Hitachi, Ltd.

Other

Hitachi Cable, Inc.

Mitsuo Kudoh

Toshihiko Fukushima

Masaaki Itoh

Mari Uchida

Tadao Otani

Fumio Tajima

Osamu Koizumi

Rumi Minakata

Syouichi Kawamata

Suetato Shibukawa

To provide a high heat transfer performance with a heat transfer pipe used to a condenser and an evaporator in a refrigerating cycle using a refrigerant mixture, the heat transfer pipe includes main grooves and auxiliary grooves each formed on the inner surface of the heat transfer pipe with the main grooves intersecting the auxiliary grooves, wherein the main grooves are separate by ridges, and the ridges are divided into ribs by the auxiliary grooves, and wherein a length of the ribs formed along the direction of the main grooves is made longer than the length of the ridges, a width of the auxiliary grooves is made smaller than the length of the ribs and further the auxiliary grooves are formed in a direction where a pressure gradient in the heat transfer pipe is reduced.

Heat transfer pipe for refrigerant mixture

In a heat transfer tube for a zeotropic refrigerant mixture, the inner surface of the tube in which the zeotropic refrigerant mixture flows is formed with grooves having cross portions where the grooves intersect with each other, or the inner surface of the tube is formed with a plurality of independent projections. Thus, concentration boundary layers generated in the zeotropic refrigerant mixture are stirred to reduce the thickness of the concentration boundary layers, thereby decreasing the diffusion resistance and promoting the stirring effect. Consequently, there can be provided a heat transfer tube for a zeotropic refrigerant mixture which exhibits a high heat transfer performance, and a heat exchanger of a cross-fin tube type, a refrigerator and an air conditioner which include such heat transfer tubes.

Refrigeration cycle

A rotating motor is provided which permits heat to be efficiently dissipated from all of the stator, rotor, and inner and outer races of bearings. This assures that the rotor exhibits a high intensity as it turns. Also, long bearing life is assured. A coolant enters a cooling passage formed in a first end bracket from entrance pipes and makes a half revolution, thus cooling a first one of the bearings. Also, the coolant cools the rotor via cooling disks and rotor disks. Then, the coolant flows into an outer surface-cooling passage in a motor housing and takes a zigzag course so as to make a substantially half revolution, thus cooling the stator. The coolant then flows into a cooling passage in a second end bracket and makes one revolution, thus cooling a second bearing. At the same time, the rotor is cooled via the cooling disks and rotor disks. Subsequently, the coolant enters another outer surface-cooling passage and makes a substantially half revolution, thus cooling the stator. The coolant then flows into another cooling passage in the aforementioned first end bracket and makes a substantially half revolution, thus cooling the first bearing again. Also, the rotor is cooled via the cooling disks and rotor disks.

Rotating motor and motor-driven vehicle

Growing community of inventors

Tsuchiura, Japan

Mitsuo Kudoh