Method of manufacturing cylinder apparatus

A method of manufacturing a shock absorber, the shock absorber comprising:

• a cylinder having a fluid sealed therein;
• a piston slidably fitted in the cylinder;
• a piston rod connected to the piston;
• and
• a damping valve device adapted to control a flow of fluid caused by sliding movement of the piston, the damping valve device including an annular disk valve having an annular elastic seal member of rubber material fixed to one side thereof;
• the method comprising:
• the step of fixing the elastic seal member to the disk valve, the step including:
• a deforming step of deforming the disk valve into a shape that is convex on one side;
• and
• a fixing step of fixing the elastic seal member to the one side of the disk valve deformed in the deforming step.

A method of manufacturing a disk valve for a shock absorber, the method comprising the step of:

• providing a first mold member and a second mold member;
• the first mold member being shaped in a cylinder, one end of which is closed, to form a bottom and outer periphery of a cavity, the bottom of the first mold member being curved at a predetermined curvature or sloped at a predetermined angle so that a center of the bottom projects convexly;
• the second mold member having a mold part fittable into the first mold member, the mold part adapted to abut at a distal end thereof against the disk valve set in the first mold member to form the cavity when the first mold member and the second mold member are closed,
• the second mold member being provided with a passage for filling the cavity with a rubber material to form an elastic seal member, the distal end of the mold part, which abuts against the disk valve, being curved or sloped in conformity to the curvature or angle of the bottom of the first mold member;
• the method further comprising the steps of:
• setting a disk valve blanked from a plate material on the bottom of the first mold member;
• closing the first mold member and the second mold member to form the cavity by the mold part and to press and deform the disk valve into a shape that is convex on one side;
• filling a rubber material into the cavity through the passage and vulcanizing and curing the rubber material to mold and fix an elastic seal member to the disk valve;
• and
• opening the first mold member and the second mold member after the rubber material in the cavity has been cured, and removing the disk valve having the elastic seal member fixed thereto.