KR100371230B1 - Weight detecting device a microwave oven - Google Patents

Abstract

The object of the present invention is to realize a miniaturization and a low cost in a weight detection apparatus used in a microwave oven and the like, and to enable high-precision weight detection.

As a means for solving this, the thrust shaft 41 which displaces in the thrust direction according to the weight, the first relative displacement detecting member 42 which rotates in accordance with the displacement of the thrust shaft, and the thrust shaft 41 The second relative displacement detecting member 43 and the first and second relative displacement detecting members 42 and 43 rotating under the rotational driving force from the rotating driving means 12 without being rotated depending on the displacement of the. Thrust shaft 41 is displaced by engaging the first and second relative displacement detecting members 42 and 43 and the thrust shaft 41 with a position fixing means for fixing the position in the circumferential direction. When the first relative displacement detection member 42 is rotated by a predetermined rotational angle according to the displacement amount, when the second relative displacement detection member 43 is rotated under the driving force from the rotation driving means 12, the rotation force Can be transmitted to the first relative displacement detecting member 42 and the thrust shaft 41. Rotational displacement means (consists of a pin 44a, an inclined groove provided in the first relative displacement detecting member 42 and an axial groove provided in the second relative displacement detecting member 43), A magnet and a hall element 47 for outputting a signal corresponding to the relative displacement amount of the first relative displacement detection member 42 with respect to the second relative displacement detection member 43 are provided.

Description

WEIGHT DETECTING DEVICE A MICROWAVE OVEN}

The present invention relates to a weight detection device for electrically detecting the weight in the thrust direction and an improvement of a microwave oven using a two-weight detection device.

Recently, microwave ovens have been used as sensors for measuring temperature or weight. Conventionally, the weight detection device as a weight sensor has been adopted various methods such as capacitive type and piezoelectric element type, but nowadays, capacitive type is mainstream. The capacitive weight detection device detects a small amount of displacement of an output shaft (thrust shaft) that is displaced by the weight of a cook placed on a turntable based on a change in capacitance between parallel plates.

However, in the conventional capacitive weight detection device, the oscillation circuit is provided and the capacitance of the variable capacitor is changed to the distance between electrodes. Therefore, there is a concern that the stray capacitance generated in the wiring pattern on the printed circuit board, etc. may be affected. In order to cope with this, it is necessary to secure a predetermined capacitance or more. In addition, considering the non-uniformity of component dimensions, a distance between electrodes is required. For this reason, there exists a problem that the opposing area between electrodes increases, and an apparatus becomes large.

In addition, when the conventional weight detection device is applied to a microwave oven, the displacement amount in the thrust direction of the turntable can be detected, but the rotation driving means and the weight detection device for rotating the turntable are independent. Therefore, after assembling each other, the two are combined, so that the number of assembling steps increases and the shape after combining the two is difficult to be compacted, thereby making it impossible to avoid the enlargement of the apparatus.

It is therefore an object of the present invention to provide a weight detection device capable of miniaturization and stable weight detection and a microwave oven using the weight detection device.

According to the weight detecting apparatus of the present invention, when the thrust shaft is displaced in the thrust direction according to the weight, the first and second relative displacement detecting members are rotated relative to the thrust shaft by a predetermined rotational angle according to the displacement amount of the thrust shaft. The positional relationship of both is maintained by the position fixing means. By this operation and position fixation, the relative displacement amount of both relative displacement detection members is reliably quantified by a stable operation, and converted into weight by weight conversion means. Specifically, a signal proportional to the relative displacement amount of the first relative displacement detection member relative to the second relative displacement detection member, for example, a time interval ratio signal proportional to this relative displacement amount, is output as a weight detection signal, and the weight The weight is detected based on the detection signal.

As a means for outputting the weight detection signal, for example, a magnet and a hall element are used, and the weight detection signal is based on the relative displacement between the magnet on the side of the first relative displacement detection member and the magnet on the side of the second relative displacement detection member. To get

As described above, the weight detection device of the present invention, unlike the capacitive weight detection device, copes with various problems that the capacitance type has in the past, for example, to affect floating capacity generated in a wiring pattern on a printed board. Since a certain amount of capacitance is ensured, there is no problem such as an increase in the opposing area between electrodes or an increase in size of the device, so that a small and highly accurate weight detection is possible. In addition, since the position fixing is performed reliably, it is possible to supply a numerically stable amount of displacement.

In the weight detecting apparatus of the present invention, the basic configuration and operation are as described above, that is, when the thrust shaft is displaced in the thrust direction according to the weight, the first and second relative displacement detecting members are thrust according to the displacement amount of the thrust shaft. It rotates relative to the axis by a predetermined rotational angle. In addition, these first and second relative displacement detecting members are urged in the thrust direction by the urging means, and the end faces are pushed to the reference plane at all times. Therefore, since the start of operation of the first and second relative displacement detection members (starting of the detection operation of the heavy object) is always made in a position where the reference planes are in contact with each other, high-precision weight detection becomes possible. In addition, the combination of the above-described configuration, that is, the configuration related to the position fixing improves the detection accuracy.

In addition, a microwave oven using such a weight detection device as a weight detection device for measuring the weight of a cooked product placed on a turntable can be made to have a small weight detection portion, thereby miniaturizing the entire microwave oven. In particular, when the second relative displacement detecting member serves as the output value of the deceleration lubrication heat which slows down the rotational force from the driving source for rotating the turntable, the rotation driving means and the weight detecting part can be integrated. Compared with the conventional part having a separate part, it is possible to reduce the number of assembly steps and to reduce the number of assembly steps.

1 is a side sectional view showing an embodiment of a weight detection apparatus of the present invention.

2 is an exploded perspective view of the weight detection apparatus shown in FIG.

3 is a plan view of the weight detection apparatus shown in FIG. 1 seen from the bottom of FIG. 1;

Figure 4 is a bottom view of the weight detection device shown in Figure 1 seen from above.

5 is a perspective view illustrating in detail the first relative displacement detection member shown in FIGS. 1 and 2.

6 is a perspective view illustrating in detail the second relative displacement detection member shown in FIGS. 1 and 2.

Fig. 7 shows the effect of the bushing spring as the position fixing means in the weight detecting apparatus according to the embodiment of the present invention. The figure which shows how much difference there existed in the measurement conversion value with weight, (a) is a case where a bushing spring is not arrange | positioned and (b) is a graph when a bushing spring is arrange | positioned.

FIG. 8 is a diagram showing the relationship between the first relative displacement detection member and the second relative displacement detection member of the weight detection apparatus shown in FIG. 1, (a) is a front view when no load is applied to the turntable; FIG. , (b) is a front view where the maximum load on the turntable is applied.

9 is a sectional view taken along the line IX-IX of FIG. 1.

Fig. 10 is a diagram showing the characteristics of the coil springs used in the weight detection apparatus shown in Fig. 1;

FIG. 11 is a plan view showing a leaf spring of the weight detection device shown in FIG. 1; FIG.

Fig. 12 is a view showing the effect of the leaf spring as the biasing means in the weight detection device shown in Fig. 1, (a) when arranging the leaf spring, (b) does not arrange the leaf spring. In each case, a graph showing the nonuniformity between the actual weight and the measured conversion value.

FIG. 13 is a view for explaining the positional relationship between the magnets on the side of the first relative displacement detection member and the magnets on the side of the second relative displacement detection member and the arrangement of the hall IC of the weight detection apparatus shown in FIG. a) is a figure which shows the case where a load is not applied to a turntable, (b) is a figure which shows the case where the maximum load is applied to a turntable.

FIG. 14 is a diagram showing an output signal of the hall IC used in the weight detection apparatus shown in FIG. 1, (a) is a diagram showing an output signal when no load is applied to the turntable, (b) A diagram showing an output signal when the maximum load is applied to the turntable.

Fig. 15 shows the load on the turntable of the weight detection device shown in Fig. 1 as the horizontal axis, and the magnet on the first relative displacement detection member side with respect to the Hall IC output by the magnet on the second relative displacement detection member side. Graph showing the time interval of Hall IC output by the vertical axis (= phase difference of magnet (A) (B)).

Fig. 16 shows the load applied from the turntable to the weight detection apparatus shown in Fig. 1 as the horizontal axis, and the magnet on the second relative displacement detection member side with respect to the Hall IC output by the magnet on the side of the first relative displacement detection member. Graph showing the time interval of Hall IC output by the vertical axis (= phase difference of magnet (A) (B)).

Next, an embodiment of the present invention will be described with reference to FIGS. 1 to 16. In this embodiment, an example in which the weight detection device is applied to a microwave oven will be described. When applied to a microwave oven, the amount of displacement of the turntable on which the food is placed is taken out as a signal indicating the weight of the food as described above, and the control such as determining the irradiation time of the microwave based on the signal indicating the weight. Is done.

First, the overall configuration will be described with reference to FIGS. 1 to 6. The weight detection apparatus 1 rotates the turntable 11 in large divisions and simultaneously rotates the first and second relative displacement detection members 42 and 43, which will be described later, integrally with the thrust shaft 41. It consists of the drive means 12 and the weight detection part 13 which detects the thrust displacement amount of the turntable 11, and each of these components is accommodated in one metal casing 14. As shown in FIG. In addition, the casing 14 is composed of a case body 14a and a case cover 14b, and the first and second relative displacement detection members are formed by the bottom surface of the case body 14a and both inner surfaces of the case cover 14b. (42) (43) is arrange | positioned in the up-down direction. That is, the bottom surface of the case body 14a and the case cover 14b are both square plates of the casing 14.

The rotation driving means 12 includes a motor 20 as a driving source (a synchronous motor is used here), a first gear 31 as deceleration lubrication heat which decelerates the rotational force of the motor 20 and transmits it to the turntable 11; The second gear 32, the third gear 33, the second relative displacement detecting member 43 serving as the output gear, the reversing prevention lever 34a and the reversing prevention lever which prevent the reversal of the motor 20. It consists of a gear 34 for reversing prevention lever rotation arrange | positioned coaxially with 34a. In addition, the reversing prevention lever 34a and the reversing prevention lever rotation gear 34 are urged in the thrust direction by the spring 34b.

The motor 20 is comprised from the coil 21, the rotor 22, the fixed shaft 23, the pinion 24 fixed to the rotor 22, the stop plate 25, etc. Further, at the root portion of the ions 24, projections 24a and 24a are provided to prevent the reversal of the rotor 22 by contacting the reversal prevention lever 34a when the rotor 22 rotates. Therefore, when the rotor 22 rotates in the forward direction, the protrusions 24a of the rotor 22 and the reversal prevention lever 34a do not engage, and the rotor 22 rotates freely, but the reverse rotation is prevented when the rotor 22 rotates in the reverse direction. The projection 34c of the lever 34a collides with the projection 24a to prevent rotation of the rotor 22.

The first gear 31 and the second gear 32 are attached between the stop plate 25 and the case cover 14b by the shafts 31a and 32a, respectively, and the third gear 33 is the shaft ( 33a) is attached between the case body 14a and the case cover 14b. In addition, although the extreme value constituting the stator of the motor 20 is erected from the case body 14a toward the rotor 22, the label 26 is provided in the case so as to prevent a hole which becomes the remainder which formed the extreme value. It adheres to the main body 14a.

The weight detection unit 13 is coupled to the thrust shaft 41 and the thrust shaft 41 having one end fixed to the center of the turntable 11 and displaced in the thrust direction according to the weight applied to the turntable 11. The first and second relative displacement detection members 42 and 43, and the two relative displacement detection members 42 and 43, which are provided in accordance with the displacement amount of the thrust shaft 41, A rotational displacement means 44 for rotating displacement, a bushing spring 45 as position fixing means for fixing the positional relationship in the rotational direction of the first and second relative displacement detecting members 42 and 43, and will be described later. The main components include the weight detection signal output means and the coil spring 46 disposed on the front end side of the thrust shaft 41. The signal output from the weight detection signal output means is converted into weight by weight conversion means (not shown) made of a microcomputer.

In addition, the first and second relative displacement detecting members 42 and 43 are provided coaxially to the thrust shaft 41 so as to be paired with each other. The first relative displacement detection member 42 is rotated according to the displacement of the thrust shaft 41 in the thrust direction, and the second relative displacement detection member 43 is the thrust of the thrust shaft 41. It rotates by receiving the rotation drive force by the rotation drive means 12, without rotating depending on the displacement of the direction. The second relative displacement detecting member 43 also serves as an output gear that is coupled to other teeth as part of the deceleration lubrication train constituting the rotation driving means 12.

The rotation displacement means 44 engages the first and second relative displacement detecting members 42 and 43 and the thrust shaft 41, and when the thrust shaft 41 is displaced in the thrust direction, the first displacement means 44 is used. The relative displacement detecting member 42 is rotated about the thrust shaft 41 by a predetermined rotational angle in accordance with the displacement amount of the thrust shaft 41, and the second relative displacement detecting member 43 is a rotation driving means. When rotating under the driving force at (12), the rotational force is transmitted to the thrust shaft 41. The rotation displacement means 44 is an inclined groove 42b and 42c formed in the first relative displacement detecting member 42 and an axial groove 43b formed in the second relative displacement detecting member 43. 43c and the grooves 42b and 43b and the grooves 42c and 43c when the first and second relative displacement detecting members 42 and 43 are fitted to the thrust shaft 41 to fit each other. It consists of the pin 44a inserted in the overlapping part of 43c), respectively. These details will be described later.

The bushing spring 45 is formed of a coil spring and serves as position fixing means for fixing the positional relationship in the rotational direction of the first and second relative displacement detecting members 42 and 43. If the position fixing by this bushing spring 45 is not performed, a nonuniformity will arise at the time of a weight measurement.

That is, when the motor 20 is configured to be bidirectionally rotated, and the configuration of the position fixing bushing spring 45 is not arranged, as shown in FIG. 7A, the turntable 11 is clockwise (hereinafter, Non-uniformity occurs in the measurement conversion value when rotating in the CW direction) and when rotating in the counterclockwise direction (hereinafter referred to as CCW direction).

On the contrary, even if the bidirectional rotation is possible, if the position fixing bushing spring 45 is arranged, as shown in Fig. 7 (b), the measurement is performed when the turntable 11 rotates in the CW direction and when it rotates in the CCW direction. The nonuniformity does not arise in conversion value. In addition, even when the motor 20 is rotated in one direction and the turntable 11 is rotated in one direction as in the present embodiment, the bushing springs 45 allow the first and second relative displacement detection members 42 and 43. Positional relationship in the circumferential direction can be fixed accurately.

In addition, in the above-described position fixing means, as shown in FIG. 9, the bushing spring 45 moves the first relative displacement detecting member 42 in the circumferential direction with respect to the second relative displacement detecting member 43. As shown in FIG. 8, each contact position W1 of the groove | channel 42b and the groove | channel 42c formed in the pair of the pin 44a and the 1st relative displacement detection member 42 is made into the groove | channel 42b as shown in FIG. One side 42c1 and 42b1 of 42c is provided. On the other hand, the contact position W2 of the pin 44a and the grooves 43b and 43c when the turntable 11 rotates is always positioned at the other sides 43b2 and 43c of the grooves 43b and 43c. do. As a result, since the pins 44a are suppressed so as not to rattle in the overlapping grooves, the positional relationship in the circumferential direction of the first and second relative displacement detecting members 42 and 43 is always fixed in the same state.

The bushing spring 45 stores the protrusion 51d of the first relative displacement detecting member 42 and the second relative displacement detecting member 43 formed on the same radius about the thrust shaft 41. Both ends are supported in the compressed state in the containment part which consists of the wall 52d and the pressing protrusion 52e. Accordingly, the bushing spring 45 is configured to impart a bias force in the circumferential direction with respect to the first relative displacement detection member 42 on the basis of the second relative displacement detection member 43. This auxiliary force generates the first relative displacement detecting member 42 in the axial force F1 toward the reference plane side described later by contacting the pin 44a. For this reason, the axial position of the 1st relative displacement detection member 42 also becomes a constant position (= the position which contacts a reference plane).

The weight detection signal output means outputs a signal corresponding to the relative displacement amount of the first and second relative displacement detection members 42 and 43 as the weight detection signal. The weight detection signal output means includes three magnets (B1) (B2) and (B3) serving as the to-be-detected body provided on the side of the first relative displacement detection member 42 as shown in FIG. 9, and the second relative displacement detection member. Three magnets (A1) (A2) and (A3) serving as the to-be-detected body provided on the (43) side, and magnets generated by these magnets (B1 to B3) and (A1 to A3) are converted into electrical signals. It becomes the hall IC 47 which consists of. In addition, these details are demonstrated later.

The weight detection part 13 of such a structure is demonstrated in more detail. As shown in FIG. 1, one end (rear end) of the thrust shaft 41 is coupled to or fixed to the turntable 11, and transmits the rotational force of the motor 20 to the turntable 11 while cooking the turntable 11. As the product is raised, it is lowered in the thrust direction together with the turntable 11. On the other end (tip) side of the thrust shaft 41, a push 48 and a cap member 49 for pushing down the coil spring 46 are attached.

As the coil spring 46, a coil spring called a so-called square coil spring having a four-sided cross section is used, and a bias force is applied to the thrust shaft 41 against the force to be lowered by the thrust shaft 41. That is, the thrust shaft 41 is supported by the coil spring 46 and is displaced in the thrust direction against the restoring force of the coil spring 46 according to the weight.

In addition, the first relative displacement detecting member 42 has a cylindrical shape as shown in Fig. 5, and a hole 42a through which the thrust shaft 41 penetrates is formed in the center thereof. In the side cylindrical portion, a pair of grooves 42b and 42c are formed at positions facing each other with a central axis therebetween. The grooves 42b and 42c are formed to be inclined at a predetermined angle with respect to the central axis direction. Further, magnet loading portions 51a, 51b, 51c for loading magnets B1, B2, and B3 arranged at intervals of 120 DEG are provided outside the side cylindrical portions. The magnet loading portion 51a, which is one of these magnet loading portions 51a, 51b, 51c, is used for fixing the positional relationship in the rotational direction of the first and second displacement detecting members 42, 43. A protrusion 51d is provided to hang the one end side of the bushing spring 45. Moreover, the other end side of this bushing spring 45 is loaded in the storage part which consists of the containment wall 52d and the pressing protrusion 52e provided in the 2nd relative displacement detection member 43. As shown in FIG.

On the other hand, the second relative displacement detection member 43, which also becomes an output value, has a cylindrical shape with one end at the bottom and the other end opened as shown in FIG. 6, and the inner diameter thereof is the first relative displacement detection member ( Slightly larger than the outer diameter of 42, the inner cylinder portion 43a is formed concentrically. The outer diameter of the inner cylindrical portion 43a is slightly smaller than the inner diameter of the first relative displacement detecting member 42, and the side cylindrical portion has a recessed in a pair of axial directions at opposing positions with the central axis of the cylinder interposed therebetween. 43b and 43c are formed.

A hole 43d for penetrating the thrust shaft 41 is formed in the central portion at the bottom side of the second relative displacement detecting member 43. In addition, the second relative displacement detecting member 43 is provided with a tooth on its outer surface and meshes with the third tooth 33 of the rotation driving means 12 to serve as an output tooth.

The second relative displacement detection member 43 is in contact with a leaf-like spring 50 whose one end is a metal plate-like spring member shown in FIG. The leaf-shaped spring 50 is disposed between the first and second relative displacement detecting members 42 and 43 and the inner circumference of the case cover 14b, which is a rectangular plate on one side of the casing 14. The leaf-shaped spring 50 extends outward so as to be curved toward the case cover 14b rather than the outer circumferential portion of the rounded ring portion 50a formed in a flat plate shape as shown in FIG. It consists of ten spring parts 50b which came out, and each spring part 50b touches the inner surface of the case cover 14b, and the round ring part 50a makes the 2nd relative displacement detection member 43 and this The first relative displacement detecting member 42 is attached to the case body 14a side via the member 43. In this way, the leaf spring 50 is a biasing means for biasing the first and second relative displacement detecting members 42 and 43 in the thrust direction.

In addition, the first relative displacement detecting member 42 and the second relative displacement detecting member 43 have an end portion and an inlet portion of the grooves 42b and 42c of the first relative displacement detecting member 42. The first relative displacement detection member 42 is inserted into the second relative displacement detection member 43 with the open end of the relative displacement detection member 43 facing. As a result, the inner cylindrical portion 43a of the second relative displacement detection member 43 is inserted into the first relative displacement detection member 42.

At the bottomed end of the second relative displacement detecting member 43, a cylindrical protrusion 43e (see Fig. 2) projecting outward is formed, and the cylindrical protrusion 43e has a leaf-shaped spring 50 ) Is reaching. As a result, the second relative displacement detecting member 43 is urged by the subordinate force F2 on the bottom surface side of the case body 14a. On the open end side of the second relative displacement detection member 43, a flat washer 54 is disposed between the inner surface of the case body 14a and the first and second relative displacement detection members 42 and 43. It is deployed. In this way, the second relative displacement detecting member 43 is urged by the leaf-shaped spring 50 on one side and pushes the other to the washer 54 so that the movement in the vertical direction is restricted.

The first relative displacement detection member 42 is pushed toward the washer 54 by the subordinate force F2 via the second relative displacement detection member 43. As described above, the second relative displacement detecting member 42 is also pushed against the washer 54 by F1 generated by the biasing force of the bushing spring 45.

In this way, the washer 54 has the first and second relative displacement detecting members 42 and 43 when the turntable 11 is not loaded with weight (ie, the initial state) or when the cooking member is not placed on the turntable 11. It is meant to reach at the same time. That is, the washer 54 has a reference surface that supports the cross-sections of the first and second relative displacement detecting members 42 and 43 that are urged by the leaf spring 50, which is the urging means in the initial state or during cooking. The first and second relative displacement detecting members 42 and 43 are configured to be relative displacement on this reference plane according to the weight of the turntable 11. By this structure, the relative displacement of both by weight is stable and reliable, and the weight detection without an error is attained.

Moreover, although each cross section of the 1st and 2nd relative displacement detection members 42 and 43 pressed by the leaf-shaped spring 50 touches the washer 54 simultaneously, the 1st relative displacement detection member ( 42 may be configured to contact the washer 54, or only the second relative displacement detecting member 43 may be configured to contact the washer 54. When only the second relative displacement detecting member 43 is in contact with the washer 54, the first relative displacement detecting member 42 also has the washer 54 due to the force F1 of the bushing spring 45. Will reach. The washer 54 is provided so that the first and second relative displacement detecting members 42 and 43 rotate smoothly. However, the washer 54 may be directly removed from the bottom surface of the case body 14a as a reference surface.

In this embodiment, the leaf spring 50 or the bushing spring 45 presses the first and second relative displacement detecting members 42 and 43 in the thrust direction and serves as a reference plane. ) Is configured to support the cross section of both. This configuration has the same effect as that shown in FIG. FIG. 12 shows the result of the weight detection of seven weights (each weight having a different weight every 1 kg) having an actual weight of 1 to 7 kg on the turntable 11 three times for each weight. 12 (a) is a case in which the leaf spring 50 is disposed to bias the first and second relative displacement detecting members 42 and 43 in the thrust direction, and FIG. 12 (b) shows the leaf spring ( The actual weight and measured conversion value when 50) are not arranged are shown.

According to the two graphs of FIG. 12, in the case where "leaf springs are arranged" shown in FIG. In the `` leafless spring not shown '' shown in the drawing, the actual weight and the measured conversion value are inconsistent in all three experiments. The members 42 and 43 are urged in the thrust direction to reliably contact the washer 54 serving as a reference plane, thereby enabling accurate weight detection of the weight detecting apparatus 1 of this embodiment.

2, the pin 44a is attached to the thrust shaft 41 so that the both ends of the pin 44a may protrude to both sides (referred to right and left) across the center axis of the thrust shaft 41 at right angles. do. The protrusions at the left and right sides of the pins 44a are coupled to the grooves 43b and 43c in the axial direction formed in the inner cylindrical portion 43a of the second relative displacement detecting member 43, and at the same time detect the first relative displacement. Engages with the inclined grooves 42b and 42c formed in the dragon member 42. In addition, one end of the pin 44a has a groove 43b and a first relative displacement detecting member 42 formed in the inner cylindrical portion 43a of the second relative displacement detecting member 43, as shown in FIG. The slits 43f are arranged so as to face each other.

The thrust shaft 41 has its tip end penetrating the washer 54 and the bearing member 53a from the case body 14 to reach the cap member 49 disposed in the protruding cylindrical portion 14c, and the turntable 11 The cap spring 49 is pushed by the weight applied to the coil) to compress the coil spring 46. At this time, the tip of the thrust shaft 41 is in contact with the cap member 49 through the push 48, and is rotatable about the push 48. The rear end side of the thrust shaft 41 penetrates through the bearing member 53b from the case cover 14b to the outside and is engaged or fixed to the turntable 11.

The thrust shaft 41 is attached in such a state. That is, as described above, the pin 44a attached to the thrust shaft 41 has grooves 43b and 43c on the side of the second relative displacement detecting member 43 (in the same direction as the central axis, that is, in the axial direction). And grooves 42b and 42c on the side of the first relative displacement detection member 42 (which are formed to be inclined at a predetermined angle with respect to the center axis direction). For this reason, when the thrust shaft 41 is pushed and lowered, the groove | channel 43b (43c) and the 1st relative displacement detection member 42 of the pin 44a by the side of the 2nd relative displacement detection member 43 are operated. Attempts to move downward through the grooves 42b and 42c. At this time, the second relative displacement detecting member 43 is not rotated because the movement in the rotational direction is restricted and the grooves 43b and 43c are the same as the axial direction. On the other hand, the first relative displacement detecting member 42 moves in the rotational direction about the thrust shaft 41 by the pin 44a moving downward. This will be described with reference to FIG. 8.

In the state of FIG. 8A, the pin 44a and the first and second relative displacement detecting members 42 are provided in the initial state of the thrust shaft 41 (the food is not placed on the turntable 11). 43 shows the relationship between the grooves 42b, 42c and 43b, 43c. Fig. 8 (b) shows the pin 44a and the first and second relative displacement detecting members 42 and 43, respectively, with the simmered product on the turntable 11 and the thrust shaft 41 lowered as much as possible. The relationship between the grooves 42b, 42c and 43b, 43c is shown. As can be seen from FIG. 8 (b), when the food is placed on the turntable 11, the first relative displacement detecting member 42 is rotated by a predetermined angle, and the grooves 42b and 42c are arranged around the circumference. It is moved (rotated) by the distance L in the direction.

When a load is applied to the turntable 11 in this manner, the thrust shaft 41 is displaced (falls) in proportion to the load, so that the first relative displacement detecting member 42 is rotated by the distance L at the maximum. It is possible to move to.

In addition, as shown in FIG. 1, when the turntable 11 is driven to rotate, when the motor 20 is energized, the rotational force is transmitted from the first gear 31 to the third gear 33. It is transmitted to the second relative displacement detecting member 43 engaged with the third tooth 33. When the second relative displacement detecting member 43 rotates, the rotational force is transmitted to the thrust shaft 41 by the pin 44a via the contact position W2 described above, thereby turning the turntable 11. Can be rotated.

Thus, the groove | channels 42b and 42c provided in the pin 44a, the 1st relative displacement detection member 42 side, and the groove | channel 43b and 43c provided in the 2nd relative displacement detection member 43 side fall down. When the thrust shaft 41 is displaced in the thrust direction, the first relative displacement detecting member 42 is rotated about the thrust shaft 41 by a predetermined rotational angle in accordance with the displacement amount of the thrust shaft 41. And when the second relative displacement detection member 43 rotates under the driving force of the rotation driving means 12, the pin 44a or the like to transmit the rotational force of the motor 20 to the thrust shaft 41 It works. In other words, the pin 44a or the like constitutes the above-described displacement direction converting means.

The following means means for outputting an electrical signal corresponding to the magnitude of the load applied to the turntable 11 by the relative movement of the first relative displacement detection member 42 with respect to the second relative displacement detection member 43, i.e., weight The detection signal output means will be described.

As shown in FIG. 13, three magnets B1 (B2) and B3 are arranged on the same plane at equal intervals in the first relative displacement detecting member 42. As shown in FIG. Between each of these magnets is 120 degrees apart. On the other hand, three magnets A1 (A2) and A3 are arranged on the same plane at equal intervals in the second relative displacement detecting member 43. Between each of these magnets is 120 degrees apart. In the state where the first and second relative displacement detecting members 42 and 43 are fitted to be coaxial as described above, the six magnets A1, A2, A3, B1 and B2 described above. (B3) is disposed on the same plane so that the corresponding magnets, that is, magnets (A1) and magnets (B1), magnets (A2) and magnets (B2), magnets (A3) and magnets (B3) are 33.24 ° apart, respectively. do.

In the vicinity of the magnet, a hall IC 47 for converting the magnet into an electric signal and outputting it is fixedly arranged. The hole IC 47 is configured such that the terminal portion protrudes out of the casing 14 via a hole (not shown) provided in the bottom surface of the case body 14a. The protruding portion is a printed circuit board 55 (Fig. 3) and is covered by a holder 56. On this printed board 55, parts such as a connector 57 are also attached.

13 (a) and (b) are diagrams for explaining the positional relationship between the magnets A1, A2, A3, magnets B1, B2, and B3, and the hole ICs 47. For the sake of simplicity, some parts of the structures shown in Figs. 1 to 9 used in the above description are not shown as they are.

The magnets A1 (A2) and A3 and the magnets B1 (B2) and B3 are differently arranged on the same plane. That is, different arrangements such as the magnet A1, the magnet B1, the magnet A2, the magnet B2, the magnet A3, and the magnet B3 are arranged so that they are arranged on the same plane. FIG. 13A shows the positional relationship corresponding to the state shown in FIG. 8A, and is the positional relationship when the thrust shaft 41 is in an initial state (without cooking placed on the turntable 11). . 13 (b) shows the positional relationship corresponding to the state shown in FIG. 8 (b), where 7 kg of food is placed on the turntable 11 and the thrust shaft 41 is lowered as much as possible. The relationship is shown.

In Fig. 13A, the distance between a pair of magnets (for example, magnet A1 and magnet B1) arranged in the proximity position is 33.24 °. When the cookware (which is referred to as 7 kg) is placed on the turntable 11 and the thrust shaft 41 is lowered as much as possible, the first relative displacement detecting member 42 rotates as much as possible, as shown in FIG. It is in the same state. Then, as shown in FIG. 13 (b), the magnets B1, B2, and B3 of the first relative displacement detection member 42 move in the maximum direction by 20 degrees. Therefore, as mentioned above, the space | interval of a pair of magnets (for example, magnet A1 and magnet B1) arrange | positioned in the proximal position in an initial state opens to 53.24 degrees.

The operation in such a configuration will be described. First, when no food is placed on the turntable 11, the relationship between the first relative displacement detection member 42 and the second relative displacement detection member 43 is in a state as shown in Fig. 8A. In this state, the magnets A1 (A2) and A3 and the magnets B1 (B2) and B3 have a positional relationship as shown in Fig. 13A.

If the motor 20 rotates in this state, the second relative displacement detecting member 43 also starts to rotate, and the Hall IC 47 can obtain an output as shown in Fig. 14A. That is, the hall IC 47 outputs a signal at a time interval proportional to the angle between adjacent magnets. That is, when the magnets A1, B1, and A2 are mounted, the magnets A1 and A2 are separated by 120 °, and the angle between the magnets A1 and B1 is 33.24 °. The angle between (A2) is 86.76 °.

Here, when only the magnets A1 (A2) and A3 in the second relative displacement detection member 43 are considered, the signal As1 of the hall IC 47 by the magnet A1 is rotated according to the rotation of the turntable 11. ) And the time to the signal As2 of the Hall IC 47 by the magnet A2 (the time between the centers of the time widths in each signal) are t, this time t remains unchanged at an angle of 120 °. The corresponding time. Therefore, when the food is not placed on the turntable 11, the signal As1 is first output from the hall IC 47 between the magnet A1 and the magnet B1, and the time corresponding to the angle 33.24 ° is 0.28. When t elapses, the signal Bs1 is output. The relationship between the magnet A2 and the magnet B2 and the magnet A3 and the magnet B3 is also the same.

The signal Bs1 is output from the hall IC 47 between the next magnet B1 and the magnet A2, and the signal As2 is output when the time corresponding to an angle of 86.76 ° = 0.72t elapses. The relationship between the magnet B2 and the magnet A3 and the magnet B3 and the magnet A1 is also the same.

As a method of time measurement between signals output from the hall IC 47, the length between signal centers (signal centers) is measured as described above. This allows the Hall IC 47 to measure the center of the output signal in order to cope with it because the width of the output signal may change with temperature.

On the other hand, if any dish is placed on the turntable 11 and cooking is started, the thrust shaft 41 descends together with the turntable 11 by the weight of the dish while the turntable 11 starts to rotate.

Accordingly, the first relative displacement detecting member 42 is rotated in proportion to the amount of falling of the turntable 11, and the first relative displacement detecting member 42 rotates in proportion to the falling amount of the turntable 11, such as the magnet B1 for the magnet A1 and the magnet B2 for the magnet A2. The angle between magnets between adjacent magnets changes. At this time, since the turntable 11 is in the rotational state, the signal As1 for the magnet A1, the signal Bs1 for the magnet B1, and the signal for the magnet A2 are provided from the hall IC 47. As2 outputs a signal to the magnet B2 in correspondence with the passage of the magnet, like the signal Bs2 and the like. However, at this time, the time interval between the signals As1 and Bs1 becomes longer than the time interval in the initial state described above = 0.28t. On the other hand, the time interval between the signals Bs1 and As2 becomes shorter than the time interval in the initial state described above = 0.72t.

For example, when 7 kg of food is placed on the turntable 11 as an extreme example, the magnets A1, A2, A3 and the first relative displacement detection member on the second relative displacement detection member 43 side are provided. The relationship between the magnets B1, B2, and B3 on the (42) side becomes a positional relationship as shown in Fig. 13B. That is, in the initial state of the magnet on the side of the first relative displacement detection member 42 and the magnet on the side of the second relative displacement detection member 43, the angle between the magnets in the proximal position (for example, the magnet A1 and the magnet ( The angle between the magnets of B1) spreads to 53.24 °, and the angle with the magnet (for example, magnet A2 in magnet B1) arranged at a position not close to is narrowed to 66.76 ° so that the Hall IC ( 47, an output as shown in FIG. 14B can be obtained.

As can be seen from FIG. 14B, the time intervals of the signal As1 for the magnet A1 and the signal Bs1 for the magnet B1 are the signals As1 and the magnet (A1) for the magnet A1. 0.44t, which is about 44% of the time interval t of the signal As2 for A2). That is, in the initial state (the state in which no food is placed on the turntable 11), the time interval between the signal As1 and the signal Bs1 is 0.28t, but when 7 kg of food is placed on the turntable, the signal As1 The time interval of the and signal Bs1 becomes 0.44t, and the signal of another time interval can be taken out from the hall IC 47 according to the weight of the food. Therefore, the weight of a foodstuff can be measured using the output of this hall IC 47. In addition, converting this displacement amount by weight is performed by the microcomputer (not shown).

15 shows the load (weight of the cooked goods) applied to the turntable and the first relative displacement detection member 42 side with respect to the Hall IC output by the magnet A1 on the second relative displacement detection member 43 side. The time interval of the Hall IC output by the magnet B1 is expressed as a percentage, and each time interval t between the magnets A1, A2, and A3 is 100%, which is a percentage of t. The same applies to the relationship between the magnet B2 for the magnet A2 and the magnet B3 for the magnet A3. As can be seen from FIG. 15, when the load is 0, 28% (0.28t), when the load is 1 kg, about 30% (0.30t), and when the load is 4kg, about 38% (0.38t) As shown in Fig. 3, the time interval becomes longer in proportion to the load, and the maximum load (7 kg) is about 44% (0.44t).

On the other hand, Fig. 16 shows the load (weight of the cooked goods) applied to the turntable and the second relative displacement detection member 43 side with respect to the Hall IC output by the magnet B1 on the first relative displacement detection member 42 side. The time interval of the Hall IC output by the magnet A2 is expressed as a percentage, and each time interval t1 between the magnets A1, A2, and A3 is 100%, which is a percentage of t. The same applies to the relationship between the magnet A3 for the magnet B2 and the magnet A1 for the magnet B3. As can be seen in FIG. 16, 72% (0.72t) is 0 for load, about 70% (0.70t) for 1 kg, and 62% (0.62t) for 4 kg. The time interval becomes shorter in proportion to the load and becomes about 56% (0.56t) at the maximum load (7 kg). That is, the detection amount curves of FIGS. 15 and 16 are inputted in advance to the microcomputer as the weight conversion means. In addition, the time interval of the Hall IC by the magnet A1 and the mark B1 can be obtained to convert the weight of the cooked food.

Based on such a relationship, the weight of the cooked food can be detected, and if the weight of the cooked food is known, the cooking time or the like taking into account it can be automatically set.

However, in the above description, the magnets on the second relative displacement detection member 43 side and the magnets on the first relative displacement detection member 42 side are composed of three pairs of three each, but may be more or one pair. . In principle, the magnet on the side of the second relative displacement detection member 43 and the magnet on the side of the first relative displacement detection member 42 have the same amount of displacement of the turntable 11 as the pair of magnets. It is possible to take out by displacement of the time interval. However, in order to be usable regardless of the difference between the 50-zone and 60-zone regions, the reference time as shown in Fig. 14 (in this case, the magnets A1 and A2 on the side of the second relative displacement detection member 43). It is preferable to express it as the displacement amount (= ratio) with respect to the time interval t between magnets of (A3), so that the magnets of the first and second relative displacement detection members 42 and 43 are all used to obtain the displacement amount. It is preferable to provide at least three.

As described above, in the above-described embodiment, the displacement amount in the thrust direction of the turntable 11 is converted into the displacement amount in the rotational direction of the first relative displacement detecting member 42 and is proportional to the displacement amount in the rotational direction thereof. Output is obtained, and the weight of the cooked food placed on the turntable 11 is detected based on the output displacement of the hall IC 47. In addition, these weight detection operations can be performed while the turntable 11 is rotated by placing a dish on the turntable 11 and starting cooking, and the maximum weight of the turntable 11 can be performed while turning the round table 11 effectively. It becomes possible.

In addition, when the turntable 11 is rotated, the first and second relative displacement detecting members 42 and 43 may fix the positional relationship in the circumferential direction by the bushing spring 45, and at the same time, the washer serving as a reference plane ( 54 is pressed against the leaf spring 50. As a result, the positional relationship does not deviate during rotation, and thus accurate displacement amount, that is, accurate weight detection can be performed.

The rotary drive means 12 for rotating the turntable 11 and the weight detector 13 for detecting the weight are housed in one casing 14, that is, the weight detector 13 is rotated. (12) Since the structure is incorporated in the inside, the weight detection unit 13 and the rotary driving means 12 can be assembled separately, thereby reducing the number of assembly steps, and combining them together. This can make the cost cheaper.

In addition, although the above-described embodiment is a suitable embodiment of the present invention, various modifications are possible within the scope not departing from the gist of the present invention. For example, in the above-described embodiment, the turntable 11 is described as only rotating in one direction, but the turntable 11 may be bidirectionally rotated. In this case, in the present invention, the bushing spring 45 as the position fixing means is configured to fix the position in the circumferential direction of the first and second relative displacement detecting members 42 and 43 as described above. Since non-uniformity does not arise and it can respond only by correct | amending a fixed value according to a rotation direction, the effect as a detection apparatus is exhibited further.

In the above-described embodiment, the displacement amount is detected by the magnetic detection means by the magnets A1, A2, A3, B1, B2, B3 and the Hall IC 47, but this is also realized by other means. It is possible. For example, a plurality of slits overlapping each other are provided on both the first relative displacement detecting member 42 and the second relative displacement detecting member 43, and the thrust shafts are displaced in the thrust direction to overlap each other. The length may be changed.

In this configuration, the slits are fitted so that photoelectric conversion means such as port diodes and port transistors are disposed to face each other, and the slit lengths of the overlapping slits are changed by displacing the thrust shafts in the thrust direction. Then, the change in the slit length of the slit overlapping each other is taken out as the output signal interval in the port transistor, and the weight can be detected based on this. Accordingly, the same weight as in the above-described embodiment can be detected.

In the above-described embodiment, the first relative displacement detection member 42 is rotated by the displacement of the thrust shaft 41 in the thrust direction, and the second relative displacement detection member 43 is not displaced. Both members 42 and 43 may be displaced together or only the second relative displacement detecting member 43 may be displaced. The magnet may adopt other shapes or configurations, such as making the outer circumferential portion of the circular rubber magnet convex. Alternatively, the coil spring 46 may be a circular one or a coil spring having a different shape instead of the rectangular coil spring. Instead of the coil springs, other springs such as leaf springs or dish springs may be used, or other elastic members such as rubber or plastics.

In addition, the bushing spring 45 may be made of rubber or another elastic member instead of the coil spring. The leaf springs 50 may be provided with three spring portions 50b at 120 ° intervals instead of 10, or six at 60 ° intervals. It is also possible to use other biasing means such as a dish spring and a rubber member instead of the leaf spring 50.

In addition, in the above-described embodiment, the case of detecting the weight of the cookware in the microwave has been described as an example, but the present invention is not limited to the microwave but can be applied to the weight detection of another apparatus such as an oven or a toaster. Moreover, this invention is applicable also to the weight detection of articles other than a cooking goods.

As described above, in the weight detecting apparatus of the present invention, the first relative displacement detecting member that rotates in accordance with the displacement in the thrust direction of the thrust shaft displaced in the thrust direction according to the weight to be detected, and the rotation driving force from the driving source. The second relative displacement detection member is rotated by receiving, and the signal according to the relative displacement amount of the first relative displacement detection member with respect to the second relative displacement detection member is output as a weight detection signal. As a result, the weight can be detected, which makes it possible to miniaturize the weight of the conventional capacitive weight detector. Further, since the first and second relative displacement detecting members can fix the positional relationship in the circumferential direction by the position fixing means, the weight can be accurately detected even during rotation.

In the weight detecting apparatus according to the present invention, the first and second relative displacement detecting members are urged in the thrust direction by the urging means and pushed to the reference plane. The numerical value becomes more reliable and accurate weight detection is possible.

Claims (8)

delete A thrust shaft displaced in the thrust direction according to the weight to be detected; A first relative displacement detecting member provided coaxially with the thrust shaft and rotating according to the displacement in the thrust direction of the thrust shaft; A second relative displacement detection member provided coaxially to the thrust shaft so as to be paired with the first relative displacement detection member, and rotating by receiving a rotation driving force from a driving source; Combining the first and second relative displacement detection members with the thrust shaft, When the thrust shaft is displaced in the thrust direction, at least the first relative displacement detecting member is rotated by a predetermined rotational angle about the thrust shaft in accordance with the displacement amount of the thrust shaft, and the second relative displacement detecting member is Displacement direction converting means for transmitting the rotational force to the first relative displacement detecting member and the thrust shaft when rotating by receiving the driving force from the driving source; And a weight detection signal output means for outputting a signal according to a relative displacement amount of said first relative displacement detection member to said second relative displacement detection member as a weight detection signal. The method of claim 2, The weight detection signal output means is an electrical detection means using a magnet and a Hall element, wherein the magnet is provided on the first relative displacement detection member and the second relative displacement detection member, respectively, and the Hall element is the first relative displacement. On the side of the first relative displacement detection member that is fixedly disposed at a position capable of detection with respect to each of the magnets emitted by the detection member side magnet and the second relative displacement detection member side, and which rotates with respect to this hall element. Detects magnetism from the magnet on the magnet and the second relative displacement detection member side, outputs a signal of a time interval corresponding to the relative displacement amount of the first relative displacement detection member to the second relative displacement detection member side, and A weight detection device, characterized in that output as a weight detection signal. A thrust shaft displaced in the thrust direction according to the weight to be detected; first and second relative displacement detection members provided in conjunction with the thrust shaft; and two relative displacement detection members, A rotation displacement means for rotating the predetermined amount relatively in accordance with the displacement amount, a position fixing means for fixing the positional relationship in the rotational direction of the first and second relative displacement detecting members, and the first and second relative displacements. A rotary drive means for rotating the detecting member together with the thrust shaft, and a detector disposed in the detectable region of the detected object provided in the first and second relative displacement detecting members, respectively, to detect the detected object. And the relative displacement amount of the first and second relative displacement detecting members which are displaced by the rotational displacement means by this detector and fixed by the position fixing means. And a weight conversion means for detecting by using integral rotation of said first and second relative displacement detection members and converting this displacement amount into weight. The method of claim 4, wherein And said position fixing means is provided between both of said first and second relative displacement detecting members and comprises a bushing spring for applying a force in the circumferential direction thereof. A thrust shaft displaced in the thrust direction according to the weight to be detected; first and second relative displacement detection members provided in conjunction with the thrust shaft; and two relative displacement detection members, A rotational displacement means for rotating a predetermined amount relatively in accordance with the displacement amount, a biasing means for biasing the first and second relative displacement detecting members in a thrust direction, and a first and a second relative stressed by the biasing means. A reference surface receiving a cross section of the displacement detecting member, rotation driving means for integrally rotating the first and second relative displacement detecting members with the thrust shaft, and the first and second relative displacement detecting members. The first and second relative displacement inspections, each having a detector disposed in a detectable region of the detected object and detecting the detected object, and displaced by the detector to the rotation displacement means. Weight detecting device, characterized in that the relative amount of displacement of the member and at the same time detection using the first and second integral rotation of the relative displacement detection member provided on the weight in terms of translation by means of a displacement amount by weight. The method of claim 6, The biasing means comprises a plate-like spring member disposed between an inner surface of one top plate of the metal casing covering the weight detecting device and the first and second relative displacement detecting members, and the reference plane is the one rectangular plate. And a flat plate washer disposed between the inner surface of the other square plate of the casing or the inner surface of the casing, and the first and second relative displacement detecting members. A microwave oven having a weight detecting device that makes the turntable displaceable in the thrust direction in accordance with the weight applied to the turntable and detects the weight applied to the turntable based on the displacement amount. A microwave oven provided with the weight detecting apparatus according to claim 4.