Brake caliper device having automatic pad wear compensation mechanism

A brake caliper device adapted to be used with a brake disk, the brake disk having a first side surface and a second side surface opposite to the first side surface, said brake caliper device comprising:

• a main body unit that includes
• a first seat adapted to be disposed proximally to the first side surface of the brake disk, and formed with a mounting hole extending along a mounting axis, and
• a second seat co-movably connected to said first seat, adapted to be disposed proximally to the second side surface of the brake disk, and cooperating with said first seat to define a receiving space therebetween for receiving a part of the brake disk;
• a first pad that is adapted to be disposed between said first seat and the first side surface of the brake disk;
• a second pad that is adapted to be disposed between said second seat and the second side surface of the brake disk;
• a caliper actuator unit that is mounted to said mounting hole of said first seat and that includes
• an actuating member,
• a bolt member abutting against said actuating member, and
• a threaded sleeve threadedly engaged to said bolt member;
• and
• a positioning unit that is mounted between said threaded sleeve and said first pad, and that includes
• a first positioning module disposed on said threaded sleeve, and having a plurality of angularly spaced-apart first recess holes surrounding the mounting axis,
• a second positioning module positioned relative to said first pad, and having a plurality of angularly spaced-apart second recess holes surrounding the mounting axis and respectively corresponding in position to said first recess holes,
• a ball retainer disposed between said first and second positioning modules, and having a plurality of angularly spaced-apart through holes surrounding the mounting axis, and
• a plurality of balls mounted to said ball retainer, and being respectively and rotatably nested to said through holes, each of said balls having two opposite sides respectively in contact with one of said first recess holes and one of said second recess holes;
• wherein, when said actuating member is driven by an external force, said actuating member is capable of vibrating axially to cause an axial vibration of said bolt member, which prompts said threaded sleeve to rotate relative to said bolt member for pushing said first pad toward the brake disk, thereby automatically providing a travel stroke that compensates for pad wear.