| 主权项 |
1. An electromagnetic linear valve comprising:
a housing which includes a hollow cylindrical body portion, a core portion which closes an opening of one end portion of the body portion, a separation portion which separates an interior defined by the core portion and the body portion into a first liquid chamber located at one side of the separation portion nearer to the core portion and a second liquid chamber located at the other side of the separation portion, a through hole which passes through the separation portion so as to provide a communication between the first liquid chamber and the second liquid chamber, an outlet port which communicates with the first liquid chamber, and an inlet port which communicates with the second liquid chamber; a plunger which is disposed in the first liquid chamber such that the plunger is movable along an axis in a state in which one end portion of the plunger faces to the core portion and the other end portion of the plunger faces to an opening of the thorough hole, the other end portion being allowed to sit on the opening as a valve body, an elastic member which applies a force to the plunger in a first direction in which the one end portion of the plunger pulls away from the core portion and in which the other end portion of the plunger comes near to the opening, and a coil which is disposed around the housing and generates magnetic field to move the plunger against the force of the elastic member in a second direction in which the one end portion of the plunger comes near to the core portion and in which the other end portion of the plunger pulls away from the opening, wherein a recess is formed in a section of an inner circumferential portion of the body portion, the inner circumferential portion intersecting with an end face of the core portion, the end face being a face, in the first direction, nearer to the opening, wherein a stepped face is formed on an outer circumferential portion of the one end portion of the plunger, whereby the plunger has a stepped shape in which an outer diameter of the one end portion is smaller in an end of the one end portion than in others of the one end portion, wherein the core portion has a concave portion which is formed in an end thereof that is nearer to the opening in the first direction, and into which a portion of the plunger is inserted, the portion of the plunger being a portion, in the second direction, nearer to the core portion than the stepped face of the plunger, wherein the stepped face is placed, in the second direction along the axis, nearer to the core portion than an end of the recess which is an end nearer to the opening in the first direction in a state in which the other end portion of the plunger sits on the opening, wherein a first-direction stepped face is a stepping face facing in the first direction is formed on one of an outer circumferential portion of the plunger and the inner circumferential portion of the body portion in order that one of (a) an intermediate portion which is a portion between the one end portion and the other end portion of the plunger and (b) an internal portion of the body portion of the housing has a stepped shape, whereby a clearance between an outer circumferential face of the plunger and an inner circumferential face of the body portion is larger in a first section than in a second section, the first section being a section, in the first direction, nearer to the opening than the first-direction stepped face, the second section being a section, in the second direction, nearer to the core portion than the first-direction stepped face, wherein the first liquid chamber includes a plunger-core-interposed liquid chamber which is defined by the one end portion of the plunger and the core portion, and whose volume is reduced as the plunger moves in the second direction, and wherein the volume of a first space that is a part of a second space that is interposed between the outer circumferential portion of the plunger and the inner circumferential portion of the body portion is less than difference between the volume of the plunger-core-interposed liquid chamber in a state in which the other end portion of the plunger sits on the opening and the volume of the plunger-core-interposed liquid chamber in a state in which the plunger is placed in the farthest position thereof in the second direction, the first space being a space presenting between the first-direction steed face and the of the recess nearer to the opening in the first direction in a state in which the other end portion of the plunger sits on the opening. |
