JP4528165B2 - Small washing machine with vibration - Google Patents

Description

  The present invention relates to a washing machine having a rotary dewatering tub inside, and more particularly to a washing machine with low vibration.

In a washing machine having a rotary dewatering tub inside such as a washing machine, there is a problem of minimizing the vibration of the dehydration tub and the washing machine generated as the motor rotates. . As a method for reducing the vibration of the washing machine, for example, in Patent Document 1, the washing leg of the washing machine is improved and the vibration frequency of the washing machine is changed by increasing the rigidity in the vicinity of the stationary leg, thereby reducing the resonance vibration. A way to reduce is shown. Patent Document 2 proposes a washing machine in which a damping structure member constituted by an annular weight and an elastic body imparting elasticity around the weight is arranged on the upper or bottom surface of the tub. Patent Document 3 proposes a washing machine in which water is injected into an outer shell portion of a water tank having a double structure to form a liquid balancer.
Patent Document 4 includes a piston that is attached to a tank having a dehydrating tank inside and vibrates with the tank, and a housing that is attached to a housing that houses the tank, and a viscous body is provided between the piston and the housing. A washing machine that has been filled to form a vibration isolator has been proposed.
Further, Patent Documents 5 to 8 describe a laundry which is provided with a coil spring or a damper body on a support body that suspends and supports a tub (including a dewatering tub or a washing tub) including a rotation mechanism on a housing. Various improvements have been proposed for vibration isolation devices.
JP 2004-154537 A JP-A-11-267393 JP 2001-259285 A JP-A-9-276585 JP-A-6-15091 JP 2000-197488 A JP 2000-342891 A JP 2002-113283 A

According to the method of Patent Document 1, vibrations that depend mainly on the rigidity of the fixed legs, such as jumping and movement due to vibrations of the washing machine, can be reduced, but the vibration frequency of the entire washing machine cannot be changed greatly. The total vibration continuously generated during driving and the noise accompanying it cannot be sufficiently reduced.
In the methods of Patent Documents 2 and 3, although the vibration of the washing tub and the dewatering tub itself can be reduced to some extent, the vibration of the washing machine as a whole cannot be sufficiently reduced.
In addition, all of the methods proposed in Patent Documents 4 to 8 exhibit a corresponding vibration reduction effect, but if the structure of the washing machine changes, detailed design must be performed each time. Therefore, finding the optimal form is not easy.
As described above, each of the means proposed so far has a certain vibration reduction effect, but there is no means that can completely prevent the washing tub and the dehydration tub itself from vibrating all over the washing machine. There is a need for a method of suppressing vibrations by combining these means.
In recent years, in order to more efficiently transport and install the washing machine, it has been required to reduce the weight of the washing machine itself. For example, the thickness of the steel plate is reduced to reduce the weight of the housing. The washing machine itself tends to vibrate.
An object of the present invention is to provide a washing machine having a small vibration as a whole washing machine, in particular, a small vibration during dehydration.

The present invention has been made to solve the above-described problems, and the gist thereof is as follows.
(1) In a washing machine having a washing tub including a dewatering tub , a stirring blade, a rotation driving device for rotating the stirring wing and / or the dewatering tub, and a housing for storing them, the washing machine has its own characteristics per second. When the vibration frequency is F1 and the rotational speed per second during dehydration of the rotary drive device is F2 , washing water is supplied to at least a pocket and / or a water supply passage provided at the top of the housing to form a weight, and F1 / A washing machine with low vibration, characterized by setting the natural frequency of the washing machine and / or the rotational speed of the rotary drive so that F2 ≦ 0.85.

According to the present invention, the ratio of the number of rotations per second during the dehydration of the rotary drive device having a natural frequency F ₁ per second as a whole washing machine to F ₂ , and F ₁ / F ₂ is 0.85 or less. As described above, by setting the natural frequency of the washing machine and / or the rotation speed of the rotary drive device, the vibration amplitude of the washing machine itself can be reduced to 1.0 mm or less, and vibrations to the surroundings by the washing machine can be reduced. , Noise can be reduced.
Preferably, the vibration amplitude can be reduced by a simple means by adjusting the natural frequency of the washing machine by providing a weight in a part of the housing.
Further, by using water as the weight, or by using water supplied as washing water to the water, the natural frequency of the washing machine can be easily adjusted by simpler means. The vibration amplitude can be reduced.
By using water as a weight, it is sufficient to supply water at the time when the weight is needed, that is, at least during washing and dehydration, and water can be drained at other times. Weight reduction can be achieved.

  The present inventors examined a method for reducing vibration during washing of a washing machine in which vibration is a problem. Among them, the vibration amplitude of the washing machine as a whole depends on the rotational drive device that rotates the dewatering tub, that is, the rotation speed of the motor and the natural frequency of the washing machine. The relationship with the overall amplitude was investigated.

FIG. 1 is a schematic cross-sectional view showing a configuration of a general washing machine 1, a washing tub 2 having a dewatering tub 3 inside, a stirring wing 4, a stirring wing, and a motor as a rotational drive device for rotating the dewatering tub. 5 and a transmission / switching mechanism 6, which are supported in a suspended manner in a housing 9 via a suspension bar 8 provided with a vibration isolator 7 as a unit.
The bottom 2a of the washing tub 2 is provided with a mechanism 10 for transmitting and switching the rotation of the motor to the stirring blade and the dewatering tub, a belt 13 and pulleys 11 and 12, etc., and a transmission / switching mechanism 6.
The rotation of the motor 5 attached to the bottom 2 a of the washing tub 2 is transmitted to the second pulley 12 of the mechanism unit 10 via the first pulley 11 and the belt 13.
The rotation of the second pulley is transmitted to the rotating shaft 14 of the stirring blade, and the stirring blade 4 provided at the tip of the second pulley rotates to stir and wash the laundry in the washing tub. Next, after draining the inside of the washing tub, the rotation of the second pulley is switched to the rotating shaft 15 of the dehydrating tub 3 by the mechanism unit 10 and the dehydrating tub rotates to dehydrate the laundry. As described above, the vibration of the washing machine is increased during the dehydrating rotation of the dewatering tank, and noise is generated.

As a general method for evaluating the operation status of a washing machine during dewatering, the inventors eccentrically load and fix a weight of 1 kg in the washing machine's dewatering tank, rotate the motor, and rotate the motor. Therefore, the operating state during dehydration was assumed. That is, it is for reproducing the eccentric state that normally occurs during dehydration and evaluating the vibration (amplitude) of the washing machine in this state. In this case, the total weight of the washing machine is 40 to 41 kg, and the rotational speed of the motor is 880 revolutions per minute (14.67 revolutions / second).
Further, a weight was further placed on the upper part of the casing of the washing machine to change the total weight of the washing machine, and the dehydration tank was rotated in the same manner, and the vibration history at that time was investigated.

Here, FIG. 4 is a perspective view showing an outline of the structure of the housing part, omitting the internal structure of the washing machine. As shown in FIG. 4, acceleration pickups A to D are provided at two locations on the upper and lower sides of the washing machine, respectively, and the overall vibration is obtained using the acceleration obtained by the pickups A and C. It was measured.
The obtained vibration history is shown in FIG.

FIG. 2 shows the vibration of the washing machine as a whole when the weight of the washing machine is changed to rotate the dewatering tub by changing the weight of the washing machine to change the natural frequency of the washing machine as a whole. A history, that is, a displacement history is shown. In the case of this washing machine, the thickness t of the steel sheet constituting the housing is 0.5 mm, and the weight without a weight is 39 kg.
As shown in FIG. 4, the vertical axis in FIG. 2 indicates the vibration history in the front-rear direction of the washing machine, and the horizontal axis indicates the vibration history in the left-right direction of the washing machine. (A) shows a case where no weight is placed, and the natural frequency F ₁ of the washing machine is 12.83 r / s, and the motor rotation speed F ₂ is constant at 14.67 r / s. The ratio F ₁ / F ₂ of the natural frequency F ₁ of the washing machine to the rotational speed F ₂ of the motor is 12.45. (B) shows a case where a weight having a mass of 1.0 kg is placed. At this time, the natural frequency F ₁ is 12.45 r / s, and F ₁ / F ₂ is 0.849. (C) is a case where a weight having a mass of 3.0 kg is placed, the natural frequency F ₁ is 11.35 r / s, and F ₁ / F ₂ is 0.774. Further, (d) is a case where a weight with a mass of 5.0 kg is placed, the natural frequency F ₁ is 10.99 r / s, and F ₁ / F ₂ is 0.749.

As can be seen from FIGS. 2A to 2D, it can be seen that the vibration decreases as F ₁ / F ₂ decreases. In other words, it can be seen that the amplitude of the entire washing machine decreases as the weight of the weight placed on the washing machine increases.
Generally, when the amplitude of vibration (corresponding to the diameter of the ellipse in FIG. 2) exceeds 1.0 mm, it is felt that the noise during use is intense, but as can be seen in FIGS. 2 (b) to 2 (d). When F ₁ / F ₂ is 0.85 or less, the amplitude is 1.0 mm or less, and the problem of noise due to vibration can be solved. Therefore, in the present invention, F ₁ / F ₂ is set to be 0.85 or less.

  Further, FIG. 3 shows a washing machine when the weight of the washing machine is changed by placing a weight on the upper part of the casing of the washing machine as in the case of FIG. 2, and the natural frequency of the whole washing machine is changed. The overall vibration history is shown, but in the case of FIG. 3, the thickness t of the steel sheet constituting the casing of the washing machine is 0.6 mm, and the weight without a weight is 40 kg. It is. This is an example in which the weight and rigidity of the washing machine are increased compared to the case of FIG.

3, the vertical axis represents the vibration history in the front-rear direction of the washing machine, and the horizontal axis represents the vibration history in the left-right direction of the washing machine. (A) shows the case where no weight is placed, the natural frequency F ₁ of the washing machine is 13.08 r / s, and the motor rotation speed F ₂ is 14.67 r / s as in FIG. Since s is constant, the ratio F ₁ / F ₂ of the natural frequency F ₁ of the washing machine to the rotation speed F ₂ of the motor is 0.892. (B) shows a case where a weight having a mass of 1.0 kg is placed, and the natural frequency F _{1 at} this time is 12.47 r / s, and F ₁ / F ₂ is 0.850. (C) is a case where a weight with a mass of 3.0 kg is placed, the natural frequency F ₁ is 11.59 r / s, and F ₁ / F ₂ is 0.790. Further, (d) is a case where a weight with a mass of 5.0 kg is placed, the natural frequency F ₁ is 11.16 r / s, and F ₁ / F ₂ is 0.761.

As can be seen from FIGS. 3A to 3D, as in the case of FIG. 2, it can be seen that the vibration decreases as F ₁ / F ₂ decreases. In other words, as the weight of the weight placed on the washing machine increases, the amplitude of the washing machine as a whole decreases, and as shown in FIGS. 3B to 3D, when F ₁ / F ₂ is 0.85 or less. The amplitude becomes 1.0 mm or less, and the problem of noise due to vibration can be solved.
Thus, even when the weight and rigidity of the washing machine are changed, it is understood that the vibration and noise of the washing machine can be reduced by setting F ₁ / F ₂ to be 0.85 or less. .

Incidentally, the natural frequency Fi (r / S) of the washing machine is expressed by the following equation.
Fi = 1 / T = (k / m) ^1/2 / 2π
Here, T: natural period (s) of the washing machine, k: rigidity (kg / mm), m: mass (kg · s ² / mm).
From this equation, it can be seen that the natural frequency of the washing machine decreases as the mass of the washing machine increases or the rigidity decreases, for example, as the thickness of the casing decreases.
Since the rigidity of the washing machine cannot be obtained by calculation, the natural frequency of the washing machine was directly obtained by the following method. That is, as shown in FIG. 4, acceleration pickups A to D are provided at two locations on the upper and lower sides of the back and one side of the washing machine, hit X is applied from the X direction, and the acceleration-time history obtained at this time is recorded. FFT analysis was performed to obtain an acceleration Fourier spectrum (hereinafter referred to as a spectrum).

FIG. 5 shows a spectrum (relationship between frequency and amplitude) in a state where no weight is placed on the casing of the washing machine (note that the weight is not loaded and fixed in the dewatering tank). a) shows the entire frequency, and (b) shows an enlarged range of 0 to 20 r / s of (a). The vertical axis in FIG. 4 represents the amplitude, and the horizontal axis represents the frequency. The frequency when the extreme value of the amplitude appears has a meaning.
The frequency at which extreme values appear in common in the four spectra obtained by the pickups A to D is the natural frequency (indicated by Fi in FIG. 5B).
In this way, the natural frequency of the washing machine can be grasped.
When measuring the natural frequency of the washing machine, it is not necessary to load and fix a weight in the dehydrating tub (washing machine), but 1 kg in the dehydrating tub (washing machine) as in the vibration history survey. The weight may be inserted and fixed, and measurement may be performed in a state where the actual usage situation is reproduced.

By the way, depending on the structural specifications of the washing machine model, the washing machine, for example, the tank, the casing, the specifications of the motor, the output, etc. are primarily designed, but on the other hand, the natural frequency F ₁ is set as described above. By measuring and adjusting the mass (weight) balance etc. of the entire washing machine so that the relationship with the motor rotation speed F ₂ is the above relational expression F ₁ / F ₂ ≦ 0.85, Can provide a small washing machine.

Moreover, if the natural vibration of the finally designed and manufactured washing machine is measured by the same method as described above and the mass (weight) of the washing machine is measured, the rigidity k of the model is obtained from the above relationship. Therefore, the natural frequency can be changed by adjusting the mass (weight) balance of the washing machine. Therefore, this makes it possible to adjust and set F ₁ / F ₂ ≦ 0.85.

In the final design, in order to obtain a predetermined F ₁ / F ₂ value for the motor rotation speed F ₂ , for example, the thickness of the steel plate constituting the casing of the washing machine is reduced to reduce the rigidity. The natural frequency F ₁ is increased by increasing the weight of other members such as a washing tub, a dewatering tub, and a motor, or by attaching a weight to the washing machine as a simple method. One method is also considered.

Further, as a means for reducing the rigidity k, it is conceivable to raise the center of gravity of the washing machine with the weight as high as possible. That is, in the equation Fi = 1 / T = (k / m) ^1/2 / 2π, k is considered to be greatly influenced by the characteristics of the portion below the weight, and the position of the weight is increased. As k can be reduced, a large effect can be obtained with a small weight. Therefore, the weight is preferably provided in the range of the upper position of the casing of the washing machine, for example, from the upper end of the casing of the washing machine to a position that is 1/3 the height of the washing machine.

However, there is a limit in reducing the rigidity of the washing machine from the viewpoint of strength, and when the weight of the washing machine is increased by increasing the weight of the washing machine, the weight of the washing machine itself is fixedly increased. Inefficiency in transportation and installation of the washing machine.
In order to improve this point, the inventors have studied a method for adjusting the natural frequency of the washing machine more efficiently, and as a result, have come up with the idea of using water as the weight of the washing machine.
Hereinafter, embodiments of the present invention will be described with reference to the drawings of the examples.

FIG. 6 schematically shows the washing machine 1 according to one embodiment of the present invention. In FIG. 6, only the housing 9 is shown, and a washing tub, a dewatering tub, a rotation drive device, and the like are not shown. The same applies to the drawings of the following embodiments.
In this embodiment, a plurality of pockets 16 (16-1, 16-2, 16-3, 16-4) for storing water are provided inside the upper corner portion of the casing 9 of the washing machine 1, and the pockets 16 (16-1, 16-2, 16-3, 16-4) are provided therein. The stored water is used as a weight.
A plurality of pockets 16 (16-1, 16-2, 16-3, 16-4) are connected by a water supply passage 17 (17-1, 17-2, 17-3). -1 is connected to a supply pipe 18 (not shown) at one end of the washing water supply pipe 18, while a discharge outlet (not shown) at the other end of the other pocket (16-4) is supplied to the washing tub. 19 is connected.
That is, if the water supply passage 17 for the water supplied to the washing tub for washing, that is, the washing water, is arranged around the casing and the pocket 16 is provided in the middle, the washing water can be used as a weight. . At this time, it is necessary to provide an opening / closing valve 20 in the water supply pipe 18 and the water injection pipe 19 so that water is held in the water supply passage 17 including the pocket 16 at least during the operation of the dehydration tank.
Thereby, during operation of the washing machine, the pocket is filled with water and functions as a weight. A pocket, a water supply path, etc. can be comprised by the metal or resin cans or pipes.
In addition, you may comprise and control so that a water supply pipe and a water injection pipe may be independently provided in each pocket 16, and water may be supplied, discharged | emitted, or water injected. Further, instead of washing water, another water may be supplied for the weight. In addition, the upper part of the casing of the washing machine is usually preferable in that there is no arrangement of electronic circuits for operation and control, and a portion that has been a space can be used effectively.

FIG. 7 schematically shows a washing machine according to another embodiment of the present invention.
In this embodiment, a water supply passage 17 for washing water is provided in the upper part of the housing 9 of the washing machine 1 so as to go around the inside of the housing. One end of the water supply passage 17 is connected to a water supply pipe 18 and the other end is connected to a water supply pipe 19 for a washing tub. An opening / closing valve 20 is provided between the water supply passage 17 and the water supply pipe and the water supply pipe, respectively. It is necessary to keep the water in the passages at least during operation of the dewatering tank. As a result, during operation of the washing machine, at least during operation of the dewatering tub, the water supply passage is filled with water, and this water functions as a weight.

FIG. 8 schematically shows a washing machine according to still another embodiment of the present invention.
In this embodiment, the water supply passage 17 for washing water is provided so as to go around the inside of the housing over the upper portion and the side surface of the housing 9 of the washing machine 1. As in the above example, one end of the water supply passage 17 is connected to the water supply pipe 18, and the other end is connected to the water supply pipe 19 for the washing tub, and is opened and closed between the water supply passage 17 and the water supply pipe and the water supply pipe, respectively. It is necessary to provide a valve 20 to keep the water in the water supply passage at least during operation of the dewatering tank. Thereby, during operation of the washing machine, the water supply pipe is filled with water and functions as a weight.

In the embodiment shown in FIGS. 6 to 8, in order to obtain the weight of water necessary as a weight, the capacity of the pocket, the number of circulations of the water supply passage arranged on the inner periphery of the housing, the length of the water supply passage, It goes without saying that the amount of water filled in the water supply passage is adjusted by adjusting the size of the pipe.
That is, as described above, according to F ₂ of the washing machine for each _model, while calculating the F1 so as to be _F 1 / F ₂ ≦ 0.85, the natural frequency of the washing machine was measured for each model F1, based on the stiffness k determined from the relationship between the weight from the weight of the washing machine required to make the desired F _1, calculated on the weight of the weight may be adjusted to them based on the weight.

In addition, a weight sensor is provided in the washing machine so that changes in weight due to the laundry put into the washing machine can be confirmed, while means for partially discharging the water in the pockets and water supply passages are provided. Accordingly, it is also preferable to adjust the weight of the weight, that is, the amount of water stored in the pocket and the amount of water in the water supply passage.
In the washing machine of the present invention, the rigidity of the fixed leg is increased as described in Patent Document 1, or the weight and the liquid balancer are installed in a water tub, a washing tub, or as described in Patent Document 2 and Patent Document 3, respectively. Needless to say, the means provided in the dehydration tank may be used in combination.

It is a schematic diagram which shows the outline | summary of a washing machine. It is a figure which shows the change of the vibration history of a washing machine when the mass of a weight is changed, (a) when there is no weight, (b) when the mass of a weight is 1.0 kg, (C) is the weight of a weight. When the mass is 3.0 kg, (d) shows the case where the mass of the weight is 5.0 kg. It is a figure which shows the change of the vibration log | history in the other washing machine at the time of changing the mass of a weight, (a) when there is no weight, (b) when the mass of a weight is 1.0 kg, (C) Shows the case where the mass of the weight is 3.0 kg, and (d) shows the case where the mass of the weight is 5.0 kg. It is a perspective view which shows the investigation method of the natural frequency and amplitude history of a washing machine. It is a figure which shows the relationship between the frequency and the amplitude at the time of hit | damaging a washing machine to the X direction, (a) is a wide range of frequency, (b) is frequency 0-20r / of (a). Each range of s is shown. It is a perspective view which shows the outline | summary of the washing machine of one Embodiment of this invention. It is a perspective view which shows the outline | summary of the washing machine of other embodiment of this invention. It is a perspective view which shows the outline | summary of the washing machine of other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Washing machine 2 Washing tub 2a Bottom part of washing tub 3 Dehydration tub 4 Stirring blade 5 Rotation drive device (motor)
6 Rotation transmission / switching mechanism 7 Vibration isolator 8 Suspension bar 9 Housing
10 Mechanical part
11 First pulley
12 Second pulley
13 belt
14 Rotating shaft (stirring blade)
15 Rotating shaft (Dehydration tank)
16,16-1,16-2,16-3,16-4 pocket
17,17-1,17-2,17-3 Water supply passage
18 Water supply pipe
19 Injection pipe
20 On-off valve

Claims (1)

In a washing machine having a washing tub including a dewatering tub , a stirring blade, a rotary drive device for rotating the stirring wing and / or the dewatering tub, and a housing for storing them, the natural frequency per second of the washing machine is F1, where the rotational speed per second during dehydration of the rotary drive device is F2 , washing water is supplied to at least a pocket and / or a water supply passage provided at the upper part of the housing to form a weight, and F1 / F2 ≦ 0 A washing machine with low vibration, characterized by setting the natural frequency of the washing machine and / or the rotational speed of the rotary drive so as to be .85.

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