Patent ID: 8957749
Filing Date: 2015-02-17
Classification: H01F

Abstract:
1. A linear solenoid comprising: a coil that is formed into an annular form; a first stationary core that is placed on one side of the coil in an axial direction; a second stationary core that is placed on the other side of the coil, which is opposite from the one side of the coil in the axial direction, wherein an air gap is interposed between the first stationary core and the second stationary core in the axial direction; a yoke that is located on an outer side of the coil in a radial direction and magnetically couples between the first stationary core and the second stationary core; a housing that holds the yoke; a shaft that is placed on an inner side of the air gap in the radial direction and is slidably supported by the first stationary core and the second stationary core, wherein the shaft is configured to reciprocate in the axial direction between an initial position, which is located on a side where the second stationary core is placed, and a full stroke position, which is located on a side where the first stationary core is placed; a movable core that is fixed to the shaft at a corresponding location, which is located between the first stationary core and the second stationary core in the axial direction, wherein when the coil is energized, the movable core is moved together with the shaft in the axial direction toward the full stroke position to a position located on the inner side of the air gap in the radial direction and conducts a magnetic flux between the first stationary core and the second stationary core through the movable core; and a non-magnetic member that is held between the first stationary core and the second stationary core and limits relative movement between the first stationary core and the second stationary core toward each other, wherein the first stationary core is formed as a single integral member and includes: a bearing portion that slidably supports and contacts the shaft; and a fixing portion that outwardly extends from the bearing portion in the radial direction and is fixed to the yoke while the non-magnetic member is clamped between the fixing portion and the second stationary core in the axial direction, wherein the bearing portion and the fixing portion are formed seamlessly as one-piece member; the yoke includes: the fixing portion of the first stationary core is fitted into the other end art of the tubular portion of the yoke, which is opposite from the one end part of the tubular portion in the axial direction, to conduct the magnetic flux between the fixing portion of the first stationary core and the tubular portion of the yoke in the radial direction; and the second stationary core contacts the bottom portion of the yoke in the axial direction and conducts the magnetic flux between the second stationary core and the bottom portion of the yoke in the axial direction; the housing is molded from resin and extends along an outer peripheral surface of the tubular portion of the yoke to circumferentially surround the tubular portion of the yoke; and a radial gap is formed between the fixing portion if the first stationary core and the tubular portion.