JP5893464B2 - Magnetron and manufacturing method thereof - Google Patents

Description

  The present invention relates to a magnetron used in a microwave oven and the like and a method for manufacturing the same.

  A general magnetron includes an anode cylinder and a plurality of vanes. The vanes are arranged radially inside the anode cylinder. The vanes are connected to each other in the circumferential direction by a pair of large and small strap rings brazed to the upper and lower ends of the vane. In the electron action space surrounded by the free ends of the plurality of vanes, a spiral cathode is disposed along the axis of the anode cylinder. Both ends of the spiral cathode are fixed to the output side end hat and the input side end hat, respectively. Further, a substantially funnel-shaped output side and input side pole piece are fixed to both ends of the anode cylinder, respectively.

  The materials used for the anode part of magnetron anode cylinder, vane, strap ring and antenna are non-magnetic, have good electrical conductivity, have good thermal conductivity, and emit gas at high temperature during magnetron operation. It is required that there are few. In general, copper or a copper alloy is often used as a material that satisfies these conditions. In particular, when joining the parts of the anode part by brazing with a continuous hydrogen furnace, oxygen-free copper with a low oxygen content is selected so as not to cause hydrogen embrittlement, and a silver alloy is used for the brazing material. It is done.

JP2011-198725A

  From the viewpoint of resource saving and recent rises in materials, magnetrons are also required to reduce material usage and costs. For this reason, it is required to reduce the amount of brazing material for joining the parts of the anode part. In addition, since a considerable amount of copper or copper alloy is used for the anode part, a reduction in the amount of use is also required.

  Accordingly, an object of the present invention is to reduce the amount of brazing material used for the anode part of the magnetron.

  In order to solve the above-mentioned problems, the present invention provides a magnetron comprising a non-magnetic inner cylinder and a non-magnetic auxiliary cylinder that is in contact with the outer surface of the inner cylinder and has a smaller coefficient of thermal expansion than the inner cylinder. An anode cylinder extending in a cylindrical shape along the plurality of vanes extending toward the central axis by diffusion bonding with the inner surface of the anode cylinder, a cathode extending spirally along the central axis, and both ends of the cathode A pair of end hats fixed to each other and a support rod connected to each of the end hats to supply a current to the cathode are provided.

  Further, according to the present invention, in the magnetron manufacturing method, a cylindrical non-magnetic inner cylinder is placed along the central axis of the auxiliary cylinder inside the non-magnetic auxiliary cylinder having a smaller coefficient of thermal expansion than the inner cylinder. An arrangement step of arranging a plurality of vanes so as to be directed from the inner surface of the inner cylinder toward the central axis, and after the arrangement process, the arranged inner cylinder, auxiliary cylinder, and vane are arranged in the center of the vane. Heating while restricting displacement in the axial direction to diffusely bond the inner surface of the inner cylinder and the vane, and after the bonding step, a spiral cathode is disposed on the central axis, A pair of end hats are fixed to both ends, and a support rod for supplying a current to the cathode is connected to each of the end hats.

  According to this invention, the usage-amount of the brazing material used for the anode part of a magnetron can be reduced.

It is a longitudinal cross-sectional view in 1st Embodiment of the magnetron based on this invention. It is a longitudinal cross-sectional view of the anode cylinder vicinity of 1st Embodiment of the magnetron based on this invention. It is a cross-sectional view of the anode of the first embodiment of the magnetron according to the present invention. It is a partially expanded longitudinal cross-sectional view at the time of joining of the vane and anode cylinder of 1st Embodiment of the magnetron based on this invention. It is sectional drawing of the vane in 2nd Embodiment of the magnetron based on this invention. It is a top view of the end surface by the side of the anode cylinder of vane in 2nd Embodiment of the magnetron based on this invention. It is a partially expanded longitudinal cross-sectional view at the time of joining of the vane and anode cylinder of 2nd Embodiment of the magnetron based on this invention. It is a longitudinal cross-sectional view of the junction part vicinity of the anode cylinder and vane of 2nd Embodiment of the magnetron based on this invention.

Embodiments of a magnetron according to the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or similar structure, and the overlapping description is abbreviate | omitted.
[First Embodiment]

  FIG. 1 is a longitudinal sectional view of a magnetron according to a first embodiment of the present invention. FIG. 2 is a longitudinal sectional view of the vicinity of the anode cylinder of the magnetron of the present embodiment. FIG. 3 is a cross-sectional view of the anode of the magnetron of the present embodiment.

  The magnetron of the present embodiment includes an anode cylinder 1, a cathode 5, a pair of end hats 6, 7 and a pair of pole pieces 8, 9 arranged along the same axis (center axis 41), and the center axis. A plurality of vanes 2 extending radially from the vicinity of 41 are provided.

  The anode cylinder 1 extends in a cylindrical shape along the central axis 41. The vane 2 extends radially from the vicinity of the central axis 41 and is fixed to the inner surface of the anode cylinder 1. The vanes 2 are each formed in a substantially rectangular plate shape. The free end 31 of the vane 2 on the side not fixed to the inner surface of the anode cylinder 1 is disposed on the same cylindrical surface extending along the central axis 41, and this cylindrical surface is called a vane inscribed cylinder. The plurality of vanes 2 are connected to each other in the circumferential direction by strap rings 3 and 4 that are paired in large and small brazed to the upper and lower ends of the vane.

  The cathode 5 has a spiral shape and is disposed inside the vane inscribed cylinder, which is an electron action space, and is disposed on the central axis of the anode cylinder 1. Further, both ends of the cathode 5 are fixed to the end hats 6 and 7, respectively. The end hats 6 and 7 are disposed outside the central axis 41 with respect to the vane 2. The end hat 6 on the antenna side (output side) is formed in a cup shape that opens toward the cathode 5, and the end hat 7 on the stem side (input side) is formed in a ring shape. The end hats 6 and 7 are made of, for example, molybdenum (Mo).

  The pair of pole pieces 8 and 9 are each formed in a funnel shape having a through hole 32 at the center. The center of the through hole 32 is located on the central axis 41. Each pole piece 8, 9 is formed so as to spread from the through hole 32 toward the outside of the central axis 41 with respect to the space sandwiched between the end hats 6, 7. The outer diameters of the pole pieces 8 and 9 are formed substantially the same as the diameter of the anode cylinder 1. The outer peripheral portions of the pole pieces 8 and 9 are fixed to both ends of the anode cylinder 1 respectively. Further, the pair of pole pieces 8 and 9 are arranged with a space between the end hats 6 and 7 interposed therebetween.

  Further, cylindrical metal sealing bodies 10 and 11 are fixed to the pole pieces 8 and 9, respectively. Each metal sealing body 10, 11 is also in contact with one end of the anode cylinder 1.

  An output-side ceramic 12 is joined to the end of the output-side metal seal 10 opposite to the pole piece 8. An exhaust pipe 13 is joined to the end of the output side ceramic 12 opposite to the metal seal. An antenna 14 is derived from the vane 2. The antenna 14 passes through the output-side pole piece 8, extends in the output portion, and the tip is clamped and fixed by the exhaust pipe 13. The entire exhaust pipe 13 is covered with a cap 15.

  An input-side ceramic 16 is joined to the end of the input-side metal seal 11 opposite to the pole piece 9. Two support rods 17 and 18 are connected to the cathode 5 via end hats 6 and 7. A filter circuit having a coil 33 and a feedthrough capacitor 34 is connected to the support rods 17 and 18, for example, through the relay plate 19 to the outside of the pipe. The coil 33 and feedthrough capacitor 34 constituting the filter circuit are housed in a filter box 27.

The inside of the magnetron in which the cathode 5 and the like are arranged is kept in a vacuum state of about 10 ⁻³ to 10 ⁻⁴ Pa, for example.

  Further, the magnets 21 and 22 and the yokes 23 and 24 are disposed so as to surround such an oscillating unit main body to form a magnetic circuit. Further, an exterior is formed by the radiator 25 for cooling the oscillating unit body, the choke coil 33 and the through transistor 34 connected to the input side, and the box 27 surrounding them.

  The anode cylinder 1 has an inner cylinder 51 and an auxiliary cylinder 52. The outer surface of the inner cylinder 51 is in contact with the inner surface of the auxiliary cylinder 52. The inner cylinder 51 is a non-magnetic material and is made of, for example, copper having high thermal conductivity and high conductivity. The auxiliary cylinder 52 is a nonmagnetic material and is formed of a material having a smaller coefficient of thermal expansion than the inner cylinder 51. As the material of the auxiliary cylinder 52, for example, austenitic stainless steel is used.

  FIG. 4 is a partially enlarged longitudinal sectional view of the magnetron vane and anode cylinder of the present embodiment when joined.

When joining the vane 2 and the anode cylinder 1, first, the inner cylinder 51 is press-fitted inside the auxiliary cylinder 52 and fitted. Next, a cylindrical jig 61 having an outer diameter corresponding to the vane inscribed circle formed by the free end 31 of the vane 2 is arranged on the center axis of the auxiliary cylinder 52 and the inner cylinder 51, and the vane 2 is placed at a predetermined position. Push into. With the columnar jig 61, the vane 2, the inner cylinder 51, and the auxiliary cylinder 52 arranged in this manner, these are heated in a high-temperature vacuum furnace or the like. The heating temperature is, for example, about 850 ° C to 900 ° C. The heating time is, for example, about 10 to 15 minutes. In addition, when a material that does not cause hydrogen embrittlement other than stainless steel is used as the material of the auxiliary cylinder 52, the auxiliary cylinder 52 may be heated in a hydrogen furnace.
The displacement of the vane 2 on the free end 31 side is limited by a cylindrical jig 61. For this reason, when the temperature becomes high, the end of the vane 2 on the inner cylinder 51 side is pressed against the inner surface of the inner cylinder 51.

  By maintaining the state in which the end surface of the vane 2 is pressed against the inner surface of the inner cylinder 51 at a high temperature for a certain period of time, the end surface of the vane 2 and the inner surface of the inner cylinder 51 are diffusion-bonded. Further, since the coefficient of thermal expansion of the auxiliary cylinder 52 is smaller than that of the inner cylinder 51, the expansion of the inner cylinder 51 is suppressed, the pressing force between the vane 2 and the inner cylinder 51 is increased, and diffusion bonding is further advanced.

  Thus, in the magnetron of the present embodiment, the anode cylinder 1 and the vane 2 are diffusion-bonded, so that it is not necessary to use a brazing material for the bonding of the anode cylinder 1 and the vane 2. Therefore, the amount of brazing material used can be reduced. Moreover, since the deformation | transformation of the inner cylinder 51 of the anode cylinder 1 can be suppressed at the time of joining at high temperature by using the auxiliary cylinder 52, the contact pressure between the inner cylinder 51 and the vane 2 is increased and more effectively. It can be diffusion bonded.

Further, the auxiliary cylinder 52 can bear the mechanical strength of the anode cylinder 1. Therefore, the thickness of the inner cylinder 51 can be reduced, and the amount of material used for the inner cylinder 51 can be reduced. When copper is used for the inner cylinder 51, the usage amount of copper can be reduced by increasing the usage amount of an inexpensive material such as austenitic stainless steel.
[Second Embodiment]

  FIG. 5 is a cross-sectional view of the vane in the second embodiment of the magnetron according to the present invention. FIG. 6 is a plan view of the end surface of the vane on the anode cylinder side in the present embodiment.

  In the magnetron of the present embodiment, the shape of the vane 92 is different from that of the first embodiment. In the vane 92 of the present embodiment, a recess 72 is formed on the end surface 71 on the side opposite to the free end 31, that is, on the side in contact with the anode cylinder 1. The depressions 72 are formed, for example, at two locations in the axial direction.

  FIG. 7 is a partially enlarged longitudinal sectional view of the magnetron vane and anode cylinder of the present embodiment when joined.

  Such a vane 92 is joined to the anode cylinder 1 in the same manner as in the first embodiment.

  FIG. 8 is a longitudinal sectional view of the vicinity of the junction between the anode cylinder and the vane of the magnetron of the present embodiment.

When the vane 92 of the present embodiment is used, when joining by heating, the end surface 70 of the vane 92 is pushed into the inner cylinder 51 by pressing, and the inner surface of the inner cylinder 51 enters the recess 72 of the vane 92. As a result, the contact area between the inner cylinder 51 and the vane 92 increases, and the surface area for diffusion bonding increases. Therefore, the bonding strength between the inner cylinder 51 and the vane 92 is increased.
[Other embodiments]

  The above-described embodiments are merely examples, and the present invention is not limited to these. Moreover, it can also implement combining the characteristic of each embodiment.

DESCRIPTION OF SYMBOLS 1 ... Anode cylinder, 2 ... Vane, 3 ... Strap ring, 4 ... Strap ring, 5 ... Cathode, 6 ... End hat, 7 ... End hat, 8 ... Pole piece, 9 ... Pole piece, 10 ... Metal sealing body, DESCRIPTION OF SYMBOLS 11 ... Metal sealing body, 12 ... Output side ceramic, 13 ... Exhaust pipe, 14 ... Antenna, 15 ... Cap, 16 ... Input side ceramic, 17 ... Support rod, 18 ... Support rod, 19 ... Relay plate, 21 ... Magnet , 22 ... magnet, 23 ... yoke, 24 ... yoke, 25 ... radiator, 31 ... free end, 32 ... through hole, 33 ... choke coil, 34 ... penetrating transistor, 41 ... central axis, 51 ... inner cylinder, 52 ... auxiliary Cylinder, 61 ... Cylinder jig, 71 ... End face, 72 ... Dimple, 92 ... Bain

Claims (3)

A non-magnetic inner cylinder and an anode cylinder that is in contact with the outer surface of the inner cylinder and has a non-magnetic auxiliary cylinder having a smaller coefficient of thermal expansion than the inner cylinder and extends in a cylindrical shape along the central axis;
A plurality of vanes extending toward the central axis by diffusion bonding with the inner surface of the anode cylinder;
A cathode extending spirally along the central axis;
A pair of end hats secured to both ends of the cathode;
A support rod connected to each of the end hats for supplying current to the cathode;
A magnetron comprising:   The magnetron according to claim 1, wherein a recess is formed in an end surface of the vane that contacts the anode cylinder. A cylindrical non-magnetic inner cylinder is disposed along the central axis of the auxiliary cylinder on the inner side of the non-magnetic auxiliary cylinder whose coefficient of thermal expansion is smaller than that of the inner cylinder. An arrangement step of arranging a plurality of vanes toward the axis;
After the arranging step, the arranged inner cylinder, the auxiliary cylinder, and the vane are heated while restricting the displacement of the vane in the central axis direction, so that the inner surface of the inner cylinder and the vane are diffusion bonded. When,
After the joining step, a step of disposing a spiral cathode on the central axis, fixing a pair of end hats to both ends of the cathode, and connecting a support rod for supplying current to the cathode to each of the end hats When,
A method for producing a magnetron, comprising:

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