JP5402406B2 - microwave - Google Patents

Description

  The present invention relates to a microwave oven with improved productivity of a rotating antenna.

  Since the microwave oven can directly heat the food that is a typical object to be heated, there is no need to prepare a pot or a pot, and it has become a cooking utensil that should be said to be indispensable for living. In a microwave oven, the size of a space for storing food is generally widespread in the width and depth directions of 300 to 400 mm and in the height direction of about 200 mm.

  In recent years, a highly convenient product has been put into practical use in which the bottom of the space for storing food is flat, the width dimension is 400 mm or more, which is relatively larger than the depth dimension, and two foods can be heated side by side. It has become. However, when two products are heated simultaneously, for example, when a frozen food and a food at room temperature are heated at the same time, the food at room temperature is completed faster. Therefore, in order to finish two items at the same time, only the colder food must be heated intensively.

  In such a case, a function capable of centrally heating only the local area is required instead of heating the entire inside of the heating chamber uniformly. As what implement | achieves this, what has enabled the concentrated heating by switching a some rotating antenna and controlling a stop position is proposed (for example, refer patent document 1).

  However, since it is costly to configure a plurality of antennas, it is expected to be realized with one rotating antenna. For example, conventionally, there is one in which one antenna is disposed at the center below the bottom of the heating chamber and is rotated (see, for example, Patent Document 2).

  The rotating antenna 1 is disposed on the heating chamber bottom surface 9, the sector top surface 3 facing the heating chamber bottom surface 9, and three side blades 5 bent from the sector top surface 3 toward the heating chamber bottom surface 9 side, Furthermore, it has short-circuit surfaces 16, 17, 18 that extend from the narrow surfaces 13, 14, 15 and do not contact the conductor surface 11 but extend in parallel through a slight gap (about 5 mm). The space surrounded by the wide surface 12, the conductor surface 11, and the three narrow surfaces 13, 14, 15 constitutes a substantially horn antenna shape, and in FIGS. 2 and 3, toward the opening opened on the right side of the horn antenna. It is thought that microwaves are emitted.

  In the conventional microwave oven, the horn antenna is also called a rotating waveguide, and the microwave is radiated in the open direction by a configuration in which only one end of the waveguide is opened. Designed with the directivity as high as possible from the center of the bottom as much as possible. Out of the two items placed on the left and right, the rotating antenna 1 is stopped and heated intensively toward the food on the low temperature side. There is a possibility of warming up.

FIG. 4A is a plan view of the rotating antenna 1 employed in the microwave oven disclosed in Patent Document 2,
4B is a cross-sectional view taken along the line AA ′ of the rotating antenna 1 in FIG. 4A, and FIG. 5 is an arrow view of the rotating antenna 1 in FIG.

In the figure, the rotating antenna 1 is composed of a rotating shaft 2, a fan-shaped top surface 3, a side wing 5, and a tail wing 7. A spacer 8 made of ethylene tetrafluoride is attached to the side wing 5. The side wing 5 is formed with a cut-and-raised portion 12, and the cut-and-raised portion 12 is formed by a pair of left and right elongated left and right sides 12 a and a central substantially rectangular center side 12 b. Moreover, the heating chamber bottom surface 9 is drawn by a two-dot chain line.

  The rotating shaft 2 has a cylindrical shape formed by drawing a sheet metal, and a so-called D-cut hole is formed at the lower end. The upper end has a flange extending outward, and is fixed to the fan-shaped top surface 3 here. The upper and lower sides of the fan-shaped top surface 3 are bent at a right angle to form a side surface 4 that is a vertical wall, and the tip is bent again at a right angle to form a side wing 5 that is a horizontal surface. The left side of the fan-shaped top surface 3 is also bent twice to form a rear side surface 6 that is a vertical wall and a tail 7 that is a horizontal surface. These fan-shaped top surface 3, side surface 4, side wing 5, rear side surface 6 and tail wing 7 are formed of a single sheet metal.

  The spacer 8 is fixed by a method to be described later, and is positioned between the heating chamber bottom surface 9 and the side blades 5 drawn by a two-dot chain line. The spacer 8 is mounted vertically, but its vertical plane is also perpendicular to a straight line connecting the center of the rotary shaft 1 and the center of the spacer 8. A waveguide 10 is welded below the bottom 9 of the heating chamber, and a motor 11 is fixed near the end thereof. The output shaft of the motor 11 is inserted into the rotary shaft 2, and the tip half of the output shaft has a D-cut shape with a size slightly smaller than the hole at the lower end of the rotary shaft 2. In the inserted state, the side blades 5 face the heating chamber bottom in parallel.

  First, as described above, the upper and lower positions of the lower end of the rotary shaft 2 into which the output shaft of the motor 11 that has been D-cut only by the first half is inserted are determined at the portion that is not D-cut. The rotating antenna 1 is parallel to the heating chamber bottom surface 9, supported by two points that are in contact with the heating chamber bottom surface 9. When the motor 11 is energized and the output shaft rotates, the rotary shaft 2 also rotates due to mutual D-cut fitting, and thus the entire rotary antenna 1 rotates. The spacer 8 in contact with the bottom surface 9 of the heating chamber is perpendicular to the straight line connecting the center of the rotating shaft 2, so that it always faces the rotation locus circle and is made of tetrafluoroethylene with low friction. Smooth rotation.

  Since the center of gravity of the rotating antenna 1 is located away from the rotating shaft 2 that is the center of rotation and is eccentric, the spacer 8 contacts the heating chamber bottom surface 9 with the tip of the fan-shaped top surface 3 and the tip of the side wing 5 tilted. To prevent it.

  Here, there are various sizes (capacities) of heating chambers depending on the type of microwave oven. Therefore, every time a model is developed or each size of the heating chamber, development / related to microwave supply (power supply) is performed. The design is adjusted and the impedance of the heating chamber viewed from the magnetron is adjusted (impedance matching), and the reflected waves from the heating chamber to the magnetron are reduced so that the microwave generated in the magnetron efficiently heats the food. There must be.

  As a method for adjusting the impedance, when the shape of the heating chamber and the basic configuration of the rotating antenna 1 are determined, the height of the rotating shaft 2 of the rotating antenna 1 (the length of protrusion into the waveguide), the length of the waveguide, and the like. A method of adjusting the height dimension is common. Among them, the impedance adjustment by adjusting the dimension of insertion of the rotating shaft 2 of the rotating antenna 1 into the waveguide, that is, the dimension in the height direction, is effective and easy to implement, and is a powerful technique.

Japanese Patent No. 3617224 Japanese Patent No. 3506125

However, in the conventional configuration, it is necessary to prepare by changing each dimension in the height direction of the output shaft of the spacer 8 or the motor 11 for each height dimension of the rotating shaft 2 of the rotating antenna 1. That is, in order to lengthen the dimension of the rotary shaft 2 in the height direction, a spacer 8 having a large dimension in the height direction and a short dimension of the output shaft are prepared. In order to shorten the dimension in the vertical direction, an object having a small dimension in the height direction of the spacer 8 and an object having a long dimension of the output shaft must be prepared.

  For this reason, the cost of parts is increased, and the productivity of the microwave oven is reduced.

  The present invention solves the above-described conventional problems, and provides a microwave oven that can share the rotating antenna and components around the rotating antenna even if the height dimension of the rotating shaft (antenna shaft) of the rotating antenna is changed. For the purpose.

  In order to solve the above-described conventional problems, a microwave oven according to the present invention includes a microwave generation unit, a waveguide that transmits a microwave generated by the microwave generation unit, and a heating chamber that houses an object to be heated. A rotating antenna disposed substantially in the center of the bottom surface of the heating chamber to radiate microwaves from the waveguide to the heating chamber, a driving unit that drives the rotating antenna, and the driving unit that controls the driving unit. A control unit that controls the orientation of the rotating antenna, the rotating antenna being disposed on a conductor surface forming the bottom surface of the heating chamber, the antenna top surface facing the conductor surface, and the conductor from the antenna top surface At least three antenna side surfaces facing the surface side, a short-circuit surface extending in parallel with a gap between the antenna side surface and the conductor surface, and a diaphragm formed to protrude downward on the antenna top surface And an antenna shaft having an upper portion fixed to the top surface of the antenna and a lower portion projecting into the waveguide. The antenna shaft has a cylindrical shape with an open top surface and a bottom surface. A shaft insertion hole is provided, and the drive shaft of the drive unit is inserted into the shaft insertion hole on the bottom surface of the antenna shaft, and the tip of the drive shaft is in contact with the diaphragm on the top surface of the antenna to support the rotating antenna. is there.

  This makes it possible to adjust the impedance by changing only the vertical dimension of the antenna axis, allowing impedance matching while sharing parts around the rotating antenna, improving the energy saving effect and generating microwaves The reliability of the means can be improved.

  The microwave oven of the present invention can achieve impedance matching while sharing parts around the rotating antenna, and can improve the energy saving effect and improve the reliability of the microwave generating means.

The block diagram which shows schematic structure of the microwave oven in Embodiment 1 of this invention. The top view of the rotating antenna of the microwave oven in Embodiment 1 of this invention Sectional drawing of the rotating antenna and motor mounting plate of FIG. (A) Plan view of a conventional rotating antenna of a microwave oven (b) A-A 'sectional view of FIG. The arrow view which looked at the rotation antenna shown in FIG. 4 from the same figure B direction

According to a first aspect of the present invention, there is provided a microwave generating means, a waveguide for transmitting the microwave generated by the microwave generating means, a heating chamber for storing an object to be heated, and a microwave from the waveguide to the heating chamber. A rotating antenna disposed at substantially the center of the bottom surface of the heating chamber to radiate a wave; a driving unit that drives the rotating antenna; a control unit that controls the driving unit to control the direction of the rotating antenna; The rotating antenna is disposed on a conductor surface that forms the bottom surface of the heating chamber, and has an antenna top surface facing the conductor surface, and at least three antenna side surfaces from the antenna top surface toward the conductor surface side. Further, a short-circuit surface extending in parallel with a gap between the antenna side surface and the conductor surface, a diaphragm formed to protrude downward on the antenna top surface, and an upper portion fixed to the antenna top surface An antenna shaft having a lower portion protruding into the waveguide, and the antenna shaft has a cylindrical shape with an open top surface and a bottom surface, and a shaft insertion hole is provided in the bottom surface of the antenna shaft to drive the drive unit. The shaft is inserted into the shaft insertion hole on the bottom surface of the antenna shaft and the tip of the drive shaft is in contact with the aperture on the top surface of the antenna to support the rotating antenna. It is possible (sharing parts), and there is no need to redesign the dimensions, that is, by changing only the height dimension in the vertical direction of the antenna axis, impedance adjustment can be made possible.

  In particular, according to the second invention, in the first invention, two spacers are symmetrically fixed to the short-circuit surface, and the short-circuit surface of the rotary antenna and the bottom surface of the heating chamber are set at a predetermined interval, whereby the rotary antenna is It can be rotatably supported at three points of the spacer and the output shaft of the motor.

  According to a third aspect of the present invention, the rotating shaft is smoothly rotated and stopped by D-cutting the driving shaft of the driving unit according to the second aspect of the present invention and having a structure that prevents rotation by the shaft insertion hole on the bottom surface of the antenna shaft. it can.

  In a fourth aspect of the invention, the plane parallel to the axial direction of the drive shaft of the drive unit of the third aspect of the invention is configured to face the left and right antenna side surfaces of the rotary antenna. Even if the rotating antenna is displaced in a direction substantially perpendicular to the connecting straight line, the rotating antenna is less likely to incline in a direction substantially perpendicular to the straight line connecting the left and right antenna side surfaces, thereby preventing the occurrence of sparks.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited by this embodiment.

(Embodiment 1)
FIG. 1 is a block diagram showing a schematic configuration of a microwave oven according to the first embodiment of the present invention, FIG. 2 is a sectional view of the rotating antenna of FIG. 1, and FIG. 3 is a plan view of the rotating antenna.

  The microwave oven according to the present embodiment includes a magnetron 21 that is a typical microwave generation unit, and a waveguide 22 having a quadrangular cross-sectional shape that propagates microwaves emitted from the magnetron 21 that serves as the microwave generation unit. The heating chamber 23 connected to the upper portion of the waveguide 22, the mounting table 24 that is fixed in the heating chamber 23 and places an object to be heated, and the heating chamber bottom surface is formed below the mounting table 24. An antenna space 25, a coupling hole 26 provided on the bottom surface at a substantially equal distance from the center of the heating chamber 23, a rotating antenna 27 arranged on the mounting table 24 and rotatable about the coupling hole 26, and the like are arranged. The motor 28 is a drive unit that drives the rotating antenna 27, and a control unit 29 that controls rotation and stop of the motor 28.

  Moreover, the setting means 30 is provided in the front of the heating chamber 24, and a user can select a cooking menu according to food or cooking contents. Based on the selection result, the control unit 29 controls the magnetron 21 to generate and stop the microwave, and controls the motor 28 to control the rotation and stop of the antenna 27. Thereby, the food mounted on the mounting table 24 can be heated and cooked.

  The rotating antenna 27 is disposed on the conductor surface 31 that forms the bottom surface of the heating chamber 23, the antenna top surface 32 facing the conductor surface 31, and the antenna side surface bent from the antenna top surface 32 toward the conductor surface 31. 33, 34, 35, and a short-circuit surface 36 extending from the antenna side surfaces 33, 34, 35. Although this short-circuit surface 36 does not contact the conductor surface 31, it is extended in parallel through a slight gap (about 5 mm).

  And the notch part is formed in the edge side where the antenna side surfaces 33, 34, and 35 of the antenna top surface 32 are not provided. It is considered that the space surrounded by the antenna top surface 32, the conductor surface 31, and the three antenna side surfaces 33, 34, and 35 constitutes a substantially horn antenna shape and microwaves are radiated from the opening.

  This configuration makes it difficult for microwaves to pass between the conductor surface 31 and the short-circuit surface 36, so that it may be considered that the conductor surface 31 and the short-circuit surface 36 are generally conductive. 31 and three antenna side surfaces 33, 34, and 35 form a substantially box-shaped shape in which the direction without the antenna side surfaces 33, 34, and 35 is opened as an opening, and a horn antenna having directivity in the direction of the opening. It is possible to act as. Therefore, a horn antenna that can be driven independently of the bottom surface of the heating chamber 23 with a simple configuration can be realized.

  A two-stage aperture is formed on the antenna top surface 32. The first diaphragm 37 is formed shallower than the second diaphragm 38. The second diaphragm 38 is formed concentrically at the central axis of the first diaphragm 37, with the bottom surface of the diaphragm being a flat surface and the side surface of the diaphragm being an inclined surface.

  The antenna shaft 39 is formed by drawing a sheet metal, has a cylindrical shape (cup shape) having an open top surface and a bottom surface, and a shaft insertion hole 41 is formed in the bottom surface. A flange 40 is formed on the periphery of the upper opening of the antenna shaft 39. The flange 40 is in close contact with the first diaphragm 37 having substantially the same size, is positioned by two positioning holes, and is crimped and fixed to the predetermined antenna top surface 32 by crimping. The antenna shaft 39 is provided through the coupling hole 26 in the antenna space 25 and the space in the waveguide 22.

  A resin output shaft 42 (drive shaft) of the motor 28 is inserted into the shaft insertion hole 41 provided in the antenna shaft 39 through the motor mounting plate 43 and the waveguide 22. The top end of the output shaft 42 is in contact with the bottom surface of the second diaphragm 38 and supports the rotating antenna 27.

  In consideration of changing the dimensions of the antenna shaft 39 by adjusting the impedance, a so-called D cut is performed from the tip of the output shaft 42 toward the motor 28. The shape of the shaft insertion hole 41 is such that when the output shaft 42 rotates, the D-cut portion of the output shaft 42 engages with the shaft insertion hole 41 and the plane parallel to the axial direction of the output shaft 42 is a rotating antenna. 27 are formed to face the left and right antenna side surfaces 33 and 35.

  Two spacers 8 and 8 are attached symmetrically on the short-circuit surface 36, and a predetermined interval is secured between the short-circuit surface 36 and the conductor surface 31 of the heating chamber 23 so that no spark is generated. Therefore, the rotating antenna 27 is supported substantially horizontally and rotatably at the three points of the spacers 8 and 8 and the output shaft 42 of the motor 28.

  When the shape of the heating chamber 23 and the basic configuration of the rotating antenna 27 are determined, impedance adjustment is performed by adjusting the height dimension of the antenna shaft 39 of the rotating antenna 27 (the protruding length dimension into the waveguide 22).

  Further, when the output shaft 42 of the motor 28 rotates, the D-cut portion of the output shaft 42 and the shaft engage with each other, and the output shaft 42 is prevented from idling (rotation stop structure).

  Furthermore, a plane parallel to the axial direction of the output shaft 42 of the motor 28 is configured to face the left antenna side surface 33 or the right antenna side surface 35 of the rotating antenna 27, and a surface that supports the rotating antenna 27 of the output shaft 42 is provided. They are arranged so as to be long in a direction substantially perpendicular to a straight line connecting the left and right antenna side surfaces 33 and 35 and short in a straight line direction connecting the left and right antenna side surfaces 33 and 35.

  As described above, according to the present embodiment, the output shaft 42 of the motor 28 is inserted into the shaft insertion hole 41 of the antenna shaft 39, but the antenna shaft 39 is connected to the output shaft in the vertical direction of the output shaft 42. Since it is not locked to 42 and can be freely performed without affecting other parts, the position of the rotating antenna 27 does not change even if the length of the antenna shaft 39 is changed. Therefore, the rotating antenna 27, the spacers 8 and 8 that support the rotating antenna 27, and the output shaft 42 of the motor 28 can be employed as they are, and there is no need to redesign the dimensions.

  That is, the impedance adjustment can be performed by changing only the vertical dimension of the antenna shaft 39.

  In addition, the rotating antenna 27 itself supports three points as usual and supports the output shaft 42 at two points, that is, the bottom surface portion of the second diaphragm 38 and the shaft insertion hole 41. In addition, the rotating antenna 27 can be held more horizontally than before without changing the fixing method of the spacers 8 and 8.

  Furthermore, the plane parallel to the axial direction of the output shaft 42 of the motor 28 is configured to face the left and right antenna side surfaces 33 and 35 of the rotating antenna 27, so that the center of gravity of the rotating antenna 27 Even if the rotation antenna 27 is displaced in a direction substantially perpendicular to the connecting straight line, the rotation antenna 27 is less likely to be inclined in a direction substantially perpendicular to the straight line connecting the left and right antenna side surfaces 33 and 35, and a spark is generated between the rotation antenna 27 and the conductor surface 31. It can be prevented from occurring.

  The microwave oven according to the present invention can improve productivity and can be applied not only to household appliances using microwaves but also to the industrial field.

8 Spacer 21 Magnetron (microwave generating means)
22 Waveguide 23 Heating chamber 27 Rotating antenna 28 Motor (drive unit)
29 Control unit 31 Conductor surface 32 Antenna top surface 33, 34, 35 Antenna side surface 36 Short-circuit surface 38 Second aperture (diaphragm)
39 Antenna shaft 41 Shaft insertion hole 42 Output shaft (drive shaft)

Claims (4)

Microwave generation means, a waveguide for transmitting microwaves generated by the microwave generation means, a heating chamber for storing an object to be heated, and for radiating microwaves from the waveguide to the heating chamber A rotating antenna disposed at substantially the center of the bottom surface of the heating chamber; a driving unit that drives the rotating antenna; and a control unit that controls the direction of the rotating antenna by controlling the driving unit. Are arranged on a conductor surface forming the bottom surface of the heating chamber, facing an antenna top surface facing the conductor surface, at least three antenna side surfaces from the antenna top surface toward the conductor surface side, and further from the antenna side surface A short-circuit surface that extends in parallel with the conductor surface via a gap, a diaphragm that protrudes downward from the antenna top surface, and an upper portion that is fixed to the antenna top surface and a lower portion that is guided It has an antenna shaft which projects into the tube, and
The antenna shaft has a cylindrical shape with an open top surface and a bottom surface. The antenna shaft bottom surface is provided with a shaft insertion hole, the drive shaft of the drive unit is inserted into the shaft insertion hole of the antenna shaft bottom surface, and the antenna ceiling A microwave oven that supports the rotating antenna by contacting a tip of the drive shaft with a diaphragm of a surface. The microwave oven according to claim 1, wherein two spacers are fixed symmetrically to the short-circuit surface, and the short-circuit surface of the rotating antenna and the bottom surface of the heating chamber are set to a predetermined interval. The microwave oven according to claim 2, wherein the drive shaft of the drive unit is D-cut and is configured to stop rotation by the drive shaft and a shaft insertion hole on the bottom surface of the antenna shaft. The microwave oven according to claim 3, wherein a plane parallel to the axial direction of the drive shaft of the drive unit faces the left and right side surfaces of the rotating antenna.