Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Panasonic Intellectual Property Management Co., Ltd.

Hideharu Hiwaki

Hiroshi Murakami

Yuichi Yoshikawa

Kiyomi Kawamura

Hisakazu Kataoka

Yuichiro Tashiro

Sunao Hashimoto

Hiroki Sato

Yoshinari Asano

Yasuharu Odachi

Koji Kuyama

Hirohito Hayashi

Haruhiko Kado

Shinichi Okuyama

Yuichi Tanabe

Hiroshi Itoh

Yasushi Kamada

Mitsuhiro Sakamoto

Toshiyuki Tamamura

Akio Ando

Yoshikazu Sengokudani

Hajime Nojima

A brushless motor includes: a motor including a stator around which a winding wire is wound and a rotor holding a permanent magnet; a motor control microcomputer; an inverter circuit in which a power element is incorporated and controls an amount of a voltage applied to the winding wire; a temperature detecting element which detects a temperature of the power element; and a current detecting element which detects a power supply current or a current of the winding wire. A first current limit value is defined by current limit value which is set such that a junction temperature of the power element does not exceed a predetermined value, the brushless motor sets a second current limit value which is higher than the first current limit value, and the brushless motor operates, based on the second current limit value only in a predetermined period after start-up of the brushless motor.

Brushless motor and washing machine provided with same

Recesses and projections that extend in an axial direction are formed on an outer-circumferential surface of a molded resin body. The recesses are provided on portions where are extended outward from teeth having the winding and are on the outer circumferential surface. In addition, further recesses and projections that extend in a radial direction are formed on an axial-direction end surface of the molded resin body. The further recesses are provided on portions of the axial-direction end surface that are aligned in the axial direction with the winding.

Motor

Recesses and projections that extend in an axial direction are formed on an outer-circumferential surface of a molded resin body. The recesses are provided on portions where are extended outward from the winding and are on the outer circumferential surface. In addition, further recesses and projections that extend in a radial direction are formed on an axial-direction end surface of the molded resin body. The further recesses are provided on portions of the axial-direction end surface that are aligned in the axial direction with the winding.

A stator of a motor includes a stator core formed of a plurality of teeth and an annular yoke connecting the teeth to each other, and windings wound on the teeth. A rotor of the motor confronts the stator while supported rotatably, and includes a rotor magnet, a rotor core, and a position sensing magnet. The motor further includes a position sensor for sensing a rotational position of the rotor and a circuit board for supplying an electric current to the windings in response to the rotational position of the rotor. The rotor magnet, the rotor core, and the position sensing magnet are integrated into one unit, which is mounted on a shaft of the rotor.

In a stator core having 'N' slots, a tooth-width centerline of a linear yoke and a first extension line extended horizontally from a center of rotary shaft toward the linear yoke form a first angle. Assume there are first point on the first extension line at a first distance from the center, a second extension line drawn at a second distance horizontally from the center toward the linear yoke and extended vertically toward arc-shaped yokes, and a third extension line drawn from the center toward teeth ends of the linear yokes with angle 'K'. The second and third extension line intersect at a second point. A line between the first and second points intersects with the first extension line, thereby forming the first angle. In this structure, 0&#x3c;a&#x3c;b, and (360/2N&#x2212;60/2N)&#xb0;&#x3c;K&#x3c;(360/2N+60/2N)&#xb0; are established, where &#x201c;a&#x201d;, &#x201c;b&#x201d; are the first and the second distances respectively.

Electrical machine having a flattened stator with inclined teeth

A motor includes a stator formed of a stator iron-core having salient pole iron-cores and windings, and a rotor having a rotor iron-core in which permanent magnets are buried. A magnetic pole centerline connecting a rotary center of the rotor to a magnetic pole center crosses an external shape of the rotor iron-core at end point X, and the magnetic-pole boundary line connecting the rotary center to a magnetic pole boundary point crosses the external shape of the rotor iron-core at end point Z. A straight line angled at a given angle &#x3b8;a from the magnetic pole centerline has end point A. Then a sectional view of the rotor iron-core shows an arc drawn between the end points X and A, and the arc's center is the rotary center. The end points A and Z are connected by one or more than one straight lines in series.

It is intended to suppress the vibration and noise during operation of a concentrated winding electric motor and to provide an electric motor with high efficiency, low vibration and low noise. A skew is formed on at least one of a stator () and a rotor (), arranged with a concentrated winding, and a winding vibration damping body () is inserted between windings () of different phases within a winding groove () and contacted therewith.

To provide a motor which can suppress vibration and noise during an operation of a concentrated winding motor and can achieve low vibration and low noise with high efficiency. Skew is formed on at least one of a stator () provided with concentrated windings and a rotor (), and the windings () of different phases in a groove () for windings are brought into contact with each other directly or via an insulating material.

A motor is provided that reduces vibration and noise by suppressing the vibration transmitted from a stator to a housing. Also an apparatus loaded with this motor is provided, that is highly efficient with less vibration and low noise. Notches formed at an outer circumference of a yoke are located on outer peripheral sides of slots, the notches are not in contact with the housing, the yoke located on outer circumferential sides of teeth is provided with axially penetrating through-holes, and an outer circumference of the stator core located on outer circumferential sides of the through-holes is in close contact with the housing, thus making it possible to obtain the motor with high efficiency, less vibration and low noise.

Growing community of inventors

Osaka, Japan

Hideharu Hiwaki