Electromagnetic linear valve

摘要

An electromagnetic linear valve which can effectively suppress a self-excited oscillation of a plunger is provided. A resilient member 64 urges a plunger 22 in a direction in which the core-opposing portions 70, 78 move away from a core portion 28, and moves the plunger 22 in a direction in which the core-opposing portions 70, 78 approach the core portion 28 in the case where an electric current is supplied to a coil 24. In the case where no electric current is supplied to the coil 24, a radially opposing surface area Sr as a surface area of portions of the core-opposing portions 70, 78 which respectively oppose inner peripheral surfaces of recessed portions 74, 76 is smaller than an axially opposing surface area St as a surface area of portions of the core-opposing portions 70, 78 which respectively oppose bottom surfaces of the recessed portions 74, 76, and the radially opposing surface area Sr becomes larger than the axially opposing surface area St in the case where an electric current is supplied to the coil 24 and the core-opposing portions 70, 78 approach most to the core portion 28.

主权项

1. An electromagnetic linear valve comprising:
a housing including: (A) a partitioning member configured to partition the interior of the housing into a first liquid chamber and a second liquid chamber and being formed with a communicating hole communicating the first liquid chamber and the second liquid chamber with each other; (B) an inlet port communicating with the first liquid chamber and configured to allow working fluid to flow into the first liquid chamber; and (C) an outlet port communicating with the second liquid chamber to allow working fluid to flow out from the second liquid chamber; a plunger disposed in the second liquid chamber and movable in the axial direction such that one end of the plunger is seated in an opening of the communicating hole; a resilient member configured to urge the plunger in one of a direction in which the one end approaches the opening of the communicating hole and a direction in which the one end is moved away from the opening; and a coil disposed around the housing and configured to generate a magnetic field for moving the plunger in a direction opposite to the direction in which the plunger is urged by the resilient member, wherein the housing includes a core portion formed of a ferromagnetic material and defining part of the second liquid chamber, the plunger includes a core-opposing portion opposing the core portion and allowing a magnetic flux to flow between the core portion and the core-opposing portion, the core portion includes a recessed portion which allows the core-opposing portion to face and enter therein, the core-opposing portion opposes a bottom surface of the recessed portion and opposes an inner peripheral surface of the recessed portion, the resilient member is configured to urge the plunger in a direction in which the core-opposing portion moves away from the core portion, and allow the plunger to move in a direction in which the core-opposing portion approaches the core portion against an urging force of the resilient member when an electric current is supplied to the coil, an outer surface of the core-opposing portion has (A) a first axially-extending surface radially opposing a second axially-extending surface of the inner peripheral surface of the recessed portion, and (B) a first radially-extending surface axially opposing a second radially-extending surface of the bottom surface of the recessed portion, and a first area between the first-axially-extending surface and the second axially-extending surface is smaller than a second area between the first radially-extending surface and the second radially-extending surface when no electric current is supplied to the coil, and the first area becomes larger than the second area when the electric current is supplied to the coil and the core-opposing portion approaches most to the core portion, the core-opposing portion is formed into a stepped shape having a large outer diameter portion and a smaller outer diameter portion having an outer diameter smaller than that of the large outer diameter portion, the small outer diameter portion being located on one of opposite sides of the large outer diameter portion which is nearer to the core portion, the recessed portion of the core portion has a stepped shape and is formed with a first recessed portion and a second recessed portion, the second recessed portion being located on an opposite side of the first recessed portion from the core-opposing portion, and a void portion is formed on the large outer diameter portion of the core-opposing portion such that a radial clearance between an inner peripheral surface of the first recessed portion and an outer peripheral surface of a first part of the large outer diameter portion is different from a radial clearance between the inner peripheral surface of the first recessed portion and an outer peripheral surface of a second part of the large outer diameter portion, the void portion being formed on one of the first part and the second part of the large outer diameter portion.