CN102575404A - Control method of laundry machine - Google Patents

Abstract

This invention discloses a control method for a washing machine. One such method includes a water supply step configured to drive the washing machine drum in a scrubbing motion when water is supplied to the washing machine's tub. Another control method includes a washing cycle with at least one water supply step configured to drive the drum for a predetermined period after water supply to the tub begins or after the water level reaches a predetermined value.

Description

Control method of washing machine

technical field

The invention relates to a control method of a washing machine.

Background technique

In general, a washing machine may include wash, rinse, and spin cycles. However, conventional washing machines have problems.

Contents of the invention

technical problem

Therefore, the present invention is directed to a control method of a washing machine.

Technical solutions

To solve the problem, an object of the present invention is to provide a control method of a washing machine including a water supply step configured to drive a drum in a scrubbing motion when water is supplied to the tub.

Beneficial effect

The present invention has the following beneficial effects.

According to the control method of the present invention described above, it is possible to provide control with an efficient washing cycle.

Description of drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention and together with the description serve to explain the principle of the invention.

In the picture:

Figure 1 is a cross-sectional view of an exemplary washing machine as embodied and broadly described herein;

2 is an exploded perspective view illustrating a washing machine according to a second embodiment to which a dehydration cycle control method is applied;

Fig. 3 is a sectional view showing the connected state of Fig. 2;

Figure 4 illustrates various drum actions and laundry motion profiles as embodied and broadly described herein;

FIG. 5 is a diagram showing driving of a water temperature and a circulation pump in a washing cycle;

6 and 7 are graphs showing changes in rpm of the drum in a dehydration cycle;

Fig. 8 is a graph showing the relationship between mass and natural frequency;

Fig. 9 is a graph showing vibration characteristics of the washing machine.

Detailed ways

As follows, a control method of a washing machine according to the present invention will be described with reference to the accompanying drawings. First, washing machines according to various embodiments to which the control method of the present invention can be applied will be described according to corresponding drawings, and the control methods will be described thereafter.

FIG. 1 is a diagram illustrating a washing machine according to a first embodiment of the present invention, to which a control method according to various embodiments can be applied.

Referring to FIG. 1 , a washing machine 100 according to a first embodiment of the present invention includes a cabinet 10 configured to define an appearance of the washing machine, a tub 20 provided in the cabinet 10 to hold wash water, and a tub 20 provided in the tub 20. The rotatable drum 30.

The cabinet 10 defines the appearance of the washing machine 100 , and constructional elements (to be described later) may be installed inside the cabinet 10 . A door 11 is coupled to the front panel of the cabinet 10 , and a user opens the door 11 to load laundry into the cabinet 10 .

The tub 20 is disposed in the cabinet 10, and the tub 20 contains washing water. The drum 30 is rotatable in the tub 20, and the drum 30 accommodates laundry therein. In this case, a plurality of lifters 31 may be provided in the drum 30, and the lifters 31 lift and lower the laundry to perform washing.

The tub 20 is supported by springs provided outside the tub 20 . A motor 40 is installed to a rear surface of the tub 20 , and the motor 40 rotates the drum 30 . When the drum rotated by the motor 40 vibrates, the tub 20 provided in the washing machine according to the first embodiment vibrates in association with the drum. If the drum 30 rotates, vibrations generated in the drum and the tub 20 may be absorbed by the damper 60 located under the tub 20 .

As shown in FIG. 1 , the tub 20 and the drum 30 may be disposed parallel to the base plate of the cabinet 10 . Alternatively, although not shown in the drawing, rear portions of both the tub 20 and the drum 30 may be inclined downward. This is because if a user loads laundry into the drum 30, it is better that front portions of both the tub 20 and the drum 30 are inclined upward. Ball balancers 70 are provided on the front and/or rear surfaces of the drum 30 to balance the vibration of the drum 30 if the drum rotates, especially at a high speed, such as a dry-spinning cycle. The ball balancer will be described in detail later.

According to the washing machine of the present embodiment, the tub may be fixedly supported to the cabinet, or it may be supported to the cabinet by a flexible support structure such as a suspension unit to be described later. Also, the support of the tub may be between the support of the suspension unit and the full fixed support.

That is, the tub may be flexibly supported by a suspension unit (to be described later), or may be completely fixedly supported so as to be more difficult to move. Although not shown in the drawings, unlike an embodiment to be described later, no case may be provided. For example, in case of a built-in washing machine, a predetermined space for installing the built-in washing machine may be formed by a wall structure or the like instead of a cabinet. In other words, the built-in washing machine may not include a cabinet configured to independently define the appearance of the washing machine.

2 is an exploded perspective view partially showing a washing machine according to a second embodiment, and FIG. 3 is a cross-sectional view showing an assembled state of the washing machine shown in FIG. 2 .

2 and 3, the washing machine according to this embodiment includes a tub 12 fixedly supported to the cabinet. The tub 12 may include a tub front 100 configured to define a front portion of the tub and a tub rear 120 configured to define a rear portion of the tub. The tub front 100 and the tub rear 120 are assembled to each other by screws, and form a predetermined space in the assembled structure to accommodate the drum. The tub rear 120 may include an opening formed in a rear surface thereof, and an inner circumference of the rear surface of the tub rear 120 is connected with an outer circumference of the rear gasket 250 . The inner circumference of the rear pad 250 is connected to the tub back 130 (tub back). The tub back 130 includes a through hole formed at the center thereof through which a shaft passes. The rear gasket 250 may be made of a flexible material that does not transmit the vibration of the tub back 130 to the tub rear 120 .

The tub rear 120 includes a rear surface 128 . The rear surface 128 of the tub rear 120, the tub back 130, and the rear gasket 250 define a rear wall of the tub. The rear gasket 250 is sealingly connected with both the tub back 130 and the tub rear 120, which prevents the washing water contained in the tub from leaking. During the rotation of the drum, the tub back 130 vibrates together with the drum. Accordingly, the tub back 130 is separated by a predetermined distance sufficient not to interfere with the tub rear 120 . Since the rear gasket 250 is made of a flexible material, the rear gasket 250 allows relative movement of the tub back 130 without interfering with the tub rear 120 . The rear liner 250 may include corrugations (waves) 252 that may extend sufficiently to allow such relative movement of the tub back 130 .

The foreign object preventing member 200 is connected to a front portion of the tub front 100 to prevent foreign objects from entering between the tub and the drum. The foreign object preventing member 200 is made of a flexible material, and it is fixedly installed to the tub front 100 . The foreign object preventing member 200 may be made of the same material as that used to make the rear pad 250, which will be referred to as a 'front pad' for convenience.

The drum 32 includes a drum front 300 , a drum center 320 and a drum back 340 . The ball balancers 310, 330 are respectively installed at the front part and the rear part of the drum. The drum back 340 is connected to a spider (spider, star wheel) 350 , and the spider 350 is connected to a shaft 351 . The drum 32 is rotated in the tub by the rotational force transmitted from the motor via the shaft 351 .

The shaft 351 passes through the tub back 130 and is directly connected to the motor 170 . Specifically, the shaft 351 is directly connected with the rotor 174 constituting the motor 170 . A bearing housing 400 is coupled to a rear surface of the tub back 130 , and the bearing housing 400 is located between the motor 170 and the tub back 130 to rotatably support the shaft 351 .

The stator 172 is fixedly mounted to the bearing housing 400 and the rotor 174 is positioned around the stator 172 . As mentioned above, the rotor 174 is directly connected to the shaft 351 . The motor 170 is an outer rotor type motor which is directly connected to the shaft 351 .

The bearing seat 400 is supported by the suspension unit relative to the casing base 600, and the suspension unit 18 includes: three vertical support suspension devices, and an oblique support suspension device configured to support the bearing seat obliquely in the front and rear directions.

The suspension unit 180 may include a first cylinder spring (cylinder spring) 520, a second cylinder spring 510, a third cylinder spring 500, a first cylinder damper (cylinder damper) 540 and a second cylinder spring. Damper 530 .

The first cylindrical spring 520 is disposed between the first suspension bracket 450 and the casing base 600 , and the second cylindrical spring 510 is disposed between the second suspension bracket 440 and the casing base 600 .

The third cylindrical spring 500 is directly connected between the bearing seat 400 and the casing seat 600 .

The first cylindrical damper 540 is obliquely installed between the first suspension bracket 450 and the rear portion of the cabinet base. The second cylindrical damper 530 is obliquely installed between the second suspension bracket 440 and the rear portion of the cabinet base.

The column springs 520, 510, and 500 of the suspension unit 180 may be elastically connected to the cabinet base 600 enough to allow the drum to move in the front-rear direction and the left-right direction without being completely fixed to the cabinet base. That is, the cylindrical springs 520, 510, and 500 elastically support the drum to allow vertical and horizontal motions of the drum relative to the connection portion with the cabinet seat.

The vertical ones of the suspensions elastically suspend the vibrations of the drum, while the inclined ones dampen the vibrations. That is to say, in a vibration system composed of springs and dampers, those installed vertically are used as springs, and those installed obliquely are used as dampers.

The tub front 100 and the tub rear 120 are firmly fixed to the cabinet 110 , and the vibration of the drum 32 is delayed by the suspension unit 180 . In essence, the structures of the tub 12 and the drum 32 may be independent. Even when the drum 32 vibrates, the tub 12 may not structurally vibrate.

The bearing housing 400 is connected with these suspension brackets through a first counterweight 431 and a second counterweight 430 .

The water supply circuit 722 is arranged in the casing 110, and the water supply circuit 722 is connected with an external water supply source (for example: a faucet). The control switch controls the water supply valve 720 to supply water to the tub 12 via the water supply line 722 . An end of the water supply line 722 is connected to the front portion of the tub 12 or the front gasket 200 so as to supply water from the front portion into the tub. If the detergent box 710 is provided along the water supply line 722, water may be supplied together with the detergent.

Meanwhile, a circulation pump 730 may be disposed under the tub 12, and the circulation pump 730 circulates water discharged from the tub 12 so that it is resupplied to the tub. If it is required to circulate water in the washing machine according to the second embodiment by means of the circulation pump 730 , the valve 732 is adjusted and the circulation pump 730 is connected to the circulation line 744 . An end of the circulation line is connected to the front portion of the tub or the front gasket 200 so as to supply water from the front portion to the inside of the tub. If it is desired to drain the tub, the circulation pump 730 is connected to the drain line 742 for draining. Although not shown in the drawings, a circulation pump configured to circulate water and a drain pump configured to drain water may be provided separately. In this case, the circulation line and the drainage line are connected to the circulation pump and the drainage pump, respectively.

The tub 12 and the drum 32 may be installed in parallel with the cabinet base 600 or obliquely at a predetermined angle with the cabinet base 600 . In this case, rear portions of the tub 12 and the drum 32 may be inclined downward to allow a user to load laundry into the drum 32 more smoothly.

If the laundry 1 is accommodated in the drum 30, 32 while the drum 30, 32 is rotated in the washing machine according to the above embodiment, noise and vibration will be generated according to the location of the laundry 1. For example, when the drums 30, 32 are rotated (hereinafter, "eccentrically rotated") with uneven distribution of laundry in the drums 30, 32, severe vibration and noise may occur. Especially when the drums 30, 32 are rotating at high speeds during the drying cycle, vibration and noise can be a problem.

Accordingly, the washing machine may include the ball balancers 70 , 310 and 330 to prevent vibration and noise due to the eccentric rotation of the drums 30 and 32 . The ball balancers 70, 310, and 330 may be provided on the front portion, the rear portion, or both.

Ball balancers 70, 310, and 330 are installed to the rotatable drums 30, 32 to reduce eccentricity. Accordingly, the ball balancers 70, 310, and 330 may have a movable center of mass. That is, the ball balancer ( 70 , 310 , and 330 ) may include balls 72 , 312 , and 332 , which have a predetermined weight, and paths in which the balls can move in a circumferential direction.

Specifically, the balls are rotated by the friction force generated when the drums 30, 32 rotate. As the drum spins, the balls are not held in the drum and spin at a different speed than the drum. Here, the clothes with eccentricity are in close contact with the inner wall of the drum, and can rotate at almost the same speed as the drum due to sufficient frictional force and lifting of the inner wall. Therefore, the spin speed of the laundry is different from that of the ball. In an initial rotation stage in which the drum has a relatively low speed, the rotation speed of the laundry is faster than that of the ball. Precisely, the angular velocity of the cloth is faster than that of the ball. Also, the phase difference between the ball and the laundry, that is, the phase difference with respect to the rotation center of the drum may be continuously changed.

If the rotation speed of the drum becomes faster, the balls will come into close contact with the outer circumferential surface of the moving path due to centrifugal force. At the same time, the ball is aligned at a position where the difference between the ball and the garment is about 90° to 180°. If the rotational speed of the drum is a predetermined value or more, the centrifugal force becomes sufficiently large, and the centrifugal force between the peripheral surface and the ball becomes a predetermined value or more so that the ball can rotate at the same speed as the drum. In this case, the ball rotates at the same speed as the drum and maintains a position 90° to 180° (preferably about 180°) from the laundry. In this specification, the case where the ball rotates relative to the drum at a predetermined position will be referred to as "eccentricity-corresponding position" or "ball-balanced" for convenience.

Accordingly, when the load of laundry is concentrated at a predetermined portion inside the drum 30, 32, the balls provided in the ball balancers 70, 310, and 330 move to positions corresponding to the eccentricity to reduce the eccentricity.

Meanwhile, the drum may be driven in various ways in the above washing machine. That is, the driving action of the drum may be appropriately determined according to each washing, rinsing, and drying-spinning cycle, or the user may appropriately determine the driving action of the drum according to characteristics of a selected program. As follows, various driving actions applicable to the control method according to the present invention will be described in detail.

Fig. 4 is a diagram illustrating various drum driving operations. FIG. 4 is a front view schematically showing the drum to show rotation of the drum. According to FIG. 4, the inside of the drum is divided into four parts counterclockwise, and the four parts are defined as the first quadrant, the second quadrant, the third quadrant and the fourth quadrant to explain the position of the clothes according to the rotation angle of the drum.

Referring to FIG. 4, the drum driving action may be embodied by combining the rotation direction, rotation speed and rotation angle of the drum. Also, due to the drum driving action, the laundry located in the drum may have different falling directions, falling points, and impacts when falling. Relatedly, the laundry in the drum may have different movements. Various drum drive actions can be embodied by controlling a motor configured to rotate the drum.

Meanwhile, when the drum rotates, the laundry is lifted by lifters (see 31 in FIG. 1 and 132 in FIG. 3 ) provided on the inner circumferential surface of the drum. Accordingly, the rotation speed, rotation direction, and rotation angle of the drum are controlled, and the impact applied to the laundry may be varied accordingly. That is, the mechanical force applied to the clothes, such as friction between clothes, friction between clothes and water, and falling impact of clothes may vary, and the degree of beating or rubbing against clothes may vary accordingly. In addition, the rotation speed, rotation direction, and rotation angle of the drum can be controlled, and the degree of distribution or turning of the laundry in the drum can be varied accordingly.

Therefore, the control method of the washing machine can provide various drum driving actions that vary according to each cycle and specific steps constituting the cycle so that an optimal mechanical force can be used to process laundry. Thereby, washing efficiency of laundry can be improved, and time required for optimal drum driving action can be shortened.

Meanwhile, the motor may be classified into a direct type directly connected to a shaft of the drum and an indirect type configured to transmit rotational force to the drum via a pulley or the like. In order to realize various drum driving actions, the motor 170 may be a direct type directly connected to the drum. Considering the rotation direction and torque of the motor, a time delay or backlash can be prevented, and in the direct type, the motion of the motor can be spontaneously transmitted to the drum.

The drum driving action is composed of rolling action, tumbling action, stepping action, rocking action, rubbing action and so on. As follows, each action will be described in detail.

FIG. 4( a ) is a diagram illustrating a rolling action, and each of the figures of FIG. 4 illustrates a rotation direction and a rotation angle of a drum and movement of laundry in the drum, thereby explaining each action.

4 (a), in the rolling action, the motors 40, 170 continuously rotate the drums 30, 32 in a predetermined direction, and the clothes on the inner peripheral surface of the drums rotate along the direction of rotation of the drums from about less than 90° The position of the angle drops to the lowest point of the drum.

That is, once the motor 40, 170 rotates the drum at about 35RPM to 45RPM, the laundry at the lowest point of the drum 30, 32 is lifted to a predetermined height along the direction of rotation of the drum 30, 32, and then from the lowest point relative to the drum. The position of the point less than 90° rolls to the lowest point of the drum. If the drum rotates clockwise, the laundry rolls in the third quadrant of the drum. The laundry is washed by friction with water, with the laundry, and with the inner peripheral surface of the drum in a rolling action. The rolling action enables full inversion of the laundry for a gentle scrub-like wash.

Meanwhile, if the drum rotates, the drum RPM of the drum driving action is determined by the relationship with the centrifugal force. That is, the greater the RPM of the drum, the greater the centrifugal force generated by the laundry in the drum. If the centrifugal force is greater than the gravitational force, the laundry will adhere to the inner peripheral surface of the drum. If the centrifugal force is less than gravity, the laundry may drop to the bottom surface of the drum. Therefore, the motion of the laundry in the drum can be changed by the relative magnitude between the centrifugal force and the gravitational force. When determining the drum RPM, it may be necessary to take into account the rotational force of the drum and the frictional force between the drum and the laundry.

In the above rolling action, the drum RPM is determined such that the centrifugal force is less than the gravitational force. That is to say, in this rolling action, the clothes roll down with the rotation of the drum, so the centrifugal force must be smaller than the gravity.

Fig. 4(b) is a diagram illustrating a scrolling operation.

Referring to FIG. 4(b), in the tumbling operation, the motors 40, 170 continuously rotate the drums 30, 32 in a predetermined direction, and the clothes on the inner circumferential surface of the drums are rotated from about 90° to 110° relative to the direction of rotation of the drums. The position drops to the lowest point of the drum.

In the tumbling action, only when the drum is controlled to rotate in a predetermined direction at an appropriate RPM, mechanical force will be generated between the laundry and the drum. Thus, a tumbling action is often used in washing and rinsing.

That is, before the motor 40, 170 is driven, the laundry loaded into the drum 30, 32 is located at the lowest point of the drum 30, 32. When the motor 40, 170 provides torque to the drum 30, 32, the drum 30, 32 rotates, and the lifter 132 provided in the inner circumferential surface of the drum lifts the laundry from the lowest point of the drum to a predetermined height. If the motor 40, 170 rotates the drum 30, 32 at about 46 to 50 RPM, the laundry will drop to the lowest point of the drum from a position of about 90° to 180° relative to the direction of rotation of the drum. In the tumbling operation, the drum RPM is determined such that the centrifugal force generated in the tumbling operation is greater than the centrifugal force generated when the drum rotates, and smaller than the gravity.

If the drum rotates clockwise during the tumbling action, the laundry is lifted from the lowest point of the drum to the second quadrant, and then dropped to the lowest point of the drum. Therefore, the tumbling action enables the laundry to be washed through impact and drop impact generated by friction with water. In the tumbling action, washing and rinsing may be performed using a mechanical force greater than that of the tumbling action. Also, the tumbling action is an action of descending the laundry in the drum, which is effective in separating entangled laundry and evenly distributing the laundry.

Fig. 4(c) is a diagram illustrating a stepping operation.

Referring to FIG. 4( c), in the stepping action, the motors 40, 70 rotate the drums 30, 32 in a predetermined direction, and the clothes on the inner peripheral surface of the drums are controlled from about 180° relative to the direction of rotation of the drums. The highest point drops to the lowest point of the drum.

Once the motor 40, 170 rotates the drum 30, 32 at an RPM of about 60 RPM to 77 RPM or higher, the laundry can be rotated by centrifugal force until reaching the highest point of the drum without falling down. During the stepping motion, if the laundry reaches near the highest point, a sudden brake is applied to the drum to maximize the impact applied to the laundry.

After the drums 30, 32 are rotated at a predetermined speed (about 60RPM to 70RPM or more) that will not cause the laundry to drop until the laundry reaches the highest point of the drum by using centrifugal force, when the laundry is located near the highest point of the drum (relative to the 180° of the rotation direction of the drum), the motor 40, 170 is controlled to supply a reverse torque to the drum 30, 32. The laundry is lifted from the lowest point of the drum in the direction of rotation of the drum. Thereafter, when the drums are momentarily stopped due to the reverse torque of the motor, the laundry descends from the highest point of the drums 30, 32 to the lowest point. Therefore, the stepping action enables the laundry to be washed by the shock generated when the laundry is dropped at the maximum height. The mechanical force generated in this stepping action is greater than the mechanical force generated in the above-mentioned rolling action or scrubbing action.

If a sudden brake is applied as in a stepping motion, the motor 40, 170 can be braked in reverse. Reverse braking is a type of motor braking by using torque generated in the opposite direction relative to the motor's rotation direction. The phase of the current applied to the motor can be reversed to produce reverse torque, and reverse phase braking enables sudden braking to be applied to the motor. Therefore, for stepping motions configured to apply strong impacts to laundry, anti-phase braking is the most suitable braking system.

According to Figure 4(c), in the stepping action, after moving from the lowest point of the drum to the highest point sequentially via the third quadrant and the second quadrant, if the drum rotates, the laundry descends to the lowest point in the inner peripheral surface of the drum. point. Because the descending distance inside the drum is greatest in the stepping action, the mechanical force can be applied to small loads.

Thus, the motor 40, 170 then applies torque to the drum 30, 32, and the motor lifts the laundry at the lowest point of the drum to the highest point in the same direction of rotation. That is, after applying torque to rotate the drum clockwise, when the laundry reaches the highest point, applying torque to rotate the drum counterclockwise, the drum suddenly stops. Thereafter, torque is applied to the drum to rotate again in a clockwise direction, embodying a stepping action. Therefore, the stepping action is an action for using the friction between the water sucked through the through hole (see 134 in FIG. 3 ) formed in the drum and the clothes and using the time when the clothes reach the highest point of the drum. The shock generated by the falling of the clothes, to wash the clothes.

For example, 4(d) is a diagram showing a rocking motion.

Referring to FIG. 4( d ), in the rocking action, the motors 40, 170 rotate the drums 30, 32 alternately clockwise and counterclockwise, and the clothes drop at about 90° to 130° relative to the direction of rotation of the drums.

That is, once the motor 40, 170 rotates the drum 30, 32 counterclockwise at about 40 RPM, the laundry at the lowest point of the drum 30, 32 is lifted by a predetermined height in the counterclockwise direction. When the clothes pass through the 90° position relative to the counterclockwise direction of the drum, the motor stops the rotation of the drum, and the clothes drop from the 90° to 130° position relative to the counterclockwise direction of the drum to the lowest point of the drum.

Therefore, the motor 40, 170 rotates the drum 30, 32 in the clockwise direction at about 40 RPM, so that the laundry is lifted by a predetermined height in the clockwise direction along the rotation direction of the drum. After the clothes pass through the 90° position in the counterclockwise direction relative to the drum, the motor stops the rotation of the drum, and the clothes drop from the 90° to 130° position in the clockwise direction relative to the drum to the lowest point of the drum.

That is, the rocking action is an action in which rotation and stop with respect to a predetermined direction and rotation and stop with respect to the opposite direction are repeated. A portion of the laundry lifted from the third quadrant of the drum to the second quadrant gently descends, and it is lifted again from the fourth quadrant of the drum to a portion of the first quadrant to repeatedly descend gently. Therefore, in the rocking action, the laundry may move in a sided "8" shape on the third and fourth quadrants of the drum.

At this time, the motor 40, 170 may use rheostat type braking. According to rheostat type braking, if the current applied to the motor is interrupted, the motor is used as a generator due to rotational inertia. If the current applied to the motor is interrupted, the direction of the current flowing in the motor's coils will change to the opposite direction of the current before the power was turned off, and a force (Fleming's right-hand rule) is applied in the direction that interferes with the rotation of the motor so that the motor brake. Unlike anti-phase braking, rheostat-type braking cannot stop the motor suddenly, but it can gently change the direction of rotation of the drum. Therefore, the rocking action is suitable for rheostat type braking and the load on the motor 40, 170 is reduced as much as possible. In addition, mechanical wear of the motor 40, 170 may be minimized, and impact applied to laundry may be adjusted simultaneously.

Fig. 4(e) shows a diagram of scrubbing operation.

Referring to Figure (e), in the scrubbing action, the motors 40, 170 rotate the drums 30, 32 alternately clockwise and counterclockwise, and reverse braking is applied to the drums so that the clothes can be rotated from the direction of rotation relative to the drums. The position of about 130° to 160° falls.

That is, once the motor 40, 170 rotates the drum 30, 32 in the counterclockwise direction at about 60 RPM, the laundry at the lowest point of the drum 30, 32 is lifted by a predetermined height in the counterclockwise direction. After the laundry passes through about 90° in the counterclockwise direction relative to the drum, the motor provides reverse torque to the drum to temporarily stop the drum. If so, the laundry on the inner peripheral surface of the drum will drop rapidly.

Accordingly, the motor 40, 170 rotates the drum at about 60 RPM in the clockwise direction to lift the dropped laundry to a predetermined height in the clockwise direction. After the laundry passes the 90° position in the counterclockwise direction with respect to the drum, the motor 40, 170 applies a reverse torque to the drum 30, 32, and the rotation of the drum is temporarily stopped. Therefore, the laundry on the inner circumferential surface of the drum descends from a position of about 130° to 160° with respect to the clockwise direction of the drum to the lowest point of the drum.

Therefore, in the scrubbing action, the laundry can be rapidly dropped from a predetermined height to be washed. Here, the motor 40, 170 may be braked in reverse phase to stop the drum.

During the scrubbing action, the rotation direction of the drum changes rapidly, and the laundry may be largely off the inner peripheral surface of the drum. Therefore, a strong scrubbing effect can be achieved during the scrubbing action. In the scrubbing action, the following process is repeated, the laundry moving to a part of the second quadrant via the third quadrant descends rapidly to descend again after moving to a part of the first quadrant via the fourth quadrant. Therefore, in the scrubbing action, the lifted laundry repeatedly descends along the inner circumferential surface of the drum.

FIG. 4( f ) is a diagram illustrating filtering operations. In the filtering action, the motor 40, 170 rotates the drum 30, 32 so that laundry does not drop from the inner circumferential surface of the drum, and water is sprayed into the drum.

That is, in the filtering action, water is sprayed into the drum while the laundry rotates in close contact with the inner peripheral surface of the drum after being dispersed. Water is drained from the laundry and the through holes of the drum from the tub 120 by centrifugal force. Since the filtering action widens the surface area of the laundry, which enables water to pass through the laundry, wash water can pass through the laundry, and the wash water can be uniformly supplied to the laundry.

Fig. 4(g) is a diagram illustrating a squeezing action. In the squeezing action, the motor 40, 170 rotates the drum 30, 32 so that the clothes will not drop from the inner peripheral surface of the drum due to centrifugal force, after that, the motor reduces the rotational speed of the drum 30, 32 to make the clothes and the drum The inner peripheral surface is separated. This process is repeated and water is sprayed into the drum during the rotation of the drum.

That is, in the filtering action, the drum continuously rotates at a speed sufficient for the laundry not to drop from the inner circumferential surface of the drum. In contrast, the rotational speed of the drum is changed to repeat the process of closely contacting the laundry in the inner peripheral surface and separating the laundry from the inner peripheral surface.

The process of spraying water to the drums 30, 32 during the filtering action and squeezing action can be implemented using a circulation path and a pump (although not shown in Figure 1). The pump communicates with the lower surface of the tub 120, and pressurizes the wash water. The end of the circulation path is connected with the pump, and water is sprayed from the upper part of the drum to the drum via the other end of the circulation path.

In the case of spraying water contained in the tub, the above-mentioned circulation path and pump are essential elements; the present invention may not exclude the case of spraying water via a path connected to an external water supply source located outside the cabinet.

Meanwhile, FIG. 5 is a diagram showing the stepping operation more clearly. Once the motor 40, 170 applies torque to the drum 30, 32 in a predetermined direction, the drum is rotated in the predetermined direction, and the laundry is lifted in a state of closely contacting the inner circumferential surface of the drum. At this time, the laundry may be rotated at about 60 RPM or higher to lift the laundry in close contact with the inner circumferential surface of the drum. Here, the rotation speed of the drum is determined by the relationship with the inner diameter of the drum, and the determined rotation speed can cause the centrifugal force to be greater than the gravitational force.

Just before the laundry reaches the highest point of the drum through the 90° position with respect to the direction of rotation of the drum 30, 32, the motor 40, 170 brakes in reverse phase to temporarily stop the rotation of the drum. The timing of reverse phase braking with respect to the motor 40, 170 is closely related to the position of the laundry in the drum. Thus, a device may be provided to determine or anticipate the position of the laundry, a sensing device comprising a Hall effect sensor configured to determine the angle of rotation of the rotor may be one example.

The control can determine the direction of rotation of the rotor as well as the angle of rotation by using Hall sensors. This technical feature is common knowledge of those skilled in the art, so a detailed description thereof will be omitted.

The controller may determine the rotation angle of the drum by using a sensing device, and control the motor 40, 170 to perform reverse phase braking before the drum has a rotation angle of 180°. Here, reverse braking means applying reverse current to rotate the drum in the reverse direction. For example, immediately after applying current to the motor to rotate the drum in a clockwise direction, quickly apply reverse current to rotate the drum in a clockwise direction.

Therefore, the drum rotating in the clockwise direction stops immediately, and the rotation angle at this time is basically 180°, so that the clothes are dropped from the highest point of the drum to the lowest point. Thereafter, continuous application of current causes the drum to rotate in a clockwise direction.

Figure 5 shows the drum rotating in a clockwise direction. Here, a stepping motion may be implemented when the drum rotates in a counterclockwise direction. Here, the stepping action places a substantial load on the motor 40, 170, and the net acting ratio of the stepping action can be reduced.

The net action ratio is the ratio of the motor drive time to the total of the drive time and rest time of the motor 40 , 170 . If the net action ratio is "1", it means that the motor is driven without stopping time. Considering the load of the motor, the stepping action can be performed with about 70% of the net action ratio. For example, the drive motor can be stopped for 4s after being driven for 10s.

Fig. 6 is a diagram more clearly showing the rubbing operation. Once the motor 40, 170 applies torque to the drum 30, 32, the laundry in the drum rotates in a clockwise direction. Here, the motor 40, 170 may be controlled to rotate the drum 30, 32 at about 60 RPM or higher in order to rotate the laundry in close contact with the inner circumferential surface of the drum. Thereafter, when the laundry passes the 90° position with respect to the rotation direction of the drum, the motors 40, 170 are braked in reverse phase, and the laundry, which is in close contact with the inner peripheral surface of the drum, thus descends to the lowest point of the drum.

When the laundry is lowered to the lowest point, the motor 40, 170 applies torque to the drum, causing the drum to rotate in a counterclockwise direction. Therefore, the laundry in close contact with the inner peripheral surface of the drum rotates in the counterclockwise direction. When the clothes are between the 90° position relative to the counterclockwise direction and the highest point of the drum from the lowest point, the motor is braked in reverse phase, and the clothes that are in close contact with the inner peripheral surface of the drum drop to the lowest point of the drum.

The scrubbing action described above creates a substantial load applied to the motors 40, 170, as in synchronous action. Thus, the net action ratio of the scrubbing action can be reduced. For example, the action of scrubbing is carried out for 10 seconds, and then stopped for 4 seconds. This process is repeated so that the net action ratio is 70%.

Although not shown in the figure, the braking type of the motor in the scrubbing action is changed to a rheostat type braking of a swinging action. The point of time of the rheostat type braking becomes the moment when the laundry reaches the 90° position with respect to the rotation direction of the drum, so a detailed description of the swinging action will be omitted.

FIG. 7 is a graph showing a comparison of washing capabilities and vibration levels for each action shown in FIG. 4 . The horizontal axis represents the washing ability, and the more you move to the left, the easier it is to separate the dirt contained in the clothes. The vertical axis represents the vibration or noise level, and the higher the vibration level is, the shorter the washing time of the same clothes is moved up.

When the laundry is particularly dirty, the step action and the scrub action are suitable for those washing programs implemented to shorten the washing time. Stepping and scrubbing actions have high vibration/noise levels, so they are not suitable for those wash programs implemented for washing sensitive fabrics and minimizing noise and vibration.

The rolling action has good washing power and low noise level with minimal laundry damage and low motor load. Thus, the tumbling action may be suitable for all washing programs, especially for dissolving detergent in the initial wash phase and for wetting the laundry.

The tumbling action has a lower washing capacity than the scrubbing action, and an intermediate noise level compared to the scrubbing action and the rolling action. The tumbling action has a lower noise level, but has a longer wash time than the tumbling action. Therefore, the tumbling action can be used for all washing programs and is suitable for washing programs that require an even distribution of laundry.

The squeezing action has a washing power similar to the tumbling action and a higher vibration level than the tumbling action. The squeezing action repeats a process of closely contacting and separating the laundry in the inner peripheral surface of the drum, and in this process, wash water is discharged out of the drum after passing through the laundry. Therefore, the squeezing action is suitable for rinsing.

The filtering action has a lower washing power than the squeezing action and a noise level similar to the rolling action. In the filtering action, water passes through the laundry and is discharged out of the drum, where the laundry is in close contact with the inner peripheral surface of the drum. Therefore, the filtering action is suitable for programs that require wetting the laundry.

The rocking action has the lowest vibration level and washing capacity, which is suitable for low noise and low vibration washing programs, and suitable for programs for washing delicate clothes.

As mentioned above, each drum drive motion has advantages and disadvantages, and it is preferable to use those various drum drive motions appropriately. Each drum driving action may have advantages and disadvantages in relation to the laundry load. Even with the same program and cycle, various drum driving actions can be appropriately used in relation to the amount of laundry.

As follows, a control method of the washing machine including the above-described drum driving action will be described. A washing machine generally includes washing, rinsing and drying cycles, and those cycles will be described from now on. Here, the washing cycle is part of various programs or it can be implemented independently.

The washing cycle may include a water supply step configured to supply water and detergent to the tub 12, 20 or the drum 30, 32 to dissolve the detergent in the water. That is, water and detergent are mixed and supplied to wash clothes. In addition, the washing cycle may include a main washing step configured to drive the drum to wash laundry. Here, the water supply step may be a preparatory step for the main washing step. Therefore, it is preferable to improve the efficiency of the water supply step to improve the efficiency of the washing cycle (including washing efficiency and shortening time efficiency).

The washing cycle may include a laundry wetting step, and/or a heating step performed between the water supply step and the main washing step. A control method regarding the water supply step of the washing cycle will be described later, and will be described in detail.

In the water supply step, the controller supplies wash water to the tubs 12 , 20 . Specifically, the controller opens the water supply valve 720 and supplies water to the tub 12 through the water supply line 722 and the detergent box 710 .

Since detergent is supplied together with water in the water supply step, detergent dissolution may be fully performed during the water supply step to improve the efficiency of the washing cycle. Therefore, in the water supply step, a predetermined process may be implemented to accelerate dissolution of the detergent in water. If water partially contacts the laundry during water supply, the water cannot evenly wet the laundry, and the efficiency of the washing cycle may decrease. Although the laundry wetting step is provided in the washing cycle, the water supply step may include a process of uniformly wetting the laundry with water. As follows, various embodiments of the detergent dissolution acceleration process and the uniform wetting process of laundry will be described.

First, the action of moving laundry in the drum (drum driving action) may apply strong mechanical force to water and laundry in order to accelerate detergent dissolution. Therefore, since the laundry lifted along the rotating drum falls off the inner peripheral surface of the drum due to the braking of the drum, and since this is repeated in the stepping action, the stepping action is preferably in the water supply step to accelerate detergent dissolution. Of course, in the water supply step, the scrubbing action of repeatedly descending and lifting the laundry lifted along the rotating drum due to the braking and reverse rotation of the drum can be implemented. In the stepping action and scrubbing action, the rotating drum stops quickly, and the moving direction of the clothes changes rapidly. Therefore, they can be actions capable of applying strong impact to laundry and water, so that strong mechanical force can be provided in the initial stage of the water supply step, and detergent dissolution can be accelerated, only improving the efficiency of the washing cycle.

Detergent dissolution is accelerated by repeating the sequential combination of stepping action and scrubbing action. In this case, different types of drum driving actions are combined, and the motion type of the laundry and the water flow type may be diversified. Therefore, the efficiency of the washing cycle can be more improved.

As described above, the water supply step is a preparatory step for the main washing step. Therefore, in the water supply step, detergent dissolution and laundry wetting must be performed quickly and completely, and they may be performed regardless of the amount of laundry. However, considering the limited capacity of the drum, limited water that can be supplied to the drum, the drum driving action of the water supply step may be differentially controlled according to the amount of laundry. This is because a drum driving action capable of achieving the maximum effect of detergent dissolution and laundry wetting may differ according to the amount of laundry.

Before the water supply step, a laundry amount determination step configured to determine the amount of laundry contained in the drum may be implemented. Depending on the result of the laundry amount determining step, the drum driving action in the water supply step may be differentially controlled.

Such laundry amount determination may be implemented by measuring the current required to rotate the drum. For example, the current required to perform a tumbling action can be measured. If the drum rotates, a current value applied by the controller to perform the tumbling action may differ according to the amount of laundry, and the amount of laundry may be determined.

If the laundry amount determined in the laundry amount determining step is a preset laundry amount level or higher, it may be controlled not to perform the process of dissolving the detergent. That is, if the amount of laundry is lower than a preset level, it may be controlled to implement a process configured to accelerate detergent dissolution. This is because the driving action of the drum capable of supplying a strong mechanical force is more effective with a small amount of laundry, and also because a small amount of laundry can be sufficiently wetted with water. That is, a small amount of laundry means that the laundry needs to have less surface area in contact with water, and detergent dissolution and laundry wetting can be accomplished by mechanical force used to tumble the laundry for short periods of time. Therefore, the effect of the main washing can be partially achieved by the stepping action or the scrubbing action, and the effect of shortening the time required to perform the main washing can be expected.

In contrast, in the case of a large amount of laundry, the mechanical force may not be sufficient and the laundry may not be in sufficient contact with water. When the laundry is crumpled, water cannot be sufficiently supplied to the items in the crumpled laundry.

Therefore, if the amount of laundry is a preset level or higher, the cleaning agent dissolution acceleration process is omitted, and the laundry wetting step may be started. When the amount of laundry is a preset level or higher, it is more preferable to accelerate the dissolution of the detergent in which the laundry is in sufficient contact with water. For this, in the water supply step, a circulation step configured to circulate water contained in the tub to resupply it to the drum may be implemented.

According to the washing machine of the second embodiment described above, the tub 12 is directly fixed to the cabinet 110 and the drum 32 is disposed in the tub 12 . Since only the drum 32 rotates while the tub 12 is fixedly installed in the washing machine according to the second embodiment, it is important to prevent contact between the drum 32 and the tub 12 during rotation of the drum. Therefore, a distance between the tub 12 and the drum may be formed in the washing machine larger than that in the conventional washing machine.

If the distance between the tub 12 and the drum 32 is widened, the laundry in the drum 32 may not be sufficiently wet during water supply to the tub. In order to allow the laundry to be sufficiently wet when water is supplied, the washing machine according to the second embodiment operates the circulation pump 730, and water contained in the tub may circulate. For example, the circulation pump 730 may be driven continuously or at predetermined intervals in which the water supply valve is opened.

According to the washing machine of the second embodiment, the drum 32 is connected to the tub back 30 . The tub back 130 is supported by the suspension unit 180 via the bearing housing 400 instead of the tub 12 . Therefore, compared with the drum 30 supported by the tub back 130 directly connected to the tub 12 in the washing machine according to the first embodiment, the drum 32 provided in the washing machine according to the second embodiment, especially the front portion of the drum 32 part, with greater degrees of freedom.

If water is supplied to the tub 12, the water supply line 722 and the circulation line 744 supply water at the front portion of the tub 12, and the laundry located in the front portion of the drum may be wet first. Therefore, the load applied to the front portion of the drum 32 is greater than the load applied to the rear portion, and the front portion of the drum 32 may be downward. If the front portion of the drum is downward, noise and vibration generated during rotation of the drum will increase, and what is more, it will come into contact with the inner surface of the tub 12 . Therefore, it is necessary to uniformly wet the laundry located at the front portion and the rear portion of the drum 32 during water supply in the washing machine according to the second embodiment.

As follows, a method of controlling uniform wetting of laundry located at front and rear parts of a drum according to an embodiment of the present invention will be described when water supply is implemented in the washing machine according to the second embodiment of the present invention.

If water is supplied in the water supply step of the control method according to the first embodiment, the circulation pump 730 is driven to circulate the water, and the drum 32 is simultaneously driven. When the drum 32 is driven, the control member controls the drum 32 to be driven according to the rubbing action of the above-mentioned drum driving action.

The distance between the drum 32 and the tub 12 in the washing machine according to the second embodiment is larger than that in the conventional washing machine. Therefore, when a tumbling action is applied to the drum 32 during water supply like in a conventional washing machine, laundry located at a rear portion of the drum cannot be sufficiently wetted. That is, since the gap between the drum 32 and the tub 12 is larger than the gap formed in the conventional washing machine, the rotation of the drum will not lift the water between the drum and the tub to wet the rear of the drum. Parts of clothing.

Therefore, when the water supply step is performed according to the control method, the scrubbing action is performed instead of the rolling action. As described above, the scrubbing action rotates the drum at a higher RPM than the tumbling action, and the water located between the drum 32 and the tub 12 is lifted by the rotation of the drum 32 and falls on the laundry.

Especially, in the washing machine according to the second embodiment, rear portions of both the drum 32 and the tub 12 are in an inclined configuration. Therefore, the scrubbing action smoothly supplies the water located at the rear portion of the tub 12 to the top of the laundry. Also, the scrubbing action rapidly changes the direction of rotation of the drum 32 in clockwise and counterclockwise directions. Therefore, rapidly reversed direction application to the drum may generate a vortex in the wash water so that the laundry located at the front part, the rear part of the drum may be evenly wetted.

When the water supply valve 720 is opened for water supply, the drum 32 is driven and rotated, and the laundry moves within the drum 32 according to the driving of the drum 32 . In this case, the water supplied via the water supply line 722 connected to the front portion of the tub 12 may be mostly supplied to the moving laundry located at the front portion of the drum 32 , and the laundry located at the front portion is less than the laundry located at the drum 32 . Clothes in the back get wet fast.

The control method according to the second embodiment may not drive the drum 32 until a predetermined time elapses after the water supply valve 720 supplies water or the water reaches a predetermined water level. If the drum 32 is not driven for a predetermined time or until the water reaches a predetermined water level, the water supplied via the water supply line 722 may be mostly collected in the lower portion of the tub 12 . Here, the predetermined water level may be determined in consideration of the distance between the tub 12 and the drum. The predetermined time may be determined according to the capacities of the tub 12 and the drum 32 and the amount of laundry.

Especially, the rear portion of the tub 12 in the above washing machine is installed inclined downward, and a large amount of water is collected in the rear portion of the tub 12 . When the drum 32 is rotated for a predetermined time, laundry located at the rear of the drum 32 may be wetted by water collected in the rear of the tub 12 . When the drum 32 is driven according to the control method of the second embodiment, the drum driving action can be embodied as a tumbling action or a rubbing action.

If the water supply valve 720 is opened to supply water without driving the drum 32 according to the control method of the second embodiment, the water supply valve 720 may be switch-controlled. That is, when the water supply valve 720 is turned on to supply water, the water may have a predetermined pressure due to the water pressure of an external water supply source such as a faucet. In this case, water supplied via the water supply line 722 may be supplied to the front of the drum by water pressure to wet laundry located at the front of the drum.

Therefore, when water supply is implemented in the control method according to the second embodiment, the water supply valve 720 may be repeatedly opened and closed instead of being continuously opened. The water supply valve 720 may be controlled to turn on or off the supplied water so that the supplied water has a predetermined water pressure and does not directly flow into the drum 32 . Here, the water pressure that prevents water from directly flowing into the drum may mean a water pressure that enables water supplied via the water supply line 722 to fall down the drum, the tub, or the door and be collected in the lower portion of the tub 12, while Not sprayed into the drum by water pressure. Water dropped along the drum, tub, or door may be collected at the rear of the tub 12, and the description thereafter is similar to that mentioned above. Duplicated descriptions will therefore be omitted.

Meanwhile, when water is supplied in the water supply step, the laundry may be crumpled and a part of the laundry may be wetted. In particular, the laundry located in the center of the crumpled laundry ball may not be wet, and only the laundry located on the outside of the crumpled laundry ball is wetted. If only part of the laundry is wet, the washing will not be carried out smoothly in the washing cycle, but the washing efficiency will be reduced. If the laundry is crumpled, a control method according to the third embodiment configured to evenly wet the crumpled laundry will be described.

The control opens the water supply valve 720 for water supply, and at the same time it drives the circulation pump 730 to circulate the water. The controls can drive the drum 32 during filtering action.

That is, the control may control the drum to rotate at a predetermined RPM. Here, the predetermined RPM is determined as the RPM that enables the laundry to be in close contact with the inner wall of the drum without falling due to gravity when the drum is rotated. Therefore, the predetermined RPM may be set so that the centrifugal force applied to the rotating drum is greater than the gravitational acceleration, and the predetermined RPM may be set lower than the excessive period (excessive period) of the washing machine to generate resonance (about 200RPM to 350RPM), if the drum is at Above the RPM rotation than this transition period, the noise and vibration generated by the resonance can increase significantly. Therefore, the predetermined RPM may be set at about 100 RPM to 170 RPM.

Once the controller rotates the drum 32 at a predetermined RPM, the laundry is in close contact with the inner wall of the drum 32 due to centrifugal force, and water supplied via the circulation line 744 and the water supply line 722 is distributed according to the rotation of the drum 32 . The distributed water is supplied to the drum 32 toward the laundry against the inner wall of the drum 32 so that the laundry may be evenly wetted.

Meanwhile, a control method configured to uniformly wet laundry applied to the washing machine according to the second embodiment is described, but the present invention is not limited thereto. For example, this control method is applicable to the washing machine according to the first embodiment.

In the water supply step, one of the process of accelerating the dissolution of the detergent and the process of uniformly wetting the laundry described above may be performed, or both may be performed. Both processes can be performed sequentially or repeatedly, and sequentially or reversely, and various combinations of the two processes are possible.

Therefore, the controller controls the rotation of the drum in the laundry wetting step to wet the laundry. If the water does not have to be heated, a heating step configured to heat the water using a heater provided in the tub may be implemented. Thereafter, the controller implements a main washing step by simultaneously driving the drum 32 and the circulation pump 730 . The drum driving action in the main washing step may be selected from among the drum driving actions according to a program selected by the user. The circulation pump 730 is driven at predetermined intervals, and the water contained in the tub 12 is circulated.

Meanwhile, the drum inside the drum type washing machine can be seen from the outside through the door 11 . Various drum driving actions may be implemented in a washing cycle and a washing program including the washing cycle according to an embodiment. Thus, the user can see the various drum drive actions performed directly within the drum. That is, soft beating washing (tumbling action), strong beating washing (stepping action), soft scrubbing washing (rolling action) and strong scrubbing washing (scrubbing action) can be identified with the naked eye. Therefore, the user can feel that washing is performed well, which can produce an effect of improving user's sensory satisfaction, and an effect of substantially improving washing efficiency.

Meanwhile, FIG. 8 shows a graph representing the relationship between mass and natural frequency. Assume that in the vibration system of two washing machines, the two washing machines have masses m0 and m1 respectively, and the maximum laundry capacity is Δm respectively. The transition zones of the two washing machines can then be determined taking into account Δnf0 and Δnf1 respectively. In this case, the amount of water contained in the laundry will not be taken into account for the time being.

Meanwhile, referring to FIG. 8 , the washing machine with a smaller mass m1 has a larger range of the transition zone than the washing machine with a larger mass m0. That is to say, the scope of considering the change transition zone of the laundry amount becomes larger as the quality of the vibration system becomes smaller.

The extent of these transition zones will review prior art washing machines and the washing machine of this embodiment.

A related art washing machine has a structure in which vibration is transmitted from the drum to the tub, thereby causing the tub to vibrate. Therefore, the tub is indispensable in consideration of the vibration of the prior art washing machine. However, in general, a tub not only has its own weight but also has a substantial weight for balancing at its front, rear or peripheral surface. Therefore, the prior art washing machine has a vibration system with a large mass.

In contrast, in the washing machine of this embodiment, since the tub has no counterweight and is separated from the drum due to the supporting structure, the tub may not be considered when considering the vibration of the drum. Therefore, the washing machine of the present embodiment may have a vibration system with a relatively small mass.

Then, referring to FIG. 8 , the washing machine of the prior art has a mass m0 and the washing machine of this embodiment has a mass m1 , which finally results in a washing machine of this embodiment having a larger transition zone.

Furthermore, if simply considering the amount of water contained in the laundry, Δm in Figure 8 becomes larger, making the difference in the extent of the transition zone even larger. Also, since in the prior art washing machine, even if the water is separated from the laundry when the drum is rotated, the water can be dropped from the drum into the tub, the reduction in water quality caused by dehydration is small. The washing machine of the present embodiment has the tub and the drum independent of each other due to consideration of vibration, but the water detached from the drum immediately affects the vibration of the drum. That is to say, in the washing machine of this embodiment, the influence of the quality change of the water in the laundry is greater than that of the washing machine in the prior art.

Under the influence of the above reasons, although the prior art washing machine has a transition zone of about 200˜270 rpm, the starting RPM of the transient zone of the washing machine according to the present embodiment may be similar to that of the conventional washing machine. The ending RPM of the transient region of the washing machine according to the present embodiment can be increased more than the RPM calculated by adding the starting RPM to the value of about 30% of the starting RPM. For example, the transient region ends at an RPM calculated from a value of approximately 80% of the starting RPM plus the starting RPM. According to this embodiment, the transient region may include an RPM band of approximately 200 rpm to 350 rpm.

At the same time, by reducing the vibration intensity of the drum, the unbalance can be reduced. To this end, before the rotational speed of the drum enters the transition zone, uniform laundry dispersion is performed in order to spread the laundry as much as possible in the drum.

In the case of using the balancer, a method may be considered in which the rotational speed of the drum passes through a transition zone while the movable body provided in the balancer is located on the opposite side of the unbalance of the laundry. In this case, it is preferred that the movable body is located directly opposite the unbalance in the middle of the transition zone.

However, as described above, the transient region of the washing machine according to the present embodiment is relatively wide compared with that of the conventional washing machine. Therefore, even if the uniform dispersion step or ball balancing of the laundry is performed in a lower RPM zone than the transient zone, the laundry may be messed up or the balancing may fail as the drum speed passes through the transient zone.

Therefore, balancing may be performed at least once in the washing machine according to the present embodiment before or while the drum speed passes through the transient region. Here, balancing may be defined as rotation of the drum at a constant speed for a predetermined period of time. This balance allows the relative position of the balancer's movable body to the garment, only to reduce the amount of unbalance. Relatedly, the effect of evenly dispersing the laundry. Finally, balancing is performed when the drum speed passes through the transient region, and noise and vibration due to the extension of the transient region are prevented.

Here, when the balancing is performed before the drum speed passes through the transient region, the balancing may be performed in an RPM band different from that of the conventional washing machine. For example, if the transient region begins at 200 RPM, balance is performed in the RPM band below about 150 RPM. Since conventional washing machines have a relatively not too wide transient region, it is not difficult for the drum speed to pass through the transient region even when balancing is performed at RPM below about 150 RPM. However, the washing machine according to the present embodiment has a relatively wide extended transient region as described above. If balancing is performed at a low RPM as in conventional washing machines, the position of these movable bodies may be disturbed by balancing performed with the drum passing through the transient region. Therefore, when the balancing is performed before the drum speed enters the transient region, the washing machine according to the present embodiment may increase the balancing RPM compared to the conventional balancing RPM. That is, if the start RPM of the transient region is determined, balancing is performed in a higher RPM band than the RPM calculated by subtracting a value of about 25% of the start RPM from the start RPM. For example, the initial RPM of the transient region is about 200 RPM, and balancing can be performed in the RPM band above 150 RPM and below 200 RPM.

In addition, the unbalance can be measured during balancing. That is, the control method may further include the step of measuring an unbalance amount during balancing, and comparing the measured unbalance amount with an allowable unbalance amount that allows acceleration of the drum speed. If the measured unbalance is less than the allowable unbalance, the drum speed is accelerated after balancing to be outside the transient region. In contrast, if the measured unbalanced amount is the allowable unbalanced amount or more, the clothes uniformly dispersing step may be performed again. In this case, the allowable unbalance amount may be different from the allowable unbalance amount that allows initial acceleration.

In addition, vibration characteristics of the washing machine according to the embodiment of the present invention will now be described with reference to FIG. 9 .

As the rotational speed of the drum increases, a region (hereinafter, referred to as a "transient vibration region") is generated where irregular transient vibrations with a high amplitude occur. Before the vibration is transmitted to the steady-state vibration region (hereinafter, referred to as "steady-state region"), the transient vibration region occurs irregularly with high amplitude, and if the (washing machine) vibration system is designed, the transient vibration region has Defined vibration characteristics. Although the transient vibration region differs according to the type of the washing machine, the transient vibration occurs approximately in the range of 200rpm to 270rpm. Transient vibrations are believed to be caused by resonance. Therefore, it is necessary to design the balancer by considering the effective balancing of the transient vibration region.

Meanwhile, as described above, in the washing machine according to the embodiment of the present invention, the vibration source, namely, the motor and the drum connected to the motor are connected to the tub 12 through the rear gasket 250 . Accordingly, vibrations generated in the drum are hardly transmitted to the tub, and the drum is supported by the damper and the suspension unit 180 via the bearing housing 400 . Therefore, the tub 12 may be directly fixed to the cabinet 110 without any damping means.

As a result of research by the inventors of the present invention, a vibration characteristic that is not generally observed has been found in the washing machine according to the present invention. According to a general washing machine, after a transient vibration, the vibration (displacement) becomes stable. However, in the washing machine according to the embodiment of the present invention, a region (hereinafter, referred to as "irregular vibration") may be generated in which the vibration stabilizes and becomes larger again after passing through the transient vibration region. . For example, if the maximum roller displacement or more produced in an RPM band below the transient region occurs, or the maximum roller displacement of a steady state step or more occurs in an RPM band above the transient region, then it is determined that Irregular vibration. Alternatively, if the average roller displacement in the transient region, +20% or -20% of the average roller displacement in the transient region, or 1/3 or more of the maximum roller displacement of the natural frequency of the transient region is produced, Then it can be confirmed that irregular vibration occurs.

However, as a result of research, irregular vibration occurs in the RPM band higher than the transient region, for example, in a region within the range of about 350 rpm to 1000 rpm (hereinafter, referred to as "irregular vibration region") . Irregular vibrations may result from the use of balancers, damping systems and rear pads. Therefore, in the washing machine, it is necessary to design the balancer by considering the irregular vibration region as well as the transient vibration region.

For example, if the balancer is provided with a ball balancer, it is preferable to select the structure of the balancer in consideration of the irregular vibration zone and the transient vibration zone, that is, the size (dimensions) of the balls, the number of balls, the size of the race (race, raceway) Shape, oil viscosity and oil filling level. The ball balancer has a large diameter of 255.8mm and a small diameter of 249.2mm when considering the transient vibration region and/or the irregular vibration region, especially when the irregular vibration region is considered. The space of the bearing ring containing the balls has a cross-sectional area of 411.93 mm ² . The number of front and rear balls is 14, respectively, and the size of the ball is 19.05mm. Silicone-based oils, such as polydimethylsiloxane (PDMS), are used as oils. Preferably, the oil has a viscosity of 300 CS at room temperature and a filling capacity of 350 cc.

In addition to the structure of the balancer, it is preferable to consider an irregular vibration region as well as a transient vibration region in view of control. For example, in order to prevent irregular vibration, if an irregular vibration region is determined, balancing may be performed at least once before, while, and after the drum speed passes through the irregular vibration region. Here, if the rotation speed of the drum is relatively high, the balancing of the balancer may be improperly performed, which may be performed while reducing the rotation speed of the drum. However, if the rotational speed of the drum is reduced below the transient region to perform balancing, the transient region must be passed again. During balancing by reducing the rotational speed of the drum, the reduced rotational speed may be higher than the transient region.

It will be apparent to those skilled in the art that various changes and modifications can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention that come within the scope of the appended claims and their equivalents.

Claims (15)

1. A control method for a washing machine, comprising: The water supply step is configured to drive the drum in a scrubbing action when water is supplied to the tub. 2. The control method according to claim 1, wherein at the same time as the water supply step is started, a circulation step configured to circulate the water in the tub to resupply the water to the tub is performed. 3. The control method as claimed in claim 1, wherein the washing machine includes a driving unit including a shaft connected to the drum, a bearing rotatably supporting the shaft, and a suspension assembly connected to the driving unit. and a motor to rotate the shaft. 4. The control method according to claim 1, wherein the washing machine includes a rear gasket for sealing to prevent wash water from leaking from a space between the driving unit and the tub and for making the driving A unit is movable relative to the tub. 5. The control method as claimed in claim 1, wherein the tub is more rigidly supported than the drum supported by the suspension assembly. 6. A control method for a washing machine, comprising: The washing cycle includes at least one water supply step configured to drive the drum for a predetermined period of time after starting to supply water to the tub, or after a water level reaches a predetermined value. 7. The control method as claimed in claim 6, wherein the tub and the drum provided in the washing machine respectively have rear portions inclined downward. 8. The control method as claimed in claim 6, wherein the tub and the drum provided in the washing machine respectively have rear portions inclined downward. 9. The control method as claimed in claim 8, wherein a circulation line configured to circulate water is connected to the front portion of the tub. 10. The control method according to claim 6, wherein a water supply line provided in the washing machine is connected to a front portion of the tub, and When the water supply valve is opened, the on time of the water supply valve is set to be shorter than the off time. 11. The control method according to claim 10, wherein the ON time is determined such that the water supplied via the water supply line has a pressure less than a predetermined water pressure. 12. The control method according to claim 11, wherein the ON time of the water supply valve is determined such that the water supplied via the water supply line has a predetermined water pressure high enough not to be directly supplied to the drum . 13. The control method as claimed in claim 1, wherein the washing machine includes a driving unit including a shaft connected to the drum, a bearing rotatably supporting the shaft, and a suspension assembly connected to the driving unit. seat and a motor to rotate the shaft. 14. The control method according to claim 6, wherein the washing machine includes a rear gasket for sealing to prevent wash water from leaking from a space between the driving unit and the tub, and for making the The driving unit is movable relative to the tub. 15. The control method as claimed in claim 6, wherein the tub is more rigidly supported than the drum supported by the suspension assembly.

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