Solenoid

A solenoid comprising:

• a coil configured to generate magnetic force when energized;
• a plunger formed in a columnar shape, arranged radially inside the coil, and configured to slide in an axial direction;
• a yoke that houses the coil and the plunger, includes a tubular portion, and is provided along the axial direction;
• a bottom provided along a direction that intersects the axial direction and opposed to a base end surface of the plunger;
• and
• a stator core,
• wherein,
• the stator core includes
• a magnetic attraction core that is opposed to a front end surface of the plunger in the axial direction and configured to magnetically attract the plunger by magnetic force generated by the coil,
• a slide core that includes:
• a core portion formed in a tubular shape and arranged radially outside the plunger;
• and
• a magnetic flux transmitting portion that expands radially outward from an end portion of the core portion that is opposed to the bottom, and configured to transmit magnetic flux between the yoke and the plunger through the core portion, and
• a magnetic flux passage restricting portion configured to restrict passage of the magnetic flux between the slide core and the magnetic attraction core,
• the yoke includes a magnetic flux passage area expansion portion such that the magnetic flux passes from the yoke to the magnetic flux transmitting portion through an area equal to a predetermined area threshold or larger, and
• the magnetic flux passage area expansion portion is formed on the tubular portion and protrudes radially inward from an inner peripheral surface of the tubular portion.