Abstract: A rotor for a reluctance type rotating machine includes a rotor core formed by stacking a number of annular core materials each of which includes magnetic concave and convex portions. The rotor core has two keys which are formed at two positions on an inner circumference of the rotor core. The positions are spaced 180 degrees apart from each other with respect to the rotor core. The rotor core is divided into a plurality of blocks and the core materials constituting at least one block have the magnetic concave and convex portions shifted by a predetermined angle relative to the core materials constituting the other or another block on the basis of a center line passing through the keys. A whole or part of the core materials of at least one block are located circumferentially 180 degrees apart form the core materials constituting the other or another block.

Abstract: A rotor for a reluctance type rotating machine includes a rotor core formed by stacking a number of annular core materials each of which includes magnetic concave and convex portions alternately formed on an outer circumference thereof and a central through hole, the rotor core having a key axially extending on an outer circumference, the rotor core being divided into a plurality of blocks, the core materials constituting one of at least three blocks having the magnetic concave and convex portions shifted by a predetermined angle in one of a rotating direction of the rotor and a direction opposite the rotating direction of the rotor relative to a center line passing the key, the core materials constituting each one of the blocks located at both ends of the one block having the magnetic concave and convex portions shifted by a predetermined angle in the other of the rotating direction of the rotor and the direction opposite the rotating direction of the rotor relative to a center line passing the key, and a ro

Abstract: A rotor for a reluctance type rotating machine includes a rotor core formed by stacking a number of annular core materials each of which includes magnetic concave and convex portions alternately formed on an outer circumference thereof and a central through hole, the rotor core having a key axially extending on an outer circumference, the rotor core being divided into a plurality of blocks, the core materials constituting one of at least three blocks having the magnetic concave and convex portions shifted by a predetermined angle in one of a rotating direction of the rotor and a direction opposite the rotating direction of the rotor relative to a center line passing the key, the core materials constituting each one of the blocks located at both ends of the one block having the magnetic concave and convex portions shifted by a predetermined angle in the other of the rotating direction of the rotor and the direction opposite the rotating direction of the rotor relative to a center line passing the key, and a ro

Abstract: A rotor for a reluctance type rotating machine includes a rotor core formed by stacking a number of annular core materials each of which includes magnetic concave and convex portions alternately formed on an outer circumference thereof and a central through hole, the rotor core having a key axially extending on an outer circumference thereof, the rotor core being divided into a plurality of blocks, the core materials constituting at least one block having the magnetic concave and convex portions shifted by a predetermined angle relative to the core materials constituting the other or another block on the basis of a center line passing the key, and a rotational shaft inserted through the central hole of the rotor core, the shaft having a key groove engaging the key of the rotor core.

Abstract: An impeller used for cooling a dynamoelectric machine such as electric motors includes a disk and a plurality of blades arranged on the disk in a circle at unequal spaces so that a position angle .theta.n of an n-th blade is met by an equation:.theta.n=.theta.n0+.theta.max.times.sin {2.pi..times.m.times.(n-1)/Z}where Z is the number of the blades, .theta.n0 is a position angle defining a position of the n-th blade when the blades the number of which is shown by Z are arranged on the disk at equal spaces where 1.ltoreq.n.ltoreq.Z, .theta.max is a maximum allowable angular difference, and m is a degree of a rotational frequency and takes any integer from 1 to Z-1.

Abstract: A press forming device for forming a plurality of inwardly directed projections on a circumferential wall of a tubular article to be formed. The press forming device includes a lower die holder adapted to be mounted on a lower base of a press machine, and a die fixed on the lower die holder. The die has a plurality of inside forming parts on a circumferential surface of the die, each for forming one of the projections, respectively. The press forming device further includes a plurality of punches mounted on the lower die holder around an outer circumference of the die, each being arranged to be capable of being moved towards or away from the die, and each having an outside forming part in a position facing one of the inside forming parts for forming one of the projections, respectively. The press forming device also includes an upper die holder adapted to be mounted on an upper raising and lowering base of the press machine and a plurality of pressing members of wedge shape mounted on the upper die holder.