To provide a technique capable of reducing the number of component parts while securing strength resistible to colliding force when compressed most.
A cover member includes a cylindrical side portion 421 and a cover portion 422 provided at one end in the center line direction of the side portion 421 to cover an opening at the one end. The side portion 421 and the cover portion 422 are molded so as to be integrally continued with the thickness of the cover portion 422 being larger than that of the side portion 421. One end portion 422b in the center line direction in the cover portion 422 is flat, and a projection 424 is provided at the center of the other end portion 422c so as to protrude in the center line direction beyond an outside portion 423. The projection 424 and the outside portion 423 are connected by an inclined surface 425 inclined relative to the center line direction.
KONAKAI MASAYOSHI
KANEKO KENICHIRO
Fumio Ogata
Takeshi Senda