Piston pump group for brake system and control method therefor

A piston pump group for a brake system, comprising a piston, a pump body provided with an operating chamber, and a transmission mechanism configured to drive the piston to move in the operating chamber, wherein the transmission mechanism comprises a lead screw transmission assembly, a follower, and a planetary gear assembly configured to transmit power to the lead screw transmission assembly, the follower is fixedly connected to the piston, the lead screw transmission assembly is configured to drive the follower to move relative to the operating chamber, and a limiting member configured to limit the movement of the follower is disposed between the lead screw transmission assembly and the follower;

• wherein the limiting member comprises a limiting pin forming a collision portion and the follower comprises a collision structure configured to abut the collision portion;
• wherein the planetary gear assembly comprises an inner gear ring, a planetary cover, and a plurality of planetary gear respectively meshed with the inner gear ring;
• wherein the planetary cover is connected to the inner gear ring through a positioning structure;
• wherein the lead screw transmission assembly comprises a bearing outer ring, a bearing inner ring, a bearing holder, and a lead screw, the bearing outer ring is sleeved outside the bearing inner ring, the bearing holder is disposed between the bearing outer ring and the bearing inner ring, the bearing holder is provided with a plurality of accommodation cavities configured to accommodate ball bearings, the bearing inner ring is fixedly connected to one end of the lead screw, the follower is threadably connected to the lead screw, the plurality of planetary gears are disposed on a top surface of the bearing inner ring through a planetary pin, and the planetary cover is fixedly connected to the bearing outer ring.