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 FL 1 having a penetration hole formed in the central portion thereof, a large-diameter flat portion FL 2 having a diameter larger than the diameter of the small-diameter flat portion FL 1 , and a conical-shaped slanting portion SL for connecting the large-diameter flat portion FL 2 and small-diameter flat portion FL 1 to each other. Of the pair of pole pieces 14 and 30 , the input side pole piece 30 includes, besides the penetration hole 30 A formed in the central portion thereof, three or more, preferably, four penetration holes 30 B respectively formed in the slanting portion SL thereof, each hole having an area of 16.6 mm 2 .
1. A magnetron, comprising:
a cylindrical-shaped anode barrel member having two openings respectively formed in the two end portions thereof;
a cathode structure member disposed on the center axis of the anode barrel member;
more than one anode vane disposed radially through an action space in the periphery of the cathode structure member and fixedly mounted on the inner wall surface of the anode barrel member; and
a funnel-shaped input side pole piece disposed on the side of one of the two openings of the anode barrel member for supply of power to the cathode structure member, the input side pole piece including a small-diameter flat portion having a penetration hole formed in the central portion thereof, a large-diameter flat portion having a diameter larger than the diameter of the small-diameter flat portion, and a conical-shaped slanting portion for connecting the large-diameter flat portion and small-diameter flat portion to each other,
wherein the input side pole piece further includes, besides the penetration hole formed in the central portion of the small-diameter flat portion, three or more penetration holes respectively formed in the slanting portion thereof.
2. Microwave using equipment comprising a magnetron as set forth in claim 1 .
3. A pole piece manufacturing method for manufacturing a magnetron comprising:
a cylindrical-shaped anode barrel member having two openings respectively formed in the two end portions thereof;
a cathode structure member disposed on the center axis of the anode barrel member;
more than one anode vane disposed radially through an action space in the periphery of the cathode structure member and fixedly mounted on the inner wall surface of the anode barrel member; and
a funnel-shaped input side pole piece disposed on the side of one of the two openings of the anode barrel member for supply of power to the cathode structure member, the input side pole piece including a small-diameter flat portion having a penetration hole formed in the central portion thereof, a large-diameter flat portion having a diameter larger than the diameter of the small-diameter flat portion, and a conical-shaped slanting portion for connecting the large-diameter flat portion and small-diameter flat portion to each other,
wherein there is formed a penetration hole over the large-diameter flat portion and slanting portion of the input side pole piece so as to extend in the axial direction of the input side pole piece.
4. The pole piece manufacturing method as set forth in claim 3 , wherein the area of the penetration hole is 16.6 mm 2 or smaller and three or more such penetration holes are formed at given intervals in the peripheral direction of the slanting portion of the input side pole piece.
5. The pole piece manufacturing method as set forth in claim 3 , wherein:
the magnetron further includes a metal ring, and the large-diameter flat portion rests on the metal ring.