JP3995509B2 - Magnetron and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a magnetron used in a microwave oven, a microwave heating device, or the like, and more specifically, at the same time as preventing fatigue fracture of a brazed portion between an anode strap ring and an anode plate and extending the life. The present invention relates to an improvement for realizing an improvement in productivity.
[0002]
[Prior art]
  10 and 11 show a conventional magnetron anode used in a microwave oven, a microwave heating apparatus, or the like.
  As shown in the figure, the anode 1 includes a cylindrical anode body 3 through which a cathode (not shown) is inserted on a central axis, magnets (not shown) provided at both upper and lower ends of the anode body 3, and the anode. An even number of anode plates (also referred to as vanes) 7a, 7b, which are radially provided on the inner peripheral surface of the main body 3 toward the central axis. 7c, ... and even number of anode plates 7a, 7b. A configuration comprising two strap rings 11 and 12 having the tip ends of 7c,... Connected to the same potential, and an antenna 15 connected to one of the anode plates for leading high frequency energy to the outside. It is.
[0003]
  Ring insertion holes 14 and 15 through which the two strap rings 11 and 12 are inserted are formed through the tip portions of the anode plates 7a, 7b, 7c,.
  Each of the strap rings 11 and 12 has a C-ring shape obtained by bending a rod-shaped member having a predetermined length into an annular shape having a predetermined diameter.
[0004]
  One strap ring 11 is inserted into the ring insertion hole 14 of each anode plate 7a, 7b, 7c,... And then the opening of the ring insertion hole 14 is opened with respect to the even-numbered anode plates 7b, 7d, 7f,. The edges are electrically and mechanically joined by brazing with a high melting point brazing material (for example, silver brazing). Therefore, the ring insertion holes 14 formed in the even-numbered anode plates 7b, 7d, 7f,... Are connected to the outer peripheral surface of the strap ring 11 to be inserted and the inner peripheral surface of the hole in order to braze the strap ring 11 to be inserted. The inner diameter is set so that the gap between the two becomes smaller. Further, as shown in FIG. 11, the ring insertion holes 14 formed in the odd-numbered anode plates 7a, 7c, 7e,... Have an inner diameter of the even-numbered anode so that the strap ring 11 to be inserted is not in contact. It is set larger than the ring insertion hole 14 formed in the plates 7b, 7d, 7f,.
[0005]
  The other strap ring 12 is inserted into the ring insertion hole 15 of each anode plate 7a, 7b, 7c,..., And then opened to the odd-numbered anode plates 7a, 7c, 7e,. The edge is electrically and mechanically joined by brazing with a high melting point brazing material. Therefore, the ring insertion hole 15 formed in the odd-numbered anode plates 7a, 7c, 7e,... Has an outer peripheral surface of the strap ring 12 to be inserted and an inner peripheral surface of the hole to braze the strap ring 12 to be inserted. The inner diameter is set so that the gap between the two becomes smaller. Further, as shown in FIG. 11, the ring insertion holes 15 formed in the even-numbered anode plates 7b, 7d, 7f,... Have an inner diameter of the odd-numbered anode so that the strap ring 12 to be inserted is not in contact. It is set larger than the ring insertion hole 15 formed in the plates 7a, 7c, 7e,.
[0006]
  That is, the odd-numbered anode plates 7a, 7c, 7e,... Are connected to each other at the same potential via the strap ring 11 connected by brazing. On the other hand, the even-numbered anode plates 7b, 7d, 7f,... Are connected to each other at the same potential via the strap ring 12 connected by brazing.
[0007]
  The opposite ends of the strap ring 11 and the strap ring 12 are connected to each other by brazing with a high melting point brazing material as shown in FIG. In FIG. 12A, a portion indicated by reference numeral 18 is a brazing portion made of a high melting point brazing material.
  Further, the joining of the strap rings 11 and 12 and the anode plates 7a, 7b, 7c,... By brazing is performed on all the rod-like members constituting the strap rings 11 and 12, as shown in FIG. The periphery is brazed with a high melting point brazing material. In FIG. 12A, a portion indicated by reference numeral 19 is a brazing portion made of a high melting point brazing material.
[0008]
  The brazing portions 18 at the ends of the strap rings 11 and 12 are usually positioned in the ring insertion holes 14 and 15 for brazing the strap rings 11 and 12, as shown in FIG. Thus, the joint strength is improved by brazing.
[0009]
[Problems to be solved by the invention]
  By the way, since the strap rings 11 and 12 and the anode plates 7a, 7b, 7c,... Described above are also conductors constituting the LC circuit, it is preferable to use a metal having excellent electrical conductivity. Has been used of 99.96% or more oxygen-free copper.
  However, oxygen-free copper has not only high electrical conductivity, but also good thermal conductivity, low physical resistance, and high thermal expansion coefficient.
[0010]
  Therefore, in the conventional magnetron in which the strap rings 11 and 12 and the anode plates 7a, 7b, 7c,... Are made of oxygen-free copper, the anode plates 7a, 7b, 7c,. Since the thermal expansion coefficient is large, the anode plates 7a, 7b, 7c,...
  When the anode plates 7a, 7b, 7c,... Are thermally expanded greatly, the strap rings 11, 12 joined to the anode plates 7a, 7b, 7c,..., And the strap rings 11, 12 and the anode plates 7a, 7b,. A large load such as a bending load or a shearing load is applied to the brazing portion 19 with 7c,. Then, repeated thermal expansion and contraction of the anode plates 7a, 7b, 7c,... Causes a fracture (crack) 21 due to fatigue failure in the brazed portion 19 as shown in FIG. There was a problem of lowering.
[0011]
  Note that the breakage of the brazing portions 18 and 19 leads to a decrease in the capacitance of the LC circuit composed of the anode body 3 and the anode plates 7a, 7b, 7c,. As a result, a malfunction occurs due to an abnormal oscillation frequency as a magnetron.
[0012]
  Furthermore, in recent years, there is a strong market demand for higher output of magnetrons.
  Increasing the output of the magnetron can be achieved by increasing the DC electric field applied between the cathode and the anode constituting the magnetron, or by increasing the magnetic field applied in the direction orthogonal to the DC electric field.
[0013]
  However, the enhancement of the DC electric field is accompanied by an increase in the amount of heat released from the cathode. When the anode plates 7a, 7b, 7c,. There is a possibility that inconveniences such as softening due to excessive temperature rise may occur. And in order to prevent the excessive temperature rise of an anode plate, if the cooling fin is enlarged so that the cooling performance by the cooling fin attached to the outer periphery of an anode may be improved, the problem that magnetron itself will enlarge will arise.
  On the other hand, the magnetic field can be increased by replacing the magnets attached to the magnetic poles at both ends of the anode with larger magnets. However, in this case as well, the magnetron itself becomes larger due to the large magnets. There was a problem that.
[0014]
  In addition, since the strap ring must be sequentially inserted through the ring insertion holes of each anode plate, there is a problem that the assemblability is poor and the productivity of the magnetron cannot be improved.
[0015]
  The present invention has been made in view of the above-described problems, and its purpose is to suppress fatigue fracture of the brazed portion between the anode strap ring and the anode plate, thereby extending the life, It is an object of the present invention to provide a magnetron that can realize downsizing and high output and can improve productivity.
[0016]
[Means for Solving the Problems]
  In order to achieve the above object, a magnetron according to the present invention comprises an even number of anode plates (vanes) radially provided toward the central axis on at least an inner peripheral surface of an anode body. In a magnetron provided with a strap ring that connects the tips of the even number of anode plates to the same potential every other piece,
  The anode plate is composed of a tip portion located on the cathode side and a main body portion excluding the tip portion, and the tip portion is formed of another metal material having higher heat resistance than the main body portion.And provided with a ring insertion hole through which the strap ring is inserted so as to straddle the main body and the tip of the anode plate.It is characterized by that.
[0017]
  During operation of the magnetron, the anode plate mounted on the anode is heated by receiving heat from the cathode.
  The temperature increase mechanism of the anode plate is that the tip of the anode plate located on the cathode side receives heat from the cathode, and the temperature of the main body rises by heat transfer according to the heat conduction characteristics of the tip. Become.
[0018]
  However, the tip portion is formed of another metal material that has better heat resistance than the main body portion, and suppresses heat conduction to the main body portion. Therefore, the tip part can suppress the temperature rise of the main body part and suppress the thermal expansion and thermal contraction of the anode plate, and the thermal expansion and thermal contraction of the anode plate can cause the brazed part between the anode plate and the strap ring. Reduce the acting load.
[0019]
  And the ring insertion hole is a completed form as an insertion hole by matching the ring insertion grooves formed on the respective abutting surfaces of the main body part and the tip part, and before the tip part is joined to the main body part If it is a stage, a strap ring can be easily assembled | attached to an anode plate by abutting a main-body part and a front-end | tip part in the state which positioned the strap ring in the ring insertion groove of the main-body part.
0020]
  In order to achieve the above object, the magnetron according to claim 2 is the magnetron according to claim 1, further comprising a body portion of the anode plate made of oxygen-free copper, and a tip portion of the anode plate. Is formed of a high heat-resistant metal containing a nickel component.
0021]
  As a highly heat-resistant metal containing a nickel component, for example, a copper / nickel alloy (Cypro) synthesized with nickel and copper in a ratio of 30:70 has a softening start temperature of 550 to 600 ° C. and a thermal conductivity of 29 W / ( m · K), the coefficient of thermal expansion is 16.2 (× 10 −6 / ° K), the melting point is 1170 ° C., and the electric conductivity is 4.6 (% IACS).
  In the case of oxygen-free copper, the softening start temperature is 200 to 220 ° C., the thermal conductivity is 391 W / (m · K), the thermal expansion coefficient is 17.7 (× 10 −6 / ° K), the melting point is 1083 ° C., The electrical conductivity is 101 (% IACS).
0022]
  That is, the copper / nickel alloy has a lower electrical conductivity than oxygen-free copper, but has a remarkably high heat resistance and a low thermal conductivity, and is therefore suitable for preventing temperature rise of the main body.
  Therefore, compared with the conventional case where the entire anode plate is made of oxygen-free copper, the thermal expansion and thermal shrinkage of the anode plate is suppressed, and the fatigue of the brazed portion caused by repeated thermal expansion and thermal shrinkage of the anode plate is suppressed. It is possible to suppress the destruction and realize a long life.
  In addition, since nickel is a magnetic material, the nickel component contained in the tip portion acts to reduce the strength difference between the magnetic field strengths of the magnets assembled above and below the anode.
0023]
  In order to achieve the above object, a method for manufacturing a magnetron according to the present invention comprises:3As described in the above, at least the even number of anode plates that are radially provided toward the central axis on the inner peripheral surface of the anode body and the strap ring that connects the tips of the even number of anode plates every other piece to the same potential In a method of manufacturing a magnetron comprising:
  The anode plate is composed of a front end portion located on the cathode side and a main body portion excluding the front end portion, and the main body portion of the ring insertion groove formed on each abutment surface of the main body portion and the front end portion. The tip end portion is joined to the main body portion with the strap ring positioned in the ring insertion groove.
0024]
  Since the strap ring is inserted through the anode plate by joining the tip to the main body, the troublesome work of penetrating the conventional strap ring through the hole in the anode plate can be omitted. Assemblability is improved and magnetron productivity can be improved.
0025]
DETAILED DESCRIPTION OF THE INVENTION
  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a magnetron according to the present invention will be described in detail based on the drawings.
  FIG. 1 is a longitudinal sectional view of a first embodiment of a magnetron according to the present invention.
  The magnetron 31 according to the first embodiment is used for, for example, an industrial microwave heating apparatus or the like, and is inserted through an anode 33 whose inside is a working space 32 and a central axis of the anode 33. A cathode 35, an antenna cylinder 37 that is assembled to the upper portion of the anode 33 and serves as a high-frequency energy emitting portion, a body case 39 that accommodates the anode 33, and an anode that is stretched between the anode 33 and the body case 39 It is comprised with the cooling fin 41 which escapes 33 heat_generation | fever to the exterior.
0026]
  The anode 33 has a cylindrical anode body 51 through which a cathode 35 is inserted on a central axis, magnetic poles 52 and 53 provided at both upper and lower ends of the anode body 51, and an inner peripheral surface of the anode body 51. An even number (10 in this example) of anode plates 55a, 55b, 55c,..., Which are radially provided toward the central axis, and the tip portions of the anode plates 55a, 55b, 55c,. Two strap rings 57 and 58 connected to the electric potential, and an antenna 61 connected to one anode plate 55a in order to extract high frequency energy to the outside.
  Magnets 62 and 63 for guiding magnetic flux to the working space 32 are provided on the outer surfaces of the upper and lower magnetic poles 52 and 53.
0027]
  As shown in FIGS. 4 and 5, the anode plates 55 a, 55 b, 55 c,... Of the present embodiment are composed of a tip portion 75 located on the cathode 35 side and a main body portion 76 excluding the tip portion 75. The tip 75 is made of another metal material that has better heat resistance than the metal material forming the main body 76.
  Specifically, the main body portion 76 of the anode plates 55a, 55b, 55c,... Is formed of oxygen-free copper having a purity of 99.96%, and the tip portion 75 is a high heat resistance obtained by synthesizing nickel and copper in a ratio of 30:70. It is made of a copper / nickel alloy.
  The distal end portion 75 is joined and integrated with the distal end surface of the main body portion 76 by a high melting point brazing material such as silver brazing.
0028]
  Ring insertion holes 65 and 66 through which the two strap rings 57 and 58 are inserted are formed through the anode plate 55a, 55b, 55c,.
  Each of the strap rings 57 and 58 is formed by inserting a linear bar member having a predetermined length into the ring insertion holes 65 and 66 of all the anode plates 55a, 55b, 55c,. It is ring-shaped. As shown in FIG. 2, small gaps S1 and S2 remain between the opposing ends of the strap rings 57 and 58.
0029]
  One strap ring 57 is inserted into the ring insertion holes 65 of all the anode plates 55a, 55b, 55c,..., And is bent into a C-ring shape, and then the odd-numbered anode plates 55a, 55c, 55e,. Thus, the opening edge of the ring insertion hole 65 is electrically and mechanically joined by brazing with a high melting point brazing material (for example, silver brazing).
  Therefore, the ring insertion holes 65 formed in the odd-numbered anode plates 55a, 55c, 55e,... Are connected to the outer peripheral surface of the strap ring 57 to be inserted and the inner peripheral surface of the hole in order to braze the strap ring 57 to be inserted. The inner diameter is set so that the gap between the two becomes smaller.
  2 and 3, the ring insertion hole 65 formed in the even-numbered anode plates 55b, 55d, 55f,... Has an odd inner diameter so that the strap ring 57 to be inserted is not in contact. It is set larger than the ring insertion hole 65 formed in the second anode plates 55a, 55c, 55e,.
0030]
  The other strap ring 58 is inserted into the ring insertion holes 66 of all of the anode plates 55a, 55b, 55c,... And is bent into a C-ring shape, and then the even-numbered anode plates 55b, 55d, 55f,. Thus, the opening insertion edge of the ring insertion hole 66 is electrically and mechanically joined by brazing with a high melting point brazing material.
  Therefore, the ring insertion holes 66 formed in the even-numbered anode plates 55b, 55d, 55f,... Are connected to the outer peripheral surface of the strap ring 58 to be inserted and the inner peripheral surface of the hole in order to braze the strap ring 58 to be inserted. The inner diameter is set so that the gap between the two becomes smaller.
  2 and 3, the ring insertion holes 66 formed in the odd-numbered anode plates 55a, 55c, 55e,... Have an inner diameter that is even so that the strap ring 58 to be inserted is not in contact. It is set larger than the ring insertion hole 66 formed in the second anode plates 55b, 55d, 55f,.
0031]
  That is, the odd-numbered anode plates 55a, 55c, 55e,... Are connected to each other at the same potential via the strap ring 57 connected by brazing. On the other hand, the even-numbered anode plates 55b, 55d, 55f,... Are connected to each other at the same potential via a strap ring 58 connected by brazing.
0032]
  As shown in FIG. 3, both end portions of the strap rings 57 and 58 are opposed to each other in the ring insertion holes 65 and 66 of the anode plate to be brazed, and the opposite end surfaces are brazed with a high melting point brazing material. It is connected by attaching to finish a continuous ring, and at the same time, the bonding strength with the anode plate is improved.
0033]
  In the magnetron 31 configured as described above, during operation, the anode plates 55a, 55b, 55c,... Equipped in the anode 33 are heated by receiving heat from the cathode 35.
  As described above, the heating mechanism of the anode plates 55a, 55b, 55c,... Receives the heat radiation of the cathode 35 by the tip portion 75 of the anode plate located on the cathode 35 side, and heats the tip portion 75. The main body 76 is heated by heat transfer according to the conduction characteristics.
0034]
  Further, the copper / nickel alloy (Cipro) forming the tip 75 in the present embodiment has a softening start temperature of 550 to 600 ° C., a thermal conductivity of 29 W / (m · K), and a thermal expansion coefficient of 16. 0.2 (× 10 −6 / ° K), melting point is 1170 ° C., and electric conductivity is 4.6 (% IACS).
  On the other hand, in the case of oxygen-free copper forming the main body 76, the softening start temperature is 200 to 220 ° C., the thermal conductivity is 391 W / (m · K), and the thermal expansion coefficient is 17.7 (× 10 −6 / ° K), melting point is 1083 ° C., and electric conductivity is 101 (% IACS).
0035]
  That is, the copper / nickel alloy used for the tip portion 75 has a lower electrical conductivity than oxygen-free copper, but has a significantly high heat resistance and a low thermal conductivity. The heat conduction is suppressed, and the temperature rise of the main body portion 76 is suppressed.
  Therefore, as described above, the tip portion 75 of each anode plate is formed of copper / nickel alloy, and the main body portion 76 is formed of oxygen-free copper, whereby the entire anode plate is formed of oxygen-free copper. Compared with the case, the temperature increase of the anode plates 55a, 55b, 55c,... That is, it is possible to reduce the load acting on the brazed portion between the anode plates 55a, 55b, 55c,...
  Therefore, it is possible to suppress the fatigue failure of the brazed portion caused by repeated thermal expansion and contraction of the anode plates 55a, 55b, 55c,.
0036]
  In addition, since nickel is a magnetic material, the nickel component contained in the tip portion 75 plays a role of reducing the magnetic field strength difference by converging the magnetic flux generated by the magnets assembled to the upper and lower magnetic poles of the anode. Therefore, the magnetic field can be increased and the output can be increased without increasing the size of the magnet, and both the magnetron can be reduced in size and increased in output.
0037]
  According to the experiments by the present inventors, when the entire anode plate is made of oxygen-free copper, the magnetic field distribution at the tip of the anode plate becomes the distribution shown by the curve F1 in FIG. When the tip of the anode plate is made of the above-mentioned copper / nickel alloy as shown in FIG. 6, the magnetic field distribution at the tip of the anode plate is the distribution shown by the curve F2 in FIG. It was confirmed that the magnetic field strength was improved.
0038]
  On the other hand, the high heat resistance metal has a characteristic that the electric conductivity is low, but the strap plates 57 and 58 that electrically and mechanically connect the anode plates 55a, 55b, 55c,. Since the main body 76 made of a metal having high conductivity is brazed, the electrical connection characteristics between the anode plates 55a, 55b, 55c,... And the strap rings 57, 58 can be maintained satisfactorily.
0039]
  In the magnetron according to the present invention, the position of the ring insertion holes 65 and 66 in each anode plate, the shape of the tip 75 formed of a high heat-resistant metal, the cross-sectional shape of the strap rings 57 and 58, etc. The present invention is not limited to the above embodiment, and can be improved as appropriate, for example, as in each of the embodiments shown in FIGS.
  In the embodiment shown in FIG. 7, the rings through which the strap rings 57 and 58 are inserted so as to straddle the main body portion 76 and the front end portion 75 constituting each anode plate 81 projecting from the inner periphery of the anode main body 51. Insertion holes 65 and 66 are provided. The point that the main body portion 76 is made of oxygen-free copper and the tip portion 75 is made of a copper / nickel alloy, which is a highly heat-resistant metal, is the same as in the first embodiment.
0040]
  In the magnetron configured as described above, the ring insertion holes 65 and 66 are inserted by matching the ring insertion grooves 65a, 65b, 66a, and 66b formed on the abutting surfaces of the main body portion 76 and the tip portion 75, respectively. If the strap ring 57, 58 is in an annular shape without a separation part, the strap ring 57, 58 is formed in the main body 76 at a stage before the tip 75 is joined to the main body 76. By positioning in the ring insertion grooves 65b and 66b and joining the front end portion 75, it can be assembled to the main body portion 76.
  An annular strap ring without a cut-off part can be easily manufactured by punching a plate material or by cutting a cylindrical body. Compared with the conventional manufacturing process of the strap ring, the manufacturing of the strap ring is facilitated.
0041]
  Further, when an annular strap ring without a separation portion is adopted, the ring insertion holes 65 and 66 are more easily assembled with the anode plate than when a conventional C ring-shaped strap ring is adopted. The troublesome work of penetrating the wire is not necessary, and a simple work of interrupting the wire is sufficient, so that the assembly of the strap rings 57 and 58 is improved and the productivity can be improved.
0042]
  An anode plate 83 shown in FIG. 8 is a further improvement of the anode plate 81 shown in FIG.
  The anode plate 83 is common to the second embodiment in that ring insertion holes 65 and 66 through which the strap rings 57 and 58 are inserted so as to straddle the main body portion 76 and the tip end portion 75 are provided. . The point that the main body 76 is made of oxygen-free copper and the tip 75 is made of a copper / nickel alloy, which is a high heat-resistant metal, is also common to the second embodiment.
  However, the tip 75 of the present embodiment has a vertical dimension shorter than that of the main body 76, and the claw portions 76 a and 76 b that hold the top and bottom of the tip 75 up and down on the top of the main body 76. Is equipped.
  As described above, by providing the main body 76 with the claw portions 76a and 76b for pressing the tip portion 75, the joining surface by brazing becomes a three-dimensional arrangement, and the joining strength can be improved.
0043]
  The anode plate 85 shown in FIG. 9 is a further improvement of the anode plate 83 shown in FIG.
  This anode plate 85 is common to the second embodiment in that ring insertion holes 65 and 66 through which the strap rings 57 and 58 are inserted so as to straddle the main body 76 and the tip 75 are provided. . The point that the main body 76 is made of oxygen-free copper and the tip 75 is made of a copper / nickel alloy, which is a high heat-resistant metal, is also common to the second embodiment.
  However, the ring insertion holes 65 and 66 are rectangular through holes, and the strap rings 57 and 58 are circular rings having a rectangular cross section.
  The ring insertion holes 65 and 66 are formed, for example, by cutting a cylindrical body formed of oxygen-free copper or the like, or by punching a plate material formed of oxygen-free copper into an annular shape, thereby forming an annular ring without separation. ing.
0044]
  In the present invention, the component ratio of the copper / nickel alloy used for the tip of the anode plate is not limited to the above embodiment.
  The component ratio can be appropriately adjusted according to the necessary heat resistance and the like.
  Moreover, the high heat-resistant metal used for the front-end | tip part of an anode plate is not restricted to said copper * nickel alloy.
  For example, if the main body of the anode plate is made of oxygen-free copper, the metal having better heat resistance than oxygen-free copper includes a copper / tin alloy in which tin is added to copper, and a zirconium alloy in which zirconium is added to copper. These copper alloys are also sufficiently useful as a high heat-resistant metal that forms the tip portion.
  The heat resistance is improved in the order of oxygen-free copper → copper / tin alloy → zirconium alloy → copper / nickel alloy. The thermal conductivity, thermal expansion coefficient, and electrical conductivity gradually decrease in the order of oxygen-free copper → copper / tin alloy → zirconium alloy → copper / nickel alloy so as to be inversely proportional to the heat resistance.
0045]
【The invention's effect】
  As described above, according to the magnetron of the present invention described in claim 1, since the main body portion of the anode plate is equipped with the tip portion excellent in heat resistance, the temperature rise due to the heat radiation of the cathode is increased. It can be suppressed. Therefore, the fatigue life of the brazed portion between the strap ring connecting the anode plates and the anode plate can be suppressed by repeated thermal expansion and contraction of the anode plates, thereby realizing a long life.
[0046]
  Furthermore, since the ring insertion grooves are formed by matching the ring insertion grooves formed on the abutting surfaces of the main body and the tip of the anode plate, the strap ring can be easily assembled to the main body even in an annular shape without a separation part. And productivity can be improved.
[0047]
  Further, in the magnetron of the present invention described in claim 2, since a high heat-resistant metal containing a nickel component is applied to the tip of the anode plate, the conventional anode plate is formed of oxygen-free copper. In comparison with the above, it is possible to suppress the thermal expansion and thermal contraction of the anode plate, to suppress the fatigue failure of the brazed portion due to the repeated thermal expansion and thermal contraction of the anode plate, and to realize a long life.
  Moreover, since nickel is a magnetic material, it acts to converge the magnetic flux generated by the magnets installed above and below the anode, thereby reducing the magnetic field strength difference. Therefore, the magnetic field can be increased and the output can be increased without increasing the size of the magnet, and both the magnetron can be reduced in size and increased in output.
0048]
  Further claims3In the method of manufacturing a magnetron according to the present invention described above, the strap ring is inserted through the anode plate by joining the main body portion and the tip portion, so that the conventional strap ring penetrates the hole of the anode plate. The troublesome work can be omitted, the assembly of the strap ring can be improved, and the productivity of the magnetron can be improved.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a magnetron according to a first embodiment of the present invention.
2 is an enlarged perspective view of an anode of the magnetron shown in FIG. 1. FIG.
3 is a cross-sectional view of the anode shown in FIG.
4 is a cross-sectional view taken along line BB in FIG.
FIG. 5 is an enlarged perspective view of the anode plate shown in FIG.
6 is a graph showing a magnetic field distribution at the tip of an anode plate (vane) in the magnetron shown in FIG. 1;
FIG. 7 is an enlarged perspective view of a second embodiment of an anode plate in a magnetron according to the present invention.
FIG. 8 is an enlarged perspective view of a third embodiment of an anode plate in a magnetron according to the present invention.
FIG. 9 is an enlarged perspective view of a fourth embodiment of an anode plate in a magnetron according to the present invention.
FIG. 10 is a perspective view of an anode in a conventional magnetron.
11 is a longitudinal sectional view of the anode shown in FIG.
12 is a cross-sectional view showing a form of a brazed portion between an anode plate and a strap ring in the anode shown in FIG. 10, wherein (a) is a cross-sectional view showing a proper bonding state, and (b) is a poor bonding. FIG.
[Explanation of symbols]
31 Magnetron
32 working space
33 Anode
35 cathode
37 Antenna tube
39 Body case
41 Cooling fin
51 Anode body
52, 53 magnetic pole
55a-55j Anode plate (Bain)
57,58 Strap ring (Strap ring)
61 Antenna
65, 66 Ring insertion hole
75 Tip
76 Body
76a, 76b Nail part
81, 83, 85 Anode plate

Claims (3)

In a magnetron comprising at least an even number of anode plates radially arranged toward the central axis on the inner peripheral surface of the anode body and a strap ring for connecting the tip portions of the even number of anode plates every other piece to the same potential ,
The anode plate is constituted by a tip portion located on the cathode side and a main body portion excluding the tip portion, and the tip portion is formed of another metal material having higher heat resistance than the main body portion , A magnetron comprising a ring insertion hole through which the strap ring is inserted so as to straddle a main body portion and a tip portion of the anode plate .   2. The magnetron according to claim 1, wherein the main body of the anode plate is made of oxygen-free copper, and the tip of the anode plate is made of a high heat-resistant metal containing a nickel component. An magnetron having at least an even number of anode plates radially arranged toward the central axis on the inner peripheral surface of the anode body and a strap ring that connects the tip portions of the even number of anode plates to the same potential every other piece. In the manufacturing method,
The anode plate is composed of a front end portion located on the cathode side and a main body portion excluding the front end portion, and the main body portion of the ring insertion groove formed on each abutment surface of the main body portion and the front end portion. A magnetron manufacturing method, wherein the tip end portion is joined to the main body portion with the strap ring positioned in a ring insertion groove.

Images