Abstract: The magnetron includes: a cylindrical-shaped anode barrel member 10 having two openings respectively formed in the two end portions thereof; a cathode structure member 12 disposed on the center axis of the anode barrel member 10; more than one anode vane 11 disposed radially through an action space 13 in the periphery of the cathode structure member 12 and fixedly mounted on the inner wall surface of the anode barrel member 10; and, a pair of funnel-shaped pole pieces 14 and 30 respectively disposed in their associated ones of the two openings formed in the two end portions of the anode barrel member 10, each pole piece including a small-diameter flat portion FL1 having a penetration hole formed in the central portion thereof, a large-diameter flat portion FL2 having a diameter larger than the diameter of the small-diameter flat portion FL1, and a conical-shaped slanting portion SL for connecting the large-diameter flat portion FL2 and small-diameter flat portion FL1 to each other.

Abstract: In the magnetron, an upper end hat 122A is used as a composing element of a cathode structure member 12A and includes a portion 122Aa which is in contact with one end portion 121a of a filament coil 121. The thickness of the portion 122Aa is reduced, whereby the portion 122Aa is held not in contact with a center lead 124. Owing to this, heat generated in the filament coil 121 can travel to the upper end hat 122A without traveling directly to the center lead 124. Therefore, even when the quantity of input power is reduced to such a degree as to be able to reduce noise, or even when the electron radiation area of the filament coil 121 is reduced, the getter effect can be displayed fully. As a result of this, noise reduction and cost reduction can be realized at the same time.

Abstract: To provide a magnetron capable of reducing noises in a low frequency band of 30 MHz or less without deteriorating the stability of a load depending on phases, and also ensuring the precision of assembly dimensions without increasing the number of components, a coiled filament 3 is arranged between an input-side end hat 61 and an output-side end hat 7 which are supported by a cathode supporting rod 8. A larger-diameter boss 61a in the end hat 61 extends to the interior of an interaction space, a smaller-diameter boss 61b and one end 3a of the filament 3 are secured to each other, and the other end 3b is secured to a boss 7a of the end hat 7. Here, the dimension of an axial free length part F which forms an electron emission part which is not secured to the end hats 61 and 7 of the filament 3 is set to 50% or more and 80% or less of the axial dimension H of plate-like vanes 2, and the electron emission part is arranged so as to be displaced to the output side.

Abstract: It is an object to provide a magnetron for a small-sized microwave oven which takes safety standards and a noise into consideration, in a magnetron 10 for a microwave oven, a pair of choke coils 16 and 17 are provided in a filter case 11, and a height H1 of the internal surface of the filter case 11 is set to be 35 to 45 mm, an outside diameter d3 of an air-core type inductance 25 is set to be 5.5 to 7.5 mm and a sectional area S of a high frequency absorbing member 27 is set to be 5 to 16 mm2. In the magnetron 10 for a microwave oven, an electrostatic capacity between capacitor terminals 15A and 15B and the filter case 11 is increased to be 500 to 700 pF.

Abstract: A magnetron comprising an anode portion having an anode cylinder and vanes, a cathode portion having a coil-shaped filament, magnetic poles disposed at the upper and lower ends of the filament, ring-shaped permanent magnets made of a Sr ferrite magnet containing La—Co, an input portion and an output portion. The diameter ?a of the inscribed circle at the ends of the vanes constituting the anode portion is in the range of 7.5 to 8.5 mm, and the outside diameter ?c of the coil-shaped filament 1 constituting the cathode portion is in the range of 3.4 to 3.6 mm.

Abstract: For an anode assembly 51 of a magnetron, a plurality of plate shaped vanes 54 radially arranged at an inner circumference of the roughly round shaped anode assembly 53 has a end portion arranged at a central axis of the anode assembly 53 with a step shape Df having a reduced thickness in a range of predetermined length L from an end portion, so that increase of the facing area of the respective adjacent plate shaped vanes 54 is suppressed while the separation distance of the end portions of the vanes is secured.

Abstract: In a magnetron apparatus in accordance with the present invention, a first notch 17, a second notch 19 and a third notch 20 are formed in each of anode segments 15 disposed radially inside an anode cylinder 6, whereby the passage of high-frequency current flowing through the resonator comprising the two anode segments 15 adjacent to each other, the anode cylinder 6 and strap rings 9 and 10 is made narrow and long.

Abstract: In a magnetron apparatus in accordance with the present invention, a first notch 17, a second notch 19 and a third notch 20 are formed in each of anode segments 15 disposed radially inside an anode cylinder 6, whereby the passage of high-frequency current flowing through the resonator comprising the two anode segments 15 adjacent to each other, the anode cylinder 6 and strap rings 9 and 10 is made narrow and long.

Abstract: A magnetron comprising an anode portion having an anode cylinder and vanes, a cathode portion having a coil-shaped filament, magnetic poles disposed at the upper and lower ends of the filament, ring-shaped permanent magnets made of a Sr ferrite magnet containing La-Co, an input portion and an output portion. The diameter &phgr;a of the inscribed circle at the ends of the vanes constituting the anode portion is in the range of 7.5 to 8.5 mm, and the outside diameter &phgr;c of the coil-shaped filament 1 constituting the cathode portion is in the range of 3.4 to 3.6 mm.