Shock absorber
A cylinder chamber filled with a liquid, a piston disposed inside the cylinder chamber, a piston rod connected to the piston, and an accumulator allowing the piston rod to generate a damping force by receiving the liquid from a compression side of the cylinder chamber are included, and on an internal periphery of the cylinder chamber, one line of a helical damping groove is formed within a stroke range of the piston, a groove width of the damping groove is constant over the entire length of the damping groove, a depth of the damping groove gradually decreases along a spiral toward the direction in which the piston rod is pushed in, and a length of the piston in a direction along the axis line is smaller than a pitch of the damping groove.
1. A shock absorber, comprising:
a cylinder chamber formed in a tube and filled with a liquid;
a piston disposed in the cylinder chamber so as to be freely displaced in a direction along an axis line of the cylinder chamber;
a piston rod, one end of the piston rod being connected to the piston and the other end of the piston rod extending out from the tube; and
an accumulator allowing the piston rod to generate a damping force by receiving the liquid from a compression side of the cylinder chamber when the piston rod is pushed into the tube by an impact force and the piston is displaced, wherein
a helical damping groove, inclined relative to the axis line, is formed on an internal periphery of the cylinder chamber so as to directly come into contact with the piston within a stroke range of the piston, and the damping groove includes only one pitch,
a groove width of the damping groove is constant over the entire length of the damping groove,
a depth of the damping groove gradually decreases along a spiral toward the direction in which the piston rod is pushed in,
the groove width of the damping groove along the axis line is equal to or greater than a length of the piston in a direction along the axis line, and
a length of the piston in a direction along the axis line is smaller than a pitch of the damping groove.
2. The shock absorber according to claim 1 , wherein a bottom wall of the damping groove is flat.
3. The shock absorber according to claim 1 , wherein the piston is supported at a tip of the piston rod in a floating state.
4. The shock absorber according to claim 1 , wherein a rod-guiding-out side end of the cylinder chamber is connected to an elastic-member chamber constituting the accumulator, the elastic-member chamber being provided therein with a flexibly constrictable and expandable elastic member.
5. The shock absorber according to claim 1 , wherein the width of the damping groove is one to two times the length of the piston.