Patent ID: 9551337
Date: 2017-01-24
CPC Classifications: F04B

Claim:
1. An electromagnetic pump comprising: a piston that moves back and forth within a cylinder; an electromagnetic portion that moves the piston forward; and a spring that moves the piston backward, the piston including a discharge check valve built in the piston, wherein: the piston is formed with a hollow portion that opens in an inner peripheral portion of an end surface of the piston, and a spring receiving surface formed on an outer peripheral portion of the end surface to receive the spring; the discharge check valve is fixed through plastic deformation of the piston by inserting the discharge check valve into the hollow portion from an opening of the piston, and partially pressing a portion of the spring receiving surface of the piston on an inner peripheral side after the insertion to recess the spring receiving surface and elevate an inner peripheral surface of the piston surrounding the hollow portion causing portions of the inner peripheral surface of the piston to project inwardly towards a central axis of the piston, and the piston includes, on an outer peripheral surface of the piston, a distal-end portion that is formed continuously with the end surface of the spring receiving surface on an outer peripheral side and a sliding portion that is formed continuously with the distal-end portion and configured to enable sliding within the cylinder, and an outside diameter of the distal-end portion is smaller than that of the sliding portion.