Abstract: A stepping motor being a motor used in oil includes a coil formed with a conductor coated with an outer coating and wound around a bobbin, and coil terminals electrically connected to the conductor at ends thereof led out from the coil, the outer coating being removed from the conductor at the ends thereof. The coil terminals are coated with a protective film made of a material having low permeability to elemental sulfur and sulfur compounds. Therefore, coil terminals and ends of the conductor are prevented from erosion by sulfur and organic sulfur compounds, thereby reducing risk of disconnection in the coil terminals and the conductor.

Abstract: An electromagnetic device including an outer casing, a shaft rotatably supported by the outer casing, and a motor main body disposed inside the outer casing. The motor main body has a stator and a rotor. The stator has coils constructed by winding conducting wires onto conducting-wire spool portions of first and second bobbins. The coils are embedded in an outer molding, cores are disposed so as to cover the outer molding, and the rotor is secured to the shaft The coils are constituted by first phase and second phase excitation coils formed by winding two of the conducting wires into unifilar windings on the conducting-wire spool portion of the first bobbin. Further, third phase and fourth phase excitation coils are formed by winding two of the conducting wires into unifilar windings on the conducting-wire spool portion of the second bobbin.

Abstract: An electromotive device includes an outer casing, a shaft supported by the outer casing, a bobbin disposed inside the outer casing so as to be disposed around the shaft on a common axis with the shaft, and a coil embedded in an outer molding, the coil being constructed by winding a conducting wire onto the bobbin, the bobbin and the outer molding being composed of an epoxy resin, which is an electrically-insulating material resistant to permeation by sulfur compounds.

Abstract: An electromagnetic device including an outer casing, a shaft rotatably supported by the outer casing, and a motor main body disposed inside the outer casing. The motor main body has a stator and a rotor. The stator has coils constructed by winding conducting wires onto conducting-wire spool portions of first and second bobbins. The coils are embedded in an outer molding, cores are disposed so as to cover the outer molding, and the rotor is secured to the shaft The coils are constituted by first phase and second phase excitation coils formed by winding two of the conducting wires into unifilar windings on the conducting-wire spool portion of the first bobbin. Further, third phase and fourth phase excitation coils are formed by winding two of the conducting wires into unifilar windings on the conducting-wire spool portion of the second bobbin.

Abstract: An electromagnetic device including an outer casing, a shaft rotatably supported by the outer casing, and a motor main body disposed inside the outer casing. The motor main body has a stator and a rotor. The stator has coils constructed by winding conducting wires onto conducting-wire spool portions of first and second bobbins. The coils are embedded in an outer molding, cores are disposed so as to cover the outer molding, and the rotor is secured to the shaft. The coils are constituted by first phase and second phase excitation coils formed by winding two of the conducting wires into unifilar windings on the conducting-wire spool portion of the first bobbin. Further, third phase and fourth phase excitation coils are formed by winding two of the conducting wires into unifilar windings on the conducting-wire spool portion of the second bobbin.

Abstract: An automatic transmission includes a transmission case containing oil, a transmission structure housed in the transmission case, for varying the ratio of rotational speeds between a driving shaft connected to wheels and an engine shaft connected to an engine, a transmission control valve housed in the transmission case, for controlling the transmission structure, and a motor as a driving source for driving the transmission control valve. The motor includes a cover, a motor body having a coil disposed under the cover and formed with a wound conductor, a shaft rotated by an electrical current applied to the coil, and a converting structure for converting the rotational movement of the shaft into linear movement. The motor is fixed to the transmission case so that the motor body is disposed in air.

Abstract: A stepping motor being a motor used in oil includes a coil formed with a conductor coated with an outer coating and wound around a bobbin, and coil terminals electrically connected to the conductor at ends thereof led out from the coil, the outer coating being removed from the conductor at the ends thereof. The coil terminals are coated with a protective film made of a material having low permeability to elemental sulfur and sulfur compounds. Therefore, coil terminals and ends of the conductor are prevented from erosion by sulfur and organic sulfur compounds, thereby reducing risk of disconnection in the coil terminals and the conductor.

Abstract: An automatic transmission includes a transmission case containing oil, a transmission structure housed in the transmission case, for varying the ratio of rotational speeds between a driving shaft connected to wheels and an engine shaft connected to an engine, a transmission control valve housed in the transmission case, for controlling the transmission structure, and a motor as a driving source for driving the transmission control valve. The motor includes a cover, a motor body having a coil disposed under the cover and formed with a wound conductor, a shaft rotated by an electrical current applied to the coil, and a converting structure for converting the rotational movement of the shaft into linear movement. The motor is fixed to the transmission case so that the motor body is disposed in air.

Abstract: An electromotive device includes an outer casing, a shaft supported by the outer casing, a bobbin disposed inside the outer casing so as to be disposed around the shaft on a common axis with the shaft, and a coil embedded in an outer molding, the coil being constructed by winding a conducting wire onto the bobbin, the bobbin and the outer molding being composed of an epoxy resin, which is an electrically-insulating material resistant to permeation by sulfur compounds.

Abstract: A stepping motor according to the present invention used in a case containing oil includes a motor having a coil formed with a conductor wound around a bobbin and a cover member enclosing the coil, and a housing which houses the motor. The cover member serves to protect the coil from being directly subjected to molding pressure when the housing is injection-molded.

Abstract: An electromagnetic device includes an outer casing, a shaft rotatably supported by the outer casing, and a motor main body disposed inside the outer casing, the motor main body having a stator and a rotor, the stator having coils each constructed by winding a conducting wire onto a bobbin, the coils being embedded in an outer molding, and cores being disposed so as to cover the outer molding, and the rotor being secured to the shaft, wherein the conducting wire of the coils is constructed by coating onto a copper wire an electrically-insulating layer composed of denatured polyimide resin which is a material resistant to permeation by sulfur compounds.

Abstract: An electromagnetic device includes an outer casing, a shaft rotatably supported by the outer casing, and a motor main body disposed inside the outer casing, the motor main body having a stator and a rotor, the stator having coils constructed by winding conducting wires onto conducting-wire spool portions of first and second bobbins, the coils being embedded in an outer molding, and cores being disposed so as to cover the outer molding, and the rotor being secured to the shaft, the coils being constituted by first phase and second phase excitation coils formed by winding two of the conducting wires into unifilar windings on the conducting-wire spool portion of the first bobbin, and third phase and fourth phase excitation coils formed by winding two of the conducting wires into unifilar windings on the conducting-wire spool portion of the second bobbin.

Abstract: A step motor is provided that makes it possible to lower the manufacturing cost and accurately control the movement of a holder. The step motor is provided with: a motor case (3); a hollow columnar stator (4) which is provided inside the motor case (3) and which generates a magnetic field; a rotor (42) which is rotatably provided in the stator (4) and which rotates in steps according to the generated magnetic field of the stator (4); an actuating shaft (43) which is fixed to the rotor (42) and which has a threaded portion (53) at one end thereof; a holder (45) which is threadably engaged with the threaded portion (53) and which is movable in the axial direction; and a guide (44) which is fixed to the motor case (3), which prevents the rotational motion of the holder (45), and which guides the holder (45) to move in the axial direction.

Abstract: A small size electric motor comprises a motor housing having a built-in stator and secured to a supporting member. The motor housing is made of a synthetic resin and has a substantially tubular heat conductive plate embedded in a portion thereof which is attached to the supporting member. The heat conductive plate is made of a metallic material, and its inner peripheral portion is projecting toward the inner side of the housing so that the heat conductive plate is brought into contact with the stator, and its outer peripheral portion is exposed to the surface to which the supporting member is attached so that the heat conductive plate is brought into contact with the supporting member. Therefore, the heat generated by the motor is radiated while transmitted from the stator to the supporting member through the heat conductive plate.