A diaphragm assembly includes a piston push block, a diaphragm, a middle piece, a balance wheel seat, and fasteners. The diaphragm includes a diaphragm body with protrusions which protrude toward the middle piece and extends into the balance wheel seat. The piston push block includes a piston head and a piston shaft. The piston head is located on the side of the diaphragm facing away from the middle piece, and the piston shaft extends towards the diaphragm and is embedded in the diaphragm protrusion. The middle piece includes a first through hole, the balance wheel seat includes a balance wheel, and the balance wheel includes an insertion hole for the corresponding diaphragm protrusion to be inserted in. The fastener fixes the piston push block, the diaphragm and the balance wheel seat from the side facing away from the working surface of the diaphragm.

A diaphragm assembly includes a piston push block, a diaphragm, a middle piece, a balance wheel seat, and fasteners. The diaphragm includes a diaphragm body with protrusions which protrude toward the middle piece and extends into the balance wheel seat. The piston push block includes a piston head and a piston shaft. The piston head is located on the side of the diaphragm facing away from the middle piece, and the piston shaft extends towards the diaphragm and is embedded in the diaphragm protrusion. The middle piece includes a first through hole, the balance wheel seat includes a balance wheel, and the balance wheel includes an insertion hole for the corresponding diaphragm protrusion to be inserted in. The fastener fixes the piston push block, the diaphragm and the balance wheel seat from the side facing away from the working surface of the diaphragm.