1. Field
Embodiments relate to a ball balancer of a washing machine, and more particularly, to a relation between a gap, between a racer and balls, and viscous oil of a ball balancer of a washing machine.
2. Description of the Related Art
Generally, washing machines wash laundry by rotating a drum containing the laundry using a driving motor. The drum is rotated at a low speed in regular and opposite directions during a washing process, and is rotated at a high speed in a regular direction during a dehydrating (drying) process.
During the dehydrating (drying) process, the drum is rotated at a high speed under the condition that laundry is not equally disposed in all regions of the drum and is crowded at a specific region of the drum, or the laundry is pushed to one side of the drum due to the accelerated rotation of the drum at an initial state of the dehydrating (drying) process. As a result, the center of gravity of the drum does not coincide with the center of rotation of the drum, thus generating vibration and noise. When the above phenomenon is repeated, components of the washing machine, including a drum, a rotary shaft, and a driving motor, break down or have a shortened life span.
Particularly, a drum washing machine has a structure in which a drum accommodating laundry is disposed horizontally so that the drum is rotated at a high speed in a dehydrating (drying) operation under the condition that the laundry is gathered together on the bottom of the drum by gravity. Thus, the center of gravity of the drum does not coincide with the center of rotation of the drum. Therefore, the drum washing machine has a great possibility of generating vibration and noise.
Drum washing machines, in which a drum is disposed horizontally, and vertical axis washing machines, in which a drum is disposed vertically, are generally provided with balancers for maintaining the dynamic balance of the drum.
Korean Patent Laid-open Publication No. 10-1999-0038279 discloses an example of a washing machine having balancers. Each of the balancers of this washing machine includes a racer installed at the upper or lower part of a drum for maintaining the dynamic balance of the drum when the drum is rotated at a high speed. Balls made of steel and freely movably are disposed in the racer, and viscous oil fills the inside of the racer.
When the drum is rotated, the drum cannot maintain its dynamic balance due to the unbalanced eccentric structure of the drum and the partial distribution of laundry in the drum. Then, the steel balls compensate for the above unbalance, thus allowing the drum to maintain its dynamic balance.
Since the viscous oil of the balancer employed by the above conventional washing machine is sensitive to an outdoor temperature, in the case that a gap between the inner wall of the racer and the steel balls is small, the ball balancer has a considerably high deviation in vibration (time) to attain a correct position according to the outdoor temperature.
On the other hand, in the case that the gap between the inner wall of the racer and the steel balls is large, the ball balancer rapidly attains a correct position, and thus the vibration of the drum is decreased. However, in this case, when the viscosity of the viscous oil is low, the ball balancer generates a large amount of noise. Further, when the gap is expanded to a certain extent, it is difficult to control vibration and noise characteristics due to the manufacturing error of the racer.