Crusher

The invention relates to the technical field of crushers, in particular to a crusher. The crusher comprises a drill rod, a shell, a machine head shell, a cylinder body, an upper piston, a lower piston, a start-stop system, a lubricating system, an oil supply system, an air inlet system and an exhaust system, wherein a first air cylinder is arranged in the cylinder body, the lower piston is provided with an impact body, and the drill rod comprises a drill bit, a limiting block and a movable rod; the lower end of the first cylinder radially expands to form a second cylinder, a limiting partition plate which can be matched with the second cylinder in an up-down sliding manner and is used for dividing the second cylinder into an upper chamber and a lower chamber radially protrudes from the lower end of the lower piston; and the lower end of the second air cylinder and the upper end opening of the machine head shell are connected and sealed, a limiting circular ring is arranged at the connecting position between t