JPH0546079B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a high-frequency heating device equipped with a rotating plate for placing an object to be heated in an oven.

[Technical background of the invention and its problems]

In high-frequency heating devices such as microwave ovens, in order to heat the heated object efficiently and uniformly,
An oven equipped with a rotating plate is known. FIG. 8 shows a rotating plate drive mechanism of a conventional microwave oven, where 1 is an oven and 2 is a rotating plate. A motor 3 constituting a drive mechanism is provided at the bottom of the oven 1, and a transmission shaft 5 is provided on the rotating shaft 4. Further, on the bottom surface of the oven 1, there are a plurality of rollers 7 supported pivotally on a roller support plate 6.
... are provided and rotatably support the rotary plate 2. This rotary plate 2 is provided with an engaging portion 8 that engages with the transmission shaft 5, so that the rotary plate 2 is rotated by the rotational force of the transmission shaft 5.

However, since the roller support plate 6 is screwed to the bottom of the oven 1 as described above, the roller support plate 6 cannot be removed. Therefore, when cleaning the inside of the oven 1, the roller support plate 6 gets in the way and it is not possible to clean every corner. Therefore, food juices and dregs tend to accumulate around the roller support plate 6, which is unhygienic.

Therefore, as shown in FIG. 9, a rotating plate 9 made of a radio wave reflecting member such as metal is engaged with the rotating shaft 4, and a rotating plate made of a radio wave transmitting member made of heat-resistant glass is mounted on the upper surface of the rotating plate 9. Some have 2 on them.
This is because there are no protruding parts such as the roller support plate 6 on the bottom of the oven 1, and the rotary plate 2 is also removable, so cleaning efficiency is greatly improved.

However, in the case of FIG. 9, since the weight of the object to be heated is supported only by the rotating shaft 5 of the motor 4, the bearings 10 and 11 that support the rotating shaft 4 must be constructed robustly, which increases costs. becomes. In addition, in order to make the rotary plate 9 detachable, the rotary shaft 4
It is necessary to provide a gap in the engaging portion 12 of the rotary plate 9 that engages with the rotary plate 9. If the object to be heated is placed at the end of the rotary plate 2, the rotary plate 2 will be tilted by the amount of the gap, and the centrifugation during rotation will occur. Combined with this force, the object to be heated may come into contact with the wall of the oven during rotation, and the bearing 10,
There is a disadvantage that uneven wear of No. 11 occurs. Also,
In the case shown in FIG. 2, since the rotary plate 2 and the rotary plate 9 rotate at the same rotation speed, the electric field within the oven 1 does not change much with respect to the food, and the absorption characteristics of radio waves to the food are not good. , heating efficiency is also poor. Another disadvantage is that the food may be heated unevenly, making it difficult to cook the food properly.

Furthermore, as shown in FIG. 10, there is also known an oven in which a roller holder 13, in which a plurality of rollers 12 are pivotally supported, is interposed between the bottom surface of the oven 1 and the rotary plate 2. This is so that the rotation of a rotating shaft 4 of a motor 3 is transmitted via a transmission shaft 5 to a rotating plate 2 supported by rollers 12 . Therefore, the rotary plate 2 and the roller holder 13 are removable,
Cleanability is also good, and the drive mechanism for the rotary plate 2 is structurally simple.

However, each of the rollers 12 only rotates in conjunction with the rotation of the rotary plate 2 between the bottom surfaces of the oven 1. Therefore, if food crumbs accumulate and solidify on the bottom of the oven 1 or if dust adheres to the bottom surface of the oven 1, the rotational driving force of the rollers 12 is weak and the rotation is blocked by the solids and dust and stops. Sometimes I put it away. When the roller 12 stops, the rotating plate 2 rotates while slipping on the roller 12, but if this state continues, the motor 3 may become overloaded and the rotation of the motor 3 may stop. Therefore, it is necessary to frequently clean the bottom surface of the oven 1 to remove deposits such as solid matter and dirt. In addition, in the case of FIG.
2, but the shape is ring-shaped, and
It is made of dielectric material such as resin. Therefore, there are disadvantages in that there is no radio wave diffusion or stirring effect, the heating efficiency is poor, and food may be heated unevenly.

Further, when the rotating plate 2 rotates, the roller holder 13 also rotates, but the rotational deviation of the roller holder 13 is restricted by the ring-shaped protrusion 13a formed on the rotating plate 2 and the bottom of the oven 1. This is the recessed portion 1a formed in the recessed portion 1a. In this case, when the roller holder 13 becomes misaligned in rotation, the convex portion 2a
The roller holder 13 itself contacts the concave portion 1a, and a force acts to return the roller holder 13 itself to the rotation center position, but the roller 12...
The torque of rotation is weak in this part, and the torque of the rotary plate 2 is weakened due to contact, making it impossible to rotate normally, or if food particles or dirt adhere to the protrusions 2a and recesses 1a, the torque is weak and the roller Holder 13
The rotation of the rotary plate 2 was obstructed, and the rotary plate 2 sometimes stopped rotating. Furthermore, when food is placed on the rotary plate 2 and placed on the roller holder 13, there are two positions for positioning: the convex portion 2a and the engaging portion of the transmission shaft 5, which has the drawback of being difficult to fit.

Further, in each of the conventional rotary drive mechanisms described above, a speed reduction mechanism is provided on the rotary shaft 4 via gears 14 and 15, and a cam 16 is formed on the gear 15. In some cases, the cam 16 turns on and off the microswitch 17 to obtain a weak high-frequency output for thawing or stewing cooking. However, in general, the rotation speed of the rotary plate 2 of a microwave oven is approximately 6 to 8 rpm (7.5 rpm), which is achieved by improving heating efficiency and reducing heating unevenness.
~10 seconds/1 revolution) is normal. On the other hand, the weak output is equivalent to about 50 to 40% of the normal output, and the gear 15
Reduce the rotation speed by about half (approximately 3 to 4 rpm, 15 to 20 seconds/1
), the cam 16 is rotated, and the micro switch 17 is turned on and off. Weak output 50% of normal
If the cam surface is formed so that it can be removed, the on time of the micro switch 17 will be 7.5 to 10 seconds, and the off time will also be 7.5 to 10 seconds.
It takes 7.5 to 10 seconds, and by repeating this process, a weak output is obtained. In addition, if the cam surface 16 is provided directly on the rotating shaft 4, the period will be 7.5 to 10 seconds, and the on time of the weak output will be about 3.8 to 5 seconds, which means that the time for high frequency radiation is too short, making it difficult to Thawing cooking or stewing cooking cannot be performed, and the number of times the micro switch 17 is turned on and off also doubles, reducing its lifespan. Therefore, a speed reduction mechanism such as gears 14, 15 is required, resulting in a complicated structure and an increase in cost.

[Purpose of the invention]

This invention was made in view of the above-mentioned circumstances, and its purpose is to improve the cleaning efficiency inside the oven, to make it possible to easily attach and detach the rotary plate despite its simple structure, and to improve heating efficiency. It is an object of the present invention to provide a high-frequency heating device that can improve heating and reduce heating unevenness.

[Summary of the invention]

In order to achieve the above object, the present invention includes a roller holder that is rotated by a rotational drive mechanism and is interposed between the bottom of the oven and the rotary plate, and a fitting that regulates the center of rotation of the rotary plate is attached to the roller holder. Further, the roller holder is provided with a plurality of rollers that transmit rotational force to the rotary plate while rolling on the bottom of the oven, and the roller holder is tilted so that the radio waves are concentrated in the center of the rotary plate. It's because I let it happen.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 21 is the main body of the high-frequency heating device, and 22 is an oven. An opening 23 is provided at the bottom of this oven 22, and this opening 23
A mounting plate 24 is provided at the lower part facing the. A motor 25 constituting a rotational drive mechanism is attached to the mounting plate 24, and a rotating shaft 26 passes through the opening 23 and projects to the inner bottom of the oven 22. On the other hand, 27 is a rotary plate on which the object to be heated is placed, and is made of a radio wave transmitting member such as heat-resistant glass or plastic. A roller holder 28 is removably interposed between the rotating plate 27 and the bottom surface of the oven 22. As shown in FIGS. 2 and 3, the roller holder 28 is made of a metal material that easily reflects radio waves. That is, 29 is a fitting part, which is a fitting part in the roller holder 28 and the rotary plate 27.
It is formed into a circular boss shape corresponding to the center of the rotary plate 27, and is adapted to fit into a projection 27a formed at the center of the rotary plate 27. Reference numeral 30 denotes a cylindrical portion protruding from the lower surface, and this cylindrical portion 30 is provided with an engaging portion 32 that engages with a pin 31 at the tip of the rotating shaft 26. Further, a plurality of roller support rods 33, for example, four roller support rods 33, for example, extend radially around the engaging portion 32, forming a radio wave agitation portion. These roller support rods 33 are inclined so that the distance from the surface of the rotary plate on which the object to be heated is placed gradually approaches toward the outer end.
Further, rollers 35... are connected to the bent portions of the tips of these roller support rods 33 via roller shafts 34...
is rotatably supported. Therefore, the rollers 35 . rolls on the bottom surface of the oven 22 and transmits its rotation to the rotary plate 27. Furthermore, roller contact surfaces 36 and 37 on the bottom surface of the oven 22 and the bottom surface of the rotary plate 27 that come into contact with the roller 35 are formed into ring protrusions 38 and 39. Further, as shown in FIG. 4, a cam 40 is fitted onto the rotating shaft 26 of the motor 25, and a micro switch 41 is in contact with the cam surface. Furthermore, the gap between the top surface of the rotary plate 27 and the bottom surface of the oven 22 has a radio wave frequency of 2450M.
It is set to approximately λ/4 of Hz (approximately 30.5 mm).

Next, the operation of the above embodiment will be explained. first,
When the motor 25 is energized, the rotating shaft 26 rotates at a required rotation speed (for example, 3 rpm), and this rotation is transmitted to the roller holder 28 via the pin 30. When the roller holder 28 rotates, the rotational force causes the rollers 35 to roll on the bottom surface of the oven 22. When the roller 35... rolls, this roller 3
The rotational force is transmitted to the rotating plate 27 which is in contact with the roller holder 5, and rotates in the same direction as the roller holder 28 at twice the number of rotations of the roller holder 28 (6 rpm). That is, as shown in FIG. 5, when the roller 35, which was initially at the position A, rotates half a turn and advances only to the position B, the rotary plate 27 is moved from the X position to the W position, and then moves to the Y position. come to the position. Therefore, roller 3
5 rotates half a turn, the roller holder 28 advances by a distance a, and the rotating plate 27 moves 2× from the W position to the Y position.
a Move. After one rotation, the roller 35 moves from A to C by a distance b, and the rotary plate 27 moves to positions V to Z.
It rotates in the same direction as the roller holder 28 at twice the rotation speed. At this time, the cam 40 fitted on the rotating shaft 26 rotates (3 rpm) due to the rotation of the rotating shaft 26.
Then, the cam surface turns on the micro switch 41.
Turn off. At this time, if the weak output is set to 50% of the normal output, the on time is 10 seconds and the off time is also 10 seconds (cycle 20
seconds). At this time, the rotation of the rotary plate 27 is given a rotational driving force by the rollers 35, but the center of rotation is regulated by the fitting portion 29 and the protrusion 27a located at the center of each. , has strong torque and can rotate normally. That is, for example, if the center of rotation of the rotary plate 27 is restricted by its peripheral portion, the rotary plate 27 will often shift outward as it rotates, and in particular,
When the rotary plate 27 rotates at twice the speed of the roller holder 28, the difference in rotation peripheral speed is large at the peripheral edge, and good regulation may not be achieved.

However, in this embodiment, since the center of rotation of the rotary plate 27 is regulated by the fitting part 29 provided corresponding to the center of the rotary plate 27, it is possible to prevent the rotation plate 27 from shifting outward. This fitting part 29
The difference in rotational circumferential speed between the rotating plate 27 and the roller holder 28 is small, and reliable regulation can be achieved, so that the rotating plate 27 rotates normally. Also, the fitting part 2
9 and the protrusion 27a are located on the underside of the rotating plate 27, so that food particles and dirt do not adhere to the rotating plate 27, and smooth rotation is possible.
Furthermore, the gap between the top surface of the rotary plate 27 and the bottom surface of the oven 22 is approximately λ/4 of the radio wave frequency of 2450 MHz.
(approximately 30.5mm). Therefore, the radio wave (arrow a) directed toward the bottom of the oven 22 and the reflected wave (arrow b) reflected by the bottom surface are transmitted to the rotating plate 2.
The electric field is synergized near the upper surface of 7, and the electric field is made uniform, and the radio waves are uniformly absorbed by the object to be heated.

Moreover, the reflected wave (arrow b) is reflected by the roller support rod 33 (arrow c), or in places where there is no roller support rod 33, it is transmitted through the rotary plate 27 (arrow d) and absorbed by the heated object. be done. In addition, the radio waves from the waveguide (arrow e) are absorbed by the object to be heated as they are, or are reflected (arrow f) when they hit the roller support rod 33 and are absorbed. The part of the heated object where radio waves are absorbed differs from moment to moment, and the object to be heated tends to be uniformly absorbed and heated by the radio waves, so uneven heating is less likely to occur, and the electric field of the oven 22 is more uniformly absorbed by the heated object. heating efficiency is improved. Furthermore, since each roller support rod 33 of the roller holder 28 is inclined as described above, the radio wave (arrow g) from the waveguide hits the roller support rod 33, and the reflecting surface thereof is inclined. Therefore, it is reflected near the center of the rotating plate 27 (arrow h). Therefore, radio waves gather near the center and the electric field becomes stronger. Since the object to be heated is placed in this strengthened electric field, radio waves are easily absorbed, further improving heating efficiency. In particular, by providing the above-mentioned radio wave reflecting effect to the roller holder 28 that rotates the rotary plate 27 at twice the speed difference, the object to be heated can be uniformly irradiated with the reflected radio waves. In other words, for example, if a rotating plate holder that rotates integrally with the rotating plate has a radio wave reflecting effect, the radio waves reflected by the rotating plate holder will only be irradiated to the same part of the object to be heated, and the heating will not occur. It can be uneven. However, in this embodiment, since there is a speed difference between the roller holder 28, which has a radio wave reflecting effect, and the rotating plate 27, the radio waves reflected by the roller holder 28 are sequentially irradiated to each part of the object to be heated. As a result, the object to be heated can be evenly irradiated with the reflected radio waves, thereby preventing uneven heating.

In the above-mentioned embodiment, the roller contact surfaces 36 and 37 on the bottom surface of the oven 22 and the bottom surface of the rotary plate 27 that are in contact with the roller 33 are connected to the ring protrusion 3.
8 and 39, it is easy to wipe off any food residue or dirt that accumulates, improving cleaning performance and ensuring normal rotation.In addition, the weight of food is easily distributed over the entire bottom of the oven 22, preventing deformation. It's hard to do. Therefore, cooking can be done in a stable electric field.

Further, in the above embodiment, the roller holder 28 is formed into a substantially cross shape and a plurality of roller support rods 33 are provided, but the present invention is not limited to this, and as shown in FIG. 6 or FIG. It may be configured as follows. That is, in FIG. 6, the roller holder 42 is formed into a disk shape, and four holes are formed at equal intervals on the flange portion 43 on the outer peripheral edge of the roller holder 42.
Book roller shafts 44 . . . are provided in a protruding manner, and rollers 45 . . . are rotatably supported on these roller shafts 44 . Further, in FIG. 7, the roller holder 46 is formed into a disk shape, and a plurality of opening windows 47 are formed on the plate surface.
. . . to form a radio wave stirring section. All of them slope upward toward the outer ends.

〔Effect of the invention〕

As explained above, according to the present invention, the following effects can be obtained.

(a) Transmit the driving force of the drive mechanism to the roller holder,
This rotational force causes the roller to roll on the bottom of the oven and rotate the rotary plate, so even if there is food particles or dirt on the bottom of the oven,
The roller rolls over these and has the effect of rotating smoothly. Therefore, there is no need to frequently clean the bottom of the oven.

(b) Since the roller holder is formed into an inclined surface shape using a radio wave reflecting member, the radio waves can be reflected by the inclined surface and irradiated onto the object to be heated on the rotary plate, thereby improving heating efficiency.

(c) By providing the above-mentioned radio wave reflection effect to the roller holder that rotates the rotary plate at twice the speed difference, the reflected radio waves can be evenly irradiated onto the object to be heated, thereby preventing uneven heating.

(d) Since the center of rotation of the rotating plate is regulated by the fitting part provided corresponding to the center of the rotating plate, unlike the case where the center of rotation is regulated by the periphery of the rotating plate, the outer side of the rotating plate is It can prevent misalignment, and
The rotation peripheral speed difference between the rotary plate and the roller holder at this fitting portion is small, so reliable regulation can be achieved, and the rotary plate can always be rotated normally.

(e) Since the rotating plate is supported by the plurality of rollers of the roller holder, there is also an effect that the rotating plate can be prevented from tilting.

[Brief explanation of the drawing]

Figures 1 to 5 show an embodiment of the present invention. Figure 1 is a longitudinal sectional front view of a microwave oven, Figure 2 is an enlarged longitudinal sectional front view of the rotary drive mechanism, and Figure 3 is the same. Plan view of roller holder, 4th
The figure is a plan view of the cam, FIG. 5 is an explanatory view of the function, FIGS. 6 and 7 are perspective views showing other embodiments of the roller holder of the present invention, and FIGS. 8 to 10 are views of the conventional roller holder. FIG. 2 is a longitudinal sectional front view of the microwave oven. 22... Oven, 25... Motor (rotary drive mechanism), 27... Rotating plate, 28, 42, 46...
Roller holder, 29... Fitting portion, 35, 45...
roller.

Claims (1)

[Claims] 1. An oven, a rotary plate provided in the oven and made of a radio wave transmitting member on which an object to be heated is placed;
A fitting part is provided between the bottom surface of the oven and the rotary plate in a manner that corresponds to the center of the rotary plate, and is removably interposed between the bottom surface of the oven and the rotary plate to regulate the center of rotation of the rotary plate. a roller holder made of a radio wave reflecting member inclined so that the distance from the surface on which the object to be heated is placed gradually approaches; and a roller holder that is rotatably supported by the roller holder and rolling on the bottom surface of the oven; The oven is characterized by comprising a plurality of rollers that transmit rotational force to the oven, and a rotational drive mechanism that is provided at the bottom of the oven and engages with an engaging portion of the roller holder to apply rotational force to the roller holder. High frequency heating equipment. 2. The high-frequency heating device according to claim 1, wherein the roller holder has a radio-wave stirring section of a roller support rod extending radially around the engaging section.