JPH01302036A - Microwave - Google Patents

Abstract

PURPOSE:To eliminate a variation with time of a measured value of a weight of food and get a stable measured value having small temperature drift by a method wherein a core member is moved up or down within a differential coil insertion hole as a leaf spring member placed below a rotary plate is displaced. CONSTITUTION:In case that a food is placed on a rotary plate 1 in an electric oven, a core member 13 can be moved up or down within an insertion hole 11a for a differential coil 11 by a displacement of each of upper and lower leaf springs 7 and 8 moved up or down in response to a weight of the food. The weight of the food can be detected as an output voltage of the differential coil caused by the moving-up or down movement of the core member 13. Accordingly, no variation with time of the measured value is found and a point adjustment is not required during use, so that this device has a remarkable effect of providing a superior convenience in use.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a microwave oven that is excellent in measuring the weight of food.

(Summary of the Invention) This invention provides a plate spring member that is displaced according to the weight of the food on the underside of a rotary plate on which food is placed, and the core member is moved through the insertion of the differential coil as the plate spring member is displaced. This is a microwave oven configured to move up and down within a hole, and measures the weight of food by converting it into DC voltage.

(Prior art and its problems) Microwave ovens that electromagnetically heat food are well known, but this type of oven is configured to measure the weight of each food placed on a rotary plate for electromagnetic heating. has been done.

For this reason, conventional microwave ovens have been provided with weight sensors using strain gauges.

In other words, a rotary plate, which is a rotatable tray for food that is rotatably installed in the microwave, is supported by a leaf spring, and a strain gauge is attached to this leaf spring with adhesive. The weight of food is measured by converting the resistance change of the strain gauge due to displacement into voltage.

However, the strain gauge-based weight sensor has a problem in that errors occur in weight measurement due to changes over time in the adhesive used to attach the strain sensor to the leaf spring or drift due to temperature.

For this reason, it is necessary to perform so-called zero-point adjustment from time to time during use to correct the weight sensor so that it shows an accurate measurement value, forcing users such as housewives to perform zero-point adjustment. There is a problem in that food weight measurement becomes inaccurate if it is used without adjustment.

(Objective of the Invention) This invention was made in view of the above-mentioned problems, and its purpose is to provide a stable measured value of food weight that does not change over time and has little temperature drift. Our goal is to provide you with an oven microwave oven that you can use.

(Structure and Effects of the Invention) In order to achieve the above object, the present invention provides an oven that has a rotary plate on which food is rotatably placed, and that measures the weight of the food placed on the rotary plate. The microwave oven includes: a leaf spring member that is displaced by a load from the rotary plate; a core member that moves up and down with the displacement of the leaf spring member; and an insertion hole into which the core member is inserted so as to be able to move up and down. and a differential coil having a coil wound around the insertion hole, and the core member moves up and down in the insertion hole of the differential coil according to the weight of the food on the rotary plate. It is characterized in that a moving coil converts the weight of food into an output voltage.

That is, as described above, the present invention is configured to displace the core member according to the weight of the food placed on the rotary plate, and detect the weight of the food from the output voltage of the differential coil due to the displacement. , the measured values do not change over time, and stable measured values with little temperature drift can be obtained.

Furthermore, since there is no need to perform zero point adjustment during use, it has the advantage of being extremely easy to use.

(Description of Embodiments) Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a sectional view showing a structure for measuring the weight of food in a microwave oven according to the present invention, and FIG. 2 is an exploded perspective view thereof.

In the same figure, 1 is a rotary plate, and the upper surface of this rotary plate 1 has a glass concave or enamel plate (
A tray (as shown) is placed on the tray, and food is placed on this tray.

The lower surface of the rotary plate 1 is covered with a support plate 2 and has a drive means 3. A spring mechanism 41 and an operating voltage mechanism 5 are arranged.

The drive means 3 includes a drive motor 6a built into a motor stand 6, and a motor shaft 6b that rotates in conjunction with the motor 6a.
is formed to protrude vertically upward from the motor stand 6, and the support plate 2
It is rotatably inserted through a hole 2a formed in the rotary plate 1, and its upper end is fitted into a fitting hole 1a provided in the center of the lower surface of the rotary plate 1, so that the rotary plate 1 is rotated according to the drive of the motor 6a. It is composed of

The spring mechanism 4 includes upper and lower leaf spring members 7 and 8 in the shape of an opening, whose middle edges are fixed in parallel to one end side of the motor base 6 via a movable plate 9, and whose ends on the opening side are fixed. are fixed to the upper and lower surfaces of the fixed base 10.

On the other hand, the fixing base 10 has a supporting piece 10a protruding from the upper surface thereof, which is inserted into the opening of the upper plate spring member 7, and the single-shaped flanges 2b, 2b of the supporting plate 2 from the left and right ends. Attachment portions 10b, 10b that are fixed to are formed in an upright manner.

Therefore, the flat plate surface of the support plate 2 is connected to the mounting part 1 of the fixed base 10.
0b and 10b, and the upper plate spring member 7
And when the support plate 2 is attached and attached to the support plate 10a of the fixed base 10,
The upper and lower leaf spring members 7.8 and the motor base 6 attached in parallel to the upper and lower leaf spring members 7 and 8 are bent downward using the fixed base 10 as a fulcrum.

Further, a differential voltage mechanism 5 consisting of a differential coil 11 is fixed to the lower surface side of the support piece 10a of the fixed base 6, and the rod-shaped portion 13a of the core member 13 is freely attached to the center of the differential coil 11. A bobbin (path shown) having an insertion hole 11a large enough to be inserted and removed, and one primary winding n4 in the center of this bobbin.
．． Furthermore, two secondary windings n2. n2- is wound, and this bobbin is surrounded by a case 11b.

Roughly speaking, in this differential coil 11, screws 12.12 passing through the support plate 2 and the support piece 10a of the fixing base 10 are screwed into the screw holes 11C and 11G provided on the top surface, so that the fixing base 10 It is fixed to the lower surface side, and the support plate 2
The core member 13 is vertically movably inserted into the bobbin insertion hole 11a through the opening 10C formed in the support piece 10a.

In other words, the upper part of the core member 13 is a rod-shaped part 13a, the diameter of which can freely go in and out of the insertion hole 11a provided in the differential coil 11, and the length of which is approximately equal to the height of the differential coil 11. are formed identically.

Further, a female screw is provided at the bottom of the lower part, and a screw 14 is inserted into the female screw and passes through the tip of the arm 9a that protrudes from the movable piece 9 that connects the upper and lower spring members 7 and 8 and the motor stand 6. The core member 13 is held upright by being screwed.

Since the differential coil 11 is fixed to the support piece 10a of the fixed base 10, its position does not move up and down, but the arm 9a is connected to the movable piece 9 and the motor base via the upper and lower spring members 7 and 8. 6 moves up and down, the core member 13 attached to the tip of the arm 9a can move up and down within the insertion hole 11a of the differential coil 11.

FIG. 3 shows the electrical configuration of the differential coil 11. When a pulse voltage having a predetermined frequency is supplied to the secondary winding n1 from a power source (not shown), the secondary winding n1 n2. An induced voltage is generated at n2- by the principle of an operating transformer.

Secondary winding n2. The voltage induced in n2- is the -th winding n
, and the secondary winding n2*n, , - are in a relationship proportional to the amount of interposition (insertion m) of the core member 13 interposed between them.

That is, as the amount of core member 13 inserted into differential coil 11 increases, in other words, as the amount of core displacement increases, the voltage across secondary windings n2*n2- changes in proportion to this.

Therefore, when the induced voltage of the secondary winding '2+ n2- is rectified by the rectifier circuits 16a and 16b and the ripple voltage is removed by the capacitor 17, the output voltage of the output terminal 18 becomes equal to that of the core member 13 as shown in FIG. It is output as something proportional to the amount of displacement.

Since the present invention is configured as described above, when food is placed on the rotary plate 1, the core member is 13 can move up and down within the insertion hole 11a of the differential coil 11, and the weight of food can be detected as the differential coil output voltage due to the up and down movement of the core member 13.

Therefore, according to the microwave oven according to the present invention, it is possible to perform stable measurements with no change in measured values over time and with little temperature drift.

Furthermore, since there is no need to perform zero point adjustment during use, it has the advantage of being extremely easy to use.

Note that it can be used as a scale by displaying the DC voltage as a graph using a well-known analog meter or converting this voltage into f-digits.

Also, the motor fixed position @L4. The distance between the upper leaf spring member 7 and the lower leaf spring member 8, and the length L3 of the upper leaf spring member 7 and the lower leaf spring member 8. By creating a structure in which the ratio of the measurement points @L2 is in a constant relationship, it is possible to obtain excellent unbalanced load characteristics.

Next, a further embodiment of the present invention will be described with reference to FIG.

That is, in this embodiment, in addition to shielding the side surfaces of the differential coil 11, the top and bottom surfaces of the differential coil 11 are further shielded.

That is, the differential coil 11 combines the coil upper frame 15b and the coil lower frame 15a, and the crimped portion 1 of the coil lower frame 15a
It is held by caulking 5c to prevent magnetic flux leakage in the vertical direction and increase output voltage by effectively utilizing magnetic flux.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a food weight measurement structure according to the present invention, Fig. 2 is an exploded perspective view of Fig. 1, Fig. 3 is a circuit diagram showing the electrical configuration of the differential coil, and Fig. 4 is A graph showing the relationship between the displacement of the core member and its output voltage, and FIG. 5 is a perspective view of a differential coil showing another embodiment of the present invention. 1... Rotary plate 2... Support plate 6... Motor stand 7... Upper spring member 8... Lower spring member 9... Movable plate 10... Fixed base 11... Differential Coil 11a...Insertion hole 13...Core member

Claims (1)

[Claims] 1. In an oven microwave oven having a rotary plate on which food is rotatably placed and measuring the weight of the food placed on the rotary plate, the weight of the food placed on the rotary plate is measured. It has a leaf spring member that is displaced, a core member that moves up and down with the displacement of the leaf spring member, an insertion hole into which the core member is inserted so as to be able to move up and down, and a coil wound around the insertion hole. The core member moves up and down in the insertion hole of the differential coil according to the weight of the food on the rotary plate, and the differential coil converts the weight of the food into an output voltage. An oven microwave oven characterized by: