A WASHING MACHINE THE WASHING EFFECTIVENESS OF WHICH IS

INCREASED

[0001] The present invention relates to a washing machine the washing

effectiveness of which is increased.

[0002] In washing machines, in the steps of washing, rinsing and spin-drying of the laundry placed in the drum, the motor rotates clockwise and/or counterclockwise at the speed suitable for the washing program and provides the balanced distribution of laundry in the drum. In the spin-drying step, the motor rotates at high speed and generally in one direction.

Therefore, the motors are designed to be powerful enough to generally rotate faster to the direction rotated in the spin-drying step than in the other direction. In the washing step, the motor performs asymmetrical rotational movements by being rotated for a longer time opposite to the spin-drying direction and for a shorter time in the spin-drying direction. Thus, the consumption of less energy is aimed since the motor rotates in the powerless direction for a longer time during washing wherein the motor draws less current. Moreover, the motor is targeted to be heated less in the asymmetrical rotational movements wherein the motor is provided to be rotated less in the powerless direction wherein the motor draws less current. The motor also heats up by drawing more current and is strained when a lot of laundry or water absorbing cotton items are loaded in the tub. However, the asymmetrical washing movement as well as contributing positively to heating of the motor also has negative effects on the washing effectiveness. The laundry cannot be cleaned effectively in washing machines that perform the washing by asymmetrical washing movements.

[0003] In the state of the art German Patent Document No. DE 10054947, the explanation is given for how the detergent is dissolved more quickly and energy is saved by means of rotational directions of the motor being asymmetrical.

[0004] The aim of the present invention is the realization of a washing machine the washing effectiveness of which is increased.

[0005] The washing machine realized in order to attain the aim of the present invention, explicated in the first claim and the respective claims thereof, comprises a control unit that controls the rotational revolution and operation of the motor which provides the drum to be rotated clockwise and/or counterclockwise. The control unit regulates the rotational movement of the motor in accordance with the data received from a sensor that detects the temperature of the motor. The control unit provides the drum to be rotated by means of asymmetrical rotational movements such that the rotation time in the first direction wherein the motor draws more current and the rotation time in the second direction wherein less current is drawn than the first direction are equal. When the motor temperature is detected to exceed the limit temperature value, the control unit provides the motor to rotate for a longer time in the second direction and thus provides the motor to perform asymmetrical rotational

movements. Consequently, as long as the motor does not heat up, the drum is rotated symmetrically and the decrease in washing effectiveness is prevented.

[0006] In another embodiment of the present invention, the control unit detects the temperature by means of the current drawn by the motor. The amounts of current drawn by the motor in both directions of rotation are calculated and if the difference is more than a certain value then the time rotated in the second direction is decreased and the washing movement ratio is changed. Thus, the motor is prevented from overheating.

[0007] In another embodiment of the present invention, the control unit

determines the motor temperature from the instantaneous resistance calculated from the voltage of the motor and the drawn current, and the resistance temperature relationship recorded in the memory thereof.

[0008] In another embodiment of the present invention, the motor temperature is detected by a sensor. The sensor can be a thermal camera or a

thermometer in different embodiments of the present invention.

[0009] In an embodiment of the present invention, if the control unit detects that the temperature falls below a limit temperature value while the motor performs asymmetrical rotational movement, the control unit provides the motor to perform symmetrical rotational movement. [0010] By means of the control unit of the present invention, washing

effectiveness is increased by starting washing with symmetrical washing movement at the start of the washing step and afterwards changing to asymmetrical movements depending on the state of the motor

temperature. Consequently, as long as the motor does not heat up, asymmetrical washing movement is not performed unnecessarily and the user is provided to receive maximum performance from the washing machine.

[001 1] A washing machine realized in order to attain the aim of the present

invention is illustrated in the attached figures, where:

[0012] Figure 1 - is the perspective view of a washing machine.

[0013] The elements in the figures are numbered as follows:

1. Washing machine

2. Drum

3. Motor

4. Control unit

5. Sensor

[0014] The washing machine (1 ) of the present invention comprises a drum (2) wherein the laundry to be washed is placed, a motor (3) providing the drum (2) to rotate in the rotational speed suitable for the washing program that consists of main washing, rinsing and spin-drying steps and a control unit (4) that controls the operation of the motor (3) with respect to the washing program selected by the user (Figure 1 ).

[0015] The control unit (4) provides the motor (3) to rotate clockwise and/or

counterclockwise at the determined speeds in the washing program in accordance with the program selected by the user. The motor (3) generally rotates successively clockwise for a time period (t1) and counterclockwise for a time period (t1 ) in the washing step and provides the laundry to be agitated and cleaned in the drum (2). In the spin-drying step, the motor (3) generally rotates at high speeds toward only one direction since the spinning process is performed by rotating at high speed. The motor (3) is designed to draw more current (11) in the spin-drying direction since the motor (3) rotates at a much higher speed in the spin-drying step than in the washing step. The motor (3) can heat up in the course of time in the first direction (d1 ) wherein the motor (3) draws more current (11 ).

Moreover, the motor (3) can also heat up when a lot of items are loaded in the drum (2) or when there is unbalanced load distribution in the drum (2).

[0016] In the washing step, the control unit (4),

- detects the temperature (T) of the motor (3),

- provides the motor (3) to perform symmetrical rotational movements such that the rotation time (t1) of the motor (3) in the first direction (d 1 ) is equal to the rotation time (t2) of the motor (3) in the second direction (d2) if the temperature (T) of the motor (3) is below a limit temperature (Tlim) value recorded in the memory thereof and

- provides the motor (3) to perform asymmetrical rotational movements such that the rotation time (t1) of the motor (3) in the first direction (d 1 ) is less than the rotation time (t2) of the motor (3) in the second direction (d2) if the temperature (T) of the motor (3) exceeds the limit temperature (Tlim) value recorded in the memory thereof.

[0017] At the start of the washing program, the motor (3) performs symmetrical rotational movements by successively rotating in equal time periods (t1 =t2), for a time (t1 ) in the first direction (d1 ) and for a time (t2) in the second direction (d2). The symmetrical rotational movements provide the laundry to be cleaned more effectively. The control unit (4) controls the motor (3) temperature (T) continuously or at certain intervals and compares the motor (3) temperature (T) with the limit temperature value (Tlim) recorded in the memory thereof. The control unit (4) provides the motor (3) to perform symmetrical rotational movements as long as the motor (3) temperature (T) does not exceed the limit temperature value (Tlim). The motor (3) temperature (T) can exceed the limit temperature value (Tlim) due to the reasons that the washing program being long, the motor (3) drawing more current (11) by rotating in the first direction (d1 ) for a long time (t1 ) or the drum (2) being loaded with too much or unbalanced load. In this situation, the control unit (4) provides the motor (3) to rotate successively for a time (t1 ) to the first direction (d1 ) and for a time (t2) to the second direction (d2) for unequal time periods (t2>t1 ). Thus, after heating up, the motor (3) rotates towards the first direction (d1) for a shorter time (t1 ) and overheating thereof is prevented. The motor (3) cools down some amount since the motor (3) draws less current while rotating in the second direction (d2). Consequently, the washing machine (1 ) is provided to have longer life by preventing the motor (3) temperature (T) from exceeding the limit temperature value (Tlim) and avoiding damages.

[0018] In an embodiment of the present invention, the control unit (4)

instantaneously compares the current (11 ) drawn by motor (3) while rotating to the first direction (d1 ) and the current (I2) drawn by motor (3) while rotating to the second direction (d2) and when the difference (ΔΙ) between the currents (11 and I2) exceeds a limit difference (Allim) value recorded in the memory thereof, decides that the motor (3) is starting to heat up. As long as the load in the drum (2) is balanced, the currents (11 , I2) drawn by the motor (3) while rotating in both directions (d1 , d2) are almost constant. In the course of time, the current drawn (11 or I2) by the motor (3) while rotating in one direction (d1 or d2) increases, for example, when the load in the drum (2) becomes unbalanced. In this situation, the control unit (4) detects that the motor (3) is starting to heat up when the difference of the current (ΔΙ) drawn by the motor (3) increases. The control unit (4) decides whether or not the motor (3) temperature (T) exceeds the limit temperature (Tlim) value by using the detected current difference (ΔΙ) and the limit difference (Allim) and temperature (T) ratios recorded in the memory thereof.

[0019] In another embodiment of the present invention, the ratio of the motor (3) resistance to the motor (3) temperature (T) is recorded in the memory of the control unit (4). The control unit (4) calculates the instantaneous resistance of the motor (3) by measuring the instantaneous voltage on the motor (3) and the instantaneous current drawn by the motor (3) and determines the instantaneous temperature (T) of the motor (3) by using the resistance and temperature ratio recorded in the memory thereof. The motor (3) temperature (T) and resistance are proportional. The resistance of the motor (3) at room temperature prior to operation is recorded in the memory of the control unit (4) by the producer. When the washing machine (1 ) starts operating, the resistance on the motor (3) and the current drawn is measured continuously and at certain intervals while the motor (3) performs symmetrical (t1 =t2) rotational movements and the instantaneous resistance of the motor (3) is calculated. The motor (3) temperature (T) is detected by comparing the calculated resistance with the motor (3) resistance at room temperature recorded in the memory of the control unit (4).

[0020] In another embodiment of the present invention, the washing machine (1 ) comprises a sensor (5) that detects the motor (3) temperature (T). The sensor (5) is for example a thermal camera or a thermometer.

[0021] In an embodiment of the present invention, the control unit (4) also detects the temperature (T) of the motor (3) after the motor (3) starts performing asymmetrical (t2>t1 ) rotational movement and if the motor (3) temperature (T) falls below the limit temperature (Tlim) value, provides the motor (3) to again perform symmetrical (t1 =t2) rotational movement. The motor (3) cools down when the motor (3) starts rotating towards the second direction (d2). The control unit (4) provides the motor (3) to perform symmetrical (t1 =t2) rotational movement after the motor (3) cools down and thus the decrease of washing effectiveness is prevented.

[0022] The washing effectiveness is increased by means of the control unit (4) controlling the motor (3) temperature (T) and providing the motor (3) to perform symmetrical (t1 =t2) rotational movement as long as the motor (3) does not exceed the limit temperature (Tlim). The laundry is provided to be cleaned in a shorter period of time. Consequently, washing programs that take less time can be used than the washing programs wherein

asymmetrical (t2>t1 ) washing is performed.

[0023] It is to be understood that the present invention is not limited to the

embodiments disclosed above and a person skilled in the art can easily introduce different embodiments. These different embodiments should also be considered within the scope of the claims of the present invention.