Washing machine with balancers and control method thereof

Abstract

Disclosed are a washing machine and a control method thereof capable of reincreasing a number of rotations of a motor after maintaining the number of rotations at a predetermined number before excessive vibration of a water tub, braking the motor when the water tub is vibrated at more than a predetermined vibration level, and reincreasing the number of rotations, thereby reducing the excessive vibration of the water tub. The control method includes detecting the number of rotations, determining whether the detected number of rotations has reached a predetermined number, controlling the motor such that the number of rotations is maintained at the predetermined number of rotations when it is determined that the detected number of rotations has reached the predetermined number, counting the time taken to maintain the number of rotations at the predetermined number of rotations, and increasing the number of rotations after a predetermined first time has elapsed.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of Korean Patent Application No. 2007-007606, filed on Jan. 24, 2007 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.BACKGROUND[0002]1. Field[0003]The present invention relates to a washing machine with balancers, and, more particularly, to a washing machine and a control method thereof that is capable of reducing vibration generated from a water tub due to eccentricity, i.e., unbalance, generated during the rotation of the washing machine.[0004]2. Description of the Related Art[0005]Generally, a washing machine (normally, a drum type washing machine) is a machine that washes laundry by lifting and dropping the laundry. The washing machine includes a water tub mounted in a housing forming the appearance of the washing machine to receive wash water, a rotary tub rotatably mounted in the water tub to receive laundry, and a motor to generate a driving...

AI Technical Summary

Benefits of technology

[0010]Therefore, it is an aspect of the invention to provide a washing machine and a control method thereof that is capable of reincreasing the number of rotations of a motor after maintaining the number of rotations of the motor at a predetermined number of rotations before excessive vibration of a water tub is generated for a predetermined time such that the motor passes through an excessive vibration generating point of the water tub.

[0011]It is another aspect of the invention to provide a washing machine and a control method thereof that is capable of braking a motor, when a water tub is vibrated at more than a predetermined vibration level after the reincrease of RPM of the motor, to lower the RPM of the motor to a predetermined number of rotations and reincreasing the RPM of the motor, thereby reliably reducing the excessive vibration of the water tub.

Problems solved by technology

When the rotary tub is rotated at high speed in an unbalanced state in which the laundry is not uniformly distributed in the rotary tub but is concentrated at a specific region of the rotary tub during a spin-drying operation of the washing machine, the rotary tub eccentrically rotates with respect to a rotary shaft.

As a result, the rotary tub collides with the water tub, thereby generating vibration and noise.

When this phenomenon repeatedly occurs, parts of the washing machine, including the rotary tub and the motor, may break down or the life of the parts of the washing machine may be shortened.

Consequently, when the rotary tub is rotated while not maintaining the dynamic balance due to the unbalanced eccentric structure of the rotary tub and the biased distribution of laundry in the rotary tub, the steel balls compensate for the eccentricity of the rotary tub such that the rotary tub is rotated while maintaining the dynamic balance.

As a result, the manufacturing costs are high.

In addition, the structure of the races is not designed to prevent the generation of the excessive vibration of the water tub based on accurate calculation, but to reduce a probability of vibration generation.

For this reason, there is still a possibility that excessive vibration is generated from the water tub.

The number of excessive vibration rotations of the water tub may be a number of rotations of the motor at a point where the excessive vibration of the water tub is generated due to the difference in rotating speed between the rotary tub and balls in the balancers before the balls reach a balancing position.

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