JPH0765731A - Magnetron anode body - Google Patents

Abstract

PURPOSE:To improve the durability of a vane for maintaining the reliability thereof and restrain cost, so that a magnetron anode body can withstand even high temperature operation under a high output condition. CONSTITUTION:Vanes 2 are radially arrayed on the internal surface of an anode cylinder 1. Strap rings 3 having a small diameter and strap rings 4 having a large diameter for connecting every other vanes 2 are arranged at the axial ends of the vanes 2, and a part of the rings 3 is fastened within a cutout groove 7 formed on the vanes 2.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to magnetron anode bodies. More specifically, the present invention relates to an anode body of a magnetron in which the portion of the vane where the strap ring is fixed is not damaged by thermal stress even in a high power magnetron.

[0002]

2. Description of the Related Art An anode body of a magnetron generally used in a microwave oven has a structure as shown in FIG.

That is, in FIG. 2, (a) is a plan view, (b) is a cross-sectional view showing the vane and the strap ring portion of (a), and the anode body is the anode cylinder 1 and its inner peripheral surface. It is composed of an even number of vanes 2 which are radially arranged, and a small-diameter strap ring 3 and a large-diameter strap ring 4 in which every other one of the vanes 2 is connected. The strap rings 3 and 4 may be provided only on one end side of the vane 2 in the axial direction, or may be provided on both axial end portions of the vane 2 as shown in FIG. It is common to connect separate vanes with two strap rings. With this structure,
An even number of small cavities 5 surrounded by the two vanes 2 and the peripheral wall of the anode cylinder 1 are formed, and the whole thereof forms a resonance cavity of the magnetron. Since the magnetron normally oscillates in the π mode, each small cavity 5 oscillates with a phase shift of π radian. Therefore, in order to stabilize the oscillation of the magnetron, every other vane is connected by the small-diameter and large-diameter strap rings 3 and 4 so as to have the same potential.

A pair of magnetic pole pieces (not shown) are arranged at both open ends of the anode cylinder 1, and on the central axis of the anode cylinder 1.
Not shown so as to form a quadrature electrostatic magnetic field together with a high voltage applied to the working space between the vane 2 and a cathode (not shown) disposed in a portion facing the tip 2a of the vane 2. A magnetic field is formed by the magnet.

Oxygen-free copper, which has good heat conduction and electric conduction and emits little gas, is generally used as a material forming the anode body of the magnetron having such a structure, but it is provided near the cathode. The attached strap rings 3 and 4 are likely to become hot, and the strap rings 3 and 4 made of oxygen-free copper are liable to be bent or bent due to repeated high thermal stress. May lead to fracture. Therefore, as a material for a strap ring that can withstand high temperatures, for example, Japanese Patent Laid-Open No. 63-1
As described in Japanese Patent No. 43722, it has been proposed to use a precipitation hardening metal with zirconium added to improve mechanical strength.

However, even if the strength of the strap ring becomes strong, the vane to which the strap ring is fixed may be pulled and may break at the portion indicated by the broken line B in FIG. That is, the radiant heat generated from the cathode (not shown) and the heat generated by the collision of electrons at the axial center end of the vane are conducted from the axial center end of the vane to the anode cylinder 1 side, and the anode cylinder 1 Heat is dissipated on the outer wall of. On this occasion,
Thermal stress is generated at the joint between the vane 2 and the small diameter strap ring 3. On the other hand, conventionally, in the groove for brazing the small diameter strap ring of the vane, the joint portion of the small diameter strap ring is formed in a step shape, and the step height is generally 0.
It is 5 to 1.5 mm. Therefore, when a thermal stress is applied to the joint, the strap ring pulls the vane and the vane breaks.

[0007]

As the conventional magnetron is repeatedly turned on and off, thermal stress is applied to the vicinity of the joint between the vane 2 and the small diameter strap ring 3 as described above, and the vane breaks. There is a problem that it will not work properly.

An object of the present invention is to provide a magnetron anode body which solves such problems, suppresses vane breakage, and has high reliability even after long-term use.

[0009]

A magnetron anode body according to the present invention comprises an anode cylinder, a plurality of vanes radially arranged on the inner peripheral surface of the anode cylinder, and an electric wire for every other vane. A magnetron anode body comprising a large diameter strap ring and a small diameter strap ring connected to
The small-diameter strap ring is fixed in a cut groove formed in the vane.

[0010]

According to the present invention, since the inner small-diameter strap ring is fixed in the cut groove formed in the vane,
The joint area between the vane and the small-diameter strap ring becomes large, the thermal stress that is a force per unit area generated between the vane and the small strap ring can be reduced, and the vane can be prevented from breaking.

That is, the brazing between the vane and the strap ring is performed by silver brazing or the like, and the vicinity of the brazed portion is mechanically weakened. However, according to the present invention, the thickness of the small diameter strap ring is increased. Then, since a part thereof is embedded in the notch groove provided in the vane and brazed, the brazing area greatly increases, and the force acting per unit area becomes extremely small. Moreover, since the strap ring is partially embedded in the cut groove, the deformation of the small diameter strap ring itself is suppressed, and the force for pulling the vane itself is weakened. As a result, breakage of the vane can be suppressed.

[0012]

The present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional explanatory view showing a vane and a strap ring portion of an embodiment of the magnetron anode body of the present invention. In FIG. 1, reference numerals 1 to 4 indicate the same parts as in FIG.

Similar to the structure shown in FIG. 2, the structure of the magnetron anode of this embodiment is such that a plurality of vanes 2 are radially brazed at the root of the inner peripheral surface of the anode cylinder 1, and A small-diameter strap ring 3 and a large-diameter strap ring 4 that connect every other vane 2 are brazed in the strap-ring groove provided in the vane. The one vane portion is shown in FIG.

According to the present invention, in the vane 2, the strap rings 3 and 4 are brazed or penetrated, and a notch groove 7 is further formed at the bottom of the groove of the small-diameter strap ring 3 part of the groove part 6, and in the notch groove 7. It is characterized in that a part of the small diameter strap ring 3 is embedded and brazed.

The depth L of the cut groove 7 is usually about 0.1 to 1 mm, preferably about 0.5 mm. If it is too deep, the thickness H of the small-diameter strap ring must be increased, which makes it difficult to process the strap ring, wastes material, and weakens the strength of the vane by forming a deep notch in the vane 2. It is not preferable. Further, if the cut groove 7 is too shallow, the purpose of increasing the joint area and preventing damage to the vane cannot be achieved. The width of the cut groove 7 is about the same as the width M of the strap ring, and is usually formed to be about 0.5 to 1 mm.

Further, since the small-diameter strap ring 3 is partially embedded in the cut groove 7, the height H thereof is 1.5 to 2.
It will be about 5 mm. As a result, in the brazed portion, the entire side wall of the small diameter strap ring 3 is brazed, and further,
Since the brazing is performed in the cut groove 7, the joining area is increased by about 1.5 times as compared with the conventional case where the height N of the strap ring is about 1 to 1.5 mm.

Therefore, even if thermal stress is generated in the brazing portion between the small diameter strap ring 3 and the vane 2 where the temperature difference becomes particularly large when the magnetron is turned on and off, the area of the brazing portion is large, so that the unit area per unit area is large. The power becomes smaller. Moreover, since a part of the small diameter strap ring 3 is embedded in the cut groove 7, the deformation of the small diameter strap ring 3 due to the thermal stress is suppressed, and the force for pulling the vane 2 due to the deformation of the small diameter strap ring 3 is also significantly suppressed. It As a result, the vane 2 can be prevented from breaking or deforming.

Further, the strap ring groove 6 provided in the vane 2 is formed to be a deep groove 2 in order to escape the strap ring 3 having a high height in a portion where the small diameter strap ring 3 is not brazed. . Therefore, the inductance of the vane 2 and the strap rings 3 and 4 and the electrostatic capacitance between the vane and the strap rings 3 and 4 change, and the resonance frequency of the resonance cavity shifts. The resonance frequency can be adjusted by reducing the height.

[0019]

According to the present invention, a notch groove is formed in the joint portion of a vane and a small-diameter strap ring, which are easily broken during operation under high power, so as to increase a joint area, and a small-diameter groove is formed in the notch groove. Since a part of the strap ring is buried and brazed, it is possible to obtain a magnetron having a high reliability and a high reliability even with a high output of the magnetron, with a simple structure and at a low cost.

[Brief description of drawings]

FIG. 1 is a partially enlarged sectional view of an embodiment of a magnetron anode body of the present invention.

2A and 2B are explanatory views of a magnetron anode body, FIG. 2A is a plan view, and FIG. 2B is a partially enlarged sectional view of FIG. 2A.

[Explanation of symbols]

 1 Anode cylinder 2 Bain 3 Small strap ring 4 Large strap ring

Claims (1)

[Claims] 1. An anode cylinder, a plurality of vanes radially arranged on an inner peripheral surface of the anode cylinder, and a large-diameter strap ring and a small-diameter strap ring electrically connecting every other vane. A magnetron anode body comprising the small diameter strap ring fixed in a groove provided in the vane.