JP2014072047A - High-frequency heater and magnetron - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable measurement of a temperature of an anode part of a magnetron with high accuracy and high heat responsiveness.SOLUTION: Grooves 82 extending in an axial direction are formed on an outer periphery of an anode cylinder 1 of a magnetron. A front end of a thermocouple 92 is made enter into the grooves 82 and be contacted on a lateral face of the grooves 82. A temperature of the anode cylinder 1 is directly measured by the thermocouple. A plurality of grooves 82 are arranged so as to be adjacent to each other to form a groove group 81, and it is preferred that the groove groups 81 are formed at positions different by 90 degree from each other around an axis of the anode cylinder. In a high-frequency heater, on the basis of the temperature measured by the thermocouple, an input energy to a cathode of the magnetron is controlled.

Description

  The present invention relates to a high-frequency heater and a magnetron.

  Magnetrons are incorporated in high-frequency heaters such as microwave ovens, and are widely used for food cooking and thawing. An output antenna protrudes from the output side of the upper end of the magnetron body. A filter circuit including a coil and a feedthrough capacitor housed in a filter box is connected to the input side at the lower end of the magnetron body. Permanent magnets are arranged on the upper and lower ends of the magnetron body. A yoke is disposed so as to surround the magnetron body and the permanent magnet, and a magnetic circuit is formed.

  A plurality of cooling fins are press-fitted into the magnetron main body and spread between the yokes to constitute a radiator (see, for example, Patent Document 1). The yoke is provided on both sides of the shaft so as to sandwich the magnetron body. The yoke is provided in a part of the periphery of the shaft of the magnetron body, and openings are formed on both sides of the shaft. These openings serve as inlets and outlets for cooling air.

  During operation, that is, when a high frequency is generated, part of the input energy (energy that does not contribute to high frequency output) becomes heat and the temperature rises. If the temperature is excessively high, the service life may be shortened or a fire may be caused. Therefore, the temperature of the anode part of the magnetron body may be managed.

  As a method of indirectly measuring the temperature of the anode part, for example, there is a method of installing a thermostat on the input yoke surface or the exhaust duct. Further, for example, a thermistor may be installed in the clearance on the exhaust side of the cooling fin. Or it may obtain | require by the relationship between the anode current measured beforehand and anode temperature by measuring an average anode current using the transformer for electric current detection.

  As a method for directly measuring the temperature of the anode part, there is a method of embedding a thermocouple in the anode cylinder. In this method, a hole that does not penetrate the cooling fin press-fit portion of the anode cylindrical portion on the exhaust side is formed, and the tip of the thermocouple is embedded. The tip of the thermocouple is fixed using an adhesive having high thermal conductivity such as silver paste, and the thermocouple wiring is fixed to the cooling fin with aluminum tape or copper wire.

JP 2012-054010 A

  When the temperature of the anode part of the magnetron is indirectly measured, the thermal response is not high and the reproducibility tends to be low. In this case, the number of parts increases and the cost increases.

  On the other hand, the method of embedding the thermocouple directly in the anode part increases the thermal response and reproducibility. However, attachment of a thermocouple requires attachment / detachment from a microwave heater such as a microwave oven, and the depth of the thermocouple must be processed with a high-precision depth. Skill is necessary. When variations occur in the depth of drilling, the hole may penetrate the anode cylinder and the function as a vacuum tube cannot be ensured, and the accuracy of temperature measurement may be lowered. In addition, since the wiring portion of the thermocouple is unstable and easily removed, it takes time to securely fix it with an aluminum tape or a copper wire, resulting in a long working time. For this reason, the method of directly embedding the thermocouple is used as a confirmation method at the time of product development, but is not used for the product itself.

  Accordingly, an object of the present invention is to enable measurement of the temperature of the anode part of a magnetron with high accuracy and high thermal response.

  In order to solve the above-described problems, the present invention provides a high-frequency heating device comprising: an anode cylinder that extends from the input side to the output side and has a groove formed along the axis on the outer periphery; and an inner wall of the anode cylinder. A plurality of vanes extending toward the axis; a cathode extending along the axis inside the anode cylinder; and a flange in contact with an outer surface of the anode cylinder, the flanges being in contact with the outer surface of the anode cylinder and spaced apart in the axial direction. A magnetron having a plurality of plate-like cooling fins extending in a direction crossing the axis, a thermocouple having a tip in contact with a side surface of the groove, and input energy to the cathode based on the temperature measured by the thermocouple And a controller for controlling.

  Further, the present invention provides a magnetron having an anode cylinder that extends from the input side to the output side and has a groove for thermocouple arrangement that extends along the axis on the outer periphery, and an inner wall of the anode cylinder that extends from the inner wall to the shaft. A plurality of vanes extending toward the axis, a cathode extending along the axis inside the anode cylinder, and a plurality of plate-like cooling fins provided in contact with and spaced from the outer surface of the anode cylinder and extending in a direction crossing the axis It is characterized by comprising.

  According to the present invention, the temperature of the anode part of the magnetron can be measured with high accuracy and high thermal response.

It is a longitudinal cross-sectional view of one embodiment of the magnetron according to the present invention. It is a cross-sectional view of one embodiment of a magnetron according to the present invention. It is a side view of the magnetron and high voltage transformer in one embodiment of the magnetron according to the present invention. It is a side view of the anode cylinder of one embodiment of the magnetron according to the present invention. It is a cross-sectional view of the vicinity of a groove group in an embodiment of a magnetron according to the present invention. It is a top view of the cooling fin of one embodiment of the magnetron according to the present invention. It is a side view of the cooling fin of one embodiment of the magnetron according to the present invention.

  An embodiment of a magnetron according to the present invention will be described with reference to the drawings. This embodiment is merely an example, and the present invention is not limited to this.

  FIG. 1 is a longitudinal sectional view of an embodiment of a magnetron according to the present invention. FIG. 2 is a cross-sectional view of the magnetron of the present embodiment. In FIG. 2, illustrations other than the anode cylinder, vane, and strap are omitted.

  The magnetron 50 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 disposed along the central axis 41, and the vicinity of the central axis 41. A plurality of vanes 2 extending radially 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 referred to as 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 is spiral 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 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 sealing body 10. A bar-shaped antenna 14 made of copper is led out from one of the vanes 2. The antenna 14 passes through the output-side pole piece 8, extends in the output portion onto the central axis 41, and the tip is sandwiched 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. The support rods 17 and 18 are led out of the pipe through a relay plate 19, for example.

  Further, the magnets 21 and 22 and the yokes 23 and 24 are disposed so as to surround the magnetron main body which is such an oscillating portion, thereby forming a magnetic circuit. The yokes 23 and 24 are bent plates, respectively, and surround the magnetron body with the central axis 41 interposed therebetween. In the space surrounded by the yokes 23, 24, an opening 62 is formed so as to face each other with the central axis 41 interposed therebetween.

  Cooling fins 25 for cooling the oscillation unit main body are provided in the space surrounded by the yokes 23 and 24. A filter circuit having a coil 33 and a feedthrough capacitor 34 is connected to the cathode 5 via support rods 17 and 18. The coil 33 and feedthrough capacitor 34 constituting the filter circuit are housed in a filter box 27.

  FIG. 3 is a side view of the magnetron in the present embodiment.

  The magnetron 50 is disposed along the central axis 41 of the magnetron 50. On the output side of the magnetron 50, the exhaust pipe 13 covered with the cap 15 is located.

  A fan 60 is disposed in the vicinity of the magnetron 50. The fan 60 is rotated by a driving mechanism such as a motor (not shown) to generate cooling air 61 that flows toward the central axis 41 of the magnetron 50. The fan 60 faces one of the openings 62 surrounded by the yokes 23 and 24. The cooling air 61 flows from the opening 62 into the space surrounded by the yokes 23 and 24, and flows out from the other opening 62 as exhaust heat air 63.

  FIG. 4 is a side view of the anode cylinder of the present embodiment.

  On the side surface of the anode cylinder 1, groove groups 81 are formed at two locations. The groove group 81 is formed outside the portion where the vane 2 from which the antenna 14 is led is in contact, and at a position rotated 90 degrees around the central axis 41 with respect to the outside.

  In each groove group 81, three grooves 82 are formed. Each groove 82 extends in a direction parallel to the central axis 41. The groove 82 is carved to a depth that does not penetrate the anode cylinder 1. For example, the depth of the groove 82 is half of the thickness of the anode cylinder 1.

  FIG. 5 is a cross-sectional view of the vicinity of the groove group in the present embodiment.

  Each groove 82 has a V-shaped cross section. The cross-sectional shape of the groove 82 may be, for example, U-shaped or concave.

  FIG. 6 is a top view of the cooling fin in the present embodiment. FIG. 7 is a side view of the cooling fin of the present embodiment.

  The cooling fin 25 has a rectangular flat plate portion 70 and protruding portions 71 and 72 protruding from the long sides thereof. One protruding portion 71 is bent upward at a point where it is bent downward from the flat plate portion 70. The other projecting portion 72 is bent upward from the flat plate portion 70. The sides of the protruding portions 71 and 72 opposite to the flat plate portion 70 are bent so as to be in contact with the yoke 24.

  A circular hole 75 having an inner diameter substantially the same as the outer diameter of the anode cylinder 1 passes through the center of the flat plate portion 70. A cylindrical contact surface 73 in contact with the anode cylinder 1 extends upward around the hole 75.

  A through hole 83 is formed in the cylindrical contact surface 73. The through hole 83 is, for example, an ellipse. The through hole 83 is formed at a position perpendicular to the protruding direction of the protruding portions 71 and 72 of the cooling fin 25.

  In addition, two protrusions 93 are formed on the flat plate portion 70 on the straight line extending from the central axis 41 toward the through hole 83.

  The cooling fin 25 is attached to the anode cylinder 1 such that the anode cylinder 1 is fitted into a hole 75 formed in the flat plate portion 70 and the cylinder contact surface 73 is in contact with the outer surface of the anode cylinder 1. There are a plurality of cooling fins 25 attached to the anode cylinder 1.

  The tip 91 of the thermocouple is in contact with the anode cylinder 1 through the through hole 83 formed in the cylindrical contact surface 73 of the cooling fin 25. More specifically, the tip 91 of the thermocouple enters one of the grooves 82 of the anode cylinder 1 and is in contact with the side surface of the groove 82. The tip 91 of the thermocouple is fixed to the groove 82 with an adhesive having high thermal conductivity such as silver paste.

  The wiring 92 connected to the tip 91 of the thermocouple is fixed by the protrusion 93 of the flat plate portion 70 of the cooling fin 25. This wiring is further connected to a controller of a high-frequency heating device using a magnetron. In this high-frequency heating device, the input energy to the cathode 5 and the like are controlled by the controller based on the temperature of the anode cylinder 1 measured with a thermocouple.

  Thus, according to this Embodiment, the temperature of the anode cylinder 1 of a magnetron can be measured directly. For this reason, the temperature inside the anode cylinder 1 can be directly measured with high accuracy and high thermal response.

  Since the anode cylinder 1 has a groove 82, the tip 91 of the thermocouple can be easily brought into contact with the side surface of the groove 82 by moving the tip 91 of the thermocouple against the groove 82. . Further, the wiring 92 connected to the tip 91 of the thermocouple can be easily fixed by the protrusion 93 provided on the cooling fin 25.

  Further, by forming the groove group 81 with the plurality of grooves 82, the tip of the thermocouple is placed in any one of the grooves 82 even if the angular assembly around the central axis 41 to the cooling fin 25 of the anode cylinder 1 is slightly shifted. 91 is easy to enter. Further, by arranging the grooves 82 of the groove group 81 so as to be adjacent to each other in the circumferential direction, that is, substantially without a circumferential surface between the adjacent grooves 82, the circumferential surface, that is, the outer surface of the anode cylinder 1. The possibility that the tip 91 of the thermocouple is fixed while being in contact with the surface becomes small. Thus, the assembly of the high frequency heater using this magnetron is easy.

  Two groove groups 81 are formed at positions 90 degrees around the central axis 41. The magnetron body of the same design may be used for a product group in which the orientation of the opening 62 of the yokes 23 and 24 differs by 90 degrees with respect to the antenna 14 extraction position. If there is only one groove group 81, there is a possibility that the groove group 82 does not face the opening 62. However, by forming two groove groups 81 as in the present embodiment, the groove group 81 is moved to the groove group 81. Can be easily accessed from the opening 62. In order to avoid the influence of the cooling air 61, it is necessary to dispose it on the exhaust heat air 63 side, and the groove group 81 is preferably formed at a position facing the opening 62 not facing the fan 60.

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 ... cooling fin, 27 ... filter box, 31 ... free end, 32 ... through hole, 33 ... coil, 34 ... through capacitor, 41 ... central axis, 50 ... magnetron , 60 ... fan, 61 ... cooling air, 62 ... opening, 63 ... exhaust hot air, 70 ... flat plate portion, 71 ... projection, 72 ... projection, 73 ... cylindrical contact surface, 75 ... hole 81 ... groove groups, 82 ... groove, 83 ... through hole, 91 ... thermocouple tip 92 ... wire, 93 ... projection

Claims (5)

An anode cylinder extending from the input side to the output side and having a groove extending along the axis on the outer periphery; a plurality of vanes extending from the inner wall of the anode cylinder toward the axis; and the inside of the anode cylinder A cathode extending along the axis, a plurality of plate-like cooling fins each having a flange in contact with the outer surface of the anode cylinder and spaced apart in the axial direction and extending in a direction crossing the axis; and the groove A thermocouple having a tip in contact with the side surface of the magnetron, and
A controller for controlling the input energy to the cathode based on the temperature measured by the thermocouple;
A high-frequency heating device comprising: The flange is formed with a through hole at a position in contact with the groove,
The wiring connected to the tip of the thermocouple passes through the through hole,
The high-frequency heating device according to claim 1.   The high frequency heating apparatus according to claim 1 or 2, wherein the groove is plural and forms a groove group adjacent to each other in the circumferential direction.   The high-frequency heating device according to claim 3, wherein the groove group includes a plurality of grooves and is formed at a position 90 degrees apart from the axis. An anode cylinder which is a cylinder extending from the input side to the output side and in which a groove for thermocouple arrangement extending along the axis is formed on the outer periphery;
A plurality of vanes extending from the inner wall of the anode cylinder toward the axis;
A cathode extending along the axis within the anode cylinder;
A plurality of plate-like cooling fins that are in contact with the outer surface of the anode cylinder and spaced apart and spread in a direction crossing the axis;
A magnetron comprising:

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