JP2607760B2 - Drum type washing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drum type washing machine for controlling the operation according to the state of laundry.

[0002]

2. Description of the Related Art There is known a conventional drum type washing machine in which a user selects a washing course according to the type of laundry. However, whether or not high-speed dehydration is possible by automatically detecting the amount of laundry put in and performing a washing operation suitable for the amount of cloth and detecting the balance state of the laundry when the drum rotates at low speed There is no known automatic judgment.

[0003]

In a conventional drum-type washing machine that cannot detect the amount of laundry, the same operation is performed when the amount of laundry is small or large. Not only does it occur, but wasted water and time is wasted. Further, the conventional method is a method in which the rotation is temporarily stopped during dehydration, and then the rotation is stopped when the vibration exceeding the limit is generated. The present invention has been made in view of such circumstances, and provides a drum type washing machine that automatically detects an amount of laundry and performs a washing and dehydrating operation suitable for the amount.

[0004]

A drum-type washing machine according to the present invention comprises a motor for rotating a drum, a control means for controlling a rotation speed of the motor, a current detection means for detecting a motor current, and a rotation cycle of the drum. Period detecting means for detecting
A control means for changing the rotation speed of the drum from low speed to high speed, comparing the rotation period of the drum with the fluctuation period of the motor current, and determining the capacity of the laundry in the drum from the drum rotation speed at which both periods match. A drum-type washing machine characterized by comprising:

[0005]

[Action] The rotational speed of the drum is changed from a low speed to a high speed, and the rotational cycle of the drum is compared with the fluctuation cycle of the motor current.
It was found during the experiment that the capacity of the laundry in the drum was determined from the drum rotation speed at which both periods coincided.
Therefore, it is possible to determine the optimal spinning speed and time for the detected laundry volume. For example, when the amount of laundry is large, increase the spinning speed and lengthen the time, and when the amount is small, shorten the time and shorten the operation time or reduce the rotation speed to reduce the amount of laundry. Wrinkles can be reduced. As for the balance state of the laundry, since the vibration amount at high speed can be predicted before the vibration increases at a relatively low speed, if it is determined that high-speed rotation is impossible, the laundry should be loosened again at that point Then, since the process shifts to the dehydration step again, an operation without generating abnormal amplitude can be performed.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings. This does not limit the present invention.

As shown in FIG. 1, the entire structure of the drum type washing machine has a water tub 2 elastically supported by a spring 11 inside an outer box 8. A drum 3 for storing laundry during washing is accommodated in a water tub 2, and a drum horizontal shaft 4 fixed to a side plate thereof is rotatably supported by the water tub 2 via a bearing 13. A motor 9 provided at the bottom of the water tank 2 drives the drum 3 via a pulley 21, a belt 23 and a pulley 22. The drum 3 has a large number of small holes 18 formed on the entire surface of the peripheral wall portion 5 for the passage of the washing liquid and the discharge of the dehydrating liquid. A baffle plate 17 is provided on the peripheral wall portion 5 so as to protrude inward in parallel with the drum horizontal axis. The drum 3 is provided with a loading port 15 for taking in and out the laundry, and the loading port 15 is positioned above when the drum is stopped. As described above, in a drum type washing machine of a type in which laundry is taken in and out from above, that is, a so-called top-loading type, the drum 3 is formed by rolling a metal plate into a peripheral wall portion 5 and a side plate portion 1 punched into a disk shape.
9 are assembled by caulking at each end. Such a drum type washing machine puts laundry into the drum 3 from the inlet 15 and immerses the laundry in the washing liquid supplied from the water supply pipe 20 into the water tub 2, and then drives the drum 3 to rotate at a low speed. Do the washing by doing.

At this time, the laundry is pressed against the peripheral wall 5 by the centrifugal force generated by the rotation of the drum 3, and is lifted by the baffle plate 17 to near the top apex of the drum 3. Fall. Thus, this operation is repeated, and the laundry is hit and washed by the impact force at the time of falling.

As means for detecting the rotation period of the drum 3, a permanent magnet 2 is attached to a pulley 22 which rotates coaxially with the drum 3.
The reed switch 25 is installed at a position facing the permanent magnet 24 on the side surface of the water tank 2 so that the contact of the reed switch 25 opens and closes each time the drum makes one rotation. This may be an optical element.

FIG. 2 is a block diagram of a main part of the electric circuit of the embodiment shown in FIG. Although a commutator motor is used as the motor 9 to perform speed control by the phase control method, a speed control motor of another method may be used. In FIG. 2, a one-chip microcomputer (hereinafter referred to as a microcomputer) 26 detects an output signal of a rotation speed detection circuit 27 coupled to the motor 9 and fires a triac 28 so that the speed of the motor 9 becomes a set speed. The feedback control for changing the angle is performed. On the other hand, the rotation cycle of the drum is detected by the microcomputer 26 by opening and closing the contact of the reed switch 25. The motor current Im is supplied to the current transformer 29.
, Is rectified by the diode bridge 30, smoothed by the capacitor 31,
output as m. This DC voltage Vm is supplied to the microcomputer 26
Is detected. The resistor 32 is a discharging resistor for the capacitor 31.

FIG. 3 shows the relationship between the motor energizing current Im and the converted DC voltage signal Vm.
m is proportional to the motor current Im. (Hereafter, this DC
The voltage signal is called a motor energization current signal. )

FIG. 4 is an explanatory diagram showing the relationship between the capacity of the laundry in the drum and the motor energizing current signal, and FIG.
Is a drum rotation period signal obtained from the reed switch 25, and is detected by the microcomputer as a pulse every rotation of the drum 3.

(B), (c), and (d) are motor energization current signals when laundry of 1/4, 1/2, and 1/1 of the rated capacity of the drum is stored, respectively. In the case of (b),
When the drum rotation speed is around 80 rpm, all the laundry adheres to the peripheral surface of the drum 3 due to the centrifugal force, and the cloth distribution state in the drum does not change even if the drum rotation speed is increased thereafter. The change in energy expended on the body amplitude, ie, the phase of the change in the motor current signal, does not change even when the rotation speed is increased. That is,
In (b), the phase of the maximum point of the motor energization current signal is around 180 ° with one rotation of the drum being 360 °, and does not change even if the drum rotation speed changes.

On the other hand, in case (c), the attachment of the laundry to the drum starts at around 100 rpm, and the state of the laundry does not change even if the drum rotation speed increases thereafter.

Next, the case (d) indicates that the laundry starts to stick to the drum peripheral surface when the drum rotation speed is around 120 rpm.

FIG. 5 is a flowchart for detecting the capacity of the laundry using the above phenomenon. In FIG. 5, the drum 3 is rotated at a drum rotation speed of 80 rpm (step 101), and the microcomputer measures the time from when the drum rotation period signal is input to when the motor energization current signal reaches the maximum value. (0.75 seconds at 80 rpm), calculate the phase difference from the ratio of the two, and store it in the memory in the microcomputer (
Step 102).

Thereafter, the drum rotation speed is increased to 100 rpm (step 103), the phase difference is calculated in the same manner as described above, and compared with the phase difference at 80 rpm (step 104).
If it is the same, it is determined that the capacity of the laundry is less than 1/4 of the rated capacity (step 105).

Otherwise, a 700 rpm phase difference of 8
The data is rewritten to the memory storing the phase difference of 0 rpm (step 106).

Thereafter, the drum rotation speed is increased to 120 rpm (step 107), and the phase difference at that time is reduced to 100 rpm.
It is compared with the phase difference at the time (step 108), and if they are the same, it is determined that the capacity of the laundry is 1/4 to 1/2 of the rated capacity (step 109).

Thereafter, the capacity of the laundry is determined in the same manner. Needless to say, the capacity of the laundry determined as described above is used as data of the optimal automatic operation in each of the washing steps.

Next, a method of detecting the state of deviation of the laundry in the drum will be described with reference to FIG.

Attachment of the laundry to the inner surface of the drum is achieved at a certain drum rotation speed (in the example of FIG. 4, laundry having a rated capacity of 140 rpm is attached). After the drum rotation speed has been increased to this sticking state, if the balance state of the laundry is biased, the motor energization current signal will stably undulate as described above.

FIG. 6 shows, as an example, the change in the motor energization current signal when the total unbalanced weight is 200, 500, and 1000 g. It can be seen that the amplitude increases. By calculating the ratio between the maximum and minimum of these signals, the actual unbalance weight can be estimated.

Needless to say, these relationships are determined in advance by actually measuring the relationship between the motor energizing current signal of the drum type washing machine to be controlled and the unbalanced weight.

The amount of change in the signal can be calculated as long as the relationship between the unbalanced weight and the washing machine to be controlled becomes clear, for example, by calculating the difference between the maximum value and the minimum value as well as the above calculation. Such an operation may be performed.

Based on the unbalance weight estimated in this way, in the above example, when the drum is rotated at a high speed (generally about 1000 rpm) in consideration of the unbalance weight at 140 rpm, Estimate whether or not the vibration exceeds the allowable limit. If it is determined that the vibration does not exceed the allowable limit, shift to the high speed rotation as it is. If it is determined that the vibration will exceed the allowable limit, perform cloth loosening at the low speed rotation again and then again at 140 rpm. To determine whether high-speed rotation is possible.

[0027]

According to the present invention, by detecting the capacity of the laundry, it is possible to reduce wasted time and water amount by a suitable operation control in the case of a small capacity, and to realize reliable washing in the case of a large capacity. In addition, the estimation of the unbalanced weight before execution of high-speed rotation indicates that if the unbalanced weight is large, the cloth will not be loosened again after reaching the vibration limit as in the past.
Low vibration, low noise, and reduced operation time can be realized.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view of a drum type washing machine showing one embodiment of the present invention.

FIG. 2 is a block diagram of a main part of the electric circuit of the embodiment shown in FIG.

FIG. 3 is a waveform diagram showing a relationship between a motor energizing current and a converted motor energizing current signal.

FIG. 4 is a waveform diagram showing a motor energization current signal with respect to a change in the capacity of laundry.

FIG. 5 is a flowchart illustrating a procedure for detecting the capacity of laundry.

FIG. 6 is a waveform diagram illustrating a relationship between an unbalanced weight of laundry and a motor energization current signal.

[Explanation of symbols]

 a Motor 25 Reed switch 26 Microcomputer 27 Rotational speed detection circuit 28 Triac 29 Current transformer

Claims (2)

(57) [Claims] 1. A motor for rotating a drum, a control unit for controlling a rotation speed of the motor, a current detection unit for detecting a motor current, a period detection unit for detecting a rotation period of the drum, and a rotation speed of the drum. Change from low speed to high speed and compare the rotation period of the drum with the fluctuation period of the motor current,
A drum-type washing machine comprising a control means for determining a capacity of laundry in a drum from a drum rotation speed at which both periods coincide. 2. The method according to claim 1, wherein the control means determines the degree of deviation of the laundry in the drum from the magnitude of a change in the motor current when the drum rotates at a predetermined speed.
A drum-type washing machine as described.