Washing machine

Abstract

A direct drive washing machine is disclosed which is capable of performing a washing operation by efficiently converting electric energy supplied into an electric motor (10) into mechanical energy or with less vibration and noise. When a washing operation is carried out with efficient energy conversion, an acceleration time and a deceleration time of an agitator (8) rotated by the motor (10) are controlled on the basis of a measured value of a vibration sensor (25) or a measured value of clothes weight so that vibration of a water-receiving tub (4) becomes maximum. On the other hand, when a quiet washing operation with less vibration is carried out, the acceleration time and the deceleration time of an agitator (8) rotated by the motor (10) are controlled on the basis of the measured value of the vibration sensor (25) or the measured value of clothes weight so that vibration of the water-receiving tub (4) becomes minimum.

Description

TECHNICAL FIELD [0001] The present invention relates to a washing machine with a construction that an agitator and a rotating tub are rotated directly by a brushless motor. BACKGROUND ART [0002] Full automatic washing machines have conventionally been used as means for removing soil adherent to clothes at home. The full automatic washing machine is provided with mechanisms for automatically carrying out sequential steps of wash, rinse and dehydration in the same tub. [0003] An agitator is turned alternately in the positive and negative directions in each of the wash and rinse steps, whereas the agitator and the rotating tub serving as a wash tub and a dehydration tub are rotated at high speeds in the same direction. In order that these two driving manners may be carried out, recent full automatic washing machines employ a direct drive system transmitting torque developed by a motor rotor only via a clutch mechanism directly to the agitator or rotating tub without provision of reduct...

AI Technical Summary

Benefits of technology

[0007] A washing machine of the present invention which comprises a water-receiving tub elastically suspended in an outer cabinet, a rotating tub provided in the water-receiving tub, an agitator provided in the rotating tub, an electric motor provided on an underside of the water-receiving tub for direct driving the agitator, and a control device controlling the motor and the overall washing machine, is characterized in that the control device controls either one or both of an acceleration time and a deceleration time of the motor in a washing operation so that vibration of the water-receiving tub becomes maximum. Consequently, electric energy supplied to the motor can efficiently be converted to mechanical energy for the wash liquid and clothes in the washing operation.

[0008] Further, a washing machine of the present invention is characterized in that the control device detects a weight of clothes put into the rotating tub prior to the washing operation and subsequently reads an acceleration time corresponding to a detected weight value from a chart storing relationship between weight of clothes and an acceleration time required for the vibration of the water-receiving tub to become maximum corresponding to the weight of clothes and that the control device controls either one or both of the acceleration time and the deceleration time of the motor in the washing operation so that the acceleration time and / or the deceleration time corresponds to the read time. Consequently, electric energy supplied to the motor can efficiently be converted to mechanical energy for the wash liquid and clothes in the washing operation.

[0009] Further, a washing machine of the present invention which comprises a water-receiving tub elastically suspended in an outer cabinet, a rotating tub provided in the water-receiving tub, an agitator provided in the rotating tub, a vibration sensor detecting vibration of the water-receiving tub, an electric motor provided on an underside of the water-receiving tub for direct driving the agitator, and a control device controlling the motor and the overall washing machine, is characterized in that the control device controls either one or both of an acceleration time and a deceleration time of the motor in a washing operation so that a value of vibration detected by the vibration sensor during the wash operation becomes maximum. Consequently, electric energy supplied to the motor can efficiently be converted to mechanical energy for the wash liquid and clothes in the washing operation.

[0010] Further, a washing machine of the present invention which comprises a water-receiving tub elastically suspended on an outer cabinet, a rotating tub provided in the water-receiving tub, an agitator provided in the rotating tub, an electric motor provided on an underside of the water-receiving tub for direct driving the agitator, and a control device controlling the motor and the overall washing machine, is characterized in that the control device controls either one or both of an acceleration time and a deceleration time of the motor in a washing operation so that vibration of the water-receiving tub becomes minimum. Consequently, a noise-reduced operation with less vibration can be realized in the washing operation.

[0011] Further, a washing machine of the present invention is characterized in that the control device detects a weight of clothes put into the rotating tub prior to the washing operation and subsequently reads an acceleration time corresponding to a detected weight value from a chart storing relationship between weight of clothes and an acceleration time required for the vibration of the water-receiving tub to become maximum corresponding to the weight of clothes and that the control device controlling either one or both of the acceleration time and the deceleration time of the motor in the washing operation so that the acceleration time and / or the deceleration time corresponds to the read time. Consequently, a noise-reduced operation with less vibration can be realized in the washing operation.

[0012] Further, a washing machine of the present invention which comprises a water-receiving tub elastically suspended in an outer cabinet, a rotating tub provided in the water-receiving tub, an agitator provided in the rotating tub, a vibration sensor detecting vibration of the water-receiving tub, an electric motor provided on an underside of the water-receiving tub for direct driving the agitator, and a control device controlling the motor and the overall washing machine, is characterized in that the control device controls either one or both of an acceleration time and a deceleration time of the motor in a washing operation so that a value of vibration detected by the vibration sensor during the washing operation becomes minimum. Consequently, a noise-reduced operation with less vibration can be realized in the washing operation.

Problems solved by technology

However, in the conventional washing machine employing the direct drive system, vibrating characteristics of various mechanisms of the washing machine are not sufficiently considered for the wash step.

Accordingly, torque developed by the motor is not efficiently transmitted to rotating objects including the motor rotor, the agitator, wash liquid and clothes.

Thus, electric energy supplied to the motor is not effectively used in many cases.

Further, even when a quiet operation with less vibration is desired, for example, an outer or water-receiving tub resonates to produce noise, resulting in problems concerning noise in many cases.

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