Patent ID: 6408883
Filing Date: 2002-06-25
Classification: G05D,Y10T

Abstract:
An electromagnetic valve comprising:an electromagnetic driving portion having a plunger reciprocally driven in accordance with a supplied electric current; a sleeve axially connected with the electromagnetic driving portion, the sleeve having a generally cylindrical wall that defines an axially extending through hole, and a plurality of first fluid passages passing therethrough, the first fluid passages defining an input port and a discharge port, the axially extending through hole including a first portion in which the input and discharge ports are located, a second portion located adjacent the electromagnetic driving portion, a third portion located close to an end of the sleeve which is remote from the electromagnetic driving portion, and a feedback chamber located between the first portion and the second portion, the second portion having a smaller inner diameter than that of the first portion, the third portion having a larger inner diameter than that of the first portion, the sleeve further defining a second fluid passage as an output port which opens at an axial end of the sleeve; a spool defining a third fluid passage which communicates with the second fluid passage, the spool being a slidably supported in the cylindrical wall of the sleeve and reciprocally operated by the plunger to vary a flow rate of fluid between the input port and the output port and between the discharge port and the output port, the spool being composed of smaller diameter portions than the third portion of the axially extending through hole to be insert into the sleeve from the third portion, and having a first land located in the first portion to control the flow rate between the input port and the output port and between the discharge port and the output port, and a second land located in the second portion; and urging means disposed in the third portion of the sleeve for urging the spool against the plunger.