Drum washing machine and method for cleaning tub thereof

Patent metadata

Field	Value
Publication number	US-11214909-B2
Application number	US-201716074109-A
Country	US
Kind code	B2
Filing date	Jan 20, 2017
Priority date	Feb 1, 2016
Publication date	Jan 4, 2022
Grant date	Jan 4, 2022

Abstract

A drum washing machine implements a control method, allowing a tub of the drum washing machine to be easily cleaned. The method includes supplying washing water during a first water supplying step to the interior of the tub while a drum rotatably supported in the tub rotates at a water-supplying RPM. A first wash step is executed following completion of the first water supplying step, and includes accelerating rotation of the drum from the water-supplying RPM to a first-wash RPM to that create a circulatory flow in which the washing water falls from the top of opposite ends of the tub while circulating along the inner circumferential surface of the tub due to the rotational power of the drum. A wash draining step is started during the first wash step, and includes turning on the drain pump and controlling the amount of the washing water in the tub.

First claim

What is claimed is:

1. A method of controlling a washing machine, wherein the washing machine comprises a tub and a drum rotatably supported in the tub, the method comprising:
supplying wash water to the tub in a first water supply step while the drum is rotated at a water supply RPM;
starting a first washing step after the first water supply step is complete, the first washing step comprising accelerating the rotating drum from the water supply RPM to a first washing RPM, wherein the rotational force of the drum and a frictional force between the wash water and the rotating drum causes the wash water to form a circulating water current along an inner circumferential surface of the tub and an outer circumferential surface of the drum, lifting the wash water from a lower part of the tub to an upper part of the tub, and washing the surfaces of the tub and the drum; and
starting a wash water draining step during the first washing step, the wash water draining step comprising switching on a drainage pump to adjust an amount of the wash water held in the tub.

2. The method of claim 1 , wherein the wash water draining step comprises adjusting the amount of the wash water drained by the drainage pump to lower a water level in the tub to a water level that at least reaches a lower end of the drum.

3. The method of claim 1 , wherein the wash water draining step is completed at the same time as or before a spin cycle is complete.

4. The method of claim 1 , further including a spin cycle comprising:
removing moisture from laundry loaded in the drum during a plurality of spinning steps by accelerating the drum, and
continuously rotating the drum during the first water supply step while decelerating a rotation of the drum to the water supply RPM at a same time as at least one of the spinning steps ends with the drum rotating at the water supply RPM.

5. The method of claim 1 , wherein the first water supply step rotates the drum at the water supply RPM at the same time as a rinse cycle ends.

6. The method of claim 1 , wherein the water supply RPM is a minimum RPM which is able to prevent laundry rotated along the rotating drum from being separated from an inner circumferential surface of the drum by a centrifugal force.

7. The method of claim 1 , wherein the first water supply step supplies the wash water to a water level at which a user is able to check operation of the first washing step from outside the drum.

8. The method of claim 1 , wherein the first water supply step supplies the wash water to a water level which is at least at a height from a lower end of the tub to the lower end of the drum.

9. The method of claim 8 , wherein when the sensed eccentricity value is greater than a reference eccentricity value, the spin cycle starts in a state where the drainage pump is switched off to keep the wash water remaining in the tub.

10. The method of claim 1 , wherein the first washing step switches off the drainage pump.

11. The method of claim 1 , wherein an eccentricity value of the drum is sensed in at least one of the first water supply step or the first washing step.

12. The method of claim 11 , wherein when the sensed eccentricity value is greater than a reference eccentricity value, the wash water remaining in the drum is drained and the first water supply step then re-starts.

13. The method of claim 1 , further comprising:
performing a second water supply step once the first washing step is complete, the second water supply step including allowing additional water supply to the tub while the drum is rotated at the water supply RPM; and
performing a second washing step once the second water supply step is complete, the second washing step including accelerating and rotating the drum at a second washing RPM higher than the water supply RPM and lower than the first washing RPM such that the wash water which has been increased by the additional water supply forms the circulating water current.

14. The method of claim 13 , wherein the second water supply step includes continuously rotating the drum, which is decelerated to the water supply RPM at the same time when the first washing step ends, at the water supply RPM.

15. The method of claim 1 , further comprising:
accelerating the drum to a spinning RPM in a spinning step during a rinse cycle for removing moisture from laundry loaded in the drum; and
performing a braking step after the spinning step, the braking step including applying a preset braking force to the rotating drum by colliding the supplied wash water with the rotating drum and supplying the wash water toward the outer circumferential surface of the drum such that the wash water collided with the drum strikes and washes at least one point of the inner circumferential surface of the tub.

16. The method of claim 15 , wherein the spinning step includes supplying the wash water toward the outer circumferential surface of the rotating drum.

17. The method of claim 15 , wherein the spinning step comprises,
maintaining the spinning RPM for rotating the drum, and
supplying the wash water toward the outer circumferential surface of the rotating drum while maintaining the spinning RPM.

18. The method of claim 15 , wherein the braking step includes switching off the drainage pump.

19. The method of claim 15 , wherein during the braking step, the wash water is supplied via a plurality of wash water supply units provided to strike a plurality of points of the inner circumferential surface of the tub, and the wash water supply units are spaced a preset distance apart from each other along a longitudinal direction of the tub.

20. The method of claim 15 , wherein the first water supply step is performed after the braking step and includes continuously rotating the drum at the water supply RPM after the drum is decelerated to the water supply RPM in the braking step.

Assignees

• Lg Electronics Inc

Inventors

• Kwon Sunku
• Choi Kahyung
• Kim Youngho
• Seo Inhyouk
• Oh Youngkee

Classifications

• D06F39/083

  Liquid discharge or recirculation arrangements · CPC title

• D06F39/085

  Arrangements or adaptations of pumps · CPC title

• D06F33/42

  of draining · CPC title

• D06F2105/02

  Water supply · CPC title

• D06F35/008 Primary

  for disinfecting the tub or the drum · CPC title