JPH05180445A - Microwave oven - Google Patents

Abstract

PURPOSE:To enable the weight of food placed on a turn-table tray to be accurately calculated without having any relation with the positional relation of the food. CONSTITUTION:A projection 8 is arranged at a bottom surface of an oven 7, and a supporting roller for supporting a turn-table tray passes through the projection. As the tray 1 is controlled under its rated speed, driving torque of the motor 2 becomes the value corresponding to the weight of the food placed on the tray 1. Then, the driving torque is varied as the supporting roller 6 passes through the projection 8 and its varying pattern is varied in response to the positional relation of the food. However, the mean value of the driving torque during one rotation of the turn-table tray is assumed to be substantially constant without having any relation with the arrangement if the weight of the food is kept same. Logic calculation control circuit 15 calculates the mean value of the driving torque from the control data attained by the motor driving circuit 14 and further calculates the weight of the food in response to it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave oven equipped with food weight detection means.

[0002]

2. Description of the Related Art Some microwave ovens are equipped with a weight detecting means for detecting the weight of foods mounted on a turntable tray by recognizing the drive torque of a turntable motor. As a microwave oven of this type, there is a conventional microwave oven as shown in FIG. 12 (Japanese Patent Laid-Open No. 63-27).
1030 publication). In this microwave oven, a gear 55 is fitted to a shaft 52a of a motor 54 that drives a turntable tray 52 installed in the oven 51, and the rotation of the gear 55 is detected by a microswitch 56. And
The microcomputer 60 is the microswitch 56
Based on the detection result of, the switching means 6 is driven through the drive circuit 63 so that the rotation of the motor 54 becomes a predetermined rotation speed.
4 is controlled to change the power supply frequency of the motor 54, and the torque of the motor 54 is calculated from the power supply frequency, thereby detecting the weight of the food on the turntable tray 52. Then, based on the detected weight, the relay 62
The magnetron 59 is controlled via the.

FIG. 13 is a modification of FIG. In this microwave oven, the supporting structure of the center shaft 5 of the turntable tray 1 is simplified by providing the supporting roller 6 on the turntable tray 1. Further, a perforated rotary disk 10 that rotates together with the center shaft 5 and a photo interrupter 11 that detects the rotation of the rotary disk 10 are provided to enable more accurate rotation speed detection. The turntable tray 1 is driven by a motor 2 via a gearbox 3. The detection result of the photo interrupter 11 is input to the logic operation control circuit 15. The logic arithmetic control circuit 15 controls the power supply frequency of the motor 2 via the motor drive circuit 14 so that the rotation speed of the motor 2 becomes a predetermined rotation speed, calculates the torque from the power supply frequency, and thereby the weight of the food. To detect. Then, based on the detected weight, the magnetron 18 is controlled via the magnetron drive high voltage power supply circuit 16. The microwave output from the magnetron 18 is guided by the waveguide 19
It is supplied to the oven 7 through the opening 20 and heats the food on the turntable tray 1.

[0004]

By the way, the conventional weight detection method described above recognizes the weight of food by the relationship between the moment of inertia of the turntable tray in the initial stage of rotation and the initial drive torque. When it is located in the part, a certain relationship is established between the starting torque of the motor and the inertia time until the turntable tray reaches constant speed rotation and the food load weight, and the weight of the food can be detected.
When the food is located in the peripheral portion of the tray, the moment of inertia at the initial stage of rotation of the tray depends on the degree of eccentricity of the food on the tray, so that correct weight detection cannot be performed and there are the following problems. If the food is placed eccentrically to the center of the tray, the weight detection error increases. In the case of a plurality of foods, the detection weight error becomes large depending on the pattern of placing on the tray. When the turntable tray supports the center axis, friction between the bearing and the center axis, or when the turntable tray is supported by the support rollers located on the outer circumference, friction between the support roller and the floor surface causes the tray to rotate initially. The driving torque is greatly different, and the food weight detection error increases. Since the food weight recognition at the beginning of the cooking and heating of the microwave oven is performed only by the tray rotation initial timing, it is impossible to automatically correct the cooking and heating program due to the weight change of the food during the cooking and heating. Therefore, an object of the present invention is to provide a weight detection means that can continuously recognize the weight without causing the above-mentioned or the weight detection error and also while the turntable tray is rotationally driven and the food is heated. It is to provide a microwave oven.

[0005]

In order to achieve the above object, a first aspect of the present invention is directed to a turntable tray installed in an oven, a motor for rotating the turntable tray, and a rotation with the turntable tray. And a plurality of support rollers that are rotatably fixed to the support member in the circumferential direction and that rotate on the bottom surface of the oven as the support member rotates and that support the turntable tray. Rotation speed detection means for detecting the rotation speed of the motor, and drive voltage control means for controlling the drive voltage of the motor so that the rotation speed of the motor becomes a predetermined rotation speed based on the detection result of the rotation speed detection means. A driving torque calculating means for calculating the driving torque of the motor based on the driving voltage of the motor, and a driving torque calculating means for calculating the driving torque. A microwave oven equipped with a weight calculating means for calculating the weight of the food placed on the turntable tray based on the drive torque, which is 1 on the circumference of the bottom surface of the oven in contact with the supporting roller. A protrusion through which the supporting roller passes is provided at a position or a plurality of positions, and the weight calculation means calculates the drive torque calculated by the drive torque calculation means.
It is characterized in that the weight of the food is calculated based on the average value of rotation.

A second aspect of the invention is a turntable tray installed in an oven, a motor for rotating the turntable tray, a support member fixed to the oven, and a circumferential direction on the support member. A plurality of support rollers that are rotatably fixed to the turntable tray and that support the turntable tray; rotation speed detection means for detecting the rotation speed of the motor; and rotation of the motor based on the detection results of the rotation speed detection means. Drive voltage control means for controlling the drive voltage of the motor so that the speed becomes a predetermined rotation speed, drive torque calculation means for calculating the drive torque of the motor based on the drive voltage of the motor, and the drive torque calculation The weight calculation means for calculating the weight of the food placed on the turntable tray based on the driving torque calculated by the means is provided. In the sub-range, a protrusion through which the support roller passes is provided at one or more locations on the circumference of the lower surface of the turntable tray that are in contact with the support roller, and the weight calculation means is the drive torque calculation means. The weight of the food is calculated on the basis of the average value of the drive torque calculated for one turn of the turntable tray.

[0007]

In order to control the turntable tray to rotate at a constant speed, it is necessary to control the drive torque of the motor in accordance with the weight of the food placed on the turntable tray.
In the first aspect, the drive voltage control means controls the drive timing of the motor so that the rotation speed of the motor becomes a predetermined rotation speed in response to the detection result of the rotation speed detection means. By the control of the drive timing, a current sufficient for the motor to generate a necessary drive torque flows through the motor. When the turntable tray rotates, the supporting roller passes through the protrusion on the bottom surface of the oven, and the driving torque varies. The pattern of fluctuations in this drive torque differs depending on whether the food is placed in the center of the turntable tray or on the periphery, and when there are multiple food items, the way they are placed varies, but If the weight is the same, the average value of the drive torque during one rotation period of the turntable tray can be regarded as substantially the same, and therefore the weight of the food can be calculated from the average value of the drive torque. The driving torque calculating means calculates the driving torque of the motor based on the driving voltage of the motor, and the weight calculating means calculates the driving torque calculated by the driving torque calculating means based on the average value of one turn of the turntable tray. Calculate the weight of the above foods. Therefore, the weight of the food can be accurately calculated regardless of how the food is placed on the turntable tray. In addition, the weight of food is not calculated by calculating the driving torque in the initial stage of rotation, but the weight of food is calculated from the average value of the driving torque during one rotation of the turntable tray. Weight change can be detected.

According to the second aspect of the invention, the drive torque fluctuates when the turntable tray rotates on the support roller and the protrusion provided on the lower surface of the turntable tray passes through the support roller. The operations of the drive voltage control means, the drive torque calculating means, and the weight calculating means are the same as those in the first invention. Therefore, similar to the first aspect, the weight of the food can be accurately calculated regardless of how the food is placed on the turntable tray, and the weight change of the food during cooking and heating can be detected.

[0009]

The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 is a sectional view showing a schematic configuration of an embodiment of the present invention. FIG. 11 shows the appearance of this microwave oven.
In FIG. 1, 1 is a turntable tray (hereinafter, simply referred to as a tray), 2 is a turntable motor (hereinafter, simply referred to as a motor), 3 is a gear box, 5 is a center shaft, and 6 is for supporting the tray 1. It is a support roller. The rotation of the motor 2 is performed by the gear box 3 and the center shaft 5
Is transmitted to Tray 1 via. Further, the support roller 6 rotates together with the tray 1 and passes through the protrusion 8 provided on the bottom surface of the oven 7. The relationship between the support roller 6 and the protrusion 8 is shown in FIG. As shown in FIG. 2, a support roller supporter 2 serving as a support member fixed to the center shaft 5.
Two support rollers 6 mounted on the outer periphery of the two at equal intervals
(Indicated by symbols A, B and C, respectively) pass through four protrusions 8 circumferentially equidistantly provided on the bottom surface of the oven in order. Returning to FIG. 1, 10 is a perforated rotary disk attached to the output shaft of the motor 2, 11 is a photo interrupter as a rotational speed detecting means for detecting the rotation of the disk 10, and 14 is a drive voltage controlling means. Motor drive circuit, 15 is a logic operation control circuit as drive torque calculation means and weight calculation means, 16 is a magnetron drive high voltage power supply circuit, 18 is a magnetron, 19 is a waveguide, and 20 is a waveguide opening. As will be described later in detail, the logic operation control circuit 15 receives a signal from the photo interrupter 11 so that the number of rotations of the tray 1 becomes a predetermined number of rotations and the motor drive circuit 14 supplies the motor drive power supply. And the weight of the food on the tray 1 is detected from the control data. Then, based on the detected weight, the magnetron 18 is driven via the magnetron drive high voltage power supply circuit 16.

FIG. 3 (a) is a linearly developed view for explaining the positional relationship between the support roller 6 and the oven bottom surface projection 8 of FIG. When the support roller supporter 22 rotates in the direction of the arrow from the state of FIG. 2, first the roller A passes through the protrusion, then the roller C and then the roller B passes through the protrusion, and each roller A is rotated by 90 degrees. , B, and C each pass through the protrusion once. FIG. 3 (b) shows a case where five protrusions 8 are provided on the bottom of the oven, and the protrusions pass through the protrusions in the order of rollers A, B, and C by the movement in the direction of the arrow, and each roller makes one protrusion by rotating 72 degrees. Pass twice. FIG. 4 shows a situation in which the support roller 6 passes through the oven bottom surface protrusion 8. Further, FIG. 5 shows a variation state of the tray drive torque due to the passage of the protrusion 8. FIG. 5 (a) shows the fluctuation of the torque applied to the tray when one roller passes through one protrusion.
With or without the tray,
4 shows four kinds of torque fluctuation situations when there is no food load, when the food load is light, and when the food load is heavy. When the roller 6 passes over the oven bottom surface projection 8, large torque fluctuations appear when passing over the upward slope and the downward slope of the projection 8. Since this torque fluctuation level is almost proportional to the load applied to the rollers 6, the weight of the food placed on the tray can be calculated by calculating the load applied to each roller 6. Also, FIG.
(B) and (c) show the state of torque fluctuations when the food load is placed on the central portion and the peripheral portion of the tray, respectively.
When the food load is placed on the central portion of the tray, the load applied to each roller is equal, so that the torque fluctuation is constant as shown in FIG. 5 (b). On the other hand, when the food load is placed on the periphery of the tray, the load applied to each roller is not the same. Therefore, as shown in FIG. different.
However, since the arithmetic average value of these torque fluctuations is constant regardless of the position of the food, accurate weight recognition can be performed by obtaining the arithmetic average value.

FIG. 6 is a diagram for explaining the constant speed rotation control of this embodiment. FIG. 6A is a diagram for explaining power transmission from the motor to the tray, and FIG. 6B is a control circuit diagram of the motor. A perforated rotary disk 10 for detecting the motor speed is attached to the rotary shaft of the DC motor 2, and a turntable is connected to the rotary shaft via a gear box 3. Although the perforated rotary disk 10 is provided between the motor 2 and the gearbox 3 in this figure, the perforated rotary disk 10 may be provided after the gearbox 3 as shown in FIG. The rotation of the motor 2 is detected by the photo interrupter 11 combined with the perforated rotating disk 11. This photo interrupter 11 has a photodiode 30 to which a resistor 32 is connected.
And a phototransistor 31 to which a resistor 33 is connected. When the disk 10 rotates and the hole comes between the photodiode 30 and the phototransistor 31, the light emitted by the photodiode 30 enters the phototransistor 31 through the hole of the rotating disk 10, and the phototransistor 31 Are conducted, and a current flows through the resistor 33. No current flows through the resistor 33 while there is no hole between the photodiode 30 and the phototransistor 31. The logic operation control circuit 15 detects the number of rotations of the motor 2 from the fluctuation (ON-OFF pulse) of the potential at the connection point between the phototransistor 31 and the resistor 33. That is, the holes on the perforated rotary disk are provided at equal angles on the outer circumference, and the rotation speed of the motor 2 can be determined by the cycle of the ON-OFF pulse.

In order to drive the turntable tray 1 at a constant speed rotation (for example, about 6 rpm), the pulse period previously obtained from the relationship between the reduction gear ratio of the gearbox 3 and the number of holes in the rotating disk 10, and the photo period. It is necessary to compare the pulse periods obtained from the interrupter 11 and control the drive torque of the DC motor 2. As shown in FIG. 6B, the DC motor 2 has a diode 26 connected in parallel and a power transistor 27 connected in series, and DC power is supplied from the series power supply 25 through the power transistor 27. In the torque control of the DC motor 2, the power transistor 27 is turned ON-OF via the motor drive circuit 14.
It can be performed by controlling F. In this case, as shown in FIGS. 7A-1 and 7A-2, a pulse voltage having a constant period T (for example, about 100 msec) is applied to the power transistor 2.
7 (b) and a method of controlling the torque by adjusting the average current to the motor by changing the duty ratio (T _on / T) of the pulse voltage (motor drive control pulse) while applying it to the base of FIG. -1) and (b-2), the frequency of the pulse voltage is changed, for example, between several 10 Hz and several 100 Hz, and the current is adjusted using the frequency characteristic of the impedance of the motor 2 to control the torque. There is a way to do. In any case, the drive current applied to the motor 2 is controlled by the switching control of the power transistor 27 to control the torque.

When the fluctuation of the torque due to the rotation of the turntable tray shown in FIG. 5 is canceled to rotate the turntable tray at a constant speed, it is necessary to control the motor drive current according to the fluctuation of the torque of the tray. At this time, the turntable tray rotation torque can be detected by counting and calculating the timing of the switching control pulse applied to the power transistor 27. The rotational torque applied to the motor when each support roller passes through the protrusions on the bottom of the oven varies depending on the food weight.The duty ratio or frequency of the motor drive control pulse is numerically calculated, and the average of the fluctuation values is calculated from the measured data. The food weight can be detected by multiplying the coefficient.

FIG. 8 is a flow chart showing an example of the constant speed rotation control when the rotation torque control of the motor 2 is performed by the duty ratio (duty cycle ratio) of the motor drive control pulse. After the motor drive circuit 14 is turned on in step S1, the duty cycle ratio is stepped up in step S2. For example, if the duty ratio of a pulse having a period of 100 msec is increased / decreased in 1% steps, the duty ratio is sequentially increased by the start of the motor drive circuit 14 from the duty ratio of 0% to the start of motor rotation. And step S3
Then, the ON-OFF output of the photo interrupter 11 is detected, and the initial rotation is detected. If the motor 2 is not rotating, the process proceeds to step S9 to determine whether the motor 2 is in the locked state or not (this determination may be made from the abnormally large duty ratio). Alternatively, it may be performed by separately measuring the current value of the motor 2). If the motor 2 is in the locked state, the operation is stopped in step S10. If the motor 2 is rotating in step S3, the process proceeds to step S4, and it is determined whether the duty ratio at the initial start time is the torque in the state where the turntable tray is placed.
If there is no tray load, the operation proceeds to step S10 to stop the operation. If there is a tray load, the process proceeds from step S5 to step S6, and the pulse timing output from the photo interrupter 11 is compared with the pulse timing corresponding to a preset turntable rotation speed (for example, 3 rpm), and the motor 2 It is determined whether the rotation speed is higher or lower than the set rotation speed. If the rotation of the motor 2 is slower than the set value, the process returns to step S2 to step up the duty cycle ratio, and if not, the process proceeds to step up S8 to step down the duty cycle ratio and then returns to step S3 to return to the motor 2 The duty ratio is increased or decreased until the number of rotations of the motor matches the set number of rotations to maintain the rotation speed of the motor at a constant value.

FIG. 9 is a flow chart in the case of calculating the weight of food based on the duty cycle ratio obtained in FIG. 8 and cooking based on the calculation result. First, after starting the cooking operation in step N1, step N
In 2, the logic operation control circuit 15 reads the duty ratio of the motor drive power source in the state of constant speed rotation, and calculates and calculates the food weight from the variation of the duty ratio.

For example, the torque applied to the tray rotation shaft and the motor drive average current are as shown in FIGS. 10 (a) and 10 (b), respectively. The logic operation control circuit 15 is shown in FIG.
The duty ratio is read at the torque data sampling timing shown in 0. Taking into consideration the weight detection accuracy when the food on the tray is placed at an eccentric position, the turntable tray makes one rotation for the average period of torque fluctuation. Every time the support roller supporting the tray makes 1/2 rotation, the same torque state is established. The maximum value of the duty ratio when the motor is rotating is dm
If ax and the minimum value are dmin, the difference D is D = dmax−dmin
Becomes When the number of protrusions on the bottom surface of the oven is 4, the maximum / minimum torque cycle is obtained 6 times, and the simple average from D ₁ to D ₆ is calculated and set as Dave. That is, Dave = (D ₁ + D ₂ + D ₃ + D ₄ + D ₅ + D ₆ ) / 6 The ratio between the food weight and the above Dave is obtained in advance by experimental data analysis, and the ratio is α, the food weight Fw is Fw = It can be calculated as α ・ Dave. This is the average of one turntable tray rotation, and the detected weight does not change whether the food is placed in the center of the tray or in the periphery. When the number of protrusions on the bottom of the oven is 5, the maximum / minimum cycle is 8 times for one turntable tray rotation, and a more accurate food weight can be calculated by calculating the data average 8 times.

Returning to the flowchart of FIG. 9, step N
In 3, the presence or absence of food load is determined based on the result of the weight calculation in step N2. If there is no food load, the process proceeds from step N3 to step N8 to stop the operation. If there is a food load, proceed to step N4. In step N4, the food weight data obtained in step N2 is added to the preselected cooking software program, the operation sequence until the end of cooking is arithmetically processed, and heating is started. Next, in step N5, the duty cycle ratio of the drive power source of the motor 2 that is rotating at a constant speed is read, and the food weight is calculated and calculated from the variation status. Then, in step N6, the calculated food weight is calculated in step N2.
Determine whether it is equivalent to the initial food weight calculated in. If they are not the same, the process proceeds to step N9 to compare with the predicted weight variation value according to the cooked food sequence, and step N10
Then, it is judged whether the food weight is within the predicted weight fluctuation value. If it is not within the predicted weight fluctuation value, it is determined that the state is abnormal and the operation is stopped in step N8. Equal weight in step N6, or step N6
If it is not judged to be an abnormal state in 10, the process proceeds to step N7, and it is determined whether or not the cooking of the food is completed. If it is not completed, the process proceeds to step N5.

As described above, the projection 8 is formed on the bottom of the oven.
Is provided so that the support roller 6 that supports the turntable tray 1 passes through the protrusion 8 and the weight of the food is calculated from the fluctuation of the driving torque of the motor 2. Accurate weight calculation can be performed even when placed eccentrically to the center. Also, since the weight of the food is calculated from the average torque during one turn of the turntable tray, the weight change of the food during cooking and heating can be calculated, and the cooking and heating program can be automatically corrected due to the weight change. Become. In the above embodiment, the support roller 6 is fixed to the support roller supporter 22 that rotates together with the turntable tray 1, and the protrusion 8 is provided on the bottom of the oven so that the support roller 6 can pass through the protrusion 8. The roller 6 may be directly fixed to the turntable tray 1, or the support roller supporter to which the support roller is fixed is fixed to the oven, and a protrusion is provided on the bottom surface of the turntable tray 1 so that the protrusion passes through the support roller. You may do so.

[0019]

As is apparent from the above, the microwave oven according to the first aspect of the present invention is rotatably fixed in the circumferential direction to a support member that rotates together with a turntable tray, and the microwave oven of the oven is rotated as the support member rotates. Protrusions through which the support rollers pass are provided at one or more locations on the circumference of the bottom surface of the oven that rotate on the bottom surface and contact a plurality of support rollers that support the turntable tray, and the rotation detection means is the above-mentioned. The drive voltage control means detects the rotation speed of the motor that rotationally drives the turntable tray, and drives the motor so that the rotation speed of the motor becomes a predetermined rotation speed based on the detection result of the rotation speed detection means. The voltage is controlled, the drive torque calculating means calculates the drive torque of the motor based on the drive voltage of the motor, and the weight calculating means calculates the drive torque of the motor. Since the weight of the food is calculated based on the average value of the driving torque calculated by the calculation means for one turn of the turntable tray, the weight of the food can be calculated regardless of how the food is placed on the turntable tray. The weight can be accurately calculated, and the weight change of food during cooking and heating can be calculated.

In the microwave oven of the second invention, the turntable is fixed to a supporting member fixed to the oven so as to be rotatable in the circumferential direction, and a plurality of supporting rollers supporting the turntable tray are in contact with each other. Protrusions through which the supporting rollers pass are provided at one or more positions on the circumference of the lower surface of the tray, the rotation detecting means detects the rotation speed of the motor for rotationally driving the turntable tray, and the drive voltage control means, The drive voltage of the motor is controlled so that the rotation speed of the motor reaches a predetermined rotation speed based on the detection result of the rotation speed detection means, and the drive torque calculation means controls the motor based on the drive voltage of the motor. The driving torque of the turntable tray is calculated as an average value of the driving torque calculated by the driving torque calculating means by the weight calculating means. Since so as to calculate the weight of the food Zui, it can accurately calculate the weight of the food regardless way of placing the food on the turntable tray,
In addition, it is possible to calculate the weight change of the food during cooking and heating.

[Brief description of drawings]

FIG. 1 is a sectional view showing a schematic configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing a positional relationship between a support roller and a protrusion in the above embodiment.

FIG. 3 is a development view showing the positional relationship between the support roller and the protrusions, where (a) shows four protrusions and (b) shows five protrusions.
The case of one place is shown.

FIG. 4 is a diagram showing a state in which the support roller passes through a protrusion.

FIG. 5 is a diagram for explaining fluctuations in the drive torque of the motor in the above embodiment.

FIG. 6A is a diagram for explaining the transmission of torque in the above embodiment and a motor control circuit diagram.

FIG. 7 is a diagram showing a relationship between a switching pulse for controlling a power supply voltage of the motor and a duty ratio or frequency of the switching pulse and a motor torque.

FIG. 8 is a flowchart of constant speed rotation control in the above embodiment.

FIG. 9 is a weight recognition outline flowchart in the cooking operation program in the above embodiment.

FIG. 10 is a diagram showing a torque applied to a tray rotating shaft and a motor drive average current in the above-described embodiment.

FIG. 11 is an external view of the above embodiment.

FIG. 12 is a configuration diagram of a conventional example.

FIG. 13 is a diagram showing a modification of the conventional example.

[Explanation of symbols]

1 ... Turntable tray, 2 ... Motor, 3 ... Gear box, 6 ... Support roller, 7 ... Oven, 8 ... Protrusion, 1
0 ... Perforated rotating disk, 11 ... Photo interrupter, 14
... Motor drive circuit, 15 ... Logic operation control circuit, 22
... Support roller supporter, 25 ... DC power supply circuit, 27 ... Power transistor.

Claims (2)

[Claims] 1. A turntable tray installed in an oven, a motor for driving the turntable tray to rotate, a support member that rotates together with the turntable tray, and a rotatably fixed to the support member in a circumferential direction. And a plurality of support rollers that rotate on the bottom surface of the oven and support the turntable tray as the support member rotates, a rotation speed detection unit that detects the rotation speed of the motor, and the rotation speed detection unit. Drive voltage control means for controlling the drive voltage of the motor so that the rotation speed of the motor becomes a predetermined rotation speed based on the detection result of the means, and the drive torque of the motor is calculated based on the drive voltage of the motor. On the turntable tray based on the driving torque calculation means for performing the driving torque calculation means and the driving torque calculated by the driving torque calculation means. A microwave oven equipped with a weight calculating means for calculating the weight of placed food, wherein the protrusions on one side or a plurality of places on the bottom surface of the oven that come into contact with the supporting roller pass through the supporting roller. And the weight calculating means calculates the weight of the food product based on an average value of the drive torque calculated by the drive torque calculating means for one turn of the turntable tray. microwave. 2. A turntable tray installed in an oven, a motor for driving the turntable tray to rotate, a support member fixed to the oven, and a rotation member fixed to the support member in a circumferential direction. In addition, a plurality of supporting rollers for supporting the turntable tray, a rotation speed detecting means for detecting the rotation speed of the motor, and a rotation speed of the motor having a predetermined rotation speed based on the detection result of the rotation speed detecting means. Drive voltage control means for controlling the drive voltage of the motor, drive torque calculation means for calculating the drive torque of the motor based on the drive voltage of the motor, and drive torque calculated by the drive torque calculation means A microwave oven equipped with a weight calculating means for calculating the weight of the food placed on the turntable tray based on Protrusions through which the support roller passes are provided at one or more locations on the circumference of the lower surface of the turntable tray that come into contact with the support roller, and the weight calculation means calculates the drive torque calculated by the drive torque calculation means. A microwave oven, wherein the weight of the food is calculated based on an average value of one turn of the turntable tray.