Sanyo Electric Co., Ltd.

Kazuki Miki

Setsuo Hasegawa

Noriyuki Murao

Satoshi Nakai

Noriyuki Okada

Masayuki Aiga

A magnetron has an anode cylinder, a plurality of vanes arranged radially within the anode cylinder, a magnetic piece disposed at an open end section of the anode cylinder, an anode vacuum container including a metal container disposed to cover an upper surface of the magnetic piece, a cathode disposed along a central axis of the vacuum container, and an antenna externally discharging microwaves. The magnetic piece and the metal container are placed, in that order, on a shelf formed inwardly on a thin end section projecting from the open end section of the anode cylinder. When tightly welding the thin end section, a predetermined number of projections, projecting inwardly from the thin end section of the anode cylinder, loosely secure an outer perimeter bend of the metal container. The metal container is then accurately tightly welded to the anode cylinder without the metal container shifting off-center.

Method for making magnetrons

A magnetron including a tubular metallic container which is air-tightly connected to an anode, cathode leads for supporting a cathode with filaments being disposed in a central axial portion of the anode, a stem insulator formed with through holes through which the cathode leads pass, and external terminals formed with planar portions which are air-tightly connected to a surface of the stem insulator opposite to a surface facing the tubular metallic container and with connecting portions which are air-tightly connected to the cathode leads. The connecting portions are arranged to be bent in an axial direction of the cathode leads. It is possible to exhibit the effect of preventing vacuum break from occurring by oxidation or the like since the increase in the area of the connecting portions will result in elongation of the distance between the end portions of the connecting portions and the through holes.

Magnetron with external terminals having connecting portions which are air-tightly connected to cathode leads

A magnetron including a cathode terminal of a magnetron main body and an inductor connected to the cathode terminal to constitute a filter, wherein the inductor includes an air-core coarse inductor and a cored inductor connected in series, the air-core coarse inductor being connected to the cathode terminal side, and the air-core coarse inductor includes a large pitch winding provided on the cathode terminal side and a small pitch winding provided on the opposite side.

Magnetron and microwave heating device

A ring-shaped depressed groove is formed between a joining surface of a stem insulating material with a tubular metal container and a joining surface with cathode leads and A metallized layer formed at joining surface and joining surface is separated from edges and of ring-shaped depressed groove The resulting magnetron reliably prevents discharges generated between the joining surface of the stem insulating material, with the tubular metal container, and the joining surface, with the cathode leads.

Magnetron

A magnetron comprising an anode portion, a cathode portion provided in a center of the anode portion, a cylindrical interaction space formed of the anode portion and the cathode portion, and iron magnetic pole pieces located at both ends of the interaction space in an tube axis direction thereof. A relationship between a thickness Tg (mm) of a tapered portion of the magnetic pole pieces and a magnetic flux Bg (mT, at 25&deg; C.) of a center of the interaction space is set to satisfy 155<Bg/Tg<165. It is possible to obtain a magnetron with substantially constant oscillating efficiencies, and it is accordingly possible to stabilize outputs of the microwave oven and to enable easy control of heating food.

Magnetron having magnetic pole pieces providing a specific magnetic flux to thickness ratio

A magnetron including: an anode cylinder in which a plurality of vanes are formed, a filament provided at a center of the anode cylinder, a top hat which supports an upper end of the filament, a top lead for connecting the top hat at an upper end of the top lead, an end hat which supports a lower end of the filament, an end lead for connecting the end hat at an upper end of the end lead, a stem metal hermetically sealed at an open end of the anode cylinder through a pole piece, and a choke disposed inside the stem metal, wherein the choke is disposed approximately in a position of wavelength of a predetermined high frequency from the top hat in a distance along a surface of the top lead. It is possible to suppress generation of undesired high frequency, especially of the fifth high frequency, from the input portion.

Magnetron with a fifth harmonic choke

In an interaction space (4) defined between a cathode (3) and forward end portions of vanes (2), a permanent magnet (12) applies a uniform direct-current magnetic field along an axial direction of the cathode (3). Direct-current or low-frequency high voltage is applied between the cathode (3) and the respective vanes (2). Spaces (14) enclosed by respective pairs of adjacent vanes (2) and the inner wall of an anode cylinder (1) define cavity resonators. High-frequency electric fields formed in the cavity resonators are concentrated to the forward end portions of the vanes (2), and partially leak into the interaction space (4). Under such conditions, an electron group emitted from the cathode (3) rotates about the cathode (3) in the interaction space (4), thereby interaction takes place between the electron group and the high-frequency electric fields, to oscillate microwaves. The inner surface of a flange part (6) of a top hat (7) supporting one end of a filament (5) of the cathode (3) is located in a position closer to the interaction spaces (4) by length within a range of 0.1 to 0.6 mm from first end surfaces of the vanes (2) along the axial direction, thereby to suppress undesired fifth harmonic generated with the microwaves of a basic frequency at this time.

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Himeji, Japan

Kazuki Miki