a roughly frame-like shape with openings at the top and sides.

[0024] The "front side of the fixed member 1" mentioned above refers to one side in the thickness direction of the fixed member 1, on which the head 20 of the fastener 10 is positioned. Furthermore, the legs 30 of the fastener 10 are inserted into the fixing hole 3, and the "back side" of each part of the fastener (head, legs, ribs, etc.) refers to the side facing the direction in which the legs 30 are inserted into the fixing hole 3. Moreover, the "front side" of each part of the fastener refers to the side opposite to the insertion direction.

[0025] Furthermore, the inner surfaces of each side wall portion 22 and intermediate wall portion 23 are provided with a plurality of support pieces 24 for supporting the elongated member 5, and a plurality of retaining pieces 25 for preventing the elongated member 5 from being pulled out of the holding space R.

[0026] Next, the leg portion 30 will be described in detail. As shown in the cross-sectional perspective view in Figure 2 and the axial longitudinal section (section along the axial direction) of the leg portion 30 in Figure 5, the leg portion 30 has a columnar portion 31 extending from the back side of the head portion 20, a pair of side portions 35, 35 connected to the columnar portion 31 (here, a pair of side portions 35, 35 provided via connecting portions 33, 33 at locations facing each other radially on the columnar portion 31), and a plurality of locking pieces 40 that protrude from the outer surface 31a of the columnar portion 31 between the pair of side portions 35, 35 and are arranged at predetermined intervals in the axial direction of the columnar portion 31, and engage with the fixing holes 3.

[0027] More specifically, a columnar portion 31 extends for a predetermined length from the center of the back surface of the bottom portion 21 that constitutes the head portion 20. As shown in the axial cross-section (cross-section perpendicular to the axial direction) of the leg portion 30 in Figures 3 and 4, the columnar portion 31 has a pair of substantially arc-shaped outer surfaces 31a, 31a that are arranged opposite each other in the circumferential direction, and a pair of flat surfaces 31b, 31b that are arranged perpendicular to the pair of outer surfaces 31a, 31a and are parallel to each other, resulting in an irregular cross-sectional shape.

[0028] Furthermore, as shown in Figures 3 and 4, connecting portions 33, 33 are provided on a line segment L1 that passes through the axis C of the columnar portion 31 and is perpendicular to the pair of outer surfaces 31b, 31b (the widthwise center of the outer surface 31b of the columnar portion 31).

[0029] The central inner surfaces (facing surfaces with respect to the columnar portion 31) of the pair of side portions 35, 35 are connected to the tips of the pair of connecting portions 33, 33, and the pair of side portions 35, 35 are connected to the pair of outer surfaces 31b, 31b of the columnar portion 31 via the connecting portions 33, 33. The outer surfaces 35a, 35a of the pair of side portions 35, 35 are arc-shaped to fit into the circular fixing holes 3, thereby suppressing rattling when the leg portion 30 is inserted into the fixing holes 3. The inner surfaces 35b, 35b of the pair of side portions 35, 35 are flat surfaces parallel to each other.

[0030] Furthermore, as shown in Figure 5, the locking piece 40 has a base portion 41 that protrudes from the outer surface of the columnar portion 31, an extension portion 45 that extends inclined toward the head portion 20, and a connecting portion 43 that connects the base portion 41 and the extension portion 45.

[0031] In this embodiment, the base 41 of the locking piece 40 protrudes perpendicularly from the outer surfaces 31a, 31a of the columnar portion 31 with respect to the axial direction of the columnar portion 31 (meaning the direction along the axis C of the columnar portion 31). A connecting portion 43 is positioned at the tip of the protruding base 41, and an extension portion 45 extends diagonally outward toward the head portion 20 via the connecting portion 43.

[0032] Furthermore, the portion of each locking piece 40 that extends beyond the tip in the protruding direction of the rib is configured to extend inclined toward the head 20. In this embodiment, as shown in Figure 5, the extended portion 45 of each locking piece 40 extends inclined toward the tip in the protruding direction of the ribs (first rib 50 and second rib 55) in relation to the ribs. In other words, this extended portion 45 constitutes the "portion that extends beyond the rib" in the present invention.

[0033] In this embodiment, the locking piece 40 has a constant width in the circumferential direction and is formed with a constant thickness from the base end to the tip in the protruding direction.

[0034] Furthermore, as shown in Figure 5, the connecting portion 43 that connects the base portion 41 and the extension portion 45 has curved surfaces 43a, 43a on both sides 43a in the thickness direction (direction along the axial direction of the columnar portion 31), except for the connecting portion 43 of the locking piece 40 that is closest to the axial tip portion 31c of the columnar portion 31 (the end opposite to the head portion 20). The connecting portion 43 of the locking piece 40 that is closest to the axial tip portion 31c of the columnar portion 31 has a curved surface 43a on the head portion 20 side in the thickness direction.

[0035] Furthermore, as shown in Figure 5, a first R-shaped portion 70, which has an R-shaped curved surface, is provided at the connection point between the columnar portion 31 and the base portion 41 of the locking piece 40, on the side opposite to the head portion 20. Specifically, the corner of the connection point on the side opposite to the head portion 20 is thickened by building up material, and a recessed R-shaped (recessed R-shaped) curved surface is formed in this built-up portion, and this portion constitutes the first R-shaped portion 70.

[0036] In this fastener 10, the locking pieces 40, 40, which are arranged adjacent to each other in the axial direction of the columnar portion 31, have ribs (first ribs 50) extending from the base portion 41 that protrudes from the outer surface 31a of the columnar portion 31, and are provided on both sides of the locking piece 40 in the circumferential direction, with the ribs (first ribs 50) extending from the base portion 41 that protrudes from the outer surface 31a of the columnar portion 31.

[0037] The ribs provided on both sides of the circumferential direction of the locking piece 40 form a pair of first ribs 50, 50. Furthermore, a second rib 55, which is different from the first ribs 50, is provided between the pair of first ribs 50, 50 of the locking piece 40. In other words, the ribs in this embodiment consist of a pair of first ribs 50, 50 provided on both sides of the circumferential direction of the locking piece 40, and a second rib 55 provided between the pair of first ribs 50, 50. Each rib 50, 55 is configured to connect the bases 41 of multiple locking pieces 40 in the axial direction of the columnar portion 31.

[0038] To elaborate on the above configuration, as shown in Figures 2-5, the first rib 50 and the second rib 55 protrude from the substantially arc-shaped outer surface 31a of the columnar portion 31. Furthermore, each of the first rib 50 and each of the second rib 55, excluding the head connecting portion 51 (see Figure 3) described later, has a constant amount of protrusion from the outer surface 31a and a constant thickness in the circumferential direction, and is in the shape of a thin plate extending in the axial direction of the columnar portion 31.

[0039] The portion of the first rib 50 adjacent to the head 20 has a head connecting portion 51 at one end in the axial direction, which is thicker than the rest of the rib. This head connecting portion 51 is connected to the back surface of the bottom 21 of the head 20, and the other end in the axial direction is connected to the surface side (the side facing the bottom 21 of the head 20) of the base 41 of the locking piece 40 that is closest to the head 20.

[0040] Furthermore, the portion 55 of the second rib 55 adjacent to the head 20 has one axial end (the end on the head 20 side) connected to the back side of the bottom 21 of the head 20, and the other axial end is connected to the front side (the side of the head 20 facing the bottom 21) of the base 41 of the locking piece 40 that is closest to the head 20.

[0041] Furthermore, the ribs 50, 55 other than those adjacent to the head 20 are connected at both axial ends to the front and back surfaces of the bases 41, 41 of the locking pieces 40, 40 adjacent to the columnar portion 31 in the axial direction. That is, one axial end of the ribs 50, 55 (the end closer to the head 20) is connected to the back surface of the base of a predetermined locking piece 40, and the other axial end (the end opposite to the one end) is connected to the surface of the base of another locking piece 40 that is axially adjacent to the predetermined locking piece 40.

[0042] Furthermore, as shown in Figures 2 and 3, the head connecting portion 51 of the first rib 50 has a circumferential thickness T1 that is thicker than the portion of the first rib 50 other than the head connecting portion 51 and the second rib 55, and the amount of protrusion from the outer surface 31a of the columnar portion 31 is greater than the amount of protrusion from the outer surface of the columnar portion of the first rib 50 other than the head connecting portion 51 and the second rib 55. This head connecting portion 51 constitutes the "thick portion" in the present invention.

[0043] Furthermore, the outer surface 51a of the head connecting portion 51, like the outer surface 35a of the side portion 35, has an arc shape that fits into the circular hole-shaped fixing hole 3, and contributes to suppressing rattling when the leg portion 30 is inserted into the fixing hole 3.

[0044] Furthermore, as shown in Figure 4, the length of the first rib 50 protruding from the outer surface 31a of the columnar portion 31 is shorter than the length of the locking piece 40 protruding from the outer surface 31a of the columnar portion 31.

[0045] Furthermore, as shown in Figures 3 and 4, the second rib 55 is positioned on a line segment L2 that passes through the axis C of the columnar portion 31 and is perpendicular to the line segment L1 (the circumferential center of the outer surface 31a of the columnar portion 31).

[0046] As shown in Figure 4, the circumferential thickness T1 of the first rib 50, excluding the head connecting portion 51, is the same as the circumferential thickness T2 of the second rib 55. Furthermore, the amount of protrusion of the columnar portion 31 of the first rib 50 from the outer surface 31a is the same as the amount of protrusion of the columnar portion 31 of the second rib 55 from the outer surface 31a.

[0047] Furthermore, as shown in Figures 2 and 5, a second R-shaped portion 75 is provided at the tip end of the ribs 50 and 55 in the protruding direction (the direction of protrusion from the outer surface 31a of the columnar portion 31) opposite to the head 20, where it connects to the extended portion 45 of the locking piece 40. Specifically, the above-mentioned connecting portion is thickened by building up material, and a recessed R-shaped (recessed R-shaped) curved surface is formed in this built-up portion, and this portion constitutes the second R-shaped portion 75.

[0048] Furthermore, as shown in Figure 5, the radius of curvature of the second R-shaped portion 75, which has an R-shaped curved surface, is set to be smaller than the radius of curvature of the first R-shaped portion 70, which also has an R-shaped curved surface. In other words, the second R-shaped portion 75 has a steeper R-shaped curved surface than the first R-shaped portion 70.

[0049] In this fastener 10, a first groove 60 is formed between the side portion 35, the columnar portion 31, the locking piece 40, and the rib among the multiple ribs that is closest to the side portion 35, extending in the axial direction of the columnar portion 31.

[0050] Specifically, as shown in Figures 2-5, a first groove 60 is formed between the inner surface 35b of the side portion 35 and one circumferential side surface of the columnar portion 31, the locking piece 40, and the second rib 55, extending along the axial direction of the columnar portion 31. Furthermore, the first groove 60 is formed continuously without interruption from the portion of the columnar portion 31 closer to the head portion 20 than the axial tip, to the bottom portion 21 of the head portion 20. Moreover, as shown in Figures 3 and 4, the inner surfaces on both sides in the circumferential direction of the first groove 60 are parallel to each other, and the bottom portion 61 is an R-shaped curved surface.

[0051] Furthermore, a second groove 65 extending in the axial direction of the columnar portion 31 is formed between a pair of ribs 50, 50 provided on both sides of the locking piece 40 and a plurality of locking pieces 40, 40 adjacent to the columnar portion 31 in the axial direction. In addition, a second groove 65 extending in the axial direction of the columnar portion 31 is also formed between a plurality of ribs adjacent to the columnar portion 31 in the circumferential direction and the head 20 and the locking piece 40 adjacent to the head 20.

[0052] Specifically, as shown in Figures 2-5, a second groove 65 is formed between the first rib 50, the second rib 55, and the bases 41, 41 and connecting portions 43, 43 of the multiple locking pieces 40, 40 (which can also be described as the area enclosed by the ribs and other parts). Furthermore, a second groove 65 is also formed between the first rib 50, the second rib 55, the head 20, and the bases 41 and connecting portions 43 of the locking pieces 40 adjacent to the head 20 (which can also be described as the area enclosed by the ribs and other parts). As shown in Figures 3 and 4, the inner surfaces on both sides in the circumferential direction of the second groove 65 are parallel to each other, and its bottom is the outer surface 31a of a columnar portion 31 that is roughly arc-shaped.

[0053] Furthermore, the depth of the first groove 60 from the outer surface of the leg portion 30 is set to be greater than the depth of the second groove 65 from the tip surface of the rib.

[0054] In other words, as shown in Figure 4, when the depth from the extension of the outer surface of the side portion 35 constituting the leg portion 30 to the deepest part of the bottom 61 of the first groove portion 60 (which can be said to be the maximum depth of the first groove portion 60) is defined as the depth D1 of the first groove portion 60 from the outer surface of the leg portion 30, and the depth from the tangent of the curve passing through the tips of the multiple ribs 50, 55 to the deepest part of the bottom of the second groove portion 65 (which can be said to be the maximum depth of the second groove portion 65) is defined as the depth D2 of the second groove portion 65 from the tip surface of the rib, each groove portion 60, 65 is formed such that D1 is greater than D2.

[0055] Furthermore, all parts of the fastener 10 described above (head 20, leg 30, columnar part 31, side part 35, locking piece 40, first rib 50, second rib 55, etc.) are integrally formed from a predetermined synthetic resin material.

[0056] Furthermore, the fastener 10 having the above configuration can be molded, for example, by a mold 80 as shown in Figure 7. This mold 80 has a pair of molds 81 and 82 that can move closer to and away from each other via a dividing line PL. When the pair of molds 81 and 82 are closed, a cavity V corresponding to the outer shape of the fastener 10 is defined inside the mold 80. Then, with the pair of molds 81 and 82 closed, the fastener 10 is injection molded by injecting molten synthetic resin into the cavity V.

[0057] (modified version) The shape, structure, and layout of the head and legs that constitute the fastener in the present invention, as well as the columnar parts, side parts, locking pieces, ribs (first rib), second rib, and first grooves and second grooves formed on the legs, etc., are not limited to the above-described embodiments.

[0058] For example, the columnar portion constituting the leg may be cylindrical, elliptical, or prismatic. Also, the outer surface of the side portion constituting the leg may be flat. Furthermore, the circumferential width of the locking piece may be wider at the base end in the protruding direction and gradually or stepwise narrowing towards the tip in the protruding direction, or the thickness of the locking piece may be thicker at the base end in the protruding direction and gradually or stepwise thickening towards the tip in the protruding direction.

[0059] Furthermore, in this embodiment, the ribs are configured such that a pair of first ribs 50, 50 and a second rib 55 are provided on both sides in the circumferential direction on one side of the columnar portion 31 of the leg portion 30, that is, three rows of ribs are arranged in the circumferential direction on one side of the columnar portion. However, for example, two rows of ribs or four or more rows of ribs may be arranged in the circumferential direction on one side of the columnar portion, and it is sufficient that ribs are provided on both sides in the circumferential direction of the locking piece.

[0060] Figure 8 shows a modified example of the fastener. In this modified example, the fastener has ribs 50, 50 provided only on both sides of the locking piece 40 in the circumferential direction, and has a configuration in which two rows of ribs are arranged.

[0061] Furthermore, in this embodiment, the ribs 50 and 55, except for the head connecting portion 51 of the first rib 50, have a constant amount of protrusion from the outer surface 31a of the columnar portion 31 and a constant thickness. However, for example, the amount of protrusion of the rib from the outer surface of the columnar portion may be varied in the axial direction of the leg portion, or the thickness of the rib may be made thicker at the base end closer to the outer surface of the columnar portion and gradually thinner towards the tip.

[0062] Furthermore, the first rib 50 does not need to have a thick head connecting portion 51. In addition, the thickness T1 of the first rib 50 may be made thicker or thinner than the thickness T2 of the second rib 55. Furthermore, the amount of protrusion of the columnar portion 31 of the first rib 50 from the outer surface 31a may be made larger or smaller than the amount of protrusion of the columnar portion outer surface of the second rib 55. In addition, the radius of curvature of the second R-shaped portion 75 may be set to be the same as or larger than the radius of curvature of the first R-shaped portion 70.

[0063] Furthermore, the ribs may extend from the base of the locking piece, protrude from the outer surface of the columnar portion, and be arranged in multiple locations in the circumferential direction of the locking piece (however, it is necessary that ribs be arranged on at least both sides of the locking piece in the circumferential direction). That is, a rib extending a predetermined length in the axial direction may be provided from both the front and back surfaces of the base of a given locking piece, and one end of this rib in the axial direction may not be connected to the base of another locking piece.

[0064] (Effects and Benefits) Next, an example of how to use the fastener 10, which has the above configuration, and its effects will be described.

[0065] When holding and fixing the elongated member 5 to the fixed member 1 via the fastener 10, for example, the elongated member 5 is inserted into the housing space R from the upper opening side of the head 20 of the fastener 10, and the elongated member 5 is housed and held in the housing space R by a plurality of retaining pieces 25.

[0066] In this state, the axial tip of the leg portion 30 is inserted into the fixing hole 3 from the opening side on the front side of the member to be fixed 1. As a result, the outer surfaces 35a, 35a of the pair of side portions 35, 35 of the leg portion 30 are guided by the inner circumference of the fixing hole 3, and the tip of the extension portion 45 of the locking piece 40 is pressed against the inner circumference of the fixing hole 3. The extension portion 45 bends and deforms in a direction approaching the columnar portion 31, and the leg portion 30 is inserted into the fixing hole 3.

[0067] Then, the leg portion 30 is inserted into the fixing hole 3 until the bottom portion 21 of the head portion 20 abuts against the periphery of the fixing hole 3 on the front side of the member to be fixed 1. When a predetermined locking piece 40 (in this case, the fourth locking piece 40 counting from the back side of the head portion 20) comes out of the opening of the fixing hole 3 on the back side of the member to be fixed 1, the predetermined locking piece 40 elastically returns to its original position, and the tip of its extended portion 45 engages with the periphery of the fixing hole 3 on the back side of the member to be fixed 1 (see Figure 6).

[0068] As a result, the fastener 10 is fixed to the fixing hole 3, and the elongated member 5 is held and fixed to the fixed member 1 via the fastener 10. The multiple locking pieces 40 (in this case, the first to third locking pieces 40 from the back of the head) that are prevented from coming out of the opening of the fixing hole 3 have the tips of their extended portions 45 pressed against the inner circumference of the fixing hole 3, so that the entire locking piece 40 is maintained in a bent state.

[0069] Furthermore, in this fastener 10, ribs 50 and 55 extending from the base 41 of each locking piece 40 are provided on both sides of the locking piece 40 in the circumferential direction. As a result, both sides of the base 41 of each locking piece 40 in the circumferential direction are firmly supported by the columnar portion 31 via the ribs 50 and 55. Using this firmly supported base 41 as a fulcrum, the bending deformation performance of the portion of each locking piece 40 that extends beyond the protruding tip of the ribs 50 and 55 (in this case, the extended portion 45) can be appropriately exercised. This makes it less likely for each locking piece 40 to get caught on the inner circumference of the fixing hole 3 when inserting the leg portion 30 into the fixing hole 3, making insertion smoother.

[0070] Furthermore, because the extended portion 45 of each locking piece 40 extends inclined toward the head portion 20, when inserting the leg portion 30 into the fixing hole 3, the locking piece 40 is less likely to catch on the inner circumference of the fixing hole 3, making insertion easier and smoother.

[0071] Furthermore, since the ribs (first ribs 50) are provided on both sides of each locking piece 40 in the circumferential direction, the strength and rigidity of the base portion 41, which is the root portion of each locking piece 40, can be increased, and the length of the extension portion 45 of each locking piece 40 can be shortened, thereby increasing the strength and rigidity of the extension portion 45, and thus improving the overall strength and rigidity of the locking piece.

[0072] Therefore, when the fixed member 1 is thick and there are variations in the inner diameter or burrs in the fixing hole 3, or when there are none, the force that pulls out the fastener 10 from the fixing hole 3 can be increased when a pulling force or twisting force is applied to the fastener 10 fixed in the fixing hole 3.

[0073] Furthermore, since ribs (first ribs 50, 50) are provided on both sides of the circumferential direction of each locking piece 40, when inserting the leg portion 30 into the fixing hole 3, or when a pulling force or twisting force is applied to the fastener 10 fixed to the fixing hole 3, even if the pair of side portions 35, 35 collapse radially inward due to the inner circumference of the fixing hole 3 and come into contact with the circumferential side surface of the locking piece 40, the strength and rigidity of the base portion 41, which is the root part of the locking piece 40, are increased by the ribs 50, 50, thus preventing damage to the locking piece 40.

[0074] Furthermore, the first groove 60 ensures that the side portion 35 of the leg portion 30 is reliably separated from one circumferential side portion of each locking piece 40, thereby enabling the desired values ​​(design values) for the aforementioned deflection deformation performance, strength, and rigidity of each locking piece 40. Additionally, the second groove 65 ensures that the gap between the ribs in each locking piece 40 is appropriately maintained.

[0075] As described above, the fastener 10 provides a fastener that, while suppressing the insertion resistance (which can also be called the insertion force) of the leg portion 30 into the fixing hole 3, also improves the withdrawal force of the leg portion 30 of the fastener 10 from the fixing hole 3 (the resistance force when the leg portion 30 of the fastener 10 is pulled out of the fixing hole 3, i.e., the difficulty of pulling out the leg portion 30 of the fastener 10 from the fixing hole 3), thanks to the first groove portion 60, the portion of the locking piece 40 that extends beyond the tip of the protruding first rib 50 (here, the extended portion 45), and the first rib 50.

[0076] Furthermore, in this embodiment, the first ribs 50, 50 forming the ribs are configured to connect the bases 41 of the multiple locking pieces 40 in the axial direction of the columnar portion 31.

[0077] According to the above embodiment, the first ribs 50, 50 connect the bases 41 of the multiple locking pieces 40 in the axial direction of the columnar portion 31. Therefore, these first ribs 50, 50 can further increase the strength and rigidity of the base 41 of each locking piece 40, thereby improving the overall strength and rigidity of the locking pieces and further improving the pull-out force against the fixing hole 3.

[0078] Furthermore, since the bases 41 of each locking piece 40 are connected by the first ribs 50, 50, it becomes easier to form the first groove 60 and the second groove 65 to be longer in the axial direction. This ensures that the first groove 60 separates the side 35 of the leg portion 30 from one side of each locking piece 40 in the circumferential direction, and the second groove 65 ensures that the gap between the ribs in each locking piece 40 is more appropriately secured. As a result, the desired values ​​for the deflection deformation performance, strength, and rigidity of each locking piece 40 can be obtained more reliably.

[0079] Furthermore, the second ribs 55, 55 also connect the bases 41 of the multiple locking pieces 40 in the axial direction of the columnar portion 31, so the same effect as the first ribs 50, 50 can be obtained.

[0080] Furthermore, as shown in Figure 4, the rib (first rib 50) protrudes from the outer surface 31a of the columnar portion 31, and the length of the protrusion of the rib (first rib 50) from the outer surface 31a of the columnar portion 31 is shorter than the length of the protrusion of the locking piece 40 from the outer surface 31a of the columnar portion 31.

[0081] According to the above embodiment, since the length of the first rib 50 protruding from the outer surface 31a of the columnar portion 31 is shorter than the length of the locking piece 40 protruding from the outer surface 31a of the columnar portion 31, the bending deformation performance of the locking piece 40 is ensured, maintaining the insertability of the leg portion 30 into the fixing hole 3, while increasing the strength and rigidity of the base portion, which is the root of the locking piece 40, thereby further improving the force required to remove the leg portion 30 of the fastener 10 from the fixing hole 3.

[0082] Furthermore, in this fastener 10, multiple ribs 50, 55 that connect the bases 41, 41 of the locking pieces 40, 40 in the axial direction are arranged in the circumferential direction of the locking piece 40. This makes it easier to flow the molten resin during injection molding of the fastener 10 and suppresses casting defects such as voids and sink marks on the base 41 side of the locking piece 40.

[0083] In other words, as described above, the fastener 10 is formed by a mold 80 as shown in Figure 7, for example. During injection molding, as shown by arrow F in Figure 7, the molten resin flows smoothly through the cavities for forming the ribs 50 and 55 and reaches every corner of the cavity for forming the locking piece 40, so that the locking piece 40 can be formed with high precision.

[0084] Furthermore, as shown by the dashed line in Figure 7, if the ribs are connected to form a thickened portion N in order to ensure the rigidity of the base 41 side of the locking piece 40, voids and sink marks are likely to occur on the base 41 side of the locking piece 40 due to well-known reasons such as a decrease in solidification rate and solidification shrinkage.

[0085] In contrast, the fastener 10 has multiple ribs arranged in the circumferential direction of the locking piece 40, which minimizes the thickness of the base portion 41 of the locking piece 40, thereby suppressing the occurrence of voids and sink marks on the base portion 41, while ensuring the strength and rigidity of the base portion 41, and increasing the force required to remove the leg portion 30 from the fixing hole 3.

[0086] Furthermore, in this embodiment, the ribs provided on both sides of the locking piece 40 in the circumferential direction form a pair of first ribs 50, 50, and a second rib 55 is provided between the pair of first ribs 50, 50 of the locking piece 40.

[0087] According to the above embodiment, since the rib has the above configuration, even if the leg portion 30 is tilted relative to the center of the fixing hole 3 when inserting the leg portion 30 into the fixing hole 3, the pair of first ribs 50, 50 and the second rib 55 make balanced contact with the inner circumference of the fixing hole 3, thereby further suppressing the insertion resistance of the leg portion 30 into the fixing hole 3, and further increasing the strength and rigidity of the base portion 41 of the locking piece 40, thereby further improving the force required to remove the leg portion 30 from the fixing hole 3.

[0088] Furthermore, in this embodiment, the first rib 50 has a thicker portion (head connecting portion 51) that is thicker than the circumferential thickness T2 of the second rib 55.

[0089] According to the above embodiment, since the first rib 50 has the thickened portion (head connecting portion 51), the second rib 55, which is thinner than the thickened portion of the first rib 50, makes it easier to flex and deform the circumferential middle portion of the locking piece 40, thereby further suppressing the insertion resistance of the leg portion 30 into the fixing hole 3. At the same time, the thickened portion of the first rib 50 further increases the strength and rigidity of both sides of the locking piece 40 in the circumferential direction, thereby further improving the force required to remove the leg portion 30 from the fixing hole 3.

[0090] Furthermore, in this embodiment, as shown in Figure 4, the depth D1 of the first groove 60 from the outer surface of the leg portion 30 is set to be greater than the depth D2 of the second groove 65 from the tip surface of the rib.

[0091] According to the above embodiment, since the first groove 60 is set as described above, both circumferential sides of the locking piece 40 can be easily deformed by bending, and the resistance to inserting the leg portion 30 into the fixing hole 3 can be further suppressed.

[0092] Furthermore, in this embodiment, the locking piece 40 has a base portion 41 that protrudes perpendicularly from the outer surface of the columnar portion 31 with respect to the axial direction of the columnar portion 31, and an extension portion 45 that extends inclined toward the head portion 20.

[0093] According to the above embodiment, since the locking piece 40 has the above configuration, for example, when the fastener 10 is injection molded using a mold 80 as shown in Figure 7, it becomes easier to remove multiple locking pieces 40 from the mold while still providing multiple ribs.

[0094] In other words, when the molded fastener 10 is removed from the mold 80 after injection molding, the locking piece 40 is subjected to what is called forced removal (the locking piece 40 is removed while catching on a convex shape or the like inside the mold). However, even in such cases, because the extension 45 has the above configuration, it can be removed smoothly, thereby improving the manufacturability of the fastener 10.

[0095] Furthermore, in this embodiment, as shown in Figure 5, a first R-shaped portion 70 is provided on the side opposite to the head 20 at the connection point between the columnar portion 31 and the base 41 of the locking piece 40, and as shown in Figures 2 and 5, a second R-shaped portion 75 is provided on the tip side in the protruding direction of the ribs 50 and 55, opposite to the head 20, at the portion that connects to the extended portion 45 of the locking piece 40, which is also an R-shaped portion.

[0096] According to the above embodiment, the first R-shaped portion 70 makes it easier to die-cut the connection between the columnar portion 31 and the base portion 41 of the locking piece 40, thereby improving the manufacturability of the fastener 10. Furthermore, the second R-shaped portion further increases the strength and rigidity of the portion that connects to the extended portion 45 of the locking piece 40 on the tip side in the protruding direction of the ribs 50 and 55, opposite to the head portion 20, thereby further improving the force required to remove the leg portion 30 from the fixing hole 3. [Examples]

[0097] The insertion resistance (insertion force) and removal force of the fastener legs into the fixing holes were tested.

[0098] (Examples) A fastener of Example 1 was manufactured, having a structure similar to the fasteners shown in Figures 1-7, with three rows of ribs arranged circumferentially around the locking piece. A fastener of Example 2 was also manufactured, having a structure similar to the fastener shown in Figure 8 (a modified example), with two rows of ribs (50, 50) arranged on both sides of the locking piece 40 in the circumferential direction. Other parts are the same as the fastener of Example 1.

[0099] (Comparative example) As shown in Figure 9, a comparative fastener was manufactured in which the base 41 side of the locking piece 40 lacked a rib and had a thickened portion W. The other parts were the same as those of the fasteners in Examples 1 and 2.

[0100] (Insertion force confirmation test) The legs of each fastener in Examples 1 and 2 and the Comparative Example were inserted into a circular fixing hole at a constant speed, and the insertion force (insertion resistance) was measured. The results are shown in Figure 10. A smaller insertion force indicates that the legs are easier to insert into the fixing hole.

[0101] (Insertion resistance test) The legs of each fastener in Examples 1 and 2 and the Comparative Example were fixed into circular fixing holes, and the legs were pulled out of the fixing holes while the legs were still fixed. The extraction force when the legs were completely removed from the fixing holes was measured. The results are shown in Figure 1. A larger extraction force indicates that it is more difficult to pull the legs out of the fixing holes.

[0102] (Test results) Compared to the fasteners in Examples 1 and 2, the fasteners in Examples 1 and 2 were found to maintain a pulling force from the fixing hole while reducing the insertion force into the fixing hole (see Figure 10) (see Figure 11).

[0103] It should be noted that the present invention is not limited to the embodiments described above, and various modified embodiments are possible within the scope of the gist of the present invention, and such embodiments are also included in the scope of the present invention. [Explanation of symbols]

[0104] 3... Fixing hole, 10... Fastener, 20... Head, 30... Leg, 31... Columnar part, 35... Side part, 40... Locking piece, 41... Base, 45... Extension, 50... First rib, 51... Head connecting part (thickened section), 55... Second rib, 60... First groove, 65... Second groove, 70... First R-shaped part, 75... Second R-shaped part.

Claims

1. A fastener that is inserted into a fixing hole and fixed in place, It has a head and legs that are connected to the head and inserted into the fixing holes, The leg portion comprises a columnar portion extending from the back side of the head portion, a pair of side portions connected to the columnar portion, and a plurality of locking pieces that protrude from the outer surface of the columnar portion between the pair of side portions and are arranged at predetermined intervals in the axial direction of the columnar portion, and that engage with the fixing holes. A first groove is formed between the locking piece and the side portion, extending in the axial direction of the columnar portion. A fastener characterized in that ribs extending from the base of the locking piece are provided on both sides of the locking piece.

2. The fastener according to claim 1, wherein the rib is configured to connect the bases of the plurality of locking pieces in the axial direction of the columnar portion.

3. The fastener according to claim 1 or 2, wherein the rib protrudes from the outer surface of the columnar portion, and the length of the rib protruding from the outer surface of the columnar portion is shorter than the length of the locking piece protruding from the outer surface of the columnar portion.

4. The fastener according to claim 1 or 2, wherein the ribs provided on both sides of the locking piece in the circumferential direction form a pair of first ribs, and a second rib is provided between the pair of first ribs of the locking piece.

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