JPS626410Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a microwave oven, and more specifically, to an electronic microwave oven equipped with an infrared temperature detection device that detects the temperature of food by entering infrared rays emitted by food placed in a heating chamber. This is an improvement of the above-mentioned detection device in a microwave oven.

When equipping a microwave oven with an infrared temperature detection device, it is necessary to sufficiently isolate the infrared sensor included in the device from the microwaves leaking from the heating chamber, and to prevent the temperature inside the device from rising due to the heat transmitted from the heating chamber. It must not rise.

The present invention satisfies the above requirements and also provides a device with a simplified structure.The present invention will be explained in the following examples.

The infrared temperature detection device 1 is mounted on the outer surface of the upper wall 2 of the heating chamber of the microwave oven with screws, and the device includes a first metal box 4 surrounding the infrared sensor 3, and a first metal box 4 surrounding the box. It has a cooling air inlet 6 connected to the blower device 5, and a second metal box 7 forming a cooling air passage between it and the first box 4 as shown by the arrow in the figure.

The second box 7 has a substantially rectangular metal upper body 7a.
and a lower body 7b are joined together at a surrounding flange 8, and a metal partition plate 9 is provided between the joints.
is inserted to divide the second box 7 into an upper chamber and a lower chamber. Hole 1 drilled around partition plate 9
0 and 10, together with exhaust holes 11 and 11 bored in the side wall of the lower body 7b, substantially constitute the cooling air passage. As a result, the heat in the heating chamber hardly causes an undesired increase in the temperature of the device.

The infrared rays emitted by food placed in the heating chamber are
Opening 12 in heating chamber upper wall 2 and second box lower body 7
The infrared rays enter the second box 7 through the infrared infrared introduction port 13 provided on the bottom wall of the heating chamber. A metal cylinder 14, which is welded and fixed in alignment with the second box 7, protrudes into the lower chamber of the second box 7. Due to the action of the plunger solenoid 15 fixed to the bottom wall of the second box lower body 7b, the shutter 17 rotates horizontally about a fulcrum shaft 16 also fixed to the bottom wall, and the upper opening of the metal cylinder 14 is caused to rotate. Open and close.

The first box 4 has a partition plate 9 as its bottom wall, and has a first side wall 4a and a second side wall 4b fixed to the bottom wall with screws. These side walls are integrally molded by aluminum die-casting, and the first side wall 4
a has a substantially rectangular frame shape, and the second side wall 4b has a substantially semicylindrical shape. The top opening of the second side wall 4b is covered by a horizontal wall 4c, which is also integrally molded, and an inner cylinder 4d, which is also integrally molded, hangs down from the horizontal wall 4c at the center of the horizontal wall 4c. A portion of the right side of the rectangular frame-shaped first side wall 4a extends inward to form a left portion of the inner cylinder 4d, so that the top opening of the inner cylinder 4d has a circular shape.

The top opening of the first side wall 4a is covered with a metal plate 20, and a motor 21 is inserted into the inner cylinder 4d. The motor 21 has a metal outer wall including its front plate, and the flange 21a of the front plate
is in contact with the lower surface of the inner cylinder 4d, and the flange 21
A pair of ears 21b formed in the inner cylinder 4d
It is screwed to the lower surface of the thick part 4e. Here, together with the partition plate 9, the first and second side walls 4a, 4b, and the metal plate 20, the outer wall of the motor 21 itself is
It should be noted that the walls of the box 4 are constructed and that the outer wall of the motor faces the cooling air path.

The hole 22 formed in the partition wall 4f that is integrally formed with the first side wall 4a and partitions the inside of the side wall is formed in the partition plate 9.
The first box 4 is aligned with the opening at the top of the metal cylinder 14 along with the infrared introduction hole 23 provided in the first box 4 .

The infrared sensor 3 is supported by an insulating plate 25 fixed to a column 24 integrally formed with the first side wall 4a, and is aligned with the infrared introduction hole 23. The infrared sensor 3 includes a pyroelectric crystal and a preamplifier that amplifies the voltage generated by the crystal, and its output signal line 26
extends to the outside via feedthrough capacitors 27 and 28, which are provided through the metal plate 20 and the second box upper body 7a, respectively. Microwave noise directly picked up by the infrared sensor 3 significantly deteriorates the S/N ratio, but the sensor 3 is double sealed with the first box 4 and the second box 7, so the microwave noise leaking from the heating chamber is prevented. effectively isolated from Since the infrared sensor 3 is isolated from the motor 21 and the solenoid 15 by the partition wall 4f, it is hardly affected by other external noises.

Chopper body 30 rotationally driven by motor 21
is made of a perforated disk, and interrupts the infrared ray introduction path leading to the infrared sensor 3 at regular intervals. A photo interrupter 31 fixed to the partition plate 9 detects the rotation of the chopper body 30, and a diode 33 insulatively attached to the lower surface of the column 32 that hangs integrally from the horizontal wall 4c detects the rotation of the chopper body 30. Detect temperature.

As is well known, the infrared sensor 3 has a chip body 30.
The food temperature is detected based on the temperature of Temperature fluctuations in the tipper body 30 are corrected. What should be noted is that the infrared sensor 3, chopper body 30, and diode 33 are housed in the first box 4 and placed under almost windless conditions. That is, as a result, the infrared sensor 3 is less susceptible to fluctuations in ambient temperature, and the difference between the temperature detected by the diode 33 and the temperature of the chopper body 30 is almost eliminated.

Although not shown, plunger solenoid 1
5. Each power supply line to the motor 21 and the photo interrupter 31 and each output signal line of the photo interrupter 31 and the diode 33 extend outside the second box 7.

The operation of the above device is as follows. In a standby state when heating is not being performed, the shutter 17 closes the top opening of the metal cylinder 14 to prevent steam and the like from the heating chamber from entering the apparatus. When heating starts, the shutter 17
is opened, and the blower device 5 operates to introduce cold air into the device, and power is supplied to the motor 21 and photointerrupter 31, so that the infrared sensor 3 obtains a temperature-corresponding signal voltage. At this time, the infrared sensor 3 detects the first and second boxes 4,
The first box 4 is double-sealed by the heating chamber 7, and is not affected by microwave noise leaking from the heating chamber.Since the area around the first box 4 is cooled, the infrared sensor 3 and the chopper body 30 are not damaged by the heat transmitted from the heating chamber. The infrared sensor 3, the chopper body 30, and the diode 33 are all placed under a windless condition, which improves the accuracy of the detected temperature.Furthermore, the motor 21 itself is cooled, so there is no increase in temperature due to its self-heating. It is now clear that there is no undesired temperature rise in the first box 4, etc. A portion of the cooling air is blown into the metal cylinder 12 to prevent steam from the heating chamber from entering the apparatus.

Thus, according to the present invention, in a microwave oven equipped with an infrared temperature detection device that detects the temperature of the food by inputting infrared rays emitted by the food placed in the heating chamber, microwaves leaking from the heating chamber and It eliminates the influence of heat transmitted from the heating chamber, and since the motor for driving the chopper body included in the device itself constitutes the necessary partition wall, the motor can be cooled with a simple configuration, and furthermore, the infrared sensor etc. can be kept in a windless state. Placed at the bottom, detection accuracy increases.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of an embodiment of the present invention, FIG. 2 is a plan view of the main part, and FIG. 3 is a perspective view of the main part. 3...Infrared sensor, 4...First box, 7
...Second box, 21...Motor, 30...Chiyotsupa body.

Claims (1)

[Scope of utility model registration request] In a microwave oven equipped with an infrared temperature detection device that detects the temperature of the food by receiving infrared rays emitted by the food placed in the heating chamber, the device includes a first metal box surrounding the infrared sensor. and a second metal box surrounding the box and having a cooling air inlet and forming a cooling air path between the box and the first and second boxes. An infrared introduction hole communicating with the heating chamber is provided to introduce the infrared rays into the heating chamber, and a chopper body is disposed in the first box to interrupt the infrared ray introduction path at regular intervals, and a wall constituting the first box is provided. A part of the microwave oven is occupied by a motor for driving the chopper body, and an outer wall of the motor faces the cooling air passage.