A three-stage air pump assembly for a pneumatic air gun, the three-stage air pump assembly comprising an air compression assembly and an energy storage assembly disposed on a gun support of the pneumatic air gun;
- wherein
- the energy storage assembly comprises an air pump and a check valve disposed at an end of the air pump;
- the air pump is a three-stage air pump;
- the three-stage air pump comprises a front fixed sheath, a rear fixed sheath, a front movable sheath, a rear movable sheath, a first tube, a second tube, a third tube, and a piston rod, where diameters of the first tube, the second tube and the third tube are successively reduced;
- an intake sleeve on the check valve is sealed and fixedly connected in the rear fixed sheath;
- front and rear ends of the first tube are sheathed on the front fixed sheath and the rear fixed sheath, respectively;
- the front fixed sheath and the rear fixed sheath are both fixedly connected to the gun body support through a connection portion that extends out of the first tube;
- an O-ring of the first tube seals between an inner wall of a rear end of the first tube between an outer wall of the rear fixed sheath;
- the front movable sheath is positioned at a front portion of the first tube;
- a steel ball is provided on an outer circumference of the front movable sheath;
- the front movable sheath is slidably mated to an inner wall of the first tube through the steel ball;
- the rear movable sheath is positioned at a rear portion of the first tube;
- a first-stage piston cup is provided between the outer wall of the rear movable sheath and the inner wall of the first tube;
- the first-stage piston cup, which is opened upon air admission and closed upon air compression, is fixed to the outer wall of the rear movable sheath;
- the second tube is coaxially disposed in the first tube;
- the front and rear ends of the second tube is sheathed in the front movable sheath and rear movable sheath respectively;
- the third tube is coaxially disposed in the second tube;
- the rear end of the third tube is sealed and fixedly connected in an intake sleeve on the check valve;
- a second-stage piston cup is provided between the inner wall of the rear movable sheath and the outer wall of the third tube;
- the second-stage piston cup, which is closed upon air admission and opened upon air compression, is fixed to the inner wall of the rear movable sheath;
- the piston rod is positioned in the third tube;
- one end of the piston rod extends out of the third tube and is hinged to the front movable sheath through a pin shaft of the front movable sheath;
- a third-stage piston cup is provided between the other end of the piston rod and the inner wall of the third tube;
- the third-stage piston cup, which is opened upon air admission and closed upon air compression, is fixed to a piston head of the piston rod;
- and
- the air compression assembly comprises a connection bar and a compression bar;
- one end of the connection bar is rotatably connected to the front movable sheath through a pin shaft of the connection bar;
- the compression bar is rotatably connected to the front fixed sheath through a front pin shaft of the compression bar;
- the other end of the connection bar is rotatably connected to a middle portion of the compression bar through a rear pin shaft of the compression bar.