JP2002273096A - Vibration detector for washing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems in a conventional washing machine, including abnormal vibration during dehydration due to failure to correctly control caused by problematic detection accuracy when unbalance occurs among fabrics during dehydration. SOLUTION: A coil, a core, a capacitor, and a diaphragm are provided in a frame and a coil spring is provided in the center of the underside of the diaphragm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to safety control of a washing machine, and more particularly to a vibration detection device for a washing machine suitable for detecting a tub hit or the like due to imbalance of a cloth during dehydration.

[0002]

2. Description of the Related Art A conventional vibration detecting device is disclosed in
As described in Japanese Patent Application Laid-Open No. 000-245990, there is one in which a detection switch is mechanically operated with a lever to perform detection.

The vibration detecting device disclosed in Japanese Patent Application Laid-Open No. 2000-245990 also serves as a water level detecting device. An inclined body is provided above a core so that a spherical body rolls on the inclined portion due to vibration or the like. The reactance of the coil changes as the spherical body rolls on the slope,
As a result, it is detected as a change in the frequency taken into the LC oscillation circuit.

In the case of this method, the size of the output is determined by the size of the spherical body and the size of the inclination. The size of the sphere is limited by the configuration and overall size of the part, reducing weight. For this reason, the inclination cannot be made large, and as a result, the change in the reactance of the coil is small, and the output is small, making it difficult for the microcomputer to make a determination. In addition, since the water level detection is also performed, the movement of the spherical body during detection may affect the detection accuracy.

On the other hand, in the system in which the mechanical switch is operated by the lever, it is necessary to determine the mounting position on the assumption of the trajectory of the tank when the cloth is unbalanced, and the mounting position is limited. Further, the lever can only detect movement in one direction, and depending on the movement of the tank, the detection accuracy may be deteriorated.

[0006] Poor detection accuracy of abnormal vibration due to imbalance of cloth may lead to a serious accident, and it is necessary to accurately detect and control operation of abnormal vibration.

[0007]

SUMMARY OF THE INVENTION The above-mentioned JP-A-2000-2
In the technique described in Japanese Patent No. 45990, when the unbalance of the cloth occurs during dehydration, the detection accuracy is difficult, the control cannot be performed correctly, and this causes abnormal vibration during dehydration.

An object of the present invention is to solve the above-mentioned problems and to provide a vibration detecting device for a washing machine which can accurately detect vibration and impact during dehydration.

[0009]

The above object can be achieved by incorporating the following contents based on a water level detecting device having a coil, a core, a condenser, and a diaphragm. 1. In order to move the core up and down efficiently, a coil spring is provided at the center of the diaphragm so that the diaphragm moves easily. 2. The receiving surface of the coil spring has a conical projection shape so that the lower end does not move when the coil spring expands and contracts. 3. Further, in order to effectively expand and contract the coil spring, the spring force is made weaker than that of the pressure spring provided on the upper portion of the diaphragm. 4. The change in the reactance of the coil is taken into the LC oscillation circuit and input to the microcomputer via the modulation circuit and the comparator circuit, thereby determining the magnitude of the vibration and shock received by the frame.

When abnormal vibration or impact occurs during dehydration, the diaphragm section including the core moves up and down due to expansion and contraction of a coil spring provided at the center of the lower surface of the diaphragm. This causes the core to move relatively between the coils, increasing or decreasing the reactance of the coils.

The change in reactance is taken into an LC oscillation circuit including a capacitor and converted into a change in frequency. Therefore, when the core moves up and down, the frequency changes intermittently, and this change is passed through a modulation circuit and a comparator circuit to cause the microcomputer to read the signal as a voltage change signal.

As described above, vibration and impact during dehydration are effectively detected.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a plan view of the washing machine according to the present embodiment, FIG. 2 is a sectional view of the washing machine according to the present embodiment, and FIG. 3 is an enlarged view of a main part of the washing machine according to the present embodiment. In FIG. 2, reference numeral 1 denotes an outer tank, and a lower part of a driving unit 4 such as an electric motor, and a stirring blade 3 connected to the driving unit 4.
have. An air trap 1 a communicating with the inside of the outer tub 1 is provided at a part of the outer periphery of the outer tub 1, and a washing and dewatering tub 2 is provided inside the outer tub 1. One end of the entire outer tub is connected to a corner of the washing machine body 100,
The other end is suspended from the washing machine main body 100 by a suspension rod 5 connected to a part of the outer tub.

Reference numeral 7 denotes a vibration detecting device for detecting abnormal vibration of the washing machine caused by imbalance of the cloth during dehydration, and also serves as a water level detecting device for detecting the water levels in the outer tub 1 and the washing / dewatering tub 2. The vibration detecting device 7 is mounted on an upper portion of an outer frame of the main body 100 of the washing machine as shown in FIG. And, it is connected to the air trap 1a and the like by a connecting tube 8 extending downward from the vibration detecting device 7 to the washing machine main body 100. Further, in order to efficiently receive vibration during dehydration, it is also possible to directly attach the air trap 1a directly without using the connecting tube 8. Reference numeral 6 denotes a control unit which controls all processes related to washing of the washing machine.

At the time of washing, first, the water supply valve 10 is operated and opened, and water enters the outer tub 1 and the washing and dewatering tub 2. The water entering the outer tub 1 and the washing / dewatering tub 2 is detected by the vibration detecting device 7 also serving as a water level detecting device, and the water entering the outer tub 1 and the washing / dewatering tub 2 reaches a predetermined water level. Operates at times and closes the water supply valve 10. Then, the driving unit 4 uses the stirring blade 3
Is rotated to stir the clothes in the washing and dewatering tub 2 to remove dirt. Since there is no risk of abnormal vibration during washing,
The vibration detecting device 7 is not functioning.

At the time of dehydration, the drain valve 9 at the lower part of the outer tub 1 operates to discharge water. The washing and dewatering tub 2 is rotated when water remains to some extent in order to prevent abnormal rotation and the like due to foaming due to the detergent during dehydration and imbalance of the cloth. At this time, the vibration detecting device 7 functions as a water level detecting device. Immediately after this,
The vibration detecting device 7 switches to a vibration detecting state and detects abnormal vibration and impact due to imbalance of the cloth.

Next, the configuration of the vibration detecting device 7 will be described with reference to FIGS.

Reference numeral 11 denotes an upper case, which is joined to a lower case 12 provided at a lower portion by ultrasonic welding or the like to constitute an outer shell which becomes a vibration detecting device main body. In the vibration detection device main body,
A circumferential groove 11a and an air chamber 11b are formed.

Further, on the upper part of the main body of the vibration detecting device, there are provided a lance 21, a capacitor 22, and a coil 2 for connection to the outside.
3 is mounted, and the charged portion including the coil 23 is sealed with a casting urethane resin (not shown) or the like to insulate it from outside air. The lead wire 23a of the coil is soldered and fixed to the terminal via the cutout portion 21a of the terminal scratched by the lead portion 22a of the capacitor 22.

A central portion has a cylindrical portion 11c communicating with the air chamber 11b, and a screw is formed on the upper portion of the cylindrical portion, and an adjusting screw 19 is engaged. Air chamber 11b and cylindrical portion 11c
A spring base rotatably engaged with a diaphragm base 15, a pressing spring 18, and an adjusting screw 19 to which a metal plate 16 for increasing inertia due to vibration and a core 17 sintered with iron powder or the like are mounted. 20 is provided mounted on the diaphragm 13. It is more advantageous to insert-mold the metal plate and the core on the diaphragm base in order to secure the assembling accuracy of the parts.

The diaphragm 13 is mounted in such a manner that the outer peripheral bead portion 13b is sandwiched between the circumferential grooves 11a of the upper case 11, and the central upper surface protruding portion 13a is inserted and fitted into the hole 15a of the diaphragm base 15 so as to move integrally. It is configured. A coil spring 1 is provided in the cylindrical recess 13c at the center of the lower surface.
4 is inserted so as to be able to expand and contract, and holds the entire diaphragm portion with a certain gap so as not to touch the inner surface of the lower case 12.

The contact portion of the coil spring on the inner surface of the lower case is guided by the tip of the conical projection 12a so that the core automatically comes out, and the position does not shift even if the coil spring 14 expands and contracts.

When the frame receives external vibration and impact, the diaphragm oscillates, causing the coil spring to move up and down, and the core above the diaphragm moves up and down to change the correlation distance with the coil. The pressurizing spring 18 is mounted so as not to apply a force to the diaphragm portion in order to make the diaphragm portion easily move when vibration or impact is applied from the outside.

Next, the operation and functions will be described by taking a washing process of a washing machine as an example.

In the case of washing, it functions as a water level detecting device.

When water is supplied, the water level in the outer tub 1 gradually rises. The air trap 1a of the outer tank and the water level detecting device 7 are communicated with each other by the connecting tube 8, and the air pressure in the air trap is received at the pressure introduction port 12a. .

As a result, the phase distance between the core 17 and the coil 23 changes, and the reactance of the coil changes. The change in the reactance is taken into the LC oscillation circuit shown in FIG. 6 and is input to the microcomputer as a change in frequency. The relationship between the oscillation frequency and the water level at this time is as shown in FIG.

At the time of drainage before rinsing, the drainage valve 9 operates to drain water, and the air pressure in the air trap section 1a gradually decreases. As a result, the diaphragm portion is lowered and the core is also lowered. When the water level in the outer tub falls further and reaches the specified water level, the microcomputer outputs and the dehydration tub 2 starts rotating.

Further, at the time of dehydration, it functions as a vibration / shock detecting device.

At the start of dehydration, most of the water is drained, and the diaphragm portion stops with the downward coil spring partially inserted into the conical projection of the lower case 12. When the pressure is lowered to this point, the diaphragm portion is shaken by minute vibrations and impacts without applying force of the pressurizing spring, which is transmitted to the coil spring, expands and contracts, and is converted into vertical movement.

The core 17 also moves up and down to change the phase distance with the coil, thereby changing the reactance of the coil. The change in the reactance is shown in FIG.
It is taken into an oscillation circuit and output as a change in frequency, and is input to a microcomputer via a modulation circuit and a comparator circuit in order to stabilize and determine a signal. The input signal at this time has an intermittent waveform corresponding to the cycle of vibration and shock as shown in FIG.

[0032]

According to the present invention, the core can be moved up and down effectively by vibration and impact due to unbalance of the cloth during dewatering, and the reactance of the coil can be easily changed. Also, signal processing can reliably process the oscillation frequency by the microcomputer through the modulation circuit and the comparator circuit. Therefore, there is no need for a switch with a lever for detecting an unbalance in use. Further, the vibration and shock can be detected in a stable manner regardless of the swing direction of the outer tub, and the magnitude of the vibration and shock can be detected by changing the determination criterion of the comparator circuit, which is effective in terms of cost and function.

[Brief description of the drawings]

FIG. 1 is a plan view of a washing machine according to the present embodiment.

FIG. 2 is a cross-sectional view of the washing machine according to the present embodiment.

FIG. 3 is an enlarged view of a main part of the washing machine according to the present embodiment.

FIG. 4 is a plan view of the vibration detection device according to the present embodiment.

FIG. 5 is a cross-sectional view of the vibration detection device according to the present embodiment.

FIG. 6 is a circuit diagram of the vibration detection device according to the present embodiment.

FIG. 7 is an output diagram when the vibration detection device according to the present embodiment is a water level detection device.

FIG. 8 is an output waveform diagram of the vibration detection device according to the present embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Outer tub, 2 ... Washing dehydration tub, 3 ... Stirring blade, 4 ... Drive part
5 Hanging rod, 6 Controller, 7 Vibration detector, 8 Connection tube, 9 Drain valve, 10 Water supply valve, 11 Upper case, 11a Circular groove, 11b Air chamber, 11c Cylindrical Part, 12 ... lower case, 12a ... pressure inlet, 12b ... conical projection, 13 ... diaphragm, 13a ... projection, 13
b: outer peripheral bead, 13c: cylindrical recess, 14: coil spring, 15: diaphragm base, 15a: hole, 16 ...
Metal plate, 17 ... Core, 18 ... Pressing spring, 19 ...
Adjustment screw, 20: spring brace, 21: spring, 21a: notch, 22: condenser, 22a: lead, 23 ...
Coil, 23a: lead wire, 100: washing machine body.

Claims (4)

[Claims] 1. A vibration detecting device for a washing machine having a coil, a core, a condenser, and a diaphragm in a frame body, wherein a coil spring is provided at a central portion of a lower surface of the diaphragm. 2. The vibration detecting device for a washing machine according to claim 1, wherein a conical projection is provided on a receiving surface of the coil spring. 3. The vibration detecting device for a washing machine according to claim 1, wherein a spring force of said coil spring is made weaker than a pressure spring at an upper portion of said diaphragm. 4. A vibration detecting device for a washing machine according to claim 1, wherein a change in the reactance of the coil is taken into an LC oscillation circuit and further inputted to a microcomputer via a modulation circuit and a comparator circuit.