Shock absorber

A shock absorber comprising:

• a cylinder in which hydraulic fluid is sealingly contained;
• a reservoir in which hydraulic fluid and gas are sealingly contained;
• a piston inserted in the cylinder in a slidable manner and configured to separate an interior portion of the cylinder into a first chamber and a second chamber;
• a base valve configured to separate the second chamber and the reservoir from each other;
• a first check valve provided in the piston and configured to allow a hydraulic fluid flow from the second chamber side to the first chamber side;
• a second check valve provided in the base valve and configured to allow a hydraulic fluid flow from the reservoir side to the second chamber side;
• a passage connecting the first chamber and the reservoir;
• and
• a damping force adjustment mechanism configured to be capable of adjusting damping force from outside between soft characteristics of a low damping force and hard characteristics of a high damping force by controlling a hydraulic fluid flow in the passage,
• at least either one of the first check valve and the second check valve being provided with orifice passages in parallel, the orifice passages being provided with a sub-check valve at passage openings,
• the sub-check valve being configured to open at lower pressure than the check valve, in which the orifice passages are provided in parallel, and allow hydraulic fluid to flow in a same direction,
• the sub-check valve being provided with a biasing member of substantially equal diameter to the sub-check valve, the biasing member being configured to bias the sub-check valve toward the passage openings, and
• the biasing member in which a protrusion that generates biasing force acting toward the sub-check valve is formed at an outer peripheral side of the biasing member, the protrusion being disposed to face the passage openings.

A shock absorber comprising:

• a cylinder in which hydraulic fluid is sealingly contained;
• a reservoir in which hydraulic fluid and gas are sealingly contained;
• a piston inserted in the cylinder in a slidable manner and configured to separate an interior portion of the cylinder into a first chamber and a second chamber;
• a base valve configured to separate the second chamber and the reservoir from each other;
• a first check valve provided in the piston and configured to allow a hydraulic fluid flow from the second chamber side to the first chamber side;
• a second check valve provided in the base valve and configured to allow a hydraulic fluid flow from the reservoir side to the second chamber side;
• a passage connecting the first chamber and the reservoir;
• and
• a damping force adjustment mechanism configured to be capable of adjusting damping force from outside between soft characteristics of a low damping force and hard characteristics of a high damping force by controlling a hydraulic fluid flow in the passage,
• at least either one of the first check valve and the second check valve being provided with orifice passages in parallel, the orifice passages being provided with a sub-check valve at passage openings,
• the sub-check valve being configured to open at lower pressure than the check valve, in which the orifice passages are provided in parallel, and allow hydraulic fluid to flow in a same direction,
• the first check valve being disposed in the first chamber, the sub-check valve being disposed in the second chamber, and
• the sub-check valve being provided with a biasing member configured to bias the sub-check valve toward the passage openings, and
• the biasing member in which a protrusion that generates biasing force acting toward the sub-check valve is formed at an outer peripheral side of the biasing member, the protrusion being disposed to face the passage openings.