Electromagnetic actuator and method for manufacturing electromagnetic actuator, and control valve for variable displacement compressor using electromagnetic actuator

An electromagnetic actuator comprising:

• a cylinder;
• a stationary core fixed at the upper inner surface of the cylinder;
• a movable core arranged at the lower portion of the cylinder;
• and
• a coil located about the cylinder, wherein the movable core moves in the cylinder in accordance with an electromagnetic force, which is generated between the stationary core and the movable core based on the current supply to the coil;
• wherein the cylinder includes a first cylindrical member made of nonmagnetic material, the first cylindrical member surrounding the stationary core and the movable core, and a second cylindrical member made of magnetic material,
• wherein a part of the first cylindrical member in the vicinity of the movable core is made thin to form a small diameter portion, and wherein the small diameter portion is fitted to the second cylindrical member.

A control valve comprising:

• a cylinder;
• a stationary core arranged in the cylinder;
• a movable core arranged in the cylinder;
• a coil located about the cylinder, wherein the movable core moves in the cylinder in accordance with an electromagnetic force, which is generated between the stationary core and the movable core based on the current supply to the coil, and wherein an electromagnetic actuator is structured by the cylinder, the stationary core, the movable core, and the coil,
• wherein the cylinder includes a first cylindrical member made of nonmagnetic material, the first cylindrical member surrounding the stationary core and the movable core, and a second cylindrical member made of magnetic material,
• wherein a part of the first cylindrical member in the vicinity of the movable core is made thin to form a small diameter portion, and wherein the small diameter portion is fitted to the second cylindrical member;
• and
• a valve body, which is connected to and driven by the movable core of the electromagnetic actuator, wherein the valve body adjusts the opening degree of a communication passage, and wherein the valve body adjusts the opening degree of the passage in accordance with the displacement of the movable core.

A method for manufacturing an electromagnetic actuator having a movable core, a cylinder, stationary core, and a coil, wherein the movable core moves in the cylinder in accordance with an electromagnetic force, which is generated between the stationary core and the movable core based on the current supply to the coil, which is located about the cylinder, wherein the manufacturing method comprising:

• preparing a first cylindrical member formed of nonmagnetic material and a second cylindrical member formed of magnetic material, wherein the first cylindrical material surrounds the stationary core and the movable core;
• fitting the first cylindrical member to the second cylindrical member;
• and
• machining the inner surface of the first cylindrical member according to a predetermined design.