Frequency sensitive type shock absorber

A frequency sensitive type shock absorber comprising:

• a piston valve coupled to one end of a piston rod and configured to divide a cylinder filled with a fluid into a compression chamber and an extension chamber;
• a connecting flow path formed in the piston rod and including an upper end in communication with the extension chamber;
• and
• an auxiliary valve coupled to the piston valve,
• wherein the auxiliary valve includes:
• a housing coupled to a lower portion of the piston valve to connect the connecting flow path and an auxiliary chamber in the auxiliary valve and including an auxiliary flow path formed in a lower portion thereof and configured to vertically pass through the lower portion;
• an upper washer and a lower washer respectively disposed at an upper portion and a lower portion of the auxiliary chamber and including through holes formed to vertically pass through the upper washer and the lower washer to be connected to the connecting flow path and the compression chamber, and first contact protrusions formed in a ring shape at edges of the through holes to protrude from corresponding surfaces;
• an upper seal and a lower seal coupled to the corresponding surfaces of the upper washer and the lower washer, respectively, and including second contact protrusions formed in a ring shape around edges of the first contact protrusions to protrude more than the first contact protrusions;
• and
• a dividing disk disposed to be spaced apart from and interposed between the upper washer and the lower washer and including an orifice hole formed to vertically pass through the dividing disk such that a fluid introduced into the auxiliary chamber flows vertically during a high frequency stroke, and one surface of the dividing disk bent to come into contact with the first contact protrusion and the second contact protrusion sequentially to close the orifice hole during a low frequency stroke.