STAKING BOLT
FIG4 is an enlarged cross-sectional view of a staking bolt according to an embodiment of the present invention
In the enlarged cross-sectional view of FIG4, when a line L parallel to the center line of the shank 11 is drawn from the tip of the ring-shaped protrusion 20, the inside of this line L is a longitudinal cross-sectional area B of the ring groove 21. In addition, the area of a rectangle surrounded by the line L, the bearing face 13 of the head 10, a vertical line M indicating the minimum diameter portion of the arc-shaped portion 17, and the line indicating the lower face of the whirl-stop protrusion 14 is a longitudinal cross-sectional area A of the minimum diameter portion 18 of the whirl-stop protrusion 14. Here, since the minimum diameter of the whirl-stop protrusion 14 is D, A = t × (D - d)/2. In the present invention, t × (D - d)/2, which is the longitudinal cross-sectional area A of the minimum diameter portion 18 of the whirl-stop protrusion 14 described above, is set equal to or greater than the longitudinal cross-sectional area B of the ring groove 21. The meaning of this will be described below.
cross-sectional view
14
whirl-stop protrusion
12
external thread
1
shown in Patent Literature head
18
minimum diameter portion minimum diameter portions
22
non-threaded portion
4
ring groove
20
ring-shaped protrusion
21
ring groove
16
inclined face
10
head
15
arms arm
3
whirl-stop protrusion
13
bearing face
['1. A staking bolt comprising: a head; and a shank having an external thread, wherein a ring-shaped protrusion at an upper end of the shank and a ring groove located closer to the head relative to the ring-shaped protrusion are formed, wherein the head is flat and on a bearing face of the head, a whirl-stop protrusion having a plurality of radially extending arms protrudes with a thickness of t from the bearing face of the head, wherein a minimum diameter D between respective arms of the whirl-stop protrusion is larger than an outer diameter d of the ring-shaped protrusion, and wherein t x (D - d)/2 which is a longitudinal cross-sectional area A of a minimum diameter portion of the whirl-stop protrusion is equal to or greater than a longitudinal cross-sectional area of the ring groove.']