Abstract: Through a housing of an electric motor, an output shaft attached to a rotor penetrates. In this housing, an air tightness test hole of the electric motor which communicates with internal space of the electric space formed with the housing and a stator is formed. Further, an oil seal which blocks aeration between the internal space and an outside of the electric motor is attached to this housing.

Abstract: A motor structure capable of easily conserving space, being low cost and having few components, while utilizing a connecting method using conductive caulking. In a motor structure, a winding wire is wound onto a stator core, a terminal member is attached to one end of the winding wire by conductive caulking, and the terminal member is directly connected to a connector by soldering. The terminal member has a wire receiving portion which receives one end of each of at least one winding wire, and a connecting portion which may be directly connected to the connector or a terminal block by soldering. The wire receiving portion is a generally cylindrical member, and the connecting portion is a rod member which may be inserted into a connecting hole of the connector.

Abstract: Through a housing of an electric motor, an output shaft attached to a rotor penetrates. In this housing, an air tightness test hole of the electric motor which communicates with internal space of the electric space formed with the housing and a stator is formed. Further, an oil seal which blocks aeration between the internal space and an outside of the electric motor is attached to this housing.

Abstract: A motor structure capable of easily conserving space, being low cost and having few components, while utilizing a connecting method using conductive caulking. In a motor structure, a winding wire is wound onto a stator core, a terminal member is attached to one end of the winding wire by conductive caulking, and the terminal member is directly connected to a connector by soldering. The terminal member has a wire receiving portion which receives one end of each of at least one winding wire, and a connecting portion which may be directly connected to the connector or a terminal block by soldering. The wire receiving portion is a generally cylindrical member, and the connecting portion is a rod member which may be inserted into a connecting hole of the connector.

Abstract: An electric motor that does not provide new terminals for carrying out conductive caulking, and further, facilitates the work of using a conductive caulking machine. An electric motor coil connecting structure that connects conductors connected to a power input member and lead terminals of coils by conductive caulking and connects the power input member and the lead terminals of the coil electrically. One end of each of the conductors is formed into a terminal-shaped portion in which the lead terminals of the coil can be fitted and temporarily retained. The lead terminals of the coil are fitted in the terminal-shaped portion of the conductors and temporarily retained, and connected by conductive caulking.

Abstract: An apparatus for manufacturing an electric motor having a laminated core structure formed by a plurality of core plates made of rolled material of electromagnetic sheet steel. The core plates are manufactured by punching rolled electromagnetic sheet steel in a die set. The rolled electromagnetic sheet steel is displaced angularly relative to the die set. The core plates have rolling directions of the electromagnetic sheet steel angularly displaced by a machine angle determined in accordance with the number of slots or poles provided in the laminated core structure so that a phase difference of cogging torques produced by magnetic anisotropy of the core plates is substantially 180°.

Abstract: An electric motor that does not provide new terminals for carrying out conductive caulking, and further, facilitates the work of using a conductive caulking machine. An electric motor coil connecting structure that connects conductors connected to a power input member and lead terminals of coils by conductive caulking and connects the power input member and the lead terminals of the coil electrically. One end of each of the conductors is formed into a terminal-shaped portion in which the lead terminals of the coil can be fitted and temporarily retained. The lead terminals of the coil are fitted in the terminal-shaped portion of the conductors and temporarily retained, and connected by conductive caulking.

Abstract: A motor capable of reducing cogging torque depending on teeth of a stator, and a motor manufacturing apparatus for manufacturing this motor. The angles of rolling directions of cores stacked are set so that the phase difference between the phases of cogging torques produced on the cores is 180° so that the cogging torques produced on the cores cancel each other to reduce the total cogging torque in the motor. The motor comprises a laminated core formed by stacking a plurality of cores made from a rolled electromagnetic sheet steel. The cores forming the laminated core have rolling directions different from each other by a specified machine angle determined depending on the number of slots and/or the number of poles, where the specified machine angle is an angle which produces a phase difference of 180° between the phases of cogging torques produced due to magnetic anisotropy of the cores and the arrangement of teeth depending on the number of slots and/or poles of the motor.

Abstract: A permanent magnetic synchronous electrical motor, in which the waveform of the induced voltage is more similar to the sine curve than the prior art, so as to reduce the torque ripple. The outer shape of a rotor core of the electrical motor is specified by using the reciprocal of the cosine function. In the invention, the range of an electrical angle of the rotor, in which the reciprocal of the cosine function is applied to the outer shape of the rotor core, is equal to or more than 160 degrees.

Abstract: A synchronous electric motor including a rotor having a rotation axis, and a stator surrounding the rotor through a gap. The rotor includes a rotor core having an outer circumferential surface extending about the rotation axis and a plurality of permanent magnets attached to the rotor core to form plural poles along the outer circumferential surface of the rotor core. The outer circumferential surface of the rotor core is provided, at each pole, with a contour deviating from a circular arc and bulging out in a radial outward direction, as seen in a cross-section perpendicular to the rotation axis. The permanent magnets include a plurality of magnet sets individually assigned to the plural poles, each set including two or more permanent magnets. The contour of the outer circumferential surface of the rotor core, at each pole, has at least partially a shape represented by a hyperbolic cosine function or a secant function.

Abstract: A motor capable of reducing cogging torque depending on teeth of a stator, and a motor manufacturing apparatus for manufacturing this motor. The angles of rolling directions of cores stacked are set so that the phase difference between the phases of cogging torques produced on the cores is 180° so that the cogging torques produced on the cores cancel each other to reduce the total cogging torque in the motor. The motor comprises a laminated core formed by stacking a plurality of cores made from a rolled electromagnetic sheet steel. The cores forming the laminated core have rolling directions different from each other by a specified machine angle determined depending on the number of slots and/or the number of poles, where the specified machine angle is an angle which produces a phase difference of 180° between the phases of cogging torques produced due to magnetic anisotropy of the cores and the arrangement of teeth depending on the number of slots and/or poles of the motor.

Abstract: A multistage oil seal (4) includes a plurality of lips (7a, 7b, 7c) in a plurality of stages disposed around a motor shaft (1) of a machine tool along the axis of the motor shaft to protect internal members of the motor from the cutting fluid. All or at least two of the lips (7a, 7b, 7c) in the plurality of stages are formed from different materials.

Abstract: A cooling jacket for an electric motor and a motor unit with a cooling jacket mounted on an electric motor having simple structure and capable of being manufactured with reduced number of processes. A cooling pipe made of copper and the like is bent, and held by plate members and lid members, and resin having high heat-conductivity is filled in between to form a series of segments of the cooling jacket. Adjacent ones of the segments are connected with each other by connecting members to form the cooling jacket. The plate members are formed to conform with a shape of the electric motor. The series of segments are mounted on an outer surface of the electric motor and gaps between the adjacent segments are adjusted to bring the plate members into close contact with the outer surface of the electric motor.

Abstract: A motor capable of reducing cogging torque depending on teeth of a stator, and a motor manufacturing apparatus for manufacturing this motor. The angles of rolling directions of cores stacked are set so that the phase difference between the phases of cogging torques produced on the cores is 180° so that the cogging torques produced on the cores cancel each other to reduce the total cogging torque in the motor. The motor comprises a laminated core formed by stacking a plurality of cores made from a rolled electromagnetic sheet steel. The cores forming the laminated core have rolling directions different from each other by a specified machine angle determined depending on the number of slots and/or the number of poles, where the specified machine angle is an angle which produces a phase difference of 180° between the phases of cogging torques produced due to magnetic anisotropy of the cores and the arrangement of teeth depending on the number of slots and/or poles of the motor.

Abstract: Flat rolled magnetic steel sheets and strip or a die is turned in the press forming process. Rotor cores are stacked with turning through an angle which is an odd number multiple of about (360°/(number of slots in the motor×natural number n×2)) and stator cores are stacked with turning through an angle which is an odd number multiple of (360°/(number of poles in the motor×natural number n×2)). Stacking with turning through an angle which is an odd number multiple converts the phases of cogging torques into mutually opposite phases and cancels and reduces the cogging torque caused by magnetic anisotropy.

Abstract: A synchronous electric motor including a rotor having a rotation axis, and a stator surrounding the rotor through a gap. The rotor includes a rotor core having an outer circumferential surface extending about the rotation axis and a plurality of permanent magnets attached to the rotor core to form plural poles along the outer circumferential surface of the rotor core. The outer circumferential surface of the rotor core is provided, at each pole, with a contour deviating from a circular arc and bulging out in a radial outward direction, as seen in a cross-section perpendicular to the rotation axis. The permanent magnets include a plurality of magnet sets individually assigned to the plural poles, each set including two or more permanent magnets. The contour of the outer circumferential surface of the rotor core, at each pole, has at least partially a shape represented by a hyperbolic cosine function or a secant function.

Abstract: A method of expanding types of synchronous motors capable of reducing the number of required stator types to use stators in common, and a synchronous motor produced by the method. A group of stators are prepared by stacking stator cores of identical shape so that heights of the stators are different from one another to be multiples of a fundamental height. A plurality of groups of rotors are prepared so that lengths of the rotors in each group are different from one another to be multiples of a fundamental length. The rotors in each group are provided with permanent magnets having a residual magnetic flux density different from that of the permanent magnets for the rotors in the other groups. A stator and a rotor corresponding to a preset output torque specification value and a preset rotor inertia specification value are respectively selected from the group of stators and the rotor groups and are combined with each other, whereby an expanded type of motor is obtained.

Abstract: Flat rolled magnetic steel sheets and strip or a die is turned in the press forming process. Rotor cores are stacked with turning through an angle which is an odd number multiple of about (360°/(number of slots in the motor×natural number n×2)) and stator cores are stacked with turning through an angle which is an odd number multiple of (360°/(number of poles in the motor×natural number n×2)). Stacking with turning through an angle which is an odd number multiple converts the phases of cogging torques into mutually opposite phases and cancels and reduces the cogging torque caused by magnetic anisotropy.

Abstract: Flat rolled magnetic steel sheets and strip or a die is turned in the press forming process. Rotor cores are stacked with turning through an angle which is an odd number multiple of about (360°/(number of slots in the motor×natural number n×2) and stator cores are stacked with turning through an angle which is an odd number multiple of (360°/(number of poles in the motor×natural number n×2)). Stacking with turning through an angle which is an odd number multiple converts the phases of cogging torques into mutually opposite phases and cancels and reduces the cogging torque caused by magnetic anisotropy.

Abstract: A multistage oil seal (4) includes a plurality of lips (7a, 7b, 7c) in a plurality of stages disposed around a motor shaft (1) of a machine tool along the axis of the motor shaft to protect internal members of the motor from the cutting fluid. All or at least two of the lips (7a, 7b, 7c) in the plurality of stages are formed from different materials.