Hitachi, Ltd.

Tosio Tomite

Nobuhiko Ogasawara

Tatsuhiro Tani

Hisanobu Kanamaru

Hidemitsu Kobayashi

Toshimi Abukawa

Hiroyuki Nagasawa

Kaniti Isii

Fumio Tajima

Kazuo Tahara

Shotaro Naito

Noriyoshi Takahashi

Hideo Tatsumi

Akira Takahashi

Rokuro Kikuchi

Kiyomasa Tsubota

Keiichi Nakatsugawa

Humio Tajima

Syuichi Takamastu

A permanent magnet field type DC machine in which the amount of flux from field poles is changed by effective use of armature reaction thereby to improve characteristics of the DC machine. There is provided a permanent magnet field type DC machine having field poles formed of permanent magnet members and auxiliary magnetic pole members of high permeability which are provided in parallel with each other in the direction of rotation on the peripheral surface of a yoke to oppose an armature with an air gap therebetween, the auxiliary magnetic pole members being magnetized by armature reaction thereby to change the total amount of field magnetic flux from the field poles, wherein the gap between the auxiliary magnetic pole members and armature is selected to be smaller than that between the permanent magnet members and armature, thereby decreasing the reluctances in the paths of the auxiliary magnetic pole members, so that the armature reaction can be effectively used.

Permanent magnet field type DC machine

A plurality of permanent magnets (4) are disposed with gaps between adjacent magnets along the inner peripheral surface of a yoke (2) of a stator for a magneto D.C. motor. In gaps between magnets, there are provided retainers (3), ech of which is made of an elastic member and consists of one surface (11) fixed on the yoke, two surfaces (12, 13) extending in the central axial direction of the D.C. motor along the side facing surfaces (71, 72) of the magnets opposite to each other on the inner peripheral surface of the yoke and two end portions (32) connecting these two surfaces (12, 13). Those two surfaces (12, 13) and end portions (32) are kept in contact with the permanent magnet from three directions, namely from both facing surfaces (71, 72) of the permanent magnet and from each of the outer surfaces (81, 82) of the magnets adjacent to each facing surface (71, 72) extending in the central axial direction, whereby the permanent magnets are pressed and clamped so as to be secured to the yoke.

Magneto D.C. motor having elastic magnet mounting retainers

In a permanent type DC motor, a stator comprises a yoke and a plurality of magnetic pole pairs composed of permanent magnets and auxiliary poles. The plurality of magnetic pole pairs are held and fixed in intimate contact with the yoke by pressingly deforming a cylindrical thin plate made of magnetic material such as a steel plate. The fixture of the magnetic pole pairs composed of the permanent magnets and auxiliary poles is attained by a projecting part formed by pressingly deforming a part of the thin cylindrical plate made of the magnetic material toward a space between the adjacent pole pairs and by using U-shaped magnetic retaining pieces.

Magnetic cover member for magnetic poles of DC motor

Two or more imbalance correcting openings with the same cross-sectional configuration are provided in an armature core in parallel to a shaft in such a manner as to be equally spaced on a circumference which is concentric with the shaft, and weights are inserted in the adjacent openings to thereby correct any imbalance, the number of adjacent openings being selected to be (N-1)/2+1 or less when the number n of openings is odd and to be n/2 or less when the number n is even.

Armature for direct current motor with imbalance correction

A direct-current machine having a rotor which includes a commutator, an armature core and an armature winding and is sustained rotatably in a field system constituted by a cylindrical housing and permanent magnets disposed inside the same. A demagnetizing force of an armature reaction due to an armature current is reduced by attaching a magnetic plate made of high saturation magnetic flux density material to a part of the pole-face of said field system of permanent magnets which is in the demagnetizing field.

Direct-current machine having permanent magnet field system

A method of production of a cylindrical body from a sheet of steel formed at opposite sides with projections and cutouts complementary to each other. The method comprises the steps of rolling the sheet of steel and inserting the projections in the cutouts to provide a cylindrical blank, and compressing at least one of inner and outer peripheral surfaces of the cylindrical blank in a radial direction to reduce the thickness of the cylindrical blank and to stretch a portion of the cylindrical blank in an axial direction whereby the projections inserted in the cutouts can be brought into intimate contact with each other at jointed portions.

Method of production of cylindrical body

A magneto device for generating signals comprises a rotor including a permanent magnet and a pole piece which are secured to a rotary body, and a stator including a stationary pole piece and a signal output coil. Formed in the outer periphery of the rotary body is a recess in which the permanent magnet and the pole piece are inserted in this order. A cylindrical key member made of a non-magnetic metal is inserted in an annular space between the wall of the recess and the permanent magnet and pole piece. The key member is plastically deformed by pressing to secure the permanent magnet and pole piece to the rotary body.

Magneto device for generating signals

A permanent magnet type motor having a stator which comprises a yoke, a plurality of main magnetic poles made of permanent magnets, and a plurality of auxiliary magnetic poles, each of the main magnetic poles and each of the auxiliary magnetic poles being juxtaposed on the inner peripheral surface of the yoke, wherein each of the auxiliary magnetic poles has an axial length larger than the thickness of an armature core and smaller than the axial length of each of the main magnetic poles, wherein each of the main magnetic poles has an inner diameter smaller than the inner diameter of each of the auxiliary magnetic poles, wherein each of the main poles, before being secured on the yoke, is machined to have the inner diameter smaller than the predetermined inner diameter by a thickness to be machined, and wherein each of the main magnetic poles is machined to have the predetermined inner diameter after it has been secured together with each of the auxiliary magnetic poles onto the yoke.

Permanent magnet type motor having improved pole structure

A d.c. dynamoelectric machine of permanent magnet type comprises an armature and a plurality of field poles, wherein each of the poles comprises a main pole part (a permanent magnet) composed by an integral combination of a first magnet formed of a magnetic material having a large coercive force and a second magnet formed of a magnetic material providing a high residual flux density and having an axial length larger than that of the armature core, and an auxiliary pole part juxtaposed and coupled to the permanent magnet and having a permeability higher than the reversible permeability of the permanent magnet, and an air gap for intercepting the path of leakage flux is defined between the permanent magnet and the auxiliary pole part.

Direct current dynamoelectric machine of permanent magnet type

A permanent field type starting motor is provided with a permanent magnet, and a non-permanent magnet auxiliary pole which has higher reversible permeability than that of the permanent magnet. The auxiliary pole is disposed in the circumferential direction of the inner circumference of a yoke and on the magnetizing side of armature reaction relative to the center of the pole. The pole arc ratio of the auxiliary pole with respect to the center angle of the field is selected in a range from 0.07 to 0.4.

Permanent magnet field type starting motor provided with an auxiliary

Method for producing a magneto device for generating signals

A field pole structure of a DC motor has a plurality of field magnetic poles attached to the inner surface of a yoke of the DC motor to oppose an armature. Each magnetic pole includes a permanent magnet, and an auxiliary pole member coupled to an end of the permanent magnet directed in opposition to the rotational direction of the armature and having permeability higher than reversible permeability of the permanent magnet. The permanent magnet has a single magnet body constructed by integrally formed first and second magnet members, the first magnet member being disposed at a half of the permanent magnet remote from the auxiliary pole member and made of a magnetic material of large coersive force, and the second magnet member being interpoled between the first magnet member and the auxiliary pole member and made of a magnetic material of large residual magnetic flux density, the boundary portion between the first and second magnet members being a region in which the magnetic material of large coersive force and the magnetic material of large residual magnetic flux density are mixed.

Field pole structure of DC motor

A joining construction between a flywheel of a flywheel magneto and a boss for mounting thereon a shaft comprises a joining portion formed on the periphery of the boss, and a joining portion of the flywheel surrounding the periphery of the boss. The joining portion of boss has an annular groove defined by a rugged bottom and both sides one of which is inclined along metal flow. The joining portion of the flywheel has the same shaped groove as one of the boss. Two the joining portions define an annular gap in which a joining member is disposed deformed by pressworking. The joining member inserted into the annular gap has the same shearing strength as the flywheel when an axial force is applied to the flywheel magneto.

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Katsuta, Japan

Tosio Tomite