JPS6123000B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water level detecting device for a washing machine having a washing and dehydrating tub in which the circumferential wall except at least the upper end side is a non-porous wall, and an object of the present invention is to detect water level accurately without using a pressure switch or an air trap device. The purpose is to perform water level detection.

In automatic washing machines, an outer tank is generally provided on the outside of a washing and dehydrating tank with small holes for dewatering on the side, and water is stored inside the outer tank during washing and rinsing. The water level was detected by operating a pressure switch based on changes in air pressure in an air trap installed on the lower side wall of the outer tank. but,
The above structure has the disadvantage that a large amount of washing water is required because water accumulates between the outside and the washing/drying tub.

Also, it is conceivable to wash water by storing water only in a washing/dehydration tank without holes for dehydration.
In this case, the water level detection method using a conventional pressure switch requires an air trap on the rotating shaft, which complicates the waterway, and also requires a drain valve and pressure switch. , which was expensive.

As an improvement to the above-described structure, a float having a magnet that moves up and down according to the water level is installed in the washing and dehydrating tank, and a reed switch that is opened and closed by the float, so that the reed switch can be used as a washing and dehydrating tank. There is a method of connecting to a control circuit via a sliding contact provided between the bearing part, but durability due to wear of the sliding part and waterproof structure have become major problems in practical use.

The present invention has been made in view of the above-mentioned conventional drawbacks, and one embodiment thereof will be described below with reference to the drawings. In Fig. 1, 1 is an outer wall, 2 is a washing/dehydration tank with a non-porous peripheral wall except for at least the upper end side;
3 is an outer tank enclosing the washing and dehydrating tank 2; 4 is a pulsator placed at the center of the bottom of the washing and dehydrating tank 2; 4a;
is a washing and dehydrating shaft that includes a washing shaft equipped with a pulsator and a dehydrating shaft equipped with a washing and dehydrating tank 2;
5 is a brake/clutch mechanism, 6 is a motor, 7 is a motor pulley, 8 is a belt, 9 is an impeller/pulley, 10 is a vibration isolation support device hanging from the upper four corners of the outer body 1, and 11 is a rotating device having a movable part. 11a is the primary winding of the transformer 11;
b is a secondary winding of the transformer 11, the primary winding 11a is fixed to the bottom of the washing and dehydrating tub 2, the secondary winding 11b is fixed to the outer tub 3, and the rotary transformer 11 is It is provided on the outer periphery of the dehydration shaft 4a.

Reference numerals 12 and 13 are electrodes for water level detection provided at a part of the bottom of the drain groove 2a provided in the vertical direction of the peripheral wall of the washing/dehydration tank 2; 12 is an electrode for water level reset detection;
Reference numerals 13a and 13b are electrodes for detecting a water level set; the electrode 13a is for detecting a high water level, and the electromagnetic electrode 13b is for detecting a low water level.

Fig. 2 is a block diagram showing the basic configuration of the water level detection circuit, where 14 is an AC power supply, 15 is a load control unit that controls the opening and closing of the relay 16, and the relay 1
6 controls loads such as the motor 6, water supply valve, and timer motor (not shown) of the washing machine. 17 is a water level setting unit that sets the water level using water level changeover switches 18a and 18b; 19 is an oscillation circuit unit that obtains an arbitrary oscillation frequency, for example, 1 MHz from the DC power supply unit 20; 11 is a rotary transformer having a movable part; 11a and 11b are the primary and secondary windings of the transformer 11 as described above, and 21 is the electrode 1 for water level detection provided on the inner peripheral wall of the washing and dehydrating tank 2.
2 shows a detection unit that detects that the electrical resistance of the sensor 22 consisting of sensors 2 and 13 has reached a predetermined value.

FIGS. 3 and 4 show how the electrode 13a is attached, and the drain groove 2a provided on the side wall of the washing and dehydrating tank 2.
A recess 2b is provided at the bottom of the electrode 1.
3a is buried so that its surface does not protrude from the recess 2b. The electrodes 13b and 12 are also attached in a similar manner. 23a, 23b
2 shows a sealing member for preventing water leakage when the electrodes 12 and 13 are fixed, and 24 shows a nut for fixing the electrodes.

Now, when the washing machine is energized, the water supply valve operates in the water supply process, and water is supplied into the washing and dehydration tank 2.
At this time, the water level detection device is also energized. At the initial stage of water supply, electrodes 12, 13a, 1 for water level detection are installed.
3b is not in contact with water. One end of the detection part 21 is attached to the pulsator 4 or the conductive part of the dehydration shaft, and the resistance value between it and the electrode is nearly infinite.

Therefore, in this state, the oscillation circuit section 19 oscillates at the set oscillation frequency, and the load control section 15
is not operating, so relay 16 is not operating,
Contact 16a of relay 16 is closed to the NC side.

Water supply continues, and the water level reset detection electrode 12
When water is supplied to the water level, the oscillation circuit section 19 cannot maintain the set oscillation frequency, and the oscillation frequency changes or the oscillation voltage slightly decreases. However, even at this time, the load control section 15 does not operate. Therefore, the relay 16 does not operate, and the relay contact 16a is closed to the NC side.

Furthermore, when water supply continues and the water level selector switch 18b for setting a low water level is closed, when the water level reaches the electrode 13b, and when the water level selector switch 18a for setting a high water level is closed, When the water level reaches the electrode 13a, the oscillation circuit 19 is unable to maintain the set oscillation frequency and oscillation stops or the oscillation voltage drops below the reference value. works, relay 1
6 is activated, the relay contact 16a is switched to the NO side, the motor 6 starts operating, the pulsator 4 rotates, and washing or rinsing is started. At this time, even if the water level drops from the water level set detection electrode 13a or 13b due to water level fluctuations, the oscillation circuit section 19 is configured to maintain the above state. When the water level falls below the reset electrode 12, the oscillation circuit section 19 oscillates again at the set oscillation frequency, the load control section 15 becomes inoperable, the relay 16 is opened, and the relay contact 16a
closes to the NC side again.

As described above, according to the present invention, a washing/water tank is provided in which the peripheral wall except at least the upper end side is a non-porous wall,
Changes in resistance between electrodes installed on the side wall of this washing and dehydrating tank are detected by a control circuit through electromagnetic coupling using a rotating transformer, and there are no sliding parts.
It is highly reliable with no problems in terms of durability, and the electrodes in the washing and dehydrating tank are electrically completely separated and generate electricity on the rotating part side, so there is no risk of electric shock, etc. There is no need to worry and it is very safe.
Furthermore, by providing the rotating transformer on the outer periphery of the washing/dehydrating shaft, the effects of surface wobbling when the washing/dehydrating tub rotates can be minimized.
The gap between the primary and secondary windings of a rotating transformer can be narrowed. Furthermore, since a magnetic material is usually used for the washing and dehydrating shaft, the electromagnetic coupling of the rotary transformer is improved, which improves detection accuracy. Furthermore, if the electrode for water level detection is buried in the recess in the side wall of the washing and dehydrating tank so that the electrode surface does not protrude from the recess, the detection sensitivity will be increased because the water-containing clothes after dehydration will not come into direct contact with the electrode. It works fine and no malfunctions occur.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of a washing machine according to an embodiment of the present invention, Fig. 2 is a block diagram showing the basic configuration of the water level detection device, and Fig. 3 is a perspective view of main parts showing the mounting state of the water level detection electrode. FIG. 4 is a horizontal sectional view of the same. 2... Washing and dehydration tank, 3... Outer tank, 11... Rotating transformer, 11a, 11b... Primary and secondary windings, 12, 13a, 13b... Electrodes.

Claims (1)

[Claims] 1. A washing/dehydration tank having a non-porous peripheral wall except for at least the upper end is provided in the outer tank, an electrode for water level detection is provided on the inner peripheral wall of the washing/drying tank, and the washing/dehydration tank rotates integrally with the washing/dehydration tank. Connecting the electrode to a secondary winding of a transformer, providing a primary winding of the transformer that is electromagnetically coupled to the secondary winding on the outer tank side, and connecting this primary winding to a water level control circuit; A water level detection device for a washing machine, wherein the transformer is provided on the outer periphery of a washing and dehydrating shaft at the bottom of the washing and dehydrating tub.