HOLLOW STABILIZER, STABILIZER MANUFACTURING DEVICE, AND METHOD FOR MANUFACTURING HOLLOW STABILIZER
FIG2 is a plan view schematically showing an example of a hollow stabilizer according to one of embodiments
FIG2 is a plan view schematically showing the hollow stabilizer 10. The material of the hollow stabilizer 10 is a pipe 40 formed of a metal (for example, spring steel) whose strength can be improved by heat treatment such as quenching. An example of an outer diameter of the pipe 40 is 22 mm and a thickness is 3 mm. An example of the radius of curvature (center radius of curvature r) of the bent parts 21 and 22 is 50 mm. In an endurance test (double swing test), one arm part 23 is fixed at fixed point A while a load in the vertical direction is applied to load point B of the other arm part 24. As shown in FIG2, the hollow stabilizer 10 has a bilaterally symmetric shape with the center in the longitudinal direction used as an axis of symmetry X1. Since the shapes of the bent parts 21 and 22 are substantially common to each other, the bent part 21 will be explained as a representative in the following descriptions. Since the other bent part 22 has the same structure, its explanations will be omitted. A specific shape of the hollow stabilizer 10 may be a three-dimensionally bent shape or one or more bent parts may be formed in the arm parts 23 and 24. In addition, one or more bent parts may be formed in the middle of the longitudinal direction of the torsion part 20.
plan view
24
arm parts arm part
12
suspension mechanism part
11
vehicle
22
bent parts bent part
20
torsion part
40
pipe
10
stabilizer
21
part parts
23
arm parts arm part
13
vehicle body
['1. A hollow stabilizer (10) disposed in a vehicle suspension mechanism part, characterized by  comprising: a torsion part (20); a bent part (21, 22) continuous with the torsion part (20); and an arm part (23, 24) continuous with the bent part (21, 22), and further comprising, when a center of bending inside is 0° and a center of bending outside is 180° in a cross section in a pipe radial direction of the bent part (21, 22), a first cross-sectional part (41) in a range from 60° to 300° centered at 0°; a second cross-sectional part (42) formed in a range from 120° to 240° centered at 180° and having a curvature smaller than that of the first cross-sectional part (41); a third cross-sectional part (43) formed in a range of more than 60° and less than 120° centered at 90° and having a curvature smaller than that of the second cross-sectional part (42); and a fourth cross-sectional part (44) formed in a range of more than 240° and less than 300° centered at 270° and having a curvature smaller than that of the second cross-sectional part (42).']