Unitized spring device and master cylinder including such device

A master cylinder comprising a cylinder main body having a cylinder bore, a piston that defines a hydraulic chamber in the cylinder bore of cylinder the main body, and a spring device providing the piston with spring force,

• said spring device comprising a pair of retainer members coupled to one another so that the axial length of the members can be increased/reduced, and a spring supported by these retainer members, said spring device being formed as a unit that can be handled independently, wherein said spring device is further characterized in that
• (A) each of said pair of retainer members is tubular in shape and hollow inside, and on the outer circumference of a first retainer member having a smaller diameter, a second retainer member having a larger diameter is fitted;
• (B) said first retainer member has a first outward claw portion at one end, said second retainer member has a second inward claw portion at one end, the second claw portion can move beyond the first claw portion to couple the first and second retainer members in the axial direction, and these first and second claw portions function to prevent one another from being pulled out in the coupled state;
• and
• (C) said first retainer member includes plural slits axially extending and dividing at least the side having said first claw portion, and thereby said first retainer member on the inner circumferential side is elastically deformed when said first and second retainer members are pressed against each other in the axial direction in order to couple them.