Provided is a motor rotor which, without changing an integral fastening structure relying on swage pins, increases resistance to the excessive excitation force of the motor rotor and which can easily prevent decreases in fastening strength; a motor that uses the motor rotor, and an electric compressor are also provided. This motor rotor is provided with a cylindrical rotor core comprising multiple laminated magnetic steel sheets, end plates and balance weights laminated on both ends of the rotor core, and multiple headed swage pins which are inserted from one side and which integrally fasten the rotor core, the end plates and the balance weights. The material of the balance weight arranged to the head of the swage pin is harder than that of the swage pin, and the material of the balance weight arranged to the swage part of the swage pin is softer than that of the swage pin.

Advantageous machines, such as flux-switching machines (FSMs) are provided. An FSM can be yokeless and can have two rotors, which can be displaced from one another (e.g., by half a pole pitch). An FSM can be a flux-switching permanent magnet machine (FSPMM), and all magnets can be magnetized in the same circumferential direction. FSMs of the subject invention are cost-effective, have high torque density, and can operate well even under fault conditions.

A blanking die apparatus includes multiple machining stations having respective cutting tools operated simultaneously to perform predetermined blanking operations on a belt-shaped workpiece fed progressively in a longitudinal direction and finally to perform a contour blanking operation on the workpiece, thereby forming core pieces used for manufacturing a laminated iron core, and an auxiliary cutting tool that forms a disposal hole by partly blanking a scrap forming area of the workpiece simultaneously with the operations of the cutting tools of the machining stations.

The rotor manufacturing method includes the step of fixing a shaft to a rotor core by hydroforming. The shaft has a cylindrical shape in which an inside diameter of a first portion of the shaft to be placed on an inner peripheral surface of a shaft insertion hole is larger than an inside diameter of a second portion of the shaft located on one side in a rotation axis direction relative to the first portion.

A field magnet manufacturing method where a bonded magnet's inner surface press-fitted in a yoke has a certain accuracy irrespective of the accuracy of the yoke's outer circumferential surface. A cylindrical bonded magnet from binding magnet particles with a thermosetting resin is fixed in a tubular yoke of magnetic material. The method includes reheating and softening the bonded magnet after thermal curing; and press-fitting in the bonded magnet after the softening step from a tapered portion on one end side of the yoke to press the bonded magnet's outer circumferential surface against the yoke's inner surface. The press-fitting includes feeding the bonded magnet relatively into the yoke while allowing a relative posture variation between the bonded magnet and the yoke so the bonded magnet's inner surface to be remolded into a shape along the inner surface of the yoke exhibits almost the same accuracy as the yoke's inner surface.

A rotor includes a rotor core lamination. The rotor core lamination includes a first metal alloy that at least partially defines adjacent magnet pockets proximate an outer periphery of the rotor core lamination. The rotor core lamination further includes a second metal alloy different than the first metal alloy that forms at least a portion of a bridge that extends between the magnet pockets. The rotor core lamination further includes permanent magnets disposed in the magnet pockets at opposing sides of the second metal alloy.

In a method for manufacturing a rotor, each of adhesive placement portions that are provided between a surface of a permanent magnet on the radially inner side and grooves is formed so as to cover a part of an adhesive applied to the permanent magnet on the radially inner side and parts of the adhesive on both sides in the circumferential direction.

A rotor coil for a revolving armature includes a strand coil that includes a part arranged in a core slot of the rotor and is composed of a plurality of element wires; and a solid coil welded to an end of the strand coil wherein the end of the strand coil and an end of the solid coil are welded by friction stir welding. A manufacturing method of a rotor coil includes the step of performing friction stir welding wherein the friction stir welding is performed for the butt joint with the end of the strand coil arranged in an advancing side defined by a rotation direction of a tool and with the solid coil arranged in a retreating side.

A method releases rotor poles of a large electrical machine from the rotor hub, which in the fitted state is located within the stator. In one method step, at least one device is introduced into the air gap between the sector and a rotor pole to be released. The device has a carrier plate and at least one cushion that can be filled with gas and is attached to the carrier plate. In a following method step, the cushions belonging to the device are filled with gas under pressure, the pressure being successively increased until the pole to be released has come away, and in that, in a following method step, the at least one device is removed from the air gap. In a further step, the released pole is pulled out of the rotor hub.

A laminated core can be contained in a rotor and/or in a stator and include at least one first sheet metal part assembly and at least one second sheet metal part assembly. The two sheet metal part assemblies are arranged alternately lying one against the other in a stacking direction. Every first sheet metal part has first teeth projecting from a connecting part radially relative to the axis of rotation. Correspondingly, every second sheet metal part has second teeth projecting from a second connecting part. The first teeth extend from the axis of rotation at a distance different from how far the second teeth extends from the axis of rotation to form a step to mesh the rotor with an associated stator and increase the air gap between them without increasing dimensions of the laminated cores in the stacking direction.