Magnetron Pole Piece Segmentation for Vacuum Conductance
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Solution Overview
Problem
Conventional magnetrons face challenges in achieving high air exhaust conductance without compromising the maximum magnetic field strength or leading to leakage of higher harmonic waves, which can result in prolonged air discharge times and potential poor vacuum conditions.
Innovation Solution
The magnetron design incorporates a funnel-shaped input side pole piece with three or more penetration holes in the slanting portion, each with an area of 16.6 mm2 or smaller, extending in the axial direction, to enhance air exhaust conductance while maintaining the magnetic field strength and preventing harmonic wave leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the penetration hole area in the input side pole piece is increased to improve air exhaust conductance, then air discharge time is reduced, but the maximum magnetic field strength decreases and higher harmonic waves leak
Solution Approach 1:
The single large penetration hole is segmented into three or more smaller penetration holes in the slanting portion of the input side pole piece. Each small hole has an area of 16.6 mm² or smaller, which collectively provides sufficient air exhaust conductance while maintaining the maximum magnetic field strength and preventing higher harmonic wave leakage that would occur with a single large hole.
2Productivity
If three or more penetration holes are added to the slanting portion of the input side pole piece, then air discharge efficiency is improved, but the device complexity increases
Solution Approach 1:
The multiple penetration holes are integrated into the slanting portion of the input side pole piece as a unified structural feature. The holes are formed at specific intervals along the slanting surface, combining multiple functional elements (air exhaust paths) into a single coordinated structure that achieves improved air discharge without requiring separate components or complex assembly procedures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design effectively shortens air exhaust time, prevents poor vacuum conditions, and maintains the maximum magnetic field strength and harmonic wave integrity, ensuring stable operation and efficient air discharge.
Implementation Method 1
there is formed a magnetic field due to the two magnets (not shown). When the direct current high voltage is applied to and between the anode vane 11 and cathode structure member 12, electrons are drawn out from the cathode structure member 12 and thus they fly out toward the anode vane 11. At the then time, the magnetic field due to the two magnets (not shown) concentrates in a gap existing between the output side pole piece 14 and input side pole piece 15, and it acts on the action space 13 in a direction perpendicular to a direction where the cathode structure member 12 and anode barrel member 10 are opposed to each other. As a result of this, electrons flown out from the cathode structure member 12 are rotated and moved in a spiral by a force which is generated by the magnetic field due to the magnets (not shown)
Implementation Method 2
electrons flown out from the cathode structure member 12 are rotated and moved in a spiral by a force which is generated by the magnetic field due to the magnets
Implementation Method 3
the air on the input side, as shown in FIG. 17, passes not only through a penetration hole 15A opened up in the central portion of the input side pole piece 15 but also through a penetration hole 21A opened up in a lower end hat 21 which constitutes the cathode structure member 13
Data Source
AI summary
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. Of the pair of pole pieces 14 and 30, the input side pole piece 30 includes, besides the penetration hole 30A formed in the central portion thereof, three or more, preferably, four penetration holes 30B respectively formed in the slanting portion SL thereof, each hole having an area of 16.6 mm2.