Pad spring

A pair of pad springs for elastically supporting a pair of pad plates on a carrier, the pad springs comprising:

• a pair of clip bases in contact with protruding surfaces of protrusions formed on two sides of the pad plates;
• a pair of first anchors connected to lower ends of the clip bases and formed to be curved in contact with lower surfaces of the protrusions;
• a pair of second anchors connected to upper ends of the clip bases and formed to be curved in contact with upper surfaces of the protrusions;
• a connector configured to connect the pair of second anchors;
• and
• a pair of retainers having one ends bonded to the pair of clip bases and formed to extend inward and the other ends curved outward to be in contact with and support the pair of pad plates and formed to extend,
• wherein the pair of retainers include an inner retainer in contact with and supporting an inner pad, which directly receives a force of a press member, of the pair of pad plates, and an outer retainer in contact with and supporting an outer pad, which indirectly receives the force of the press member, of the pair of pad plates, and
• the inner retainer is formed of a material having a higher rigidity than a material of the outer retainer to correspond to asymmetric pressure applied to the pair of pad plates,
• wherein:
• at least one opening is formed in a flat portion of each of the pair of retainers;
• and
• a total area of the opening formed in the inner retainer is smaller than a total area of the opening formed in the outer retainer.