JP2000304593A - Weight detector and microwave oven - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect weight stably and accurately by turning and displacing a member for detecting relative displacement depending on the displacement of a trust shaft displacing with a detected load while being born on a load spring, detecting the displacement and converting the displacement into a weight, and then transmitting the movement corresponding to the detected weight indirectly to the load spring. SOLUTION: A thrust shaft 41 displacing in the thrust direction depending on a load to be detected is born on a coil spring 46. Relative displacement detecting members 42, 43 engaged with the thrust shaft 41 are turned and displaced by a specified amount by a turning/displacing means 44 depending on the displacement of the thrust shaft 41 and turned integrally with the thrust shaft 41 by a rotary drive means 12. The relative displacement detecting members 42, 43 are provided with magnets to be detected and detected by means of a Hall IC secured to the casing 14 and then the displacement is converted into a weight. A metal cap 49 is provided at the end of the thrust shaft 41 on the coil spring 46 side and movement in the thrust direction corresponding to the weight of the thrust shaft 41 is transmitted indirectly to the coil spring 46.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a weight detecting device for electrically detecting a weight in a thrust direction and an improvement of a microwave oven using the weight detecting device.

[0002]

2. Description of the Related Art In recent years, in microwave ovens, sensors for measuring temperature and weight have been used as sensors for performing automatic cooking. Various types of weight detection devices, such as a capacitance type and a piezoelectric element type, have conventionally been used as a weight sensor as a weight sensor, but the capacitance type is mainly used at present. This capacitance-based weight detection device measures the minute displacement of an output shaft (thrust shaft) that is displaced by the weight of a cooked product placed on a turntable based on a change in the capacitance between parallel plates. To detect.

[0003]

However, the conventional capacitance-type weight detecting device is provided with an oscillating circuit, and the capacitance of the variable capacitor is changed by the distance between the electrodes. Therefore, there is a possibility that the capacitance may be affected by the stray capacitance generated in the wiring pattern on the printed circuit board. In order to cope with this, it is necessary to secure a certain capacitance or more. Also, in consideration of variations in component dimensions, a certain distance or more between electrodes is required. For this reason,
There is a problem that the facing area between the electrodes increases and the device becomes large.

Further, when such a conventional weight detecting device is applied to a microwave oven, the amount of displacement of the turntable in the thrust direction is detected. Each of the weight detection devices has an independent configuration, and after assembling each separately, the two are combined, so that the number of assembly steps is increased. In addition, the shape after the two are combined tends to be difficult to be compact and large. Further, if a load spring is used to restore the displacement of the turntable in the thrust direction, the detection accuracy will deteriorate if the engagement between the thrust shaft of the turntable and the load spring is not good.

Accordingly, the present invention provides a weight detecting device which enables downsizing, eliminates problems when a load spring is used, and enables stable and accurate weight detection, and an electronic device using the weight detecting device. The purpose is to provide a range.

[0006]

In order to achieve the above object, a weight detecting device according to the present invention includes a thrust shaft which is received by a load spring and is displaced in a thrust direction in accordance with a weight to be detected. Rotational displacement means for rotationally displacing the engaged relative displacement detection member by a predetermined amount according to the displacement of the thrust shaft, and rotation drive means for rotating the relative displacement detection member integrally with the thrust shaft An object to be detected provided on a member for detecting relative displacement, a detector arranged in a detectable area of the object to be detected and detecting the object to be detected, and a detector for detecting relative displacement detected by the detector Weight conversion means for converting the relative displacement amount of the member as a weight, and at the end of the thrust shaft on the load spring side, the movement in the thrust direction according to the weight of the thrust shaft is indirectly performed on the load spring. Provide a transmission member to transmit There.

According to another aspect of the present invention, there is provided a weight detecting device which receives a load spring and is displaced in a thrust direction in accordance with a weight to be detected, and a relative displacement detecting device provided in engagement with the thrust shaft. Rotation displacement means for rotating the member for rotation by a predetermined amount in accordance with the displacement amount of the thrust shaft, rotation driving means for rotating the relative displacement detection member integrally with the thrust shaft, and the relative displacement detection member. The relative displacement amount of the detected object, the detector disposed in the detectable area of the detected object, detecting the detected object, and the relative displacement detecting member detected by the detector is defined as a weight. And a weight conversion means for converting the weight, wherein the bottom of the load spring is fixed to a case holding the load spring.

According to another aspect of the present invention, in addition to the weight detecting device of the above-described invention, the thrust shaft is moved in the thrust direction according to the weight of the thrust shaft indirectly to the load spring at the end of the thrust shaft on the load spring side. A transmission member for transmitting is provided. Further, in another invention, in addition to the weight detecting device of each of the above-mentioned inventions, the transmission member is formed in a cap shape, and the load spring is formed as a coil spring. Further, in another invention, in addition to the weight detection device of the above-described inventions, when the load spring repeatedly compresses and expands, the size of each member is set so that the load spring and the transmission member do not contact the case holding the load spring. Is set.

According to another aspect of the present invention, a load spring and a transmission member are fixed in addition to the weight detecting device according to the above-described aspects.
According to another aspect of the present invention, an intervening member is further disposed between the transmission member and the thrust shaft in addition to the above-described weight detection devices. Further, in addition to the weight detecting device of each of the above-mentioned inventions, a transmission member mounted on a load spring is provided with a resin cap made of resin as an intervening member so as to rotate integrally with the thrust shaft. The resin cap is received inside the bottom of the metal cap.

According to another aspect of the invention, in addition to the weight detecting device of the above-described aspect, a lubricant is applied to a portion where the metal cap and the resin cap are in contact with each other. In another invention, in addition to the weight detection device of the above-described invention, a resin cap is disposed such that an outer peripheral side thereof is opposed to an inner side surface of the metal cap, and a gap between the opposed portions is 50 to 500 μm. Further, in another invention, in addition to the weight detecting device of each of the above-mentioned inventions, the tip of the thrust shaft on the load spring side is thinned.

According to another aspect of the present invention, in addition to the weight detecting devices of the above-mentioned inventions, a first and a second are provided in which a thrust shaft is made of ceramic and a relative displacement detecting member is engaged with the thrust shaft. A first and a second relative displacement detecting member which are relatively displaced by a predetermined amount according to the displacement amount of the thrust shaft by a rotational displacement means; The detection object is provided in each,
The weight converting means converts a relative displacement amount of the first and second relative displacement detecting members detected by the detector into a weight. According to another aspect of the present invention, in addition to the weight detecting device of the above-described aspect, a position holding unit for holding a positional relationship between the first and second relative displacement detecting members in the rotation direction is provided.

Further, the microwave oven according to the present invention has a weight detecting device which enables the turntable to be displaced in the thrust direction in accordance with the weight applied to the turntable, and detects the weight applied to the turntable based on the amount of displacement. , And the weight detecting device described in each claim is provided as the weight detecting device.

In the weight detecting device of the present invention, when the weight is added, the load spring contracts and the thrust shaft is displaced in the thrust direction. Then, the relative displacement detecting member is relatively rotated about the thrust shaft by a predetermined rotation angle in accordance with the displacement amount of the thrust shaft. This operation is detected by a detector, and the relative displacement amount of the relative displacement detection member is converted into weight by weight conversion means.

For example, the first and second relative displacement detecting members are provided by engaging the relative displacement detecting member with the thrust shaft, and the first relative displacement detecting member with respect to the second relative displacement detecting member is provided. A signal proportional to the relative displacement of the member (for example, a signal having a time interval ratio proportional to the relative displacement)
Is output as a weight detection signal, and the weight is detected based on the weight detection signal.

As described above, the weight detection device of the present invention is different from the capacitance type weight detection device in that the capacitance type conventionally has various problems, such as a wiring pattern on a printed circuit board. In order to cope with the effect of the stray capacitance that occurs during the operation, it is necessary to secure a certain level of capacitance, so that there is no problem that the facing area between the electrodes increases and the size of the device increases. Good weight detection becomes possible. Further, since the position is reliably held, the numerical value of the displacement amount can be stably supplied.

In 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, the weight detection portion can be made small, and the entire microwave oven can be used. Can be reduced in size. In particular, when the second relative displacement detecting member also serves as an output gear of a reduction gear train for reducing the rotational force from the turntable driving source, the rotation driving means and the weight detecting portion can be integrated. Therefore, as compared with the conventional one in which the rotation driving means and the weight detecting portion are separated, the size can be reduced and the number of assembling steps can be reduced.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 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, as described above, the displacement of the turntable on which the food is placed is taken out as a signal indicating the weight of the food, and the microwave irradiation time is determined based on the signal indicating the weight. Control such as determination is performed.

First, the overall structure will be described with reference to FIGS. The weight detection device 1 is roughly divided into
A rotation drive unit 12 that rotates the turntable 11 and also rotates first and second relative displacement detection members 42 and 43, which will be described later, integrally with the thrust shaft 41, and detects an amount of displacement of the turntable 11 in the thrust direction. The weight detection unit 13 is configured, and each of these components is housed in one metal casing 14. The casing 14 includes a case body 14a and a case lid 14b. The first and second relative displacement detecting members 42 and 43 are vertically moved by the bottom surface of the case body 14a and the inner surfaces of the case lid 14b. It is arranged so as to sandwich it. That is, the bottom surface of the case body 14a and the case lid 14b are both top plates of the casing 14.

The rotation drive means 12 includes a motor (a synchronous motor is used here) 20 as a drive source, and a first gear as a reduction wheel train for reducing the rotational force of the motor 20 and transmitting it to the turntable 11. 31, a second gear 32, a third gear 33, a second relative displacement detecting member 43 serving as an output gear, and a reverse rotation preventing lever 3 for preventing reverse rotation of the motor 20
4a and a reverse rotation preventing lever rotating gear 34 coaxially arranged with the reverse rotation preventing lever 34a. The reverse rotation preventing lever 34a and the reverse rotation preventing lever rotating gear 34 are urged in the thrust direction by a spring 34b.

The motor 20 includes a coil 21, a rotor 22,
It comprises a fixed shaft 23, a pinion 24 fixed to the rotor 22, a middle base plate 25, and the like. In addition, the pinion 24
Are provided with projections 24a, 24a for preventing the reverse rotation of the rotor 22 by the reverse rotation preventing lever 34a abutting when the rotor 22 reversely rotates. Therefore, when the rotor 22 rotates in the forward direction, the protrusion 2
4a does not engage with the protrusion 34c of the reverse rotation prevention lever 34a, and the rotor 22 rotates freely. However, when the rotation is reversed, the protrusion 34c of the reverse rotation prevention lever 34a abuts against the protrusion 24a to rotate the rotor 22. It is designed to block.

The first gear 31 and the second gear 32 are respectively connected to the middle base plate 25 and the case lid 1 by shafts 31a and 32a.
4b, and the third gear 33 is mounted between the case body 14a and the case lid 14b by a shaft 33a. Although the pole teeth forming the stator of the motor 20 are erected from the case main body 14a toward the rotor 22, a label 26 is attached to the case main body 14a in order to cover the remaining hole forming the pole teeth. ing.

The weight detector 13 has one end fixed to the center of the turntable 11 and a thrust shaft 41 which is displaced in the thrust direction in accordance with the weight applied to the turntable 11,
The first and second relative displacement detecting members 42 and 43 provided in engagement with the thrust shaft 41 and the two relative displacement detecting members 42 and 43 are placed in accordance with the displacement amount of the thrust shaft 41. Rotationally displacing means 4 for relatively relatively displaced rotation
4 and first and second relative displacement detecting members 42 and 43
An urging spring 45 as a position holding means for holding a positional relationship in the rotation direction of the motor, a weight detection signal output means to be described later, and a coil spring 46 serving as a load spring disposed on the distal end side of the thrust shaft 41 are mainly used. Components. The signal output from the weight detection signal output means is converted into a weight by a weight conversion means (not shown) comprising a microcomputer.

The first and second relative displacement detecting members 42 and 43 are arranged such that the thrust shaft 41 is paired with each other.
Are provided coaxially. Then, the first relative displacement detecting member 42 rotates according to the displacement of the thrust shaft 41 in the thrust direction, and the second relative displacement detecting member 4
Reference numeral 3 does not rotate due to the displacement of the thrust shaft 41 in the thrust direction, but rotates by receiving the rotational driving force from the rotational driving means 12. That is, the second relative displacement detecting member 43 is a part of the reduction gear train that constitutes the rotary drive unit 12 and also serves as an output gear that engages with another gear.

The rotation displacement means 44 engages the first and second relative displacement detection members 42 and 43 with the thrust shaft 41, and when the thrust shaft 41 is displaced in the thrust direction, the first relative displacement is detected. The displacement detecting member 42 is rotated by a predetermined rotation angle about the thrust shaft 41 in accordance with the displacement amount of the thrust shaft 41, and the second relative displacement detecting member 43 receives the driving force from the rotation driving unit 12. When rotating, the rotational force can be transmitted to the thrust shaft 41. The rotation displacement means 44 includes oblique grooves 42b and 42c formed in the first relative displacement detection member 42 and axial grooves 43b and 43c formed in the second relative displacement detection member 43.
When the first and second relative displacement detecting members 42 and 43 are fitted to the thrust shaft 41 and
b, 43b and a pin 44a that fits into each of the overlapping portions of the grooves 42c, 43c. Details of these will be described later.

The biasing spring 45 is a coil spring, and serves as position holding means for holding the positional relationship between the first and second relative displacement detecting members 42 and 43 in the rotation direction. That is, the urging spring 45 applies a circumferential force to the first relative displacement detection member 42 when the first and second relative displacement detection members 42 and 43 are fitted together. With this biasing force, the relative displacement amounts of the first and second relative displacement detecting members 42 and 43 are held, that is, the positions of both members are held. If the position is not held by the biasing spring 45, the variation tends to occur during the weight measurement, but may be omitted depending on the required accuracy.

In the present embodiment, the reverse rotation of the rotor 22 is prevented by the reverse rotation preventing lever 34a.
The turntable 11 rotates in one direction. This is because in a microwave oven, it is not particularly necessary to rotate in both directions.

The above-mentioned position holding means is, specifically, as shown in FIG. 6, when the urging spring 45 urges the first relative displacement detecting member 42 in the circumferential direction, and The contact position W1 between the groove 42b and the groove 42c provided on the first relative displacement detecting member 42 with the grooves 42b, 42
The sides 42c1 and 42b1 on one side of c are formed. On the other hand, when the turntable 11 rotates,
a and a groove 43 provided in the second relative displacement detecting member 43
The contact position W2 with the b, 43c is always located on the other side 43b2, 43c2 of the groove 43b, 43c. As a result, the pin 44a is suppressed so as not to rattle in the two overlapping grooves, and the positional relationship between the first and second relative displacement detecting members 42 and 43 in the circumferential direction is always kept the same. It has become.

The biasing spring 45 has a projection 51d of the first relative displacement detecting member 42 and a storage wall 52d of the second relative displacement detecting member 43 formed on the same radius around the thrust shaft 41. Both ends are supported in a state of being compressed in the storage section formed by the holding projection 52e.

As a result, the biasing spring 45 applies a biasing force to the first relative displacement detecting member 42 in the circumferential direction. The urging force causes the first relative displacement detecting member 42 to generate a force F1 toward the reference surface, which will be described later, by contacting the pin 44a. For this reason, the first relative displacement detecting member 42 is also always at a fixed position in the axial direction (= a position in contact with the reference plane).

The weight detection signal output means outputs a signal corresponding to the relative displacement of the first and second relative displacement detecting members 42 and 43 as a weight detection signal. As shown in FIG. 7, the weight detection signal output means includes three magnets B1, B2, and B3 serving as detection objects provided on the first relative displacement detection member 42 side, and a second relative displacement Three magnets A1, A2, A3 to be detected provided on the detection member 43 side, and these magnets B1 to B
3, a Hall IC 47, which is a Hall element fixedly disposed on the casing 14 serving as a detector for converting magnetism generated by A1 to A3 into an electric signal. The details will be described later.

The first gear 31, the second gear 32, and the third gear 33 as reduction gear trains have a gear ratio such that the rotor 22 of the motor 20 rotates an integer number of times for one rotation of the thrust shaft 41. Decide. As a result, when the position change amount in the rotation direction does not change, that is, when a predetermined weight is added, the first
When the relative displacement of the second relative displacement detecting members 42 and 43 is constant and the motor 20 is rotating, the leakage magnetic field from the motor 20 always has the same phase at each predetermined position of the thrust shaft 41, Measurement can be performed under the same conditions.

For example, the rotational position of the rotor 22 at the timing of detecting the magnetic force of the signal magnet A1 detected once per rotation is always the same. Therefore, the effect of the magnetic flux from the rotor 22 and the magnetic flux from the stator in the motor 20 on the Hall IC 47 becomes the same regardless of the number of rotations of the thrust shaft 41. Such a relationship also applies to the other magnets A2, A3, B1, B2, B3 and the motor 20. Further, the influence of the vibration by the rotor 22 is always the same. For this reason, there is no variation in the measurement result, and accurate detection can be performed.

In order to always make the influence of the rotor 22 and the like the same, in addition to the method of determining the gear ratio so that the rotor 22 rotates an integer number for one rotation of the thrust shaft 41, the thrust shaft 41 It is also possible to adopt a method of determining the gear ratio such that the rotor 22 rotates an integer number of times in two or three rotations. However, in such a case, the measurement accuracy is stabilized by performing the measurement twice (including two times) or three times (including three times).

Next, the weight detector 13 will be described in more detail. One end (rear end) of the thrust shaft 41 is engaged or fixed to the turntable 11 as described above. The thrust shaft 41 transmits the rotational force of the motor 20 to the turntable 11 and the cooked product is placed on the turntable 11. As a result, it descends in the thrust direction together with the turntable 11.

On the other end (tip) side of the thrust shaft 41, a resin cap 48 made of a resin serving as an intervening member for pushing down a coil spring 46 serving as a load spring, and a transmission member for receiving the resin cap 48 are provided. A metal cap 49 made of metal is attached. This is because the thrust shaft 41 is generally made of ceramic, and if the thrust shaft 41 is directly received by the metal cap 49, the metal side is worn and the vertical position of the thrust shaft 41 changes. In order to prevent this wear, a resin cap 4 is attached to the end of the thrust shaft 41.
8 and is rotated integrally with the thrust shaft 41. Note that the coil spring 46 is housed in a case that forms a protruding cylindrical portion 14c fixed to the case body 14a with screws. Grease R1 as a lubricant is applied between the resin cap 48 and the metal cap 49 to further reduce wear.

When the coil spring 46 moves back and forth, right and left, and in the rotation direction of the thrust shaft 41, the thrust shaft 41
The vertical position changes, and the measured value of the weight changes. Therefore, the coil spring 4 is moved so that the coil spring 46 does not move in the front-rear, left-right,
6 is fixed to the protruding cylindrical portion 14c. This fixation allows the coil spring 46 to contact the rising portion 14d provided at the center of the inside of the protruding cylindrical portion 14c so that the coil spring 46 cannot move back and forth and right and left. Further, the bottom of the coil spring 46 and the bottom of the protruding cylindrical portion 14c are adhered. Grease R2 is applied and fixed by preventing rotation. This fix
Other methods, for example, without providing the rising portion 14d,
It is possible to simply employ fixing by an adhesive or fixing by plasma welding.

When the position of the metal cap 49 shifts, the vertical position of the thrust shaft 41 changes, and the measured value changes. To prevent this, the metal cap 49 is fixed to the coil spring 46 by plasma welding R3 so that the position of the metal cap 49 does not shift. For this fixing, other fixing methods, such as fixing with an adhesive, can be adopted other than the plasma welding R3.

Further, when the metal cap 49 contacts the inner surface of the projecting cylindrical portion 14c other than the bottom portion of the coil spring 46, a part of the weight applied to the thrust shaft 41 is not applied to the coil spring 46, so that correct measurement cannot be performed. .
Therefore, when the coil spring 46 repeatedly compresses and expands,
The size of each member is set so that the coil spring 46 and the metal cap 49 do not contact the inner surface of the protruding cylindrical portion 14c. That is, a sufficient gap g1 is provided so that the outer diameter of the coil spring 46 and the outer diameter of the metal cap 49 do not contact the inner surface of the protruding cylindrical portion 14c.
The gap g1 is set to 0.2 to 1.5 mm so as to be a sufficient gap in consideration of the plasma welding R3.

Further, the resin cap 48 is arranged so that the outer peripheral side faces the inner side of the side surface of the metal cap 49, and the gap g2 at the facing portion is 50 to 500 μm. If the gap g2 is large, the radial contact portion between the resin cap 48 and the metal cap 49 may move due to an external impact. When the contact portion moves, the vertical position of the thrust shaft 41 changes, and the measured value changes. In order to prevent this, the gap g2 of the facing portion is set to
The thickness is set to 500 μm, so that the rotation of the thrust shaft 41 can be smoothly performed and the amount of movement when the thrust shaft 41 moves is reduced.
If the gap g2 is too small, the resin cap 48 comes into contact with the metal cap 49 too much, causing a problem in rotation of the thrust shaft 41.

The coil spring 46 is a so-called rectangular coil spring having a quadrangular cross section, and applies an urging force against the downward force of the thrust shaft 41 to 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. Each end of the coil spring 46 is thinned so that the upper and lower end faces are horizontal.

The load characteristics of the coil spring 46 are such that the compression length changes in direct proportion to the load, and the variation is only about 3 mm even when a load of 7 kg is applied. As described above, since the displacement of the rectangular coil spring is small even under a high load, it is advantageous when there is a restriction in space and the space in the displacement direction is suppressed, and it is desired to cope with a high load.

Further, the first relative displacement detecting member 42 includes:
As shown in FIG. 4, it has a cylindrical shape and has
A hole 42a through which the thrust shaft 41 passes is formed. A pair of grooves 42b and 42c are formed in the side cylindrical portion at positions facing each other across the central axis. The grooves 42b and 42c are formed obliquely at a predetermined angle with respect to the center axis direction. These oblique grooves 42b, 4
2c is formed into a spline shape by resin molding with a die having a punching structure. By forming the pin 44a in a spline shape, a change in the longitudinal direction of the pin 44a can be smoothly converted into a change in the rotational direction in a linear relationship.

The outside of the side cylindrical portion is 120 °.
Magnet mounting portions 51a, 51b, 51c for mounting magnets B1, B2, B3 arranged at intervals are provided. These magnet loading sections 51a, 51
b, 51c, a magnet loading portion 51a
First and second relative displacement detecting members 42 and 43
There is provided a projection 51d for locking one end of the biasing spring 45 for maintaining the positional relationship in the rotation direction. Note that the other end of the biasing spring 45 is loaded into a storage section including a storage wall 52d and a holding projection 52e provided on the second relative displacement detection member 43.

On the other hand, as shown in FIG. 5, the second relative displacement detecting member 43, which is also an output gear, has a cylindrical shape with one end having a bottom and the other end having an opening. The detection member 42 has a slightly larger diameter than the outer diameter, and has an inner cylindrical portion 43a formed concentrically inside. 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 pair of axial directions at positions opposed to each other with the center axis of the cylinder interposed therebetween. Notches 43b and 43c are formed in the groove.

Such a second relative displacement detecting member 43
A hole 43d through which the thrust shaft 41 penetrates is formed in the center portion on the bottomed end side. The second relative displacement detecting member 43 has a gear formed on the outer surface thereof, meshes with the third gear 33 of the rotation driving means 12, and also functions as an output gear.

Such a second relative displacement detecting member 43
Has one end in contact with a leaf-shaped spring 50 which is a metal plate-shaped spring member. Leaf spring 50
Are first and second relative displacement detecting members 42 and 43
And a case lid 14b serving as one top plate of the casing 14.
And between the inner surfaces of the two. This leaf spring 5
0 is the first and second relative displacement detection members 42 and 43
Is provided in the thrust direction.

The first relative displacement detecting member 42 and the second relative displacement detecting member 43 are provided with an end having an inlet portion of the groove 42b, 42c of the first relative displacement detecting member 42, The first relative displacement detecting member 42 is connected to the second relative displacement detecting member 43 so as to face the open end of the second relative displacement detecting member 43.
Is inserted into the relative displacement detecting member 43. This allows
The inner cylindrical portion 43a of the second relative displacement detection member 43 is
The state is inserted into the first relative displacement detection member 42.

A cylindrical projection 43e (see FIG. 2) projecting outward is formed at the bottomed end of the second relative displacement detecting member 43, and the cylindrical projection 43e is a leaf. It is in contact with the shaped spring 50. Thus, the second relative displacement detecting member 43 is urged toward the bottom surface of the case body 14a by the urging force F2. The case main body 14 is provided at the opening end side of the second relative displacement detecting member 43.
a and the first and second relative displacement detecting members 42,
A flat washer 54 is disposed between the washer 43. As described above, the second relative displacement detecting member 43 is urged by the leaf spring 50 from one side and is pressed against the washer 54, so that the movement in the vertical direction is restricted.

The first relative displacement detecting member 42 is
The urging force F <b> 2 is pressed against the washer 54 via the second relative displacement detecting member 43. The second relative displacement detecting member 42 is also pressed against the washer 54 by F1 generated by the urging force of the urging spring 45.

As described above, when the washer 54 is not put on the turntable 11 (ie,
If the cooking member is not placed on the turntable 11 or the first and second relative displacement detecting members 42, 4
3 come into contact with each other. That is, the washer 54 serves as a reference surface for receiving the end surfaces of the first and second relative displacement detecting members 42 and 43 urged by the leaf spring 50 serving as urging means in an initial state or during cooking. The first and second relative displacement detecting members 42 and 43 are relatively displaced from the reference plane according to the weight applied to the turntable 11.
With this configuration, the relative displacement between the two due to weight is stabilized, and weight detection without error can be reliably performed.

The end faces of the first and second relative displacement detecting members 42 and 43 urged by the leaf springs 50 are formed so as to simultaneously contact the washers 54. A configuration in which only the relative displacement detecting member 42 abuts on the washer 54 may be employed. Further, only the second relative displacement detecting member 43 is provided with the washer 5.
4, the first relative displacement detecting member 42 also comes into contact with the washer 54 by the urging force F <b> 1 of the urging spring 45. In addition, the washer 54 includes the first and second relative displacement detecting members 42 and 4.
Although 3 is provided for smooth rotation, this may be eliminated and the bottom surface of the case body 14a may be used directly as the reference surface.

In this embodiment, the first and second relative displacement detecting members 42 and 43 are urged in the thrust direction by the leaf spring 50 and the urging spring 45 as described above, and the washer 54 serving as a reference surface is provided. , So as to receive both end faces. When there is a leaf-shaped spring, the actual weight and the measured converted value are almost the same, and there is almost no variation. On the other hand, when there is no leaf-shaped spring, the actual weight and the measured converted value vary. As described above, the leaf-shaped spring 50 urges the first and second relative displacement detecting members 42 and 43 in the thrust direction to securely contact the washer 54 serving as the reference surface, thereby achieving the present embodiment. There is an effect that the weight detection device 1 in the form can perform more accurate weight detection.

A pin 44a is attached to the thrust shaft 41 such that both ends of the pin 44a protrude to both sides (referred to as left and right) across the center axis of the thrust shaft 41 at right angles. The left and right protruding portions of the pin 44a are engaged with axial grooves 43b and 43c formed in the inner cylindrical portion 43a of the second relative displacement detecting member 43, respectively.
It engages with oblique grooves 42b and 42c formed in the first relative displacement detecting member 42. Further, one end of the pin 44a is connected to the inner cylindrical portion 43 of the second relative displacement detecting member 43.
a and the first relative displacement detecting member 4
2 are engaged with slits 43f arranged opposite to each other.

The tip of the thrust shaft 41 penetrates from the case body 14 through the washer 54 and the bearing member 53a to reach the metal cap 49 disposed in the protruding cylindrical portion 14c. An operation of pressing 49 to compress the coil spring 46 is performed. At this time, the tip of the thrust shaft 41 is in contact with the resin cap 48 via the resin cap 48, and is rotatable together with the resin cap 48. The rear end side of the thrust shaft 41 penetrates through the bearing member 53b from the case lid 14b, protrudes outward, 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 pins 44a attached to the thrust shaft 41 are provided with the grooves 43b and 43c on the second relative displacement detection member 43 side (formed in the same direction as the center axis, that is, in the axial direction). And a groove 42 on the first relative displacement detecting member 42 side.
b, 42c (formed at a predetermined angle to the central axis direction and obliquely). For this reason, when the thrust shaft 41 operates to be pushed down, the pin 44
a is the grooves 43b, 43 on the second relative displacement detecting member 43 side.
c and the grooves 42b, 42c of the first relative displacement detecting member 42
Try to move down through. At this time, the movement of the second relative displacement detection member 43 in the rotation direction is restricted,
Moreover, since the grooves 43b and 43c are the same in the axial direction, they do not rotate. On the other hand, the first relative displacement detecting member 42 moves in the rotational direction about the thrust shaft 41 as the pin 44a moves downward. This will be described with reference to FIG.

FIG. 6A shows the state in which the pin 44a and the first and second relative displacement detecting members 42 and 34 in the initial state of the thrust shaft 41 (the state in which no food is placed on the turntable 11). 43 grooves 42b, 42c, 43
The relationship between b and 43c is shown. FIG. 6 (B) shows the pin 44a and the first and second pins 44a in a state where the food is placed on the turntable 11 and the thrust shaft 41 is lowered to the maximum.
Grooves 42b, 42c of members 42, 43 for detecting relative displacement of
The relationship between 43b and 43c is shown. As shown in FIG.
As can be seen from (B), the first relative displacement detecting member 42 has rotated by a predetermined angle, and the grooves 42b and 42c have moved (rotated) on the circumference by a distance L in the circumferential direction.

As described above, when a load is applied to the turntable 11, the thrust shaft 41 is displaced (down) in proportion to the load, and accordingly, the first relative displacement detecting member 42 is moved up to a maximum distance. It is possible to move by L in the rotation direction. FIG. 6B shows a state in which a maximum load (here, 7 kg) is applied to the turntable 11.

When the turntable 11 is driven to rotate, the rotational force is transmitted from the first gear 31 to the third gear 33 when the motor 20 is turned on.
Further, it is transmitted to the second relative displacement detecting member 43 meshed with the third gear 33. When the second relative displacement detecting member 43 is rotated, the rotational force is transmitted to the thrust shaft 41 by the pin 44a via the contact position W2, whereby the turntable 11 can be rotated.

As described above, the pin 44a and the grooves 42b and 42c provided on the first relative displacement detecting
Grooves 43b, 4 provided on the relative displacement detecting member 43 side of
3c, when the thrust shaft 41 is displaced in the thrust direction, the first relative displacement detecting member 42 is turned around the thrust shaft 41 by a predetermined turning angle in accordance with the displacement amount of the thrust shaft 41. Then, the second relative displacement detecting member 43
When rotates by receiving the driving force from the rotation driving means 12,
The pins 44a and the like apply the rotational force of the motor 20 to the thrust shaft 41.
The operation which can be transmitted to is performed. That is, the pins 44a and the like constitute the above-described displacement direction converting means.

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

On the first relative displacement detecting member 42, three magnets A1, A2, A3 are arranged on the same plane at equal intervals. 120 ° between these magnets
is seperated. On the other hand, on the second relative displacement detecting member 43, three magnets B1, B2, and B3 are arranged on the same plane at equal intervals. Between each of these magnets,
120 ° apart. In a state where the first and second relative displacement detecting members 42 and 43 are fitted so as to be coaxial as described above, the six magnets A1, A2, A3, B1, B2 and B3 described above , Corresponding magnets, ie, magnet A1 and magnet B
1. Magnet A2, magnet B2, magnet A3
And the magnet B3 are arranged on the same plane so as to be separated from each other by a predetermined angle, in this embodiment, 33.24 °.

In the vicinity of the magnet, there is a Hall I which is a Hall element for converting magnetism into an electric signal and outputting the electric signal.
C47 is fixedly arranged on the casing 14. Specifically, the Hall IC 47 is fixed in a recess below a support column 56a extending as a vertical wall to a holder 56, which is a resin molded component, and passes through a hole provided on the bottom surface of the case body 14a. It is configured to protrude into the casing 14. The three terminals of the Hall IC 47 are:
It projects outside the case body 14a and is soldered to a printed circuit board. Components such as connectors and chip capacitors are also mounted on the printed circuit board.

The holder 56 for fixing the Hall IC 47 is
The upper case 1 is fixed to the case body 14a.
4b is provided. That is, a projection is provided on the tip edge of the support column 56a inserted from a hole provided on the bottom surface of the case body 14a, whereas an engagement hole is provided on the upper case lid 14b. The holder 56 is fixed to the case body 14a, and at the same time, the projection of the holder 56 fits into the engagement hole.
The support column 56a is positioned and fixed so that there is no inclination.

As a result, each magnet A1, A2, A
3. The distance between the magnets B1, B2, and B3 is fixed to a predetermined gap, and the Hall IC 47 operates with high accuracy. Since the support column 56a also functions as a support wall between the upper case lid 14b and the lower case body 14a of the casing 14, the distance between the opposing surfaces is also prevented from changing (narrowing) due to thermal deformation or the like. Plays a role.
The holder 56 may be formed by shaving or pressing a metal other than the resin.

FIGS. 8A and 8B show each magnet A
FIG. 2 is a diagram for explaining a positional relationship among 1, A2, A3, magnets B1, B2, B3, and a Hall IC 47, and is a schematic diagram for easy understanding. Some parts do not directly represent the structure shown.

The magnets A1, A2, and A3 are mounted on magnet mounting portions 51a, 51b, and 51c provided at equal intervals on a circumferential portion of the second relative displacement detecting member 43, respectively, and heat-seal or bond resin. Fixed by the material. Similarly, the magnets B1, B2, and B3 are respectively mounted on magnet mounting portions 52a, 52b, and 52c provided at equal intervals on a circumferential portion of the first relative displacement detecting member 42, and heat-sealed or bonded with resin. Fixed by the material. Magnet A
1, A2, A3 and magnets B1, B2, B3 are alternately arranged on the same plane. That is, magnet A1, magnet B1, magnet A2, magnet B
2, a magnet A3 and a magnet B3 are alternately arranged, and each has a structure arranged on the same plane.

FIG. 8A shows a positional relationship corresponding to the state shown in FIG. 6A, in which the thrust shaft 41 is in the initial state (the state in which no food is placed on the turntable 11). It is a positional relationship in. FIG. 8B
6B shows a positional relationship corresponding to the state shown in FIG. 6B, and shows a positional relationship in a state in which a 7 kg cooked product is placed on the turntable 11 and the thrust shaft 41 is lowered to the maximum.

In FIG. 8A, 1
The interval between the pair of magnets (for example, the magnet A1 and the magnet B1) is a predetermined interval Y1. When the cooked product (assumed to be 7 kg) is placed on the turntable 11 and the thrust shaft 41 is lowered to the maximum, the first relative displacement detecting member 42 is rotated to the maximum and FIG. It will be like the following. Then, as shown in FIG.
Magnets B1, B of the first relative displacement detecting member 42
2 and B3 move in the circumferential direction, respectively. Therefore, as described above, in the initial state, the 1
The interval between the magnets of the set (for example, the magnet A1 and the magnet B1) is increased.

The operation of such a configuration will be described. First, when no food is placed on the turntable 11, the first relative displacement detecting member 42 is used.
FIG. 6 shows the relationship between the second member 43 and the second relative displacement detecting member 43.
The state is as shown in FIG. In this state, the magnets A1, A2, A3 and the magnets B1, B2, B
3 has a positional relationship as shown in FIG.

If the motor 20 rotates in this state, the second relative displacement detecting member 43 also starts to rotate, and an output as shown in FIG. 9A is obtained from the Hall IC 47. That is, a signal is output from the Hall IC 47 at a time interval proportional to the angle between the adjacent magnets.
That is, focusing on the magnets A1, B1, and A2, the magnets A1 and A2 are separated by an angle W, and the angle between the magnets A1 and B1 is Y1.
The angle between the magnets B1 and A2 is W-Y1 = Z1.

Here, when only the magnets A1, A2, and A3 in the second relative displacement detecting member 43 are considered,
Assuming that the time from the signal As1 of the Hall IC 47 by the magnet A1 to the signal As2 of the Hall IC 47 by the magnet A2 (the time between the centers of the time widths of the respective signals) is t as the turntable 11 rotates, this time t
Is invariant and is a time corresponding to the angle W. Therefore, when there is no cooking on the turntable 11,
First, a signal As1 is output from the Hall IC 47 between the magnet A1 and the magnet B1, and a signal Bs1 is output when a time corresponding to the angle Y1 has elapsed. The relationship between the magnet A2 and the magnet B2 and the relationship between the magnet A3 and the magnet B3 are similar to this relationship.

At this time, the magnet A1 and the magnet B
Even in the case of only one magnet, that is, only one magnet,
The time ratio corresponding to the angle between the two magnets A1 and B1 with respect to the period is calculated. If there is a tilt of the thrust shaft 41 and the tilt of the thrust shaft 41 and the holder 56 are not the same, the difference between the tilts is a measured value. Appears in In the present embodiment, since there are a plurality of pairs of magnets, there are a pair in which the detected value of the position change is large and a pair in which the detected value of the position change is large due to the inclination of the thrust shaft 41.

In this embodiment, next, the magnet B
Between the magnet 1 and the magnet A2, the signal Bs1 is output from the Hall IC 47, and after a lapse of time corresponding to the angle Z1, the signal As2 is output. In addition, magnet B2
And magnet A3 and magnet B3 and magnet A
The relationship 1 is similar to this relationship.

As described above, the time between the signals output from the Hall IC 47 is measured by measuring the length between the centers of the signals (the center of the signal width) and making one round. Each of the three values obtained is averaged. The length between the centers of the signals (the center of the signal width) is measured because the width of the output signal of the Hall IC 47 may vary depending on the temperature. It is to deal with.

On the other hand, when a cooked product is put on the turntable 11 and cooking is started, the turntable 1 is turned on.
1 starts rotating, and the thrust shaft 41 descends together with the turntable 11 due to the weight of the cooked food.

As a result, the first relative displacement detecting member 42 rotates in proportion to the descending amount of the turntable 11,
Magnet B1 and magnet A for magnet A1
The angle between the magnets between adjacent magnets changes, such as the magnet B2 with respect to the magnet B2. At this time, since the turntable 11 is in a rotating state, the Hall IC 47
From the signal As1 for the magnet A1, the signal Bs1 for the magnet B1, the signal As2 for the magnet A2, and the signal Bs2 for the magnet B2.
Thus, a signal is output corresponding to the passage of each magnet. However, the signals As1 and B at this time are
The time interval of s1 is longer than the time interval in the initial state described above. On the other hand, the time interval between the signals Bs1 and As2 is shorter than the time interval in the above-described initial state.

For example, as an extreme example, when a 7 kg cooked product is placed on the turntable 11, the magnets A1, A2, A3 on the second relative displacement detecting member 43 side and the first relative displacement detecting member 42 Side magnet B1, B
The relationship between 2 and B3 is a positional relationship as shown in FIG.
That is, in the initial state of the magnet on the side of the first relative displacement detecting member 42 and the magnet on the side of the second relative displacement detecting member 43, the angle between the magnets located close to each other (for example, the angle between the magnets A1 and B1). ) Is widened in Y2 and the angle with a magnet (for example, magnet A2 for magnet B1) arranged in a position not close to Y2 becomes narrow, so that the Hall IC 47
Output from FIG. 9B.

As can be seen from FIG. 9B, the time interval between the signal As1 for the magnet A1 and the signal Bs1 for the magnet B1 is longer than the corresponding interval in FIG. 9A. That is, in the initial state (the state where no cooked food is placed on the turntable 11), the signal A
The time interval between s1 and signal Bs1 is a short interval,
When a kilogram of cooked food is placed on the turntable, signal A
The time interval between s1 and the signal Bs1 is widened, and signals with different time intervals can be extracted from the Hall IC 47 according to the weight of the cooked product. Therefore, this Hall I
Using the output of C47, the weight of the cooked product can be measured. The conversion of the displacement into the weight is performed by a microcomputer (not shown).

FIG. 10 is a graph showing the relationship between the load applied to the turntable (the weight of the cooked product) and the Hall IC output by the magnet A1 on the second relative displacement detecting member 43 side.
The time interval of the Hall IC output by the magnet B1 on the relative displacement detection member 42 side is expressed in percentage.
Each time interval t between the magnets A1, A2 and A3 is set to 100
%, Which is a percentage of this t. Note that the same applies to the relationship between the magnet B2 with respect to the magnet A2 and the magnet B3 with respect to the magnet A3. As can be seen from FIG. 15, when the load is 0, 28% (0.28
t), about 30% (0.30t) when the load is 1kg,
When the load is 4 kg, the time interval becomes longer in proportion to the load, such as about 38% (0.38 t). At the maximum load (7 kg), the time interval becomes about 44% (0.44 t).

On the other hand, FIG. 11 shows the load (weight of the cooked product) applied to the turntable and the first relative displacement detecting member 4.
The time interval of the Hall IC output by the magnet A2 on the second relative displacement detection member 43 side with respect to the Hall IC output by the magnet B1 on the second side is expressed as a percentage, and each time interval between the magnets A1, A2, and A3. Interval t is 1
00%, which is a percentage with respect to t. The magnet A3 and the magnet B3 with respect to the magnet B2
The same applies to the relationship of the magnet A1 with respect to. This figure 1
As can be seen from FIG. 6, when the load is 0, 72% (0.
72t), about 70% (0.70%) when the load is 1 kg
t), the time interval becomes shorter in proportion to the load, such as about 62% (0.62 t) when the load is 4 kg, and about 56% (0.56 t) at the maximum load (7 kg).
Becomes

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

In the above description, the magnet on the side of the second relative displacement detecting member 43 and the magnet on the side of the first relative displacement detecting member 43 each have three magnets.
Although the configuration is made up of pairs, the number may be more, or may be one, for example. In principle, the magnet on the side of the second relative displacement detecting member 43 and the magnet on the side of the first relative displacement detecting member 42 can change the amount of displacement of the turntable 11 by the time of the Hall IC 47 even with only one pair of magnets. It is possible to take out as a displacement of the interval. But 50K
In order to be able to use regardless of the difference between the Hz region and the 60 kHz region, a reference time (in this case, the time interval between the magnets A1, A2, A3 on the second relative displacement detecting member 43 side). Displacement to t) (= proportion)
It is preferable to represent Therefore, in order to obtain the displacement amount, the magnets of the first and second relative displacement detection members 42 and 43 may be paired, but it is necessary to calculate at least two intervals.

As described above, in the above-described embodiment, the amount of displacement of the turntable 11 in the thrust direction is converted into the amount of displacement of the first relative displacement detecting member 42 in the rotational direction. Is obtained in proportion to the output of the Hall IC 47, and the weight of the food placed on the turntable 11 is detected based on the displacement of the output of the Hall IC 47. In addition, these weight detection operations can be performed during the rotation of the turntable 11 by placing cooked items on the turntable 11 and starting cooking,
This can be performed at the maximum while the turntable 11 makes one round, and efficient weight detection becomes possible.

Further, when the turntable 11 is rotated, the first and second relative displacement detecting members 42 and 43 are maintained in a circumferential positional relationship by an urging spring 45 and a washer 54 serving as a reference surface. Against the leaf spring 50. Therefore, the positional relationship does not shift during rotation, and an accurate displacement amount, that is, an accurate weight detection can be performed.

Further, a configuration in which a rotation drive means 12 for rotatingly driving the turntable 11 and a weight detection unit 13 for detecting the weight are housed in one casing 14,
In other words, since the weight detection unit 13 is incorporated in the rotation drive unit 12, the number of assembly steps can be reduced rather than assembling the weight detection unit 13 and the rotation drive unit 12 separately and then combining them. Therefore, the size can be reduced as a whole, and the cost can be reduced.

Although the above-described embodiment is an example of a preferred embodiment of the present invention, the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention. is there. For example, in the above embodiment,
Although the turntable 11 has been described as rotating only in one direction, the turntable 11 may be capable of rotating in both directions. In this case, in the present invention, as described above, the biasing spring 45 as the position holding means is configured to hold the first and second relative displacement detecting members 42 and 43 in the circumferential direction. There is no variation in measured values,
This can be dealt with only by correcting a constant value according to the rotation direction, and the effect of the detection device is further enhanced.

When the friction is small and the wear is small, the lubricant between the resin cap 48 and the metal cap 49 may be omitted. Further, as shown in FIG. 12, a configuration may be adopted in which a sheet 61 having good wear resistance is placed on the metal cap 49 as an intervening member. In this case, it is preferable that a hemispherical projection 41a is provided at the tip of the thrust shaft 41 to make the tip thinner. However, a flat shape may be used as long as the wear is small. Further, in the example shown in FIG.
c is a case where the upper side is widened, and the fixing between the coil spring 46 and the metal cap 49 and the fixing between the coil spring 46 and the protruding cylindrical portion 14c are performed by the adhesive R4.

Further, the transmitting member may be made of another member, for example, a resin material, instead of metal, and the shape may be not a cap shape but another shape such as a flat plate shape. The metal cap 49 may be fixed to the coil spring 46 by press-fitting or bonding. Furthermore, the metal cap 49
As shown in FIG. 13, the shape may be such that the center becomes lower. In this case, a hemispherical projection 48a is provided on the bottom surface of the resin cap 48, and the projection 48a is always
9 is preferably configured to abut on the center.

The thrust shaft 41 on the turntable 11 side protrudes from the cylindrical burring portion of the case cover 14b constituting the other top plate of the casing 14.
The thrust shaft 41 may be preloaded from the outer peripheral direction by a reel spring or the like serving as a tilt preventing means having a base end fixed to the case lid 14b. Thrust shaft 41
If there is a backlash, the measured value of the weight differs depending on the inclination of the thrust shaft 41, but with this structure, the thrust shaft 4
The rattling of 1 is eliminated, and the detection error can be eliminated. The member for applying the preload to the thrust shaft 41 may be a leaf spring, a resin having spring properties, a rubber material, or the like, in addition to the reel spring.

In the above embodiment, three pairs of magnets A1, A2, A3, B1, B2 and B3 are used.
It is also possible to use only one pair or another number such as two pairs or four pairs. Further, in the above-described embodiment, the displacement amount is detected by the magnetic detection means including the magnet and the Hall IC 47. However, this can be realized by other means. For example, both the first relative displacement detecting member 42 and the second relative displacement detecting member 43 are provided with a plurality of pairs of overlapping slits, and the length of the overlapping slits changes due to displacement of the thrust axis in the thrust direction. You may do it.

In the case of this configuration, the photoelectric conversion means such as the photodiode and the phototransistor are disposed to face each other with the slit interposed therebetween, and the thrust axis is displaced in the thrust direction, thereby changing the slit length of the overlapping slit. . Then, the change in the slit length of the overlapping slits is extracted as the interval of the output signal from the phototransistor, and weight detection can be performed based on this. Also in this case, the weight can be detected as in the above-described embodiment.

In the above-described embodiment, the first relative displacement detecting member 42 is rotated by the displacement of the thrust shaft 41 in the thrust direction, and the second relative displacement detecting member 43 is not displaced. However, both the members 42 and 43 may be displaced together, or only the second relative displacement detecting member 43 may be displaced. Further, the magnet may have another shape or configuration such as a configuration in which the outer peripheral portion of a circular rubber magnet is made convex.

The coil spring 46 may be a circular coil spring or other coil spring instead of a square coil spring. Further, instead of a coil spring, another spring such as a plate spring or a disc spring, or another elastic member such as a rubber material or a plastic material may be used. Further, the biasing spring 45 may be rubber or another elastic member instead of the coil spring. The leaf spring 50 is located at the position of the leaf spring 50.
Instead of 0, other urging means such as a disc spring or a rubber member may be arranged.

Further, in the above-described embodiment, the case where the weight of the cooked product in the microwave oven is detected has been described as an example. However, the present invention is not limited to the microwave oven, and other devices such as an oven and a toaster may be used. It can also be applied to the detection of weight. In addition, the present invention can be applied to the detection of the weight of an article other than a cooked article.

[0095]

As described above, in the weight detecting device of the present invention, the thrust shaft which is received by the load spring and is displaced in the thrust direction according to the weight to be detected is provided in engagement with the thrust shaft. Rotational displacement means for rotating and displacing the relative displacement detection member by a predetermined amount according to the displacement amount of the thrust shaft, and rotation driving means for rotating the relative displacement detection member integrally with the thrust shaft, Since a signal corresponding to the relative displacement of the relative displacement detection member is output as a weight detection signal, high-precision weight detection is possible with a simple configuration, and compared to a conventional capacitance-type weight detection device. And downsizing can be achieved.

According to the first aspect of the present invention, a transmission member for indirectly transmitting the movement in the thrust direction according to the weight of the thrust shaft to the load spring is provided at the end of the thrust shaft on the load spring side. Therefore, the operation of the load spring becomes stable, and wear between the thrust shaft and the load spring hardly occurs, and stable weight measurement can be performed for a long time.

According to the second aspect of the present invention, since the bottom of the load spring is fixed to the case holding the load spring, the load spring does not move in the front-rear direction, the left-right direction, and the rotation direction of the thrust shaft. As a result, a change in the measured value of the weight can be prevented. Further, according to the third aspect of the invention, similarly to the first aspect of the invention, the operation of the load spring is stabilized, and wear between the thrust shaft and the load spring is less likely to occur. Measurement can be performed.

According to the fourth aspect of the present invention, since the transmitting member has a cap shape and the load spring is a coil spring, the two can be easily combined by fitting the bottom of the cap to the center of the coil spring. Becomes Further, the thrust shaft can be inserted into the cap-shaped concave portion, which is advantageous in the space in the vertical direction.
Further, since the movement of the thrust shaft in the lateral direction is restricted by the bearing of the device, the outer periphery of the thrust shaft enters the recess, whereby the coil spring is held at the center. In addition, grease or the like for preventing wear can be put in the recess.

According to the fifth aspect of the present invention, when the load spring repeatedly compresses and expands, the size of each member is set so that the load spring and the transmission member do not contact the case holding the load spring. So that correct measurements can always be made. In the invention according to claim 6, since the transmission member is fixed to the load spring, the position of the transmission member does not shift, and the vertical position of the thrust shaft does not change. For this reason,
The measured value does not change and accurate weight detection can be performed.

According to the seventh aspect of the present invention, an intervening member is further disposed between the transmitting member and the thrust shaft. Wear is less likely to occur, and stable weight measurement can be performed for a long time. Further, in the invention according to claim 8, as an intervening member, a resin cap made of resin is put on the tip of the thrust shaft so as to rotate integrally with the thrust shaft, and a metal cap as a transmission member mounted on a load spring is provided. Since the resin cap is received on the inner side of the bottom, the operation of the load spring becomes more stable, wear is less likely to occur, and stable weight measurement can be performed for a long time.
In addition, the thrust shaft is supported at a part other than the tip, and the tip is held at a fixed position (center) by the action of the bearing, and the metal cap that receives the resin cap is also naturally fixed at the center. You. As a result, the load spring is also arranged at the center, and contact with the case side in which the load spring is incorporated is prevented.

Further, in the ninth aspect of the present invention, since the lubricant is applied to the portion where the metal cap and the resin cap are in contact with each other, wear is further reduced, and stable weight measurement can be performed for a long period of time. According to the tenth aspect of the present invention, the resin cap is disposed such that the outer peripheral side faces the inner side of the metal cap, and the gap between the opposing portions is 50 to 50 mm.
Since it is 500 μm, the vertical position of the thrust axis does not change, and the measured value becomes accurate. If this gap is large, the radial contact portion between the resin cap and the metal cap may move due to an external impact.
When the contact portion moves, the vertical position of the thrust axis changes and the measured value changes, but in the present invention, large movement of the contact portion is prevented. According to the eleventh aspect of the present invention, the tip of the thrust shaft on the side of the load spring is made thinner, so that wear is further reduced.

Further, in the twelfth aspect of the present invention, the thrust shaft is made of ceramic, and the relative displacement detecting member is a first and a second relative displacement detecting member provided in engagement with the thrust shaft. The two relative displacement detecting members are relatively rotationally displaced by a predetermined amount in accordance with the displacement amount of the thrust shaft by the rotational displacement means, and the first and second relative displacement detecting members are provided with the detected objects, respectively. Since the weight conversion means converts the relative displacement of the first and second relative displacement detecting members detected by the detector as weight, the weight can be accurately calculated with a simple structure. Measurement can be performed, and stable measurement can be performed for a long period of time.

Further, according to the thirteenth aspect of the present invention, the first
And the position holding means for holding the positional relationship in the rotational direction of the second relative displacement detecting member is provided, so that the first and second relative displacement detecting members can be moved in the circumferential direction by the position holding means. The positional relationship is maintained. Therefore, accurate weight detection can be performed even during rotation.

Further, in the microwave oven according to the present invention, since the weight detecting device for detecting the weight of the cooked product can be reduced in size, the microwave oven itself can be reduced in size.
In addition, since it is possible to detect the weight with high accuracy, it is possible to set an appropriate cooking time when performing control for automatically setting the cooking time for the weight of the cooked product.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an embodiment of a weight detecting device according to the present invention, in which a holder for a detector is omitted.

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

FIG. 3 is a partially enlarged view of a portion where a coil spring as a load spring used in the weight detection device shown in FIG. 1 is arranged.

FIG. 4 is a perspective view illustrating the first relative displacement detecting member shown in FIGS. 1 and 2 in detail.

FIG. 5 is a perspective view illustrating in detail a second relative displacement detecting member shown in FIGS. 1 and 2;

6A and 6B are diagrams illustrating a relationship between a first relative displacement detecting member and a second relative displacement detecting member of the weight detecting device illustrated in FIG. 1; FIG. 6A illustrates a state where a load from a turntable is applied; (B) is a front view when the load from the turntable is applied to the maximum.

FIG. 7 is a sectional view taken along line AA of FIG. 1;

8 is a view for explaining the positional relationship between the magnets on the first relative displacement detecting member side and the respective magnets on the second relative displacement detecting member side of the weight detecting device shown in FIG. 1 and the arrangement of the Hall ICs. (A) is a diagram showing a case where no load is applied to the turntable, and (B) is a diagram showing a case where a maximum load is applied to the turntable.

9A and 9B are diagrams showing output signals of a Hall IC used in the weight detection device shown in FIG. 1, and FIG. 9A is a diagram showing output signals when no load is applied to the turntable;
(B) is a diagram showing an output signal when a maximum load is applied to the turntable.

10 is a graph in which the horizontal axis represents the load applied from the turntable to the weight detection device shown in FIG. 1, 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. 5 is a graph in which the vertical axis represents the value (= phase difference between magnets A and B) indicating the time interval of the Hall IC output according to percentage.

11 is a graph in which the horizontal axis represents the load applied from the turntable to the weight detection device shown in FIG. 1, and the magnet on the second relative displacement detection member side with respect to the Hall IC output by the magnet on the first relative displacement detection member side. 5 is a graph in which the vertical axis represents the value (= phase difference between magnets A and B) indicating the time interval of the Hall IC output according to percentage.

FIG. 12 is a partially enlarged view showing another example of a structure of a portion where a coil spring as a load spring of the weight detection device of the present invention is disposed.

FIG. 13 is a partially enlarged view showing still another example of a structure of a portion where a coil spring as a load spring of the weight detection device of the present invention is disposed.

[Explanation of symbols]

Reference Signs List 1 weight detection device 11 turntable 12 rotation driving means 13 weight detection unit 14 casing 14a case body 14b case lid 14c protruding cylindrical portion (case) 20 motor (part of rotation driving means) 41 thrust shaft 42 first relative displacement detection Member 43 second relative displacement detecting member 44 rotational displacement means 44a pin 45 biasing spring (position holding means) 46 coil spring (load spring) 47 Hall IC (detector) 48 resin cap (intervening member) 49 metal cap (Transmission member) 55 Printed circuit board (circuit board) 56 Holder AI, A2, A3 Magnet on the second relative displacement detection member side (subject) B1, B2, B3 Magnet on the first relative displacement detection member side (Detected object)

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01L 1/14 G01L 1/14 Z (72) Inventor Noriyuki Akabane 1020 Kaga, Iida City, Nagano Prefecture Sankyo Co., Ltd. 3L086 AA04 AA12 AA14 CA04 CB03 CB04 CC08 CC11 CC14 DA16 DA18 DA19 DA20 DA23 DA28

Claims (14)

[Claims] 1. A thrust shaft which is received by a load spring and is displaced in a thrust direction in accordance with a weight to be detected, and a relative displacement detection member provided in engagement with the thrust shaft is provided with a displacement amount of the thrust shaft. Rotation displacement means for rotating and displacing a predetermined amount in accordance with the above, rotation drive means for rotating the relative displacement detection member integrally with the thrust shaft, and a detection object provided on the relative displacement detection member. A weight detector that converts a relative displacement amount of the relative displacement detection member, which is disposed in the detectable area of the detected object and detects the detected object, and that is detected by the detector, as a weight. And means,
A weight detecting device, wherein a transmission member for indirectly transmitting a movement in a thrust direction according to a weight of the thrust shaft to the load spring is provided at an end of the thrust shaft on the load spring side. 2. A thrust shaft which is received by a load spring and is displaced in a thrust direction in accordance with a weight to be detected, and a relative displacement detecting member provided in engagement with the thrust shaft is provided with a displacement amount of the thrust shaft. Rotation displacement means for rotating and displacing a predetermined amount in accordance with the above, rotation drive means for rotating the relative displacement detection member integrally with the thrust shaft, and a detection object provided on the relative displacement detection member. A weight detector that converts a relative displacement amount of the relative displacement detection member, which is disposed in the detectable area of the detected object and detects the detected object, and that is detected by the detector, as a weight. And means,
A weight detecting device, wherein a bottom of the load spring is fixed to a case holding the load spring. 3. A transmission member for indirectly transmitting a movement in a thrust direction according to the weight of the thrust shaft to the load spring is provided at an end of the thrust shaft on the side of the load spring. The weight detection device according to claim 2. 4. The transmission member according to claim 1, wherein the transmission member has a cap shape, and the load spring is a coil spring.
Or three weight detectors. 5. The size of each member is set so that the load spring and the transmission member do not contact the case holding the load spring when the load spring repeatedly compresses and expands. The weight detection device according to claim 1, 3 or 4. 6. The weight detecting device according to claim 1, wherein the load spring and the transmitting member are fixed. 7. An apparatus according to claim 1, further comprising an intervening member disposed between said transmission member and said thrust shaft.
7. The weight detection device according to 3, 4, 5, or 6. 8. A bottom portion of a metal cap as a transmission member mounted on the load spring, wherein a resin cap made of resin is put on the tip of the thrust shaft so as to rotate integrally with the thrust shaft. The weight detecting device according to claim 7, wherein the resin cap is received inside. 9. The weight detecting device according to claim 8, wherein a lubricant is applied to a portion where the metal cap and the resin cap are in contact with each other. 10. The resin cap is disposed such that an outer peripheral side thereof faces an inner side surface of the metal cap,
10. The weight detecting device according to claim 8, wherein a gap between the opposed portions is 50 to 500 [mu] m. 11. The weight detecting device according to claim 1, wherein a tip of the thrust shaft on the side of the load spring is made thin. 12. The thrust shaft is made of ceramic,
The relative displacement detecting member is a first and a second relative displacement detecting member provided by engaging with the thrust shaft, and these two relative displacement detecting members are connected to the thrust shaft by the rotational displacement means. The first and second members for relative displacement detection are provided with the object to be detected, respectively, and are relatively rotated by a predetermined amount according to the amount of displacement.
12. The apparatus according to claim 1, wherein a relative displacement amount of the first and second relative displacement detection members detected by the detector is converted into a weight. Weight detection device. 13. The weight detecting device according to claim 12, further comprising a position holding means for holding a positional relationship between the first and second relative displacement detecting members in a rotation direction. 14. A microwave oven having a weight detection device that enables the turntable to be displaced in the thrust direction in accordance with the weight applied to the turntable and detects the weight applied to the turntable based on the amount of displacement. 14. A microwave oven provided with the weight detection device according to claim 1 as the weight detection device.