Diaphragm type check valve and manufacture method thereof

The invention discloses a manufacture method of a diaphragm type check valve, which includes: step 1, installing a magnet on a valve sleeve notch, sleeving a valve sleeve on a riveting punch, installing the magnet in the valve sleeve in pressing mode through an oil press, and limiting the magnet through two limit steps in the valve sleeve; step 2, processing an annular groove on the axial end surface of the valve sleeve in numerical control processing mode, performing polishing processing on a sealing surface of a protrusion on the axial end surface of the valve sleeve, placing a diaphragm on the protruded sealing surface and absorbing the diaphragm through magnetic force of the magnet; step 3, assembling a punching formed blocking bowl in the annular groove on the axial end surface of the valve sleeve, and sleeving a contraction mold on the valve sleeve to perform contraction processing for the valve sleeve so as to lead the blocking bowl to be fastened in the annular groove to obtain a valve sleeve assembly; and step 4, filling the valve sleeve assembly obtained through the step 3 in a valve body, and performing rolling on the external circumferential surface of the valve body through a roller press to lead the valve body and the valve sleeve to be fastened. The diaphragm type check valve has the advantages of being good in production quality and low in manufacture cost.