KR101741549B1 - Laundry machine and method for controlling the same - Google Patents

Abstract

The present invention relates to a washing machine and a control method thereof. The present invention relates to a washing machine including a tub connected to a vibration source via a rear gasket, a ball balancer having a drum rotatably installed in the tub, and a ball, Wow; And a balancing step of balancing the balls by rotating the drum at a predetermined speed for a predetermined time based on the abnormal vibration region.

Washing machine, abnormal vibration

Description

[0001] The present invention relates to a laundry machine and method for controlling the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a washing machine and a control method thereof, and more particularly, to a washing machine and its control method capable of effectively coping with vibrations that may occur during operation of the washing machine.

Referring to FIG. 1, a conventional washing apparatus will be described as follows.

The washing machine 100 includes a cabinet 10 forming an outer appearance, a tub 20 provided in the cabinet 10 to receive washing water, and a drum 30 rotatably installed inside the tub 20 can do.

The cabinet 10 forms an appearance of the washing machine 100, and various components to be described later can be mounted on the cabinet 10. A door 12 is provided at the front of the cabinet 10 so that the user can open the door 12 and insert the object to be cleaned into the cabinet 10.

A tub 20 for receiving washing water is provided in the cabinet 10 and a drum 30 for receiving laundry to be washed is rotatably disposed inside the tub 20. In this case, a plurality of lifters 32 may be provided on the inner side of the drum 30 to draw the laundry to be lowered to the lower portion when the drum 30 rotates.

The tub 20 is supported by the upper spring 50. On the other hand, on the rear surface of the tub 20, a driving motor 40 for rotating the drum 30 is mounted. That is, the driving motor 40 is provided on the rear wall of the tub 20 to rotate the drum 30. Therefore, when the driving motor 40 rotates the drum 30 to generate vibration in the drum 30, the tub 20 also vibrates in conjunction with the drum 30. Vibrations generated in the drum 30 and the tub 20 when the drum 30 rotates are absorbed by the damper 60 and the upper spring 50 and the like.

Meanwhile, a ball balancer 70 may be provided on the front and / or rear surface of the drum 30 to compensate for the unbalance caused by the unevenness of the laundry when the drum rotates. The ball balancer 70 serves to compensate for unbalance during rotation of the drum, particularly during a spin-drying cycle in which the drum rotates at high speed, thereby suppressing the occurrence of vibration. Although the ball balancer 70 in theory compensates for unbalance, it is difficult to effectively perform this role in all operating states of the washing machine, so that the ball balancer 70, which allows the ball balancer 70 to function effectively, It is necessary to design and control.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a washing device having a ball balancer capable of effectively performing a function and a control method thereof.

In order to accomplish the above object, the present invention provides a washing machine including a ball balancer having a tub connected to a vibration source through a rear gasket, a drum rotatably installed in the tub, and a ball, Defining an abnormal vibration region of the vehicle; And a balancing step of balancing the balls by rotating the drum at a predetermined speed for a predetermined time based on the abnormal vibration region.

The balancing step is preferably performed before entering the abnormal vibration region. The balancing speed of the balancing step is preferably 350-400 rpm, more preferably 380 rpm.

The balancing step may be performed during the abnormal vibration region passage. In addition, the balancing step is preferably performed at at least one rotation speed between 400-1,000 rpm, and is more preferably performed at 600 rpm.

The balancing step may be performed after passing through the abnormal vibration region. And, the balancing speed of the balancing step is preferably selected in a speed range suitable for balancing. For example, it is preferable that the balancing step is performed at a speed of at least one of 200-800 rpm, and more preferably, the rotation speed of the drum is 380 rpm. In addition, it is preferable that the drum is operated at a constant speed for a predetermined time after passing through the abnormal vibration region.

The effects of the present invention described above are as follows.

According to the present invention, there is an advantage that the vibration can be effectively reduced even when the drum is rotating, particularly in an abnormal vibration region that can be generated during high-speed rotation.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, an embodiment of a washing machine to which the control method according to the present invention can be applied will be described, and then a control method will be described.

2 and 3, a washing machine according to a preferred embodiment of the present invention will now be described. FIG. 2 is a schematic view showing a coupling section of FIG. 3 for illustrating a coupling relationship of the washing machine according to the present embodiment.

The vibration generated in the vibration source such as the motor 170 and the drum 32 connected to the motor 170 is directly transmitted to the tub 12 in the washing machine according to the present embodiment, The tub 12 is connected to the vibration generating source through a vibration transmission blocking member or a rear gasket 250 capable of blocking and attenuating the vibration and the vibration generating source is buffered by the suspension unit 180, (Details will be described later).

The washing apparatus according to this embodiment will be described in detail.

In the washing machine 200, the tub 12 is fixedly supported by the cabinet 110. The tub 12 includes a tub front 100 constituting a front portion and a turbore 120 constituting a rear portion. The tub front 100 and the turbulator 120 are assembled by screws and form a space for accommodating the drum 32 therein. The turbine 120 has an opening at the rear. The inner circumference of the rear surface of the turbine 120 is connected to the outer circumference of the rear gasket 250. The inner circumference of the rear gasket 250 is connected to the turbobac 130. The turbobac 130 has a through hole formed at its center through which the rotating shaft passes. The rear gasket 250 is made of a flexible material so that the vibration of the turbobac 130 is not transmitted to the turbabar 120.

The turbine 120 has a rear surface 128. The rear surface 128, the turbobac 130 and the rear gasket 250 of the turbine 120 constitute the rear wall of the tub. The rear gasket 250 is connected to the turbobar 130 and the turber 120 so as to be sealed to prevent the washing water in the tub from leaking. The turbobac 130 is vibrated together with the drum when the drum rotates. At this time, the turbobac 130 is spaced apart from the turbulator 120 at a sufficient interval so as not to interfere with the turbulator 120. Since the rear gasket 250 is made of a flexible material, it allows the turbobac 130 to relatively move without interfering with the turber 120. The rear gasket 250 may have a pleated portion 252 that can be extended to a sufficient length to allow such relative movement of the turb back 130.

A foreign matter jam preventing member 200 for preventing foreign matter from entering between the tub 12 and the drum 32 is connected to the front portion of the tub front 100. [ The anti-jamming member 200 is made of a flexible material and fixed to the tub front 100. The foreign matter jam preventing member 200 may be made of the same material as the rear gasket 250. The foreign matter-preventing member 200 is referred to as a front gasket for convenience's sake.

The drum 32 is composed of a drum front 300, a drum center 320, a drum bag 340, and the like. Ball balancers 310 and 330 are installed on the front and rear portions of the drum 32, respectively. The drum bag 340 is connected to a spider 350 and the spider 350 is connected to a rotating shaft 351. The drum 32 is rotated in the tub 12 by the rotational force transmitted through the rotating shaft 351. [

The rotation shaft 351 is connected to the motor 170 directly through the tub back 130. Specifically, the rotor 172 of the motor 170 and the rotary shaft 351 are directly connected. The bearing housing 400 is coupled to the rear surface of the turbobac 130. The bearing housing 400 rotatably supports the rotary shaft 351 between the motor and the turbobac 130.

A stator 174 is fixed to the bearing housing 400. The rotor 172 is positioned so as to surround the stator 174. The rotor 172 is directly connected to the rotary shaft 351 as described above. The motor 170 is an outer rotor type motor and is directly connected to the rotary shaft 351.

The bearing housing 400 is supported from the cabinet base 600 through a suspension unit 180. The suspension unit 180 includes three vertical supports and two inclined supports that obliquely support the forward and backward directions.

The suspension unit 180 includes a first cylinder spring 520, a second cylinder spring 510, a third cylinder spring 500, a first cylinder damper (installed symmetrically on the opposite side of the second cylinder damper, (Not shown), and a second cylinder damper 530.

The first cylinder spring 520 is connected between the first suspension bracket 450 and the base 600. The second cylinder spring 510 is connected between the second suspension bracket 440 and the base 600. The third cylinder spring 500 is directly connected between the bearing housing 400 and the base 600. The first cylinder damper 540 is inclined between the first suspension bracket 450 and the rear portion of the base and the second cylinder damper 530 is inclined between the second suspension bracket 440 and the rear portion of the base. Is being installed. The bearing housing 400 and the suspension brackets 450 and 440 are connected by a first weight 431 and a second weight 430.

The cylinder springs in the suspension unit 180 may be connected to the cabinet base 600 in a completely fixed manner, and may be connected to allow a certain degree of elastic deformation so as to allow the drum to move back and forth and to the left and right. That is, it is elastically supported so as to allow a certain degree of rotation about its supporting point connected to the base. The vertical installation of the suspension unit 180 elastically buffers the vibration of the drum, and the inclined installation can be configured to attenuate the vibration. That is, in the vibration system including the spring and the damping means, the vertically installed part serves as a spring and the inclined part serves as a damping means.

As described above, the tub 12 is fixed to the cabinet 110, and the vibration of the drum 32 is buffered and supported by the suspension unit 180. The supporting structure of the tub 12 and the drum 32 may be substantially separated from each other and the tub 12 may not be vibrated even when the drum 32 vibrates. That is, the vibration generated in the turbobac 130 generated by the driving motor 170 is not transmitted to the tub 12 by the rear gasket 250. That is, in the washing apparatus according to the present embodiment, when the vibration occurs due to the rotation of the motor 170 and the drum 32, the tub 12 does not vibrate in conjunction with the drum 32. Therefore, the tub 12 according to the present embodiment can be directly coupled to the cabinet 110 without the damping means. The tub 12 may be secured to the interior of the cabinet 110 by a separate assembly (e.g., screw threads, bolts, etc.). As described above, in the present embodiment, since the vibration of the tub 12 is substantially eliminated, the tub 12 can be directly connected to the cabinet 110, and the space between the tub 12 and the cabinet 110 can be minimized Therefore, there is an advantage that the size of the drum 32 can be increased when the size of the same cabinet 110 is used.

On the other hand, when the laundry is accommodated in the drum 32 and the drum 32 rotates in the washing machine, there is a possibility that the vibration is largely generated according to the distribution of the laundry. For example, when the drum 32 rotates in an unbalanced state in which the laundry is not evenly distributed in the drum 32, vibrations may occur particularly. In particular, vibration may be more problematic when the drum 32 is accelerated at a high speed for dehydration.

Accordingly, the washing machine may include ball balancers 310 and 330 to compensate for unbalance when the drum 32 rotates. The ball balancers 310 and 330 may be provided on the front side and / or the rear side of the drum 32.

The structure of the ball balancers 310 and 330 will be described in detail.

The ball balancer 310 includes a race 312a, a ball 312 that is freely received in the race, and oil that is filled in the race 312a to control movement of the ball. The ball is generally made of steel, and silicone oil is generally used.

The operation principle of the ball balancer is as follows.

The unbalanced eccentric structure of the drum 32 itself and the biased distribution of the laundry in the drum 32 can rotate the drum 32 without maintaining dynamic balance. At this time, the ball 312 compensates the dynamic unbalance UB, so that the drum can maintain a dynamic balance. That is, when dynamic unbalance occurs in the drum 32, the ball 312 moves to a position symmetrical to the place where the dynamic unbalance occurs, thereby compensating for the unbalance of the drum 32. [

However, for all rotational speeds of the drum 32, it is practically difficult for the ball 312 to be automatically positioned in the opposite direction of unbalance (hereinafter "ballbalanced") to compensate for the dynamic imbalance. This is because, at a certain rotational speed, there is a difference between the rotational speed of the drum 32 and the rotational speed of the ball 312, and this difference makes it difficult for the ball 312 to reach the balancing position.

In addition, in a section where the rotational speed of the drum increases, the position of the ball 312 may change and ball balancing may not be performed. This phenomenon may occur even after the balls 312 are balanced. As the balls 312 are individually distributed and the closer to 90 degrees the unbalance position is, the greater the vibration of the drum 32, the more likely the ball balancing becomes unstable. Accordingly, in order to effectively balance the ball, the size and number of the balls 312, the shape of the race 312a, the viscosity of the oil, and the filling degree of the oil should be selected in consideration of the vibration characteristics of the washing machine.

As described above, since the design of the ball balancer is closely related to the vibration characteristics of the washing machine, the vibration characteristics of the washing machine according to the present embodiment will be described first with reference to FIG.

As the rotational speed of the drum increases, a region in which amplitude is large and irregular transient vibration occurs (hereinafter referred to as "transient vibration region") appears. The transient vibration region is an irregular and large amplitude vibration that appears before becoming a steady-state vibration (hereinafter referred to as "stable region") of vibration, and is a vibration characteristic usually determined when a vibration system (washing machine) is designed. In the washing machine according to the present embodiment, transient vibration appears at approximately 200-350 rpm, which is considered to be a fundamental vibration due to resonance. Therefore, it is necessary to design a ball balancer considering effective ball balancing in the transient vibration region.

As described above, in the washing machine according to the embodiment of the present invention, a motor, which is a vibration source, and a drum connected to the motor are connected through the tub 12 and the rear gasket 250. Accordingly, the vibration generated in the drum is hardly transmitted to the tub, and the drum is supported by the suspension housing 180, which is the buffer support means (damping means), via the bearing housing 400). Therefore, it is possible to directly fix the tub 12 to the cabinet 110 without damping means (see Fig. 2).

As a result of the study by the present inventor, vibration characteristics not generally observed in such a washing machine have been found. In general washing machines, vibration (displacement) is reduced and stabilized when passing through the transient vibration region. However, in the washing machine according to the present embodiment, the vibration is stabilized after passing through the transient vibration region, Irregular vibration ") occurs in some cases. As a result of the study, the abnormal vibration occurred in the region of about 400-1,000 rpm (hereinafter referred to as "abnormal vibration region"). The abnormal vibration is thought to be caused by the use of a ball balancer, a shock absorber (damping system), and a rear gasket. Therefore, in such a washing machine, it is necessary to design a ball balancer considering not only the transient vibration region but also the abnormal vibration region. That is, it is preferable to select the structure of the ball balancer not only in the transient vibration region but also in the abnormal vibration region, that is, the size and number of balls, the shape of the race, the viscosity of the oil, Considering the transient vibration region and / or the abnormal vibration region, particularly the abnormal vibration region, the diameter of the ball balancer is 255.8 mm in diameter and 249.2 mm in the small diameter, the cross-sectional area of the space in which the ball is accommodated in the racer is 411.93 mm 2, 14 in front and 14 in front and 19.05 mm in size. The oil was silicone oil-based PDMS (Poly Dimethylsiloxane). The viscosity of the oil was preferably 300 CS at room temperature and 350 cc of oil filling.

In addition to the structure of the ball balancer, it is preferable to consider not only the transient vibration region but also the abnormal vibration region in terms of control.

The control method of the washing machine according to the present embodiment will be described with reference to Figs. 5 to 7. Fig. In general, when washing is performed by a washing machine, the washing, rinsing and dewatering steps are included. In this embodiment, a dehydration stroke which is likely to cause abnormal vibration due to high-speed rotation of the drum will be mainly described.

FIG. 5 is a graph showing an embodiment of a control method of the washing apparatus according to the present invention, and is a graph showing a change in rotational speed of the drum with time. The horizontal axis represents time, and the vertical axis represents the target rotational speed of the drum, RPM.

For reference, before describing the control method for reducing the occurrence of abnormal vibration, the dehydration stroke will be schematically described. The dewatering process largely includes a bubble dispersion step (S100) and a dewatering step (S200). In the dewatering step (S200), the rotational speed of the drum is increased at a relatively high speed to substantially remove the moisture of the laundry (step S100) . However, such a bubble dispersion step and a dehydration step are distinguished for convenience in terms of their main function, and the function in each step is not limited to the name. For example, moisture can be removed from the laundry (cloth) by the rotation of the drum as well as the cloth dispersing even in the cloth dispersing step.

The deodorizing step S100 may include a dampening sensing step S110, a pruning step S130 and an unbalance sensing step S150, and the dewatering step S200 may include substantially dehydrating the dewatering step (S260), and an actual acceleration step (S250) for reaching the main body step S260. Here, the step of acceleration (S250) means to have the function of accelerating with the aim of the main-step (S260), and does not mean that it continues to accelerate without deceleration or constant speed. That is, the accelerating step (S250) includes the deceleration and the constant speed steps, but ultimately accelerating.

First, the bubble dispersion step (S100) will be described in detail as follows.

When the rinse cycle is finished, the bubble in the drum becomes wet by moisture. When starting the dewatering process, the control unit first senses the amount of the laundry in the drum, that is, the amount of the applied water (S110). The reason for sensing the amount of the papermaking is that the amount of the water-containing papermill is different from the weight of the dry papermill in the early stage of the washing cycle. The sensed amount of the wet cloth may be used as a factor for determining the allowable condition for accelerating the drum in the dehydrating step S200 or for determining the rotational speed Tf-RPM of the drum in the tapping step S260.

Detection of the amount of the fume is performed by accelerating the drum at a predetermined speed (A-RPM) to about 108 RPM, and then decelerating the drum by the power generation braking, which is widely known. After sensing the amount of the wet cloth, the control unit performs the unwrapping step to disperse the cloth inside the drum (S130). The deburring step is to disperse the blanks evenly inside the drum so that the blanks are concentrated in a specific area to prevent the unbalance amount of the drum from being increased. This is because when the unbalance amount is increased, the vibration increases when the rotational speed of the drum is increased. Then, an unbalance amount is sensed (S150). If the balls in the drum are not dispersed evenly and are concentrated in a predetermined area, the amount of unbalance becomes large, which may cause vibration when the rotational speed of the drum is increased later. Accordingly, the unbalance amount of the drum is sensed to determine whether the drum is accelerated or not. Unbalance detection uses the difference in acceleration when the drum is rotating. That is, according to the degree of unbalance, when the drum rotates, there is a difference in acceleration when the drum rotates downward or when it rotates upward. The control unit measures the unbalance amount by measuring the acceleration difference using a speed sensor such as a hall sensor provided in the driving motor. Therefore, in the case of detecting unbalance, even if the drum rotates, the drum inside the drum must remain attached to the inner wall of the drum without falling off, and the drum rotates at about 108 RPM.

The dehydration step (S200) will be described in detail as follows.

As described above, the dewatering step S200 can be roughly classified into a dipping step S260 for performing dewatering at a predetermined speed Tf-RPM and an acceleration step S250 for reaching the dipping step S260 have. It is necessary to pass the transient vibration region R1 and the abnormal vibration region R2 in order to reach the main phase phase, i.e., the main deafness Tf-RPM. As described above, the transient vibration region R1 is an inherent vibration characteristic determined according to the structure of the washing machine, and is approximately 200-350 RPM. According to the study by the inventor of the present invention, the abnormal vibration region R2 is considered to be the unique vibration characteristic of the present embodiment. Although the abnormal vibration does not always occur, the possibility of occurrence of the abnormal vibration is relatively large and abnormal vibration occurs at about 400-1,000 RPM Respectively.

When the rotational speed of the drum 130 passes the transient vibration region R1 and the abnormal vibration region R2, vibration occurs largely and irregularly in the washing apparatus. Therefore, it is desirable to suitably control the rotation of the drum in order to effectively pass the transient vibration region R1 and the abnormal vibration region R2. Since there are many proposals for the transient vibration region R1, a control method for the abnormal vibration region R2 will be mainly described here.

In the present embodiment, the abnormal vibration region determining step of determining the abnormal vibration region R2 of the washing machine, the step of rotating the drum at a predetermined balancing speed for a predetermined time based on the determined abnormal vibration region R2, Balancing " to < / RTI > balance the ball to be positioned opposite the unbalance.

The balancing step is preferably performed at least once before entering the abnormal vibration region R2, during passage through the abnormal vibration region R2, and after passing through the abnormal vibration region R2. This is because there is a high possibility that abnormal vibration occurs in the abnormal vibration region R2, and the balls that have been balanced are likely to deviate from the balancing position. If the ball is not in the opposite position of unbalance, the ball becomes rather unbalanced, and the vibration due to unbalance can become larger. Therefore, if balancing is performed at least once before entering the abnormal vibration region R2, during passage through the region, and after passing through, it is possible to reduce the vibration of the washing machine due to the possible abnormal vibration. In addition, if balancing is performed at least once before entering the abnormal vibration region R2, passing through the region, and passing through, water is released from the laundry as the dehydration step proceeds, and unbalance caused by difference in quantity of laundry is also compensated There is also the advantage of being able to do.

Each case will be described in detail as follows.

First, balancing (first balancing) before entering the abnormal vibration region R2 will be described.

It is preferable to maintain the drum at the predetermined balancing speed B1-RPM (hereinafter referred to as "first balancing speed") for a predetermined time t1 before entering the abnormal vibration region R2. With this configuration, since the ball can be relatively accurately positioned opposite to the unbalance once before the abnormal vibration region R2 enters, it is possible to compensate for the unbalance relatively accurately and to prevent the abnormal vibration that can occur. In addition, even if the ball deviates from the compensation position during the passage of the abnormal vibration region, it is possible to reduce the occurrence of vibration less than before balancing before entering.

The first balancing rate (B1-RPM) is preferably selected such that the ball can be effectively balanced in the ball balancer structure. The ball is not effectively balanced at the rotational speed of all the drums, and if the rotational speed of the drum is too small or too large, the balancing effect is degraded. According to the study by the present inventor, the ball was effectively balanced when the rotation speed of the drum was approximately 200-800 RPM, and the lower the speed, the more effective the constant speed.

Therefore, it is preferable to select one of the first balancing speed (B1-RPM) of 200-800 RPM. It is preferable to select one of the first balancing speed (B1-RPM) from 200 to 800 RPM, and to select the speed after passing the transient vibration region (R1). This is because, if the first balancing speed (B1-RPM) is set to the speed of the transient vibration region, there is a fear that the ball is separated from the balancing position by the transient vibration.

As a result, if the abnormal vibration region R2 is approximately 400-1,000 RPM and the transient vibration region R1 is approximately 200-350 RPM, the first balancing speed B1-RPM is preferably selected to be approximately 350-400 RPM Do. As a result of the study by the present inventors, it was preferable that the first balancing speed was 380 rpm. And maintaining the first balancing speed (B1-RPM) is preferably about 30-60 seconds.

Next, balancing (second balancing) during the passage of the abnormal vibration region R2 will be described.

It is preferable to maintain the drum at least once at the predetermined balancing speed (B2-RPM) (hereinafter referred to as "second balancing speed") for a predetermined time t2 in the abnormal vibration region R2. This is because there is a high possibility that abnormal vibration occurs in the abnormal vibration region R2, and accordingly, the ball may deviate from the balancing position while passing through the abnormal vibration region R2. Therefore, it is preferable to perform balancing once again during the passage of the abnormal vibration region R2 to accurately position the ball at the opposite position of unbalance.

The second balancing speed (B2-RPM) is also preferably selected such that the ball can be effectively balanced (200-800 RPM) on the ball balancer structure. Accordingly, if the abnormal vibration region R2 is approximately 400-1,000 RPM, it is preferable to select the second balancing speed (B2-RPM) approximately 400-800 RPM. As a result of the study by the present inventors, it was preferable that the second balancing speed (B2-RPM) was about midway of the abnormal vibration region R2, for example, 600 RPM.

Next, the balancing (third balancing) after passing through the abnormal vibration region R2 will be described with reference to Fig.

In the present embodiment, the drum is maintained at the predetermined balancing speed (B3-RPM) (hereinafter referred to as "third balancing speed") for a predetermined time t3 after passing through the abnormal vibration region R2. This is because there is a high possibility that an abnormal vibration occurs in the abnormal vibration region R2 and therefore the ball that was balanced during the passage of the abnormal vibration region R2 is disturbed and the ball may have deviated from the balancing position after passing through the abnormal vibration region R2 This is because. In other words, balancing once again after passing through the abnormal vibration region R2 reduces the vibration by compensating for the unbalance at the time of acceleration with the present deafness (Tf-RPM) or at the normal deafness (Tf-RPM) It is because.

The third balancing speed B3-RPM can be selected at a rotational speed greater than a specific speed, that is, the abnormal vibration range R2 after passing through the abnormal vibration region R2, but balancing of the ball may not be effective in this case. Therefore, it is desirable to select the third balancing speed (B3-RPM) at a speed (200-800 RPM) at which the ball can be effectively balanced on the structure of the ball balancer. Therefore, if the abnormal vibration region R2 is approximately 400-1,000 RPM, it is preferable to select the third balancing speed (B3-RPM) between approximately 400-800 RPM. That is, it is preferable to decelerate at the third balancing speed (B3-RPM) for acceleration after balancing after passing through the abnormal vibration region R2, and then accelerate again to reach the fundamental deformation rate (Tf-RPM).

Of course, in this case, the rotational speed of the drum is again passed through the abnormal vibration region R2, but according to the study of the present inventor, it is more effective than the third balancing in terms of vibration reduction. The reason for this is that abnormal vibration does not always occur, and water is dehydrated by the dehydration process to reduce the weight of the laundry itself and reduce the unbalance. Therefore, if the laundry is decelerated after being passed through the abnormal vibration region R2, Is likely to occur.

Also, for the third balancing, if the deceleration is decelerated by the third balancing speed (B3-RPM) and then accelerated again to reach the degenerate speed (Tf-RPM), the time of the step S260 may be reduced. This is because dehydration is performed even when the target moisture content of the laundry is determined, and then the process is accelerated again after decelerating to the third balancing speed (B3-RPM), thereby reducing the time of the step S260. However, as the rotational speed of the drum is higher, vibration is a problem, and the time of the bite step (S260), which is the highest rotational speed, can be reduced, thereby reducing the occurrence of vibration. That is, as a result of the study, since the vibration in the bite-in step S260 may be more problematic than the vibration that may occur again after passing through the abnormal vibration area after the third balancing, the third balancing is more effective in preventing vibration.

On the other hand, as a result of research conducted by the inventor of the present invention, it is preferable that the third balancing speed (B3-RPM) is less than 350 RPM so that the third balancing speed is lower. More preferably, the third balancing speed (B3-RPM) is preferably equal to the first balancing speed (B1-RPM), i.e., 380 rpm. That is, it is preferable to decelerate the drum speed after passing through the abnormal vibration region (Tm-RPM) to the first balancing speed (B1-RPM) to hold it for a predetermined time and then accelerate the deaccess rate (Tf-RPM) .

On the other hand, as shown in FIG. 7, the constant speed operation for a predetermined time t4 at a predetermined speed (Tm-RPM) without immediately decelerating to the third balancing speed (B3-RPM) It is possible. In this way, since the water content of the laundry can be further reduced at a constant speed (T4-RPM) for a predetermined period of time (t4), the rotation time of the drum in the highest deafness (Tf-RPM) , There is an advantage that vibration due to high-speed rotation can be reduced.

1 is a sectional view showing a general washing machine

2 is a cross-sectional view showing an embodiment of the washing machine according to the present invention

Fig. 3 is an exploded perspective view of Fig.

Fig. 4 is a graph showing the vibration characteristics of the washing machine of Fig. 2

5 is a graph showing an embodiment of the control method of the washing machine according to the present invention

6 is a graph showing another embodiment of the control method of the washing machine according to the present invention

7 is a graph showing still another embodiment of the control method of the washing machine according to the present invention

DESCRIPTION OF THE REFERENCE SYMBOLS

110: cabinet 12: tub

32: drum 310: front ball balancer

330: rear ball balancer

Claims (13)

A tub for storing washing water, a drum rotatably installed in the tub, and a ball balancer for relieving a dynamic imbalance of the drum, wherein a large amplitude and an irregular vibration are generated as the rotational speed of the drum increases A washing machine having a transient vibration area and an abnormal vibration area in which an amplitude is large and an irregular vibration is generated again in a region where the rotational speed of the drum is higher than the transient vibration area, An acceleration step of increasing the rotational speed of the drum to pass the transient vibration area; And And a balancing step performed after the acceleration step and rotating the drum at a constant speed for a predetermined time to eliminate the dynamic imbalance of the drum, Wherein a speed at which the drum rotates in the balancing step is faster than a speed at which the drum rotates in the acceleration step. The method according to claim 1, further comprising a second acceleration step performed after the acceleration step and increasing a rotation speed of the drum to pass through the abnormal vibration area. 3. The method according to claim 2, wherein the balancing step is performed before the second acceleration step. 4. The method according to claim 3, wherein the balancing step rotates the drum at a speed of 350 rpm to 400 rpm. 5. The method according to claim 4, wherein the balancing step rotates the drum at a speed of 380 rpm. 3. The method of claim 2, wherein the balancing step is performed during the second acceleration step. The method according to claim 6, wherein the balancing step rotates the drum at a speed of 400 rpm to 1,000 rpm. 8. The method of claim 7, wherein the balancing step rotates the drum at a speed of 600 rpm. delete 3. The method according to claim 2, wherein the balancing step is performed after the second acceleration step. 11. The method according to claim 10, wherein the balancing step rotates the drum at a speed of 200 rpm to 800 rpm. 12. The method according to claim 11, wherein the balancing step rotates the drum at a speed of 380 rpm. 11. The method according to claim 10, further comprising a deceleration step performed between the second acceleration step and the balancing step, wherein the deceleration step decreases the rotation speed of the drum.

Images