Patent ID: 11448204

Abstract:
To manufacture a diaphragm pump with higher reliability in which the mechanism of a main valve is simplified without a pilot chamber. A diaphragm pump 10 includes paired diaphragms 34 and 44 that define pump chambers 36, 46 and air chambers 32, 42, a main body unit 20 that slidably supports a center rod 120 at a central portion of each diaphragm 34, 44 so as to be capable of reciprocating the center rod 120, and a valve body 80 that houses a spool 100 that switches supply of a fluid to the air chambers 32 and 42 so as to reciprocate the center rod 120, the valve body 80 including a sleeve 84, and the spool 100 that is disposed inside the sleeve 84 to be reciprocated in an axial direction, wherein the spool 100 is composed of a disc-shaped portion S3, a disc-shaped portion S2, and a disc-shaped portion S1, and a surface area of each disc-shaped portion that receives a compressed air pressure has a relationship that an upper side of the disc-shaped portion S3>a lower side of the disc-shaped portion S2>an upper side of the disc-shaped portion S1.