Clinching stud bolt

Abstract

To provide a clinching stud bolt which enables improvement of quality when the clinching stud bolt is fixed to a plate to which the bolt is attached (an attachment object plate).SOLUTION: A clinching stud bolt B is fixed to an attachment object plate T in a state that the bolt is prevented from being removed and rotating and includes: a head part 1; a screw shaft part 2; a rotation prevention part 3; an annular groove part 21; and an annular protrusion part 22. The clinching stud bolt B is configured so that the attachment object plate T is sandwiched between a seating surface 21 of the head part 1 and the annular protrusion part 22. The rotation prevention part 3 is provided with a recessed part 32 which is recessed toward the upper side X2 in an advancing direction. In the recessed part, an annular seal member is provided at a neck lower part of the head part.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a clinching stud bolt having a waterproof function that is fixed to a plate material to be attached in a non-slip and non-rotating state. [Background technology]

[0002] Conventionally, there is known a clinching stud bolt (clinch stud) that is press-fitted into a mounting hole in a metal plate (mounting target plate) to be fixed in a state where it is prevented from coming out and rotating (see, for example, Patent Document 1). This clinching stud bolt has a head and a screw shank extending from the seat of the head. When fixing a separate member to the metal plate, the screw shank is inserted into a through hole in the separate member and screwed in such a way that the nut moves in the opposite direction to the screwing direction of the screw shank, and the separate member is sandwiched and fixed between the nut and the metal plate.

[0003] The clinching stud bolt described in Patent Document 1 has a non-circular anti-rotation portion (anti-rotation protrusion in the document) that bulges from the seat surface toward the downstream side of the screw shank in the screwing direction, an annular groove portion (retaining groove in the document) that is annularly recessed toward the radially inward side of the screw shank, and an annular protrusion (retaining ring in the document) that protrudes annularly at a position adjacent to the annular groove on the downstream side in the screwing direction. The technology described in Patent Document 1 provides a protrusion that protrudes on the side facing the head around the mounting hole of the metal plate, so that when the clinching stud bolt is pressed into the metal plate, the protrusion is crushed by the anti-rotation protrusion, forcing a large amount of metal into the retaining groove, increasing the pull-out load and idling torque. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-141999 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the clinching stud bolt described in Patent Document 1, the metal that is crushed and flows by the anti-rotation protrusions tends to protrude from the periphery of the mounting hole located on the opposite side of the head to the radial outside of the retaining ring, resulting in burrs. In addition, the metal that is crushed by the anti-rotation protrusions tends to flow to the radial outside of the anti-rotation protrusions and cause deformation, which tends to cause warping of the metal plate. As a result, when fixing another component to the metal plate, the burrs can scratch the other component, the burrs can fly around as foreign matter, and the warped metal plate can interfere with surrounding parts, resulting in inconveniences that degrade the quality of the product.

[0006] Therefore, there is a demand for a clinching stud bolt that can improve the quality when fixed to the plate material to which it is attached. [Means for solving the problem]

[0007] a clinching stud bolt which is fixed to a plate material to be attached in a non-slip and non-rotation-preventing state, the clinching stud bolt comprising: a head; a screw shank extending from a seating surface of the head; a detent portion which is formed in a non-circular shape surrounding the screw shank portion when viewed in the screwing direction of the screw shank portion and which bulges from the seating surface toward the downstream side of the screwing direction; an annular groove portion which is recessed in a ring shape toward the radially inward side of the screw shank portion at a position of the screw shank portion adjacent to the downstream side of the detent portion in the screwing direction; and an annular protrusion which protrudes in a ring shape toward the radially outward side of the screw shank portion at a position of the screw shank portion adjacent to the downstream side of the screwing direction with respect to the annular groove portion, the clinching stud bolt being configured so that the plate material to be attached is sandwiched between the seating surface and the annular protrusion, Effect of the Invention

[0008] The clinching stud bolt of the present invention is suitable for thin mounting plate materials, and the seal member also provides a preventive function. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a perspective view of a clinching stud bolt. [Diagram 2] FIG. 2 is a side view of the clinching stud bolt. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] FIG. 4 is an enlarged cross-sectional view of the convex portion at the position farthest from the annular protrusion. [Figure 6] FIG. 4 is an enlarged cross-sectional view of the convex portion at a position closest to the annular protrusion. [Figure 7] FIG. 2 is a cross-sectional view of the clinching stud bolt before it is pressed into the plate material to be attached. [Figure 8] FIG. 2 is a cross-sectional view of the clinching stud bolt after it has been pressed into the plate material to be attached. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of a clinching stud bolt according to the present invention will be described with reference to the drawings. In this embodiment, a clinching stud bolt that is press-fitted into a metal plate as a mounting target plate will be described as an example. However, the present invention is not limited to the following embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0011] As shown in Figs. 1 and 2, the clinching stud bolt B has a flattened cylindrical head 1 with a pair of rounded edges along the circumferential direction, and a screw shank 2 extending from a seating surface 11 of the head 1. A male thread 2A is formed in most of the screw shank 2, and the screw advance direction X of the screw shank 2 coincides with the extension direction of the screw shank 2. The screw advance direction X refers to the direction in which the clinching stud bolt B advances relative to the female thread when the male thread 2A of the screw shank 2 is screwed into a female thread (not shown). In the following description, the tip side of the screw shank 2 is referred to as the downstream side X1 in the screw advance direction, and the base end side of the screw shank 2 (the connection side of the head 1 and the screw shank 2) is referred to as the upstream side X2 in the screw advance direction.

[0012] As shown in Fig. 8, the clinching stud bolt B is fixed to the metal plate T in a state where it is prevented from slipping out and rotating, so that the male thread portion 2A of the screw shaft portion 2 protrudes from the metal plate T, and is exposed to the outside when the jig G is removed. The clinching stud bolt B is made of a metal material such as low carbon steel that is more rigid than the metal plate T, and the clinching stud bolt B is pressed into the metal plate T by a hydraulic press P, which crushes the metal plate T. As a result, the metal plate T is sandwiched between the seat surface 11 of the head 1 and an annular protrusion 22, which will be described later.

[0013] As shown in Figures 1 and 2, the clinching stud bolt B includes a rotation prevention portion 3 that bulges from the seat surface 11 of the head 1 toward the downstream side X1 in the screwing direction, an annular groove portion 21 that is recessed in an annular shape toward the radially inward side of the screw shank 2, and an annular protrusion 22 that protrudes in an annular shape toward the radially outward side of the screw shank 2. The annular groove portion 21 is located adjacent to the rotation prevention portion 3 on the downstream side X1 in the screwing direction of the screw shank 2, and the annular protrusion 22 is located adjacent to the annular groove portion 21 on the downstream side X1 in the screwing direction of the screw shank 2. In other words, the rotation prevention portion 3, the annular groove portion 21, and the annular protrusion 22 are arranged in order along the screwing direction X.

[0014] The groove width of the annular groove 21 is set according to the shape of the annular protrusion 22 and the ductility of the metal plate material T, and in this embodiment, it is set to be equal to the plate thickness of the metal plate material T (see also FIG. 8). The annular groove 21 and the annular protrusion 22 are continuous with each other in an R-shape, and the annular protrusion 22 and the male threaded portion 2A are continuous with each other in a tapered shape (see also FIG. 4). In this embodiment, the annular groove 21 has an outer diameter smaller than the outer diameter of the male threaded portion 2A formed on the screw shaft portion 2, and the annular protrusion 22 has an outer diameter larger than the outer diameter of the male threaded portion 2A formed on the screw shaft portion 2. In addition, the diameter of the annular protrusion 22 in this embodiment is set to be smaller than the diameter of the through hole Ta of the metal plate material T (see also FIG. 7).

[0015] As shown in FIG. 3, the anti-rotation portion 3 is formed in a hexagonal star shape (an example of a non-circular shape) surrounding the screw shaft portion 2 when viewed in the screw advancement direction X. The outer edge portion 31 of the anti-rotation portion 3 has a round corner portion 31a that is a plurality of (six in this embodiment) vertices arranged radially, and a plurality of (six in this embodiment) connecting edges 31b that are formed in a concave shape on the radially inward side connecting the pair of round corner portions 31a. The circumscribing circle of the plurality of round corner portions 31a has a diameter equal to that of the outer peripheral edge portion 11a of the seat surface 11. In the anti-rotation portion 3 in this embodiment, the round corner portion 31a is formed in a pointed shape, so that the connecting edges 31b can be moved as far as possible to the radially outward side compared to the case where the round corner portion 31a is formed in a bulging semicircular shape, and therefore the volume of the recessed portion 32 described later can be increased. Due to such a shape of the anti-rotation portion 3, when the anti-rotation portion 3 is press-fitted into the metal plate material T, the clinching stud bolt B is prevented from rotating with respect to the metal plate material T.

[0016] As shown in Fig. 4, the anti-rotation portion 3 is formed with a recessed portion 32 that is recessed in an annular shape toward the upstream side X2 in the screw-in direction (see also Fig. 1). This recessed portion 32 forms a convex portion 31A that protrudes toward the downstream side X1 in the screw-in direction on the outer edge portion 31 of the anti-rotation portion 3. This convex portion 31A is formed with the same height over the entire area. The metal of the metal plate T enters the recessed portion 32 and the annular groove portion 21, so that the clinching stud bolt B is prevented from slipping out and from rotating relative to the metal plate T. The volumes of the recessed portion 32 and the annular groove portion 21 that accommodate the metal of the metal plate T are set according to the volume and ductility of the metal plate T that flows as the convex portion 31A is crushed and plastically deformed (see also Fig. 8). An inner edge 32a of the recessed portion 32 reaches the annular groove 21 of the screw shaft portion 2 and is continuous with the annular groove 21 in an R-shape, and an outer edge 32b of the recessed portion 32 reaches the most protruding end 31Aa of the convex portion 31A (the outer edge 31 of the anti-rotation portion 3) and is continuous with the convex portion 31A. The recessed portion 32 and the convex portion 31A have an inclined portion 30 with an inclined cross-sectional shape, and this inclined portion 30 is a portion that connects the recessed portion 32 and the convex portion 31A. In addition, the convex portion 31A has a standing portion 31Ab on the opposite side to the screw shaft portion 2, the cross-sectional shape of which is steeper than the inclined portion 30.

[0017] The recessed portion 32 has an inclined portion 30 that is deeper from the most protruding end 31Aa toward the screw shaft portion 2, and has a linear portion 32A that is formed in a cross section that is linear and parallel to the seat surface 11 at the same height as the seat surface 11 from the inner end 30b of the inclined portion 30 to the inner edge portion 32a. In other words, the recessed portion 32 has a linear portion 32A with a gentler gradient than the inclined portion 30, with the inner end 30b of the inclined portion 30 being the gradient change end. The linear portion 32A is continuous around the axis of the screw shaft portion 2 (hereinafter referred to as the "circumferential direction") with different lengths. As a result, the cross-sectional shape of the anti-rotation portion 3 along the radial direction (cut by a line segment perpendicular to the outer edge portion 31 of the anti-rotation portion 3 and passing through the center of the screw shaft portion 2) is continuously formed with non-similar shapes all around. The convex portion 31A has an inclined portion 30 on the side of the screw shaft portion 2 and an erected portion 31Ab on the opposite side of the screw shaft portion 2, and is tapered toward the downstream side X1 in the screw advance direction by the most protruding end 31Aa connecting the inclined portion 30 and the erected portion 31Ab. In this embodiment, the inner edge portion 32a of the recessed portion 32 reaches the annular groove portion 21 over the entire circumference, and the annular groove portion 21 and the recessed portion 32 are continuous over the entire circumference (see also FIG. 1). In addition, the outer edge portion 32b of the recessed portion 32 reaches the most protruding end 31Aa of the convex portion 31A over the entire circumference, and the recessed portion 32 and the convex portion 31A are continuous over the entire circumference by the inclined portion 30. In other words, the recessed portion 32 is formed in an endless shape surrounding the screw shaft portion 2.

[0018] Fig. 5 shows an enlarged cross-sectional view of the convex portion 31A cut at a position where it is furthest from the annular protrusion 22, that is, a line segment passing through the rounded corner 31a at a position equivalent to the outer peripheral edge 11a of the seating surface 11 shown in Fig. 3, and the center of the screw shaft portion 2. Fig. 6 shows an enlarged cross-sectional view of the convex portion 31A cut at a position where it is closest to the annular protrusion 22, that is, a line segment passing through the radially innermost part of the connecting side 31b shown in Fig. 3, and the center of the screw shaft portion 2.

[0019] As shown in Figs. 5 and 6, the erected portion 31Ab of the convex portion 31A is formed perpendicular to the seat surface 11 of the head 1, and the inclination angle θ of the inclined portion 30 with respect to a virtual perpendicular line L parallel to the erected portion 31Ab is set to about 55 degrees. As shown in Fig. 5, the inclined portion 30 located at the round corner portion 31a has a connecting inclined portion 30a that connects the inclined portions 30 adjacent to each other in the circumferential direction, and the connecting inclined portion 30a is formed with a gentler gradient than the inclination angle θ. Due to the connecting inclined portion 30a, the cross-sectional shape of the inclined portions 30 of the adjacent connecting sides 31b along the radial direction of the anti-rotation portion 3 is discontinuous in the circumferential direction (see also Fig. 3). The inclination angle θ may be 45 degrees or more and 70 degrees or less, preferably 50 degrees or more and 60 degrees or less, and more preferably about 55 degrees. If the inclination angle θ is less than 45 degrees, the thickness of the convex portion 31A becomes too small, resulting in a decrease in fluidity during molding and a decrease in rigidity, whereas if the inclination angle θ exceeds 70 degrees, the convex portion 31A becomes too large, resulting in a decrease in the volume of the recessed portion 32, resulting in an insufficient metal storage volume. The height L1 of the convex portion 31A is set to about one-third the groove width L2 of the annular groove portion 21. It is preferable that the height L1 of the convex portion 31A is between one-quarter and one-half the groove width L2 of the annular groove portion 21. If the height L1 is less than one-quarter, the volume of the recessed portion 32 becomes small, resulting in an insufficient metal storage volume, whereas if the height L1 is more than one-half, the metal does not flow smoothly into the recessed portion 32.

[0020] As shown in Figs. 3 and 6, at the position where the convex portion 31A is closest to the annular protrusion 22, the inner end 30b of the inclined portion 30 in this embodiment is located slightly radially inward from the outermost periphery of the annular protrusion 22 when viewed in the screw-in direction X. With this configuration, the clinching stud bolt B in a state where it is pressed into the metal plate T can secure a large area of ​​the seating surface 11 facing the metal plate T (see also Fig. 8). As a result, it is possible to secure a large volume of the metal plate T that enters between a pair of adjacent round corners 31a of the seating surface 11, and the idling torque can be improved. In addition, since the inner end 30b of the inclined portion 30 is located radially inward from the outermost periphery of the annular protrusion 22, the thick metal accommodated in the annular groove portion 21 and the recessed portion 32 becomes dominant in terms of the pull-out load, and the pull-out load can be increased.

[0021] 7 and 8, the action and effect when the clinching stud bolt B according to this embodiment is press-fitted into a metal plate T will be described. The metal plate T is a thin metal plate such as a steel plate, in which a through hole Ta is formed in advance that is larger than the diameter of the annular protrusion 22 and smaller than the outer diameter of the anti-rotation portion 3, and which is supported by a jig G capable of withstanding the pressing force of a hydraulic press P.

[0022] 7, before being press-fitted into the metal plate T, the clinching stud bolt B has the most protruding end 31Aa of the anti-rotation portion 3 abutted against the periphery of the through hole Ta, and the hydraulic press P is abutted against the head 1. At this time, the annular protrusion 22 is housed inside the through hole Ta, and the male thread portion 2A of the screw shaft portion 2 protrudes toward the jig G.

[0023] Next, as shown in Figures 7 and 8, when the head 1 is pressed by a hydraulic press P, the clinching stud bolt B moves downward (the downstream side X1 in the screw advancement direction) while the convex portion 31A of the anti-rotation portion 3 bites into the metal plate T, and is pressed in until the bearing surface 11 abuts against the metal plate T. At this time, the metal of the crushed metal plate T equivalent to the volume of the convex portion 31A flows smoothly radially inward along the inclined portion 30 and is accommodated in the recessed portion 32 and the annular groove portion 21. As a result, the clinching stud bolt B has an excellent overall appearance when fixed to the metal plate T.

[0024] In the clinching stud bolt B according to this embodiment, the anti-rotation portion 3, which bulges from the seat surface 11 of the head 1, the annular groove portion 21, and the annular protrusion 22 are arranged in this order along the screw-in direction X, and the anti-rotation portion 3 is formed with a recessed portion 32 recessed toward the upstream side X2 of the screw-in direction. As a result, when the anti-rotation portion 3 crushes the metal plate material T, the metal of the metal plate material T enters not only the annular groove portion 21 but also the recessed portion 32, so that the metal of the metal plate material T is prevented from protruding to the radial outside of the annular protrusion 22. As a result, the occurrence of burrs is prevented, so that when another member is fixed to the metal plate material T, there is no inconvenience such as the burrs damaging the other member or the burrs becoming foreign matter and scattering around, and the quality can be improved. In addition, the metal of the metal plate material T enters the annular groove portion 21 to ensure the pull-out load, and the metal of the metal plate material T enters the recessed portion 32 to increase the shear cross-sectional area of ​​the metal plate material T, thereby improving the idling torque. Furthermore, since the metal plate material T preferentially enters the recessed portion 32, the metal plate material T is less likely to protrude radially outward from the recessed portion 32, and warping of the metal plate material T is prevented, so that there is no inconvenience such as the warped metal plate material T interfering with surrounding parts, and the quality can be improved.

[0025] In addition, since the recessed portion 32 is formed deeper closer to the screw shaft portion 2, the metal of the metal sheet material T that is crushed and flows is smoothly guided in the direction of the annular groove portion 21. Since the recessed portion 32 and the annular groove portion 21 are continuous over the entire circumference, the metal of the metal sheet material T that is crushed and flows is guided in the direction of the annular groove portion 21 without any barriers. In other words, since the recessed portion 32 has an endless shape that surrounds the screw shaft portion 2, the metal of the metal sheet material T that is crushed and flows is guided in the direction of the annular groove portion 21 without any barriers, and the volume of the recessed portion 32 is sufficiently secured. As a result, the overflow of the flowing metal is further suppressed and the occurrence of burrs is prevented, thereby improving quality.

[0026] The recessed portion 32 has an inclined portion 30 that becomes deeper from the most protruding end 31Aa toward the screw shaft portion 2, a connecting inclined portion 30a that connects adjacent inclined portions 30 in the circumferential direction and has a gentler gradient than the connecting inclined portion 30, and a straight portion 32A that is continuous so that the circumferential length is different and has a gentler gradient than the connecting inclined portion 30a. As a result, the cross-sectional shape along the radial direction of the anti-rotation portion 3 in this embodiment is formed in a continuous non-similar shape over the entire circumference. As a result, the metal of the flowing metal sheet material T enters the recessed portion 32 in a discontinuous shape in the circumferential direction, and the metal that has entered the recessed portion 32 abuts against the convex portion 31A, providing resistance during idling, thereby increasing the idling torque. In addition, by providing the straight portion 32A in the recessed portion 32, it is possible to allow a large amount of metal to enter the inner edge portion 32a of the recessed portion 32 adjacent to the annular groove portion 21, and the idling torque can be further increased.

[0027] In this embodiment, the recess 32 is extended to the outer edge 31 of the anti-rotation portion 3 to form the convex portion 31A that protrudes in a tapered manner from the outer edge 31 of the anti-rotation portion 3, so that the convex portion 31A bites into the metal plate T and improves the idling torque. Since the convex portion 31A is formed to the same height over the entire area, the convex portion 31A bites into the metal plate T evenly and can further improve the idling torque. Moreover, the convex portion 31A acts as a barrier, so that the metal of the metal plate T that has entered the recess 32 is less likely to protrude radially outward from the convex portion 31A, and warping of the metal plate T can be reliably prevented.

[0028] Furthermore, because the convex portion 31A is inclined toward the screw shank 2 and the erected portion 31Ab on the opposite side to the screw shank 2 is erected at a steep gradient, the metal plate T is pushed further into the recessed portion 32, reliably preventing the metal plate T from protruding radially outward from the recessed portion 32. Moreover, even when the metal plate T rotates and a rotational torque is applied to the clinching stud bolt B, because the erected portion 31Ab is erected perpendicular to the metal plate T, the component force in the direction in which the clinching stud bolt B comes out is extremely small and an appropriate pull-out load can be ensured.

[0029] [Other embodiments] (1) The non-circular shape of anti-rotation portion 3 may be a hexagon with connecting side 31b formed in a straight line, or may be a polygonal shape such as a triangle, a rectangle, or a pentagon. (2) The recessed portion 32 of the anti-rotation portion 3 may have any shape, such as being partially provided along the circumferential direction, and is not particularly limited. In this case, it is preferable that the cross-sectional shape along the radial direction of the anti-rotation portion 3 is formed in a non-similar shape at least in a part in the circumferential direction. If the shape can be formed in a non-similar shape, the inclined portion 30 of the recessed portion 32 may be omitted and the recessed portion 32 may be formed only with a linear portion 32A that is continuous so that the circumferential length is different, or multiple recesses that are different in radial position may be provided along the circumferential direction. In addition, it is preferable that at least the inner edge portion 32a of the recessed portion 32 is shaped to be continuous along the circumferential direction so that the metal that has entered the recessed portion 32 can flow to the annular groove portion 21. (3) The annular groove portion 21 and the annular protrusion 22 may be formed in a polygonal ring shape instead of a circular ring shape. Also, the through hole Ta of the metal plate T may be formed to have a smaller diameter than the annular protrusion 22 so that the inner periphery of the through hole Ta is also crushed by the annular protrusion 22. (4) The most protruding end 31Aa of the convex portion 31A may be sharpened. In this case, the most protruding end 31Aa can easily bite into the metal plate T. (5) The plate material to which the attachment is to be made is not particularly limited, and may be any plate material made of a material having fluidity (ductility), in addition to the metal plate material T. (6) The screw shaft 2 may be formed with a female thread instead of the male thread 2A. [Industrial Applicability]

[0030] INDUSTRIAL APPLICABILITY The present invention can be used for a clinching stud bolt that is fixed to a plate material to be attached in a non-slip and non-rotatable state. [Explanation of symbols]

[0031] 1:Head 2: Screw shaft 3: Anti-rotation part 11: Seat 21: Annular groove 22: Annular protrusion 30: Inclined part 31 :Outer edge 31A:Convex part 31Ab: Standing part 32: Recessed section 40: Sealing material B: Clinching stud bolt T: Metal plate (mounting plate material) X: Spiral direction X1: Downward side in spiral direction X2: Upper side in spiral direction

Claims

[Claim 1] A clinching stud bolt that is fixed to a plate material to be attached in a non-slip and non-rotating state, The head and A screw shaft portion extending from the seat surface of the head portion; A rotation prevention portion that is formed in a non-circular shape surrounding the screw shaft portion when viewed in the screw direction of the screw shaft portion and that bulges out from the seat surface toward the downstream side in the screw direction; An annular groove portion is recessed in a radially inward direction of the screw shaft portion at a position adjacent to the anti-rotation portion in the screw direction, and The screw shaft portion includes an annular protrusion that protrudes annularly toward the radial outside of the screw shaft portion at a position adjacent to the annular groove portion in the screw direction, The mounting target plate material is sandwiched between the seat surface and the annular protrusion, The anti-rotation portion is formed with a recessed portion recessed toward the upstream side in the screw advancement direction, A clinching stud bolt characterized in that an annular seal member is provided inside the recess at a neck portion of the head.

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