JPH06215701A - Anode of magnetron and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide an anode of a magnetron, with which the strength of the mechanical connection of an anode vane as well as an anode cylinder is increased, and which can maintain the heat conductivity under a good condition, and to provide a manufacturing method of the anode of the magnetron. CONSTITUTION:An anode cylinder 21, and a plurality of anode wanes 22, the outer end parts of which are welded and connected to the inner circumferential wall of the anode cylinder 21, are provided, and a tamping bead 23 is formed in the axial direction, being in contact with the outer end part of the vane 22, on the inner circumferential wall of the anode cylinder 21. In the anode of a magnetron, the anode vane 22, the anode cylinder 21, and the tamping bead 23 are welded and connected to one another, in an integrated manner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetron anode and a method for manufacturing the same.

[0002]

2. Description of the Related Art For example, in a magnetron used in a microwave oven, as is well known, a microwave generated in a cavity resonator formed in an anode is taken out of a magnetron by an output antenna and guided. It is a key component that guides food into a microwave oven by means of a wave tube. The magnetron anode is constructed as shown in FIG. 13, and the outer end portions of, for example, ten anodic vanes 22 are joined to the inner peripheral wall of a copper anodic cylinder 21. -The cylinders 21 are radially arranged in the direction of the cathode on the central axis (not shown). In addition, in FIG.
A sheet is shown as a representative. Each anodic vane 22 has a pair of strap rings (not shown) formed in the upper and lower slits 2.
It is fitted in the position of 2a and is connected to every other. An output antenna lead is connected to the remaining slit 22b. A radiator (not shown) is press-fitted to the outer circumference of the anode cylinder 21 so that the heat generated at the tip of the anode vane during operation is radiated from the radiator via the anode cylinder.

In view of the operating characteristics of the magnetron,
Regarding the reliability of the joint between the cylinder and the vane, the following 2
It is necessary to consider the points. First, in order to obtain good oscillation characteristics, the mechanical bond strength between the anodic cylinder and the anodic vanes should be sufficient, and the intervals between the tips of all vanes and the cathode (not shown), It is necessary to assemble the vane tips with equal intervals. Secondly, in order to keep the temperature of the anodic vanes low, it is necessary to improve the thermal conductivity between the anodic cylinder and the anodic vanes and enhance the heat radiation effect.

[0004] A brazing method using a brazing material such as silver brazing and a hydrogen furnace for brazing has been conventionally used for joining the anodic cylinder and the anodic vane. Recently, for the purpose of energy saving by abolishing expensive brazing material and brazing equipment, it is desired to perform laser welding instead of brazing. To solve such a problem, one of the inventors of the present invention invented laser welding so that 20 to 90% of the total area of the end face of the anodic vane to be joined to the anodic cylinder remains as a non-melted portion. . It is JP-A-3-
This is disclosed in Japanese Patent Publication No. 98242.

In this method, as shown in FIG. 14 (a), the vane 22 is pressed against the inner circumference of the anodic cylinder 21 as shown by the arrow F while the laser beam L is obliquely irradiated from the outside. It is moved in the axial direction as indicated by arrow P. At that time, an inert gas such as argon is blown onto the surface to be welded from the irradiation direction of the laser beam. Thus, the fusion zone 31
Weld both by. Incidentally, FIG. 14 (b) is a partial cross-sectional view taken along line 13b-13b of FIG. 14 (a), and FIG. 14 (c) shows the fusion zone 31 on the outer end face of the vane.

[0006]

However, the invention disclosed in the above publication includes points to be further improved. That is, as shown in FIG. 14, when the range of the melted portion 31 of the anodic vane outer end face 22c to be joined to the anodic cylinder 21 is small, the thermal conductivity becomes small and the heat radiation effect becomes poor. In addition, the mechanical welding strength becomes weak. on the other hand,
If the range of the fusion zone is too large as shown in FIG.
5 (b) and (c), indicated by reference numeral 32, has a welding defect such as a hole due to the penetration of the laser beam or a melted portion as shown by a dotted line. Further, when the entire area of the outer end surface of the vane becomes the fusion zone, the dimensional position of the vane is changed due to the pressing force when welding the vane from the inner side to the outer side as shown by the arrow F or the shrinkage during cooling of the fusion zone. As a result, good oscillation characteristics cannot be obtained. To prevent this, the non-welded portion 33 must be provided as a contraction stopper. As described above, when an attempt is made to expand the range of the fusion zone in consideration of the mechanical strength and the heat radiation effect, there is a disadvantage that a welding defect or a dimensional change due to shrinkage occurs.

[0007] Since the anodic vane is manufactured by punching a copper plate by a press, the outer end surface becomes almost right angle.
On the other hand, since the anode cylinder is a cylinder, when the two are positioned, a gap 34 is formed in the axial direction as shown in FIG. 16 (a). Since there is a gap 34 between the anodic cylinder 21 and the anodic vane 22, a blower 35 as shown in FIG. 7B is likely to occur in laser welding.
The blower 35 is a void defect, and the inside thereof is filled with the inert gas blown during the laser welding, and there is a disadvantage that the blowout region gradually enters the vacuum region after the completion of the anode. Alternatively, it may cause a crack in the fusion zone 31. The existence of the gap between the anodic cylinder and the anodic vane causes the blow-35 during welding.

The present invention has been made in view of the above circumstances, and does not cause a dimensional change due to welding defects or shrinkage, expands the penetration range as compared with the prior art, has a strong mechanical bonding strength, and has a good heat dissipation effect. -The purpose of the present invention is to provide a cord and a manufacturing method thereof.

[0009]

However, the invention disclosed in the above publication includes points to be further improved. That is, in order to achieve the object, the anode of the magnetron of the first invention has a projecting bead formed along the axial direction on the inner peripheral wall of the anode cylinder in contact with the outer end of the anode vane. , An anode vane, which is welded to an anode cylinder and a projecting bead, and is a magnetron anode.

The second aspect of the present invention is the projecting beam of the first aspect of the invention.
It is an anode of a magnetron characterized in that the vanes are mechanically fixed by the projecting beads by caulking the blades. In a third aspect of the invention, when the outer end portion of the anode cylinder is welded to the inner peripheral wall of the anode cylinder by a laser beam radiated from the outside of the anode cylinder, the inner peripheral wall of the anode cylinder is welded in advance. A long protruding bead is formed in the axial direction adjacent to the position of the anodic vane, and the anodic vane is arranged so as to be partially adjacent to the protruding bead, and the anodic vane corresponding to the position of the anodic vane is formed. A method of manufacturing an anode of a magnetron, characterized by irradiating a laser beam from the outside of the cylinder to melt and join the portions where the anode cylinder, anode vane and projecting beads are in contact with each other. Is. A fourth aspect of the invention is an anode at a position where the outer end portion of the anodic vane is in contact when forming the projecting bead of the third aspect of the invention.
This is a method of manufacturing an anode of a magnetron, characterized in that the inner surface of the cylinder is flattened.

[0011]

According to the first and second aspects of the invention, since the anodic vanes are welded to both the anodic cylinder and the projecting bead, the penetration range is wide and, as a result, the mechanical joining strength is increased. However, good thermal conductivity is maintained and reliability is improved.

According to the third and fourth aspects of the invention, since the outer end of the vane is positioned in contact with the projecting bead, the assembly is easy and the precision is high. Further, even if the irradiation intensity of the laser is increased, the melted range is less likely to be expanded further in the lateral direction of the projecting bead, and there is no risk of perforation or melt start. Thus, the reliability of the welded parts of the anode vane and the anode cylinder is improved.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. The same parts are designated by the same reference numerals. Example 1

The anode of the magnetron according to the present invention is constructed as shown in FIGS. That is, the completed anode is the anode cylinder 21 as shown in FIG.
The outer peripheral portions of, for example, 10 anodic vanes 22 are joined to the inner peripheral wall of the anodic vanes 22, and these anodic vanes 22 are radially arranged toward a cathode (not shown) on the central axis. In the drawings and the following description, one anode vane is shown as a representative. A projecting bead 23, an anode cylinder 21, and an anode provided adjacent to the anode vane.
The parts of the dovein 22 that are in contact with each other are fusion-bonded.

Next, the manufacturing method will be described. First, as shown in FIG. 2, approximately half of the wall thickness is inwardly projected from the outside of the anodic cylinder 21 made of copper by a punch so that the height h of the anodic vane 22 is almost equal to the inner peripheral wall. A pair of projecting beads 23 are provided in the axial direction. At this time, the projecting beads 23 may be larger or slightly smaller than the height h of the anodic vanes 22, but it is preferable that the contact area is large in consideration of enlarging the welded portion.
Further, the shape of the projecting bead is not limited to the rectangular parallelepiped as shown in the drawing, but may be a bead whose one surface is in contact with the vane and whose cross section is triangular, for example. Next, as shown in FIG. 2, the anodic vane 22 is inserted between the pair of projecting beads as shown by the arrow, and the outer end surface is brought into close contact with the inner surfaces of the anode cylinder 21 and the projecting beat 23. Thereafter, as shown in FIGS. 3 and 4, while pressing the anode vane 22 in the direction of the anode cylinder as indicated by arrow F, the laser beam L is slanted from the outside of the anode cylinder 21 so as to correspond to the position of the anode vane 22. It is irradiated from the direction and moved as indicated by an arrow P to weld and join. Similarly, a total of 10 anodic vanes 22 are radially laser-welded to the inner peripheral wall of the anodic cylinder 21. At this time, the non-melting portions 33 as stoppers for the movement or contraction of the vane during melting and cooling are left at both ends in the axial direction of the vane. As shown in FIG. 5, the melting state of the projecting beads on the outer surface of the vane and the plane along the outer surface of the vane is about a half or more of the lateral width of the projecting beads 23 on the entire surface except the non-melting portion 33 of the vane and on both sides. It is melted and joined. As a result, the anode cylinder and the vane are laser-welded in a wide area including a part of the projecting bead to complete a reliable magnetron anode. Example 2

The embodiment 1 is characterized in that the laser beam L is applied to the two places and welded at the time of melting as shown in FIG. In this case, the non-melted portion 33 extending in the axial direction is left at the center of the outer end surface of the vane to prevent the vane from moving or deforming. Third Embodiment A feature of the first embodiment is that a U-shaped protruding bead and a caulking bead are provided on the protruding bead.

In the manufacturing method, first, when the projecting beads are provided,
As shown in FIG. 7, a punch bead 23 is provided in a U shape by a punch. Next, an anode vane is installed as shown in FIG. At this time, all of the vanes 22 are inserted from the upper side of the drawing into the inside of the U-shaped projecting beads 23 and positioned. The vane comes into contact with the connecting portion 23a of the projecting bead, and the axial position thereof is determined. Next, as shown in FIG. 9, both ends of the projecting bead 23 in the axial direction are crushed from both sides to provide caulking 24 to mechanically fix the anodic vane 22. Then, as shown in FIG. 10, welding is performed by the laser beam L. In this case, a part of the connecting portion 23a of the projecting bead is also melted to form the melted portion 31, whereby a joint portion having a wider melted region can be obtained. Since the caulking 24 remains unmelted and serves as a stopper for shrinkage due to movement of the vane before and after welding and cooling of the melted portion, there is almost no unmelted portion at the center of the outer end surface of the vane. It is possible to obtain a magnetron anode having good thermal conductivity and increased mechanical bonding strength. Further, since the anodic vanes are fixed by the caulking 24, it is not necessary to press the vanes from the inside during welding. Further, since the anode vane can be installed from the upper side by providing the U-shaped projecting bead 23, the installation of the anode vane can be performed accurately and easily. In this embodiment, the U-shaped protruding bead 2
3 and the caulking 24 are used together, but they may be used individually. Example 4

In the first embodiment, when the protruding beads are provided on the anode cylinder, the flat central protruding portion 25 as shown in FIG.
Using an inner jig 26 having the above, a punch 27 is used to protrude from the outside as shown by an arrow S. As a result, as shown in FIG. 12, a joined surface 28 in which the outer end surface of the anode vane and the inner surface of the anode cylinder are in close contact with each other with a flat surface is obtained. Thus, by laser welding, as shown in FIG.
It is possible to reliably prevent the formation of the blow-35 as shown in (b). By flattening the joint surface in this manner, it is possible to eliminate the gap as shown in FIG. 16 (a), prevent the generation of blowers, and obtain a magnetron anode with high reliability.

[0019]

As described above, according to the present invention, a projecting bead is formed on the inner peripheral wall of the anodic cylinder in contact with the outer end of the anodic vane along the axial direction. Since the anode cylinder and the anode vanes including a part of the bead are welded and joined, the melting range is expanded. As a result, it is possible to obtain a highly reliable magnetron in which mechanical strength and thermal conductivity are kept good.

[Brief description of drawings]

FIG. 1 is a perspective view showing an anode of a magnetron according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a state during assembly of the embodiment shown in FIG.

FIG. 3 is a longitudinal sectional view showing a state of laser welding of the embodiment shown in FIG.

4 is a transverse sectional view taken along line 4-4 of FIG.

5 is a perspective view showing a melting portion of the anodic vanes and the projecting beads of FIG.

FIG. 6 is a cross-sectional view showing a main part according to another embodiment of the present invention.

FIG. 7 is a perspective view of a main part during assembly according to still another embodiment of the present invention.

8 is a perspective view showing the next assembled state of FIG. 7. FIG.

FIG. 9 is a perspective view showing the next assembled state of FIG. 8;

FIG. 10 is a vertical sectional view showing a state of laser welding in the next assembling step of FIG.

FIG. 11 is a cross-sectional view of a main part showing an assembled state of still another embodiment of the present invention.

FIG. 12 is a lateral cross-sectional view of a main part showing the next assembled state of FIG. 11.

FIG. 13 is a perspective view of a main part showing a conventional magnetron anode.

14 is a sectional view and a perspective view showing the assembled state of FIG.

FIG. 15 is a sectional view and a perspective view showing an assembled state of a conventional anode.

FIG. 16 is a cross-sectional view showing an assembled state in a conventional anode.

[Explanation of symbols]

 21 ... Anode cylinder 22 ... Anode vane 23 ... Projection bead 24 ... Caulking 31 ... Melting part

Claims (4)

[Claims] 1. An anode of a magnetron, comprising: an anode cylinder; and a plurality of anode vanes whose outer ends are welded to an inner peripheral wall of the anode cylinder. A peripheral bead is in contact with the outer end of the anodic vane and a protruding bead is formed along the axial direction. The anodic vane is welded to the anodic cylinder and the protruding bead. The magnetron's anode. 2. The projecting beads are formed on both sides of the outer end of the anodic vane, and the portions of both projecting beads contacting the axial ends of the anodic vanes are caulked to mechanically interact with each other. The magnetron anode according to claim 1, which is bound to
De. 3. A method of manufacturing an anode of a magnetron, wherein an outer end of an anode vane is welded to an inner peripheral wall of the anode cylinder by a laser beam irradiated from the outside of the anode cylinder. An axially long protrusion bead is formed adjacent to the position of the anode vane to be welded to the inner peripheral wall of the anode cylinder, and then the anode vane is partially adjoined to the protrusion bead. And irradiating a laser beam from the outside of the anode cylinder corresponding to the position of the anode vane so that the anode cylinder, the anode vane and the projecting bead contact each other. A method for manufacturing an anode of a magnetron, which comprises melting and joining the above. 4. A method of manufacturing an anode of a magnetron according to claim 3, wherein the inner surface of the anodic cylinder at the position where the outer end of the anodic vane contacts is flattened when the projecting beads are formed.