Magnetron

Patent metadata

Field	Value
Publication number	US-9852872-B2
Application number	US-201615049925-A
Country	US
Kind code	B2
Filing date	Feb 22, 2016
Priority date	Aug 29, 2013
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

Provided is a low-cost magnetron that is excellent in productivity without any adverse effect on characteristics.
Two large and small strap rings 11 ( 11 A and 11 B) are only disposed at lower ends, or input sides, of a plurality of vanes 10 ( 10 A and 10 B) in the direction of a tube axis m. Diameter Rip of a protruding flat surface 41 of an input side pole piece 18 is larger than diameter Rop of a protruding flat surface 40 of an output side pole piece 17 . Therefore, it is possible to provide a practical magnetron without a significant decrease in productivity or characteristics from a conventional one, while cutting costs by reducing the number of parts with the use of two strap rings on one side.

First claim

The invention claimed is:

1. A magnetron comprising:
an anode cylinder extending cylindrically along a tube axis;
a plurality of vanes extending from an inner surface of the anode cylinder toward the tube axis with free ends forming a vane inscribed circle;
a large strap ring and a small strap ring with respective different diameters and short-circuiting alternating ones of the plurality of vanes;
a cathode disposed along the tube axis in the vane inscribed circle formed by the free ends of the plurality of vanes;
pole pieces disposed at both ends of the anode cylinder in a tube axis direction to lead magnetic flux into an interaction space between the free ends of the plurality of vanes and the cathode; and
an antenna extending from at least one of the vanes,
characterized in that:
the strap rings are only disposed on a cathode input side end, in the tube axis direction, of the vanes,
the shape of the pole piece disposed at one end of the anode cylinder in the tube axis direction and the shape of the pole piece disposed at the other end are asymmetrical, and
the pole pieces disposed at both ends of the anode cylinder in the tube axis direction include protruding flat surfaces, and a diameter of the protruding flat surface of the pole piece disposed at one end of input side is larger than a diameter of the protruding flat surface of the pole piece disposed at the other end of output side, wherein

a diameter (Rop) of the protruding flat surface of the pole piece disposed at the output side, a diameter (Rip) of the protruding flat surface of the pole piece disposed at the input side, an inner diameter (Rsi) of the small strap ring, and an outer diameter (Rlo) of the large strap ring satisfy the following conditional expression (1):
Rop <( Rsi+Rlo )/2≦ Rip.   (1)

2. The magnetron according to claim 1 , wherein
the antenna is pulled out from a vane that is short-circuited by the large strap ring.

3. The magnetron according to claim 1 , wherein
a notch is formed in a cathode input side end portion of each of the vanes; and the large and small strap rings are each disposed inside the notch of the cathode input side end portion of the vanes.

4. The magnetron according to claim 3 , wherein
a height (HS) of the large and small strap rings in the tube axis direction, a width (WS) of the large and small strap rings in the radial direction, a height (HV) of the vanes in the tube axis direction, a width (WV) of the vanes in the radial-direction, a thickness (TV) of the vanes, and a distance (GV) between free ends of adjoining vanes satisfy the following conditional expressions (2) to (5):
7.8≦ HV≦ 8.2, in millimeters  (2)

0.1≦ HS/HV≦ 0.19  (3)

0.06≦ WS/WV≦ 0.09  (4)

GV /( GV+TV )≦0.375.  (5)

5. The magnetron according to claim 1 , wherein
there are two types of the vanes;
the vanes have press stamping directions that are the same; and
the vanes are disposed in such a way that a shear droop that is formed during press working is aligned in the same direction.

6. The magnetron according to claim 1 , wherein
an inner diameter (Rpp) of each of the pole pieces disposed at the output and input sides, and a diameter (Ra) of the vane inscribed circle, satisfy the following conditional expression (6):
0.95≦ Rpp/Ra.   (6)

7. A magnetron comprising:
an anode cylinder extending cylindrically along a tube axis;
a plurality of vanes extending from an inner surface of the anode cylinder toward the tube axis with free ends forming a vane inscribed circle;
a large strap ring and a small strap ring with respective different diameters and short-circuiting alternating ones of the plurality of vanes;
a cathode disposed along the tube axis in the vane inscribed circle formed by the free ends of the plurality of vanes;
pole pieces disposed at both ends of the anode cylinder in a tube axis direction to lead magnetic flux into an interaction space between the free ends of the plurality of vanes and the cathode; and
an antenna extending from at least one of the vanes,
characterized in that:
the strap rings are only disposed on a cathode input side end, in the tube axis direction, of the vanes,
the shape of the pole piece disposed at one end of the anode cylinder in the tube axis direction and the shape of the pole piece disposed at the other end are asymmetrical, and
the pole pieces disposed at both ends of the anode cylinder in the tube axis direction include protruding flat surfaces, and a diameter of the protruding flat surface of the pole piece disposed at one end of input side is larger than a diameter of the protruding flat surface of the pole piece disposed at the other end of output side,
wherein a height (HS) of the large and small strap rings in the tube axis direction, a width (WS) of the large and small strap rings in the radial direction, a height (HV) of the vanes in the tube axis direction, a width (WV) of the vanes in the radial-direction, a thickness (TV) of the vanes, and a distance (GV) between free ends of adjoining vanes satisfy the following conditional expressions (1) to (4):
7.8≦ HV≦ 8.2, in millimeters,  (1)

0.1≦ HS/HV≦ 0.19;  (2)

0.06≦ WS/WV≦ 0.09;  (3)

GV /( GV+TV )≦0.375.  (4)

8. The magnetron according to claim 7 , wherein
a diameter (Rop) of the protruding flat surface of the pole piece disposed at the output side, a diameter (Rip) of the protruding flat surface of the pole piece disposed at the input side, an inner diameter (Rsi) of the small strap ring, and an outer diameter (Rlo) of the large strap ring satisfy the following conditional expression (5):
Rop <( Rsi+Rlo )/2< Rip.   (5)

9. The magnetron according to claim 7 , wherein
the antenna is pulled out from a vane that is short-circuited by the large strap ring.

10. The magnetron according to claim 7 , wherein
a notch is formed in a cathode input side end portion of each of the vanes; and the large and small strap rings are each disposed inside the notch of the cathode input side end portion of the vanes.

11. The magnetron according to claim 7 , wherein
there are two types of the vanes;
the vanes have press stamping directions that are the same; and
the vanes are disposed in such a way that a shear droop that is formed during press working is aligned in the same direction.

12. The magnetron according to claim 7 , wherein an inner diameter (Rpp) of each of the pole pieces disposed at the output and input sides, and a diameter (Ra) of the vane inscribed circle, satisfy the following conditional expression (6):
0.95≦ Rpp/Ra≦ 1.13.  (6)

Assignees

• Toshiba Hokuto Electronics Corp

Inventors

• Higashi Masatoshi

Classifications

• H01J23/04

  Cathodes · CPC title

• H01J23/213

  Simultaneous tuning of more than one resonator, e.g. resonant cavities of a magnetron · CPC title

• H01J23/10

  Magnet systems for directing or deflecting the discharge along a desired path, e.g. a spiral path (magnetic focusing arrangements H01J23/08) · CPC title

• H01J25/587

  Multi-cavity magnetrons · CPC title

• H01J23/22

  Connections between resonators, e.g. strapping for connecting resonators of a magnetron · CPC title