JPH1099587A - Vibration detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the highly accurate detection of vibration waveforms with an inexpensive device by configuring a vibration detecting device which detects vibrations of a washing machine, etc. with providing an acceleration censor which comprises a piezoelectric element, weight to press the piezoelectric element, spring to inhibit the weight, and housing case for a vibrating body such as a water tank and washing tub. SOLUTION: This acceleration sensor of a vibration detecting device for observing continuous changes in waveforms of a vibrating body containing the rotating drum of a drum washing machine comprises a piezoelectric element 12, substrate 13 to fix the piezoelectric element 12, weight 14 to impose a load on the piezoelectric element 12, spring 15 to inhibit the weight 14 and cover case 16 to house the weight 14 and spring 15. A plurality of minute protrusions 17 are provided for a part of the weight 14 which comes into contact with the piezoelectric element 12. The spring 15 has a larger pressing force than the maximum acceleration of gravity which occurs in the vibrating body and the maximum load determined by the mass of the weight 14. The gap between the periphery of the weight 14 and the inner periphery of the cover case 16 is arranged to be the minimum gap for the weight 14 to be movable. Thereby, stable acceleration output is achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration detecting device suitable for detecting vibration of a washing machine or the like, and more particularly to an acceleration sensor for detecting the vibration acceleration of a vibrating body including a water tub, a washing tub and the like. The present invention relates to a vibration detecting device provided.

[0002]

2. Description of the Related Art Conventional vibration detection, for example, vibration of a water tub in a washing machine, vibration of a vibrating body including a washing tub, or vibration of an outer tub caused thereby is reduced to reduce the vibration of the washing machine generated during dehydration. Many control methods for preventing occurrence of abnormal vibration or abnormal vibration have been proposed.

[0003] For example, the apparatus disclosed in Japanese Patent Application Laid-Open No. 1-218495 has a pressure-sensitive or strain-type vibration sensor whose voltage or resistance value changes by vibration attached to an outer tub of a washing machine, and dehydration is performed by a signal thereof. It is intended to control the operation and keep the vibration during dehydration within the specified range,
Japanese Patent Application Laid-Open No. 1-268597 discloses a method in which a light detector comprising a light emitting diode and a phototransistor is provided in an outer tank, and a light detector such as a reflector is provided in a vibrating body, and a change in vibration is changed by a light change. Instead, the state of vibration is detected and the same control is performed.

Japanese Patent Application Laid-Open No. 4-208199 discloses a method in which a resonance type vibration sensor is attached to a vibrating body to detect vibration.
No. 876 discloses an ON-OFF type vibration detection switch provided in the outer tub, controls the dehydration operation based on the ON-OFF signal of the switch, and keeps the vibration during dehydration within a specified range. It is to try. As a vibration acceleration sensor consisting of a piezoelectric element and a weight,
One described in 178377 is proposed.

[0005]

In the prior art having the above-described structure, the unbalanced state of the cloth is estimated from the vibration state at the initial stage of dehydration, and dehydration is performed so as to suppress vibration during dehydration. Many methods for controlling driving, including the above example, have been proposed.
When an advanced control such as that described in Japanese Patent Application No. 8-16357 is attempted, vibration of a vibrating body including a rotating drum is required.
It is necessary to accurately observe continuous changes in the vibration waveform.

For this purpose, it is necessary to attach a vibrometer, such as an accelerometer, to the vibrating body. The accelerometer includes a pressure-sensitive type, a strain type, or a type disclosed in JP-A-1-218495. No. 208199, the resonance type and the like,
There are various types, but many are expensive. Also,
In order to perform continuous measurement of the vibration waveform at relatively low cost, for example, there is a method of combining inexpensive components described in Japanese Patent Application Laid-Open No. 1-268597 to constitute a vibrometer. There is a problem such as an error due to the deviation, and a resolution problem due to a change in intensity of light in a short distance.

In the acceleration sensor described in Japanese Utility Model Application Laid-Open No. Sho 62-178377, the weight is fixed to the surface of the piezoelectric element, and the movement of the weight is not limited. In addition, since the fixing surface between the weight and the piezoelectric element is flat, there is a problem that the pressure detection sensitivity of the weight due to acceleration is poor.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide a vibration detecting device which can detect a vibration waveform with relatively low cost and high accuracy.

[0009]

In order to achieve the above object, the vibration detecting apparatus according to the present invention is characterized in that a vibration element comprising a water tub, a washing tub and the like is provided with a piezoelectric element and a piezoelectric element. The acceleration sensor (vibration acceleration sensor) composed of the weight that applies pressure to the body, the spring that restrains the weight, and the case that houses them is fixed, so that the vibration of the vibrating body can be detected extremely easily and inexpensively. Can be.

According to the second aspect of the invention, the load (force) of the spring for restraining the weight is set to be larger than the maximum load (force) determined by the maximum acceleration generated in the vibrating body and the mass of the weight. Even when the maximum acceleration of the washing machine occurs, the weight does not separate from the piezoelectric element, a stable acceleration output can be obtained, and damage to the piezoelectric element caused by the projection provided on the weight can be reduced. In addition, since the gap between the outer periphery of the weight and the inner periphery of the cover case accommodating the weight and the spring is configured to be a minimum gap that allows the weight to move, the movement of the weight in the radial direction (radial direction) is prevented. Minimized, stable acceleration output can be obtained, and damage to the piezoelectric element caused by the projection provided on the weight can be reduced.

The invention according to claim 3 is characterized in that
Since a plurality of minute projections are provided on the surface that contacts the piezoelectric element, the load applied to the piezoelectric element is dispersed, and the damage provided to the piezoelectric element can be reduced as compared to a single projection provided with a weight, The swing of the weight can be prevented. Moreover,
The detection sensitivity can be increased as compared with a flat contact surface.

Further, the invention according to claim 4 has a structure in which the substrate for fixing the piezoelectric element and the cover case for accommodating the weight and the spring are integrated with the claws provided on the cover case, so that it is extremely simple. Can be configured as a sensor assembly. In addition, when the sensor is fixed to the vibrating body, it is configured to be fixed by both the mounting ears provided on the board and the cover case, so the board and the cover case are firmly integrated, and sufficiently withstand the vibration of the vibrating body It is possible to construct a sensor system (device) to obtain.

Further, in the invention according to claim 5, the back surface of the substrate to which the piezoelectric element is fixed is reinforced by a rib or the like, and the height of the rib is such that the mounting ear provided on the substrate is in contact with the mounting surface of the vibrating body. Because it is configured to be face to face-
A stable acceleration output can be obtained without the substrate being deformed by the pressing of the weight. Moreover, since the claws and the claw fixing holes for integrating the substrate and the cover case are configured to be displaced from the mounting ears, the strength of the mounting ears is not weakened, and a strong vibration sensor system (device) is provided. Can be achieved.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a vibration detecting apparatus according to the present invention will be described with reference to the drawings when applied to a drum type washing machine. This vibration detecting apparatus (acceleration detecting system) is a general fully automatic apparatus. Needless to say, it can be applied to a washing machine.

FIG. 1 is a schematic structural view of a drum type washing machine in which a vibration detecting device according to the present invention is implemented. In FIG. 1, reference numeral 1 denotes an outer tub, and a water tub 2 swings through a spring 3 for absorbing vibration. It is suspended freely. A vibration resistor (shock absorber) 4 is provided between the lower part of the water tank 2 and the outer tank 1 so as to suppress a steep vibration of a certain vibrating body from the water tank 2, a drum or the like.
However, this is also provided so as to be swingable, and limits vibration during dehydration.

A drum 5 is rotatably mounted inside the water tank 2 via a bearing and a shaft (not shown). The rotation of a motor 6 is transmitted from a pulley 7 to a drum pulley 9 via a belt 8 and the drum Rotates. A plurality of baffles (baffles) 10 are provided on the inner wall of the drum, and washing (tumbling washing) and rinsing are performed by lifting and dropping laundry according to rotation of the drum during washing.

Usually, tumbling cleaning and rinsing are performed at a drum rotation speed of about 55 rpm, and dehydration is performed at a rotation speed of about 1000 rpm.

Reference numeral 11 denotes an acceleration sensor which forms the vibration detecting device of the present invention. FIG. 1 shows an example in which the acceleration sensor is attached so as to detect acceleration in the left-right direction.

At the time of spin-drying, if the unbalance (offset) of the laundry is large, the vibration increases. Therefore, there is a method of controlling the spin-drying operation while detecting the unbalanced state by the vibration state of the vibrating body or the like at the beginning of spin-drying. And various publications such as those mentioned above. The device disclosed in Japanese Patent Application No. 8-16357 detects vibration at the beginning of dehydration and starts high-speed rotation when the imbalance is minimized, which is effective in reducing vibration during dehydration. .

In order to perform these controls, it is necessary to accurately observe continuous changes in the vibration waveform of the vibrating body including the rotating drum. The present invention provides a relatively inexpensive and highly accurate vibration detection device. Is provided.

First, the vibration detecting device provided by the present invention will be described with reference to FIGS.

FIG. 2 is a side view of a main part of the acceleration sensor of the vibration detecting device according to the present invention, FIG. 3 is a plan view of the main part, and FIG.
FIG. 5 is a bottom view of a main part of the acceleration sensor shown in FIG.

The acceleration sensor 11 contains a piezoelectric element 12, a substrate 13 for fixing the piezoelectric element 12, a weight 14 for applying a load to the piezoelectric element 12 by acceleration, a spring 15 for restricting the movement of the weight 14, and a weight 14 and the spring 15. Cover case 16. The piezoelectric element 12 is a substrate 13
Is fixed with, for example, an epoxy resin.

The weight 14 is provided with a plurality of minute projections 17 at a portion in contact with the piezoelectric element 12. Further, the spring 15 for restricting the movement of the weight 14 is provided between the water tub 2 and the washing tub 5.
And the pressing force greater than the maximum load (force) determined by the mass of the weight 14, and the outer periphery of the weight 14 and the cover case 1.
The gap with the inner periphery of 6 is the smallest gap in which the weight 14 can move.

Therefore, even if the vibrating body vibrates in the thrust direction at the maximum acceleration, the weight 14 does not separate from the piezoelectric element 12, so that a stable acceleration output can be obtained and the weight 1 can be obtained.
The number of protrusions 17 of the fourth damaging the surface of the piezoelectric element 12 is reduced. Further, since the movement in the radial direction can be minimized, it is effective for stable detection of acceleration and prevention of damage to the piezoelectric element 12.

The weight 14 can be made by forging of iron or stainless steel or the like, but the minute projections 17 can be formed by a separate plastic plate 19 as shown in FIG. 6, for example, as shown in FIG. As shown, weight 18 may be insert molded into plastic 20. Further, the spring 15 is shown as an example of a leaf spring in FIG. 4, but may be of course a coil spring.

The cover case 16 is provided with claws 21 for coupling to the substrate 13, and is very easily integrated as the acceleration sensor 11 by the holes 22 provided in the substrate 13. The cover case 16 and the board 13 are provided with mounting ears 23 and 24, respectively. When the acceleration sensor 11 is fixed to the vibrating body, the mounting ears 23 and 24 are used to fix the acceleration sensor 11 at the same time. , The substrate 13 and the cover case 16 are firmly integrated,
Sensor device (system) that can withstand vibration of vibrating body
Can be obtained.

A plurality of reinforcing ribs 25 are provided on the back surface of the substrate 13 in order to prevent deformation of the mounting portion of the piezoelectric element 12, and the height of the ribs 25 is determined by the mounting ears 23 and 24. Surface and surface in contact with the mounting surface of the vibrator
The reinforcement can be further enhanced by attaching the acceleration sensor 11 to the vibrating body. In addition, since the positions of the nails 21 and the holes 22 for the nails and the mounting ears 23 and 24 are appropriately shifted, the strength of the mounting ears 23 and 24 is not reduced.

FIG. 8 is an example of a change in vibration acceleration at a certain number of rotations. If the acceleration is performed so that the rotation speed becomes high at the time when the value is minimum, the unbalance of the cloth is reduced. In addition, a dehydration operation with less vibration can be performed. FIG. 9 is a block diagram showing an example of control, and 26 is an example of a control circuit of a washing machine including a microcomputer.

[0030]

According to the vibration detecting device of the present invention having the above-described structure, the invention described in claim 1 applies a piezoelectric element to a vibrating body including a water tub, a washing tub, and the like, and applies pressure to the piezoelectric element. Since the vibration acceleration sensor composed of the added weight, the spring for restraining the weight and the case for accommodating the weight is fixed, the vibration of the vibrating body can be detected extremely easily and at low cost.

According to the second aspect of the present invention, the load (force) of the spring for restraining the weight is set to be greater than the maximum load (force) determined by the maximum acceleration generated in the vibrating body and the mass of the weight. Even when the maximum acceleration of the washing machine occurs, the weight does not separate from the piezoelectric element, a stable acceleration output can be obtained, and damage to the piezoelectric element caused by the projection provided on the weight can be reduced. In addition, since the gap between the outer periphery of the weight and the inner periphery of the cover case accommodating the weight and the spring is configured to be a minimum gap that allows the weight to move, the weight moves in the radial direction (radial direction). Is minimized, a stable acceleration output can be obtained, and damage to the piezoelectric element caused by the protrusion provided on the weight can be reduced.

The invention according to claim 3 is characterized in that:
Since a plurality of minute projections are provided on the surface that contacts the piezoelectric element, the load applied to the piezoelectric element is dispersed, and the damage provided to the piezoelectric element can be reduced as compared to a single projection provided with a weight, The swing of the weight can be prevented, and the detection sensitivity can be increased as compared with the case where the contact surface is flat.

Further, the invention according to claim 4 has a structure in which the substrate for fixing the piezoelectric element and the cover case for accommodating the weight and the spring are structured to be rested by claws provided on the cover case, so that it is extremely simple. It can be configured as a sensor assembly, and when fixing the sensor to the vibrating body, it is configured to be fixed with both the mounting ears provided on the substrate and the cover case respectively, so the substrate and the cover case are firmly integrated, A sensor device (system) that can sufficiently withstand the vibration of the vibrating body can be constructed.

Further, the back surface of the substrate to which the piezoelectric element is fixed is reinforced by a rib or the like, and the height of the rib is such that the mounting ear provided on the substrate is in contact with the mounting surface of the vibrating body. Because it is configured to be face to face-
A stable acceleration output can be obtained without deformation of the board due to the pressure of the weight, and the nails and nail fixing holes for integrating the board and the cover case are configured to be displaced from the mounting ears. Therefore, a strong vibration sensor device (system) can be achieved without reducing the strength of the mounting ear portion.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a vibration detection device according to an embodiment of the present invention when applied to a drum type washing machine.

FIG. 2 is a main part side view of an acceleration sensor showing an embodiment of the vibration detection device of the present invention.

FIG. 3 is a main part plan view of an acceleration sensor showing an embodiment of the vibration detection device of the present invention.

FIG. 4 is a sectional view of an essential part taken along line AA of FIG. 3;

FIG. 5 is a bottom view of a main part of an acceleration sensor showing an embodiment of the vibration detection device according to the present invention.

FIG. 6 is an explanatory diagram of an example of formation of a weight and a minute projection showing an embodiment of the vibration detection device of the present invention.

FIG. 7 is an explanatory diagram of another example of the formation of weights and minute projections showing the embodiment of the vibration detection device of the present invention.

FIG. 8 is an explanatory diagram of an example of a change in vibration acceleration according to the embodiment of the vibration detection device of the present invention.

FIG. 9 is a control block diagram showing an embodiment of the vibration detection device of the present invention.

[Explanation of symbols]

 Reference Signs List 1 outer tub 2 water tub 5 washing tub 6 motor 11 acceleration sensor 12 piezoelectric element 13 substrate 14 weight 15 spring 16 cover case 26 control circuit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04R 17/00 H04R 17/00 Z

Claims (5)

[Claims] An acceleration sensor comprising a piezoelectric element, a weight for applying pressure to the piezoelectric element, a spring for controlling the weight, and a case for accommodating them, is fixed to a vibrating body comprising a water tub, a washing tub, and the like. A vibration detecting device for detecting a vibration waveform of a vibrating body. 2. The load of the spring for restraining the weight of the acceleration sensor is greater than the maximum load determined by the maximum acceleration generated on the vibrating body and the mass of the weight, and the outer periphery of the weight and the cover for accommodating the weight and the spring. 2. The vibration detecting device according to claim 1, wherein the gap on the inner periphery of the case is a minimum gap such that the weight can move. 3. The vibration detecting device according to claim 1, wherein a plurality of minute projections are provided on a surface of the weight of the acceleration sensor that contacts the piezoelectric element. 4. A substrate for fixing the piezoelectric element of the acceleration sensor, and a cover case for accommodating a weight and a spring are formed by claws provided on the cover case, and when the sensor is fixed to the vibrating body, 2. The vibration detecting device according to claim 1, wherein the vibration detecting device is fixed by both mounting ears provided on the substrate and the cover case. 5. The back surface of the substrate on which the piezoelectric element of the acceleration sensor is fixed is reinforced with a rib or the like, and the height of the rib is determined by the mounting ear provided on the substrate and the surface in contact with the mounting surface of the vibrator. 2. The vibration detecting device according to claim 1, wherein the claw and the claw fixing hole for integrating the substrate and the cover case are displaced from the mounting ears.