Abstract: A PDC drill bit has a drill bit body and a blade. The blade is provided with cutting teeth. At least one cushion structure is rotatably connected to the drill bit body. The cushion structure makes contact with bottom hole rock, and the cushion structure swings in a direction opposite to the cutting of the drill bit. Alternatively, a cushioning portion on the cushion structure is eccentrically arranged. Under the action of the normal force of the bottom hole rock, the cushioning portion swings to an offset side. The cushion structure is detached from the bottom hole rock and is reset towards a free state under the action of a reset mechanism. Under complex motion conditions such as compound drilling and drilling into hard or non-uniform stratum conditions, the swing of the cushion structure absorbs an impact load and avoids impact damage to the cutting teeth.

Abstract: A torque-adaptive impact tool suitable for a PDC (Polycrystalline Diamond Compact) bit is provided, which includes a PDC bit, a rotary-driving power device, and a torque-adaptive impact tool above the PDC bit. The torque-adaptive impact tool is located between the PDC bit and the rotary-driving power device, includes an outer housing, an upper end cover, a main shaft, an elastic element, an upper impact body, and a lower impact body. In a case of a normal operation of the bit, the tool does not impact the bit, but rotates along with the rotary-driving power device for drilling. In a case that a rock-breaking torque required by the bit exceeds a driving torque, the tool impact the bit.