JP7630130B2 - washing machine - Google Patents

Description

The present invention relates to a washing machine that can eliminate imbalance in the spin tub while continuing to rotate the spin tub, thereby suppressing vibrations and noise caused by eccentricity of laundry during spin drying.

In typical washing machines installed in homes or laundromats, laundry tends to be unevenly distributed in the spin tub during spin-drying, causing vibrations and noise. Furthermore, if the laundry is significantly unevenly distributed at that time, the amplitude of the spin tub becomes large when rotating, resulting in large vibrations and making it impossible to start the spin-drying operation. Therefore, Patent Document 1 discloses a technology that detects the amount and position of imbalance of the clothes in the washing tub during spin-drying, and if there is imbalance, actively resolves the imbalance in the spin tub by injecting water into multiple baffles that are evenly spaced around the periphery of the spin tub.

JP 2017-56025 A

In the washing machine of Patent Document 1, during spin-drying, the amount of imbalance is detected based on the acceleration value given by the acceleration sensor attached to the outer tub, and it is determined whether the detected amount of imbalance (M) is smaller than the imbalance amount set value (mb). The imbalance amount set value (mb) is a threshold value that indicates that the laundry is so unbalanced that noise is not generated even if adjustment water is not supplied to the baffle.

When it is determined that the unbalance amount (M), which is the eccentric load, is greater than the unbalance amount setting value (mb), water is supplied to the baffle opposite the unbalance position. Water is supplied until the unbalance amount (M) becomes smaller than the unbalance amount setting value (mb), and when the unbalance amount (M) becomes smaller than the unbalance amount setting value (mb), the water supply to the baffle is stopped, and the rotation speed of the spin tub is increased to the normal spin rotation speed, and the spin process is terminated when a predetermined spin time has elapsed.

In this way, by supplying water to the baffle facing the eccentric load while the dehydration tub is rotating at medium speed, as shown in Figure 13(a) or 13(b), when moment A1, which the eccentric load tries to tilt the dehydration tub toward the eccentric load with the support part as a fulcrum, and moment A2, which the water supplied to the baffle tries to tilt the dehydration tub toward the center of gravity of the water supplied into the baffle with the support part as a fulcrum, approximately match, there is almost no imbalance in the dehydration tub. Note that Figure 13 illustrates a case where the center of gravity of the water supplied into the baffle is located in the center of the height of the dehydration tub.

In the washing machine of Patent Document 1, while water is being supplied to the baffle facing the eccentric load, if the amount of imbalance (M) becomes smaller than the imbalance amount setting value (mb), the supply of water to the baffle is stopped. However, if an attempt is made to control the amount of water supplied to the baffle so as to minimize vibration of the spin tub, the supply of water to the baffle may be stopped after the amount of water supplied to the baffle exceeds the amount of water required to cancel out the amount of imbalance. In such a case, the moment A2 is greater than the moment A1.

For example, when the dehydration tub is rotated at a medium speed of 500 rpm, as the eccentric load increases, the moment A1 increases gradually as shown by line 1 in FIG. 14. Similarly, when the dehydration tub is rotated at a medium speed of 500 rpm, as the amount of water supplied to the baffle increases, the moment A2 increases gradually as shown by line 2 in FIG. 14. Note that lines 3 and 4 in FIG. 14 show the same changes as lines 1 and 2 when the dehydration tub is rotated at a high speed of 1200 rpm.

Here, if moment A1 is a value a, then as can be seen from line 2, moment A2 will be approximately the same as moment A1 when the amount of water supplied to the baffle reaches approximately 0.35 kg. However, consider a case where water supply to the baffle is stopped after approximately 0.55 kg of water has been supplied to the baffle. In that case, moment A1 has a value a, while moment A2 has a value c, and moment A2 is greater than moment A1. Even in this case, if the rotation speed of the spin tub is 500 rpm, the moment difference T1 between moments A1 and A2 is small, so the spin tub does not vibrate significantly.

The inventors of the present invention therefore confirmed whether, when the dehydration tub is rotating at a medium speed, if the supply of water to the baffle is stopped after an amount of water exceeding the amount of water required to cancel the imbalance is supplied, the dehydration tub would maintain a state in which it does not vibrate significantly even if it is then rotated at a high speed. They found that when the rotation speed of the dehydration tub is increased to approximately 1200 rpm, the centrifugal force increases with the increase in rotation speed, and as shown in Figure 14, the moment difference T2 between moments A1 and A2 becomes significantly larger than the moment difference T1 described above.

In this way, the inventors of the present invention have discovered that when the dehydration tub is rotating at a medium speed, even if more water than necessary is supplied to the baffle, the dehydration tub will not vibrate significantly. However, if the dehydration tub is then rotated at a high speed, the difference in moment between moment A1 and moment A2 becomes significantly large, and the dehydration tub may vibrate significantly.

The inventors of the present invention therefore realized that it is important to control the amount of water supplied to the baffle during medium speed rotation when water is being supplied to the baffle so that it does not exceed the necessary amount of water. To this end, they conducted extensive research into how to set the acceleration threshold, which is the threshold for the amount of eccentricity in the spin tub when the water injection process is terminated. As a result, they discovered that the vibration behavior of the spin tub when rotated at high speed differs depending on the position of the eccentricity in the spin tub relative to the center of gravity of the water supplied to the baffle.

That is, (1) when the eccentric position in the spin-drying tank and the center of gravity of the water fed into the baffle are at approximately the same height, if the acceleration threshold is set as small as possible and water is fed into the baffle to reduce vibration, the vibration during high-speed spin-drying will not worsen significantly even if more water than necessary is fed into the baffle.

(2) When the eccentric position in the spin tub is lower than the center of gravity of the water fed into the baffle, the distance of the eccentric load from the support fulcrum is small, so high-speed rotation can be achieved without reducing vibration during medium-speed rotation, compared to when the same eccentric load is at a position higher than the center of gravity of the water. For this reason, it is desirable to set the acceleration threshold in this case higher (lower) than when the eccentric load is at a position higher than the center of gravity of the water.

(3) When the eccentric position in the spin-drying tank is higher than the center of gravity of the water fed into the baffle, the distance of the eccentric load from the support fulcrum is large, making it difficult to achieve high speed rotation without reducing vibration during medium speed rotation compared to when the same eccentric load is lower than the center of gravity of the water. For this reason, it is desirable to set the acceleration threshold in this case smaller (stricter) than when the eccentric load is lower than the center of gravity of the water.

In this way, the present invention makes it possible to perform dehydration by rotating the dehydration tub at high speed with low vibration regardless of the eccentric position in the dehydration tub by appropriately setting the acceleration threshold based on the amount of deviation in the height direction between the eccentric position in the dehydration tub and the center of gravity of the water supplied to the baffle.

The washing machine according to the present invention comprises a dehydration tub arranged in an outer tub and having a pulsator arranged at the bottom thereof, three or more baffles arranged at equal intervals in the circumferential direction on the inner circumferential surface of the dehydration tub, a water injection device for injecting water into each of the baffles, acceleration detection means for detecting vibrations of the dehydration tub, a position detection device for transmitting a pulse signal in response to the rotation of the dehydration tub, eccentricity detection means for detecting the amount of eccentricity and the eccentricity position in the dehydration tub, and control means for controlling the water injection device to start injecting water into the baffle facing the eccentricity position when the amount of eccentricity becomes equal to or greater than a water injection threshold during the dehydration process, and to stop injecting water into the baffle when the amount of eccentricity becomes equal to or less than an acceleration threshold, and is characterized in that, when the rotation speed of the dehydration tub is greater than the resonant rotation speed, the greater the amount of deviation in the height direction between the eccentricity position in the dehydration tub and the center of gravity of the water supplied to the baffle, the greater the acceleration threshold is set to a larger value.

In the washing machine according to the present invention, it is preferable that the acceleration threshold value when the eccentric position in the dehydration tub is below the center of gravity of the water supplied to the baffle is greater than the acceleration threshold value when the eccentric position in the dehydration tub is above the center of gravity of the water supplied to the baffle, and that the acceleration threshold value when the eccentric position in the dehydration tub is at approximately the same height as the center of gravity of the water supplied to the baffle is smaller than the acceleration threshold value when the eccentric position in the dehydration tub is above the center of gravity of the water supplied to the baffle.

According to the present invention, the acceleration threshold is set to a large value when the deviation in the height direction between the eccentric position in the dehydration tank and the center of gravity of the water supplied to the baffle is large, so that more water than necessary is not added when the deviation in the height direction between the eccentric position in the dehydration tank and the center of gravity of the water supplied to the baffle is large. Therefore, it is possible to prevent the dehydration tank from vibrating significantly during high-speed rotation while minimizing vibration of the dehydration tank. Therefore, regardless of the deviation in the height direction between the eccentric position in the dehydration tank and the center of gravity of the water supplied to the baffle, the dehydration tank can be rotated at high speed with low vibration to perform dehydration.

According to the present invention, regardless of the eccentric position in the dehydration tub relative to the center of gravity of the water supplied to the baffle, it is possible to minimize vibration of the dehydration tub and prevent the dehydration tub from vibrating significantly during high-speed rotation.

1 is a perspective view showing the appearance of a washing machine 1 according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the configuration of the washing machine 1 of FIG. 2 is a cross-sectional view of a spin-drying tub 2 of the washing machine 1 of FIG. 1. FIG. 2 is a block diagram of an electrical system of the washing machine 1 of FIG. FIG. 13 is a diagram illustrating an acceleration threshold (mc). 2 is a diagram for explaining a control flow in a spin-drying process of the washing machine 1 of FIG. 1. 11 is a parameter table showing the water supply valves 31a, 31b, and 31c to be opened. 4 is a schematic diagram showing an eccentric position in the dehydration tub 2. FIG. 4 is a graph showing the relationship between the acceleration obtained from the acceleration sensor 5 and the pulse signal ps obtained from the proximity switch 55. 10 is a flowchart showing a process for measuring an amount of eccentricity and an eccentric position. 1 is a flowchart showing the procedure of a dehydration process. 1 is a flowchart showing the procedure of a dehydration process. 11 is a schematic diagram for explaining a control for canceling an unbalanced state in the dehydration tub. FIG. 13 is a graph showing the change in moment when the eccentric load or the amount of injected water increases.

The washing machine 1 according to an embodiment of the present invention will be described in detail below with reference to the drawings.

Figure 1 is a perspective view showing the exterior of a vertical washing machine (hereinafter referred to as a "washing machine") 1 according to an embodiment of the present invention. Figure 2 is a schematic diagram showing the configuration of the washing machine 1 of this embodiment. Figure 3 is a cross-sectional view of the spin tub 2 of the washing machine 1.

The washing machine 1 of this embodiment includes a washing machine 1a, a spin tub 2, an outer tub 3, a water injection device 30, a drive unit 50, and a control means 60 (see FIG. 4).

The washing machine body 1a shown in FIG. 1 has a generally rectangular parallelepiped shape. An opening 11 for loading and unloading laundry from the spin tub 2 is formed on the top surface of the washing machine body 1a, and an opening/closing lid 11a that can open and close the opening 11 is attached.

The spin tub 2 is a cylindrical member with a bottom that is arranged coaxially with the outer tub 3 and is supported so as to be freely rotatable within the outer tub 3. The spin tub 2 can accommodate laundry inside and has a number of water passage holes on its inner peripheral surface 2a.

A pulsator (agitating blade) 4 is rotatably disposed in the center of the bottom 2c of the spin tub 2. As shown in FIG. 2, the pulsator 4 has a generally disk-shaped pulsator body 4a, a number of upper blades 4b formed on the upper surface of the pulsator body 4a, and a number of lower blades 4c formed on the lower surface of the pulsator body 4a. The pulsator 4 agitates the wash water stored in the outer tub 3 to generate a water current.

The outer tub 3 is a cylindrical member with a bottom that is disposed inside the washing machine main body 1a and can store washing water inside. As shown in FIG. 2, two acceleration sensors 5 and 6 capable of detecting acceleration in three directions, left-right, up-down, and front-back, are attached to the outer peripheral surface 3a of the outer tub 3. The acceleration sensor 5 is attached near the upper end of the outer tub 3, and the acceleration sensor 6 is attached near the lower end of the outer tub 3. In this embodiment, the acceleration sensor 5 detects the acceleration of the upper end of the outer tub 3, and the acceleration sensor 6 detects the acceleration of the lower end of the outer tub 3, but the acceleration of the upper end or lower end of the spin tub 2 is assumed to be substantially the same as the acceleration of the upper end or lower end of the outer tub 3. Therefore, in the washing machine 1 of this embodiment, the two acceleration sensors 5 and 6 constitute an acceleration detection means for detecting the vibration of the spin tub 2.

As shown in FIG. 3, three baffles (water injection pipes) 8 are provided on the inner peripheral surface 2a of the dehydration tub 2 at equal intervals (equal angles) in the circumferential direction. Each baffle 8 extends vertically from the bottom 2c to the upper end of the dehydration tub 2, and is formed to protrude from the inner peripheral surface 2a of the dehydration tub 2 toward the axis S1. Each baffle 8 is hollow and has an arc-shaped cross section. In this way, the shape of the baffle 8 protrudes little toward the axis S1 of the dehydration tub 2 and expands circumferentially of the dehydration tub 2, which prevents the storage space of the dehydration tub 2 from becoming narrow.

As shown in FIG. 2, a horizontally long circulating water port 8a is formed at the upper end of the baffle 8. Also, an opening 8c is formed at the lower end of the baffle 8, which opens near the bottom 2c of the spin tub 2, more specifically, below the pulsator body 4a.

Therefore, in the washing process performed with the drain valve 3n _a (see FIG. 2) of the drain pipe 3n connected to the bottom of the outer tub 3 closed and the wash water stored in the outer tub 3, the wash water agitated by the lower blade portion 4c of the pulsator 4 enters through the opening 8c, runs up inside the baffle 8, and is discharged from the circulating water port 8a, shower-washing the clothes, as shown by the arrows in FIG. 2. By repeating this operation, the wash water circulates inside the spin tub 2. In other words, the baffle 8 has a function of circulating the wash water.

The water injection device 30 injects conditioning water into the three baffles 8 individually. The water injection device 30 has three water injection hoses 30a connected to the three baffles 8, respectively, and a water supply valve 31a is disposed on each of the water injection hoses 30a. The water injection hoses 30a are provided in the same number as the three baffles 8, and are attached to the upper ends of the three baffles 8, respectively. In this embodiment, tap water is used as the conditioning water.

The drive unit 50 shown in FIG. 2 rotates the pulley 52 and belt 53 using the motor 51, and also rotates the drive shaft 54 extending toward the bottom 2c of the spin tub 2, thereby providing driving force to the spin tub 2 and the pulsator 4, causing them to rotate. The washing machine 1 mainly rotates only the pulsator 4 during the washing process, and rotates the spin tub 2 and the pulsator 4 together at high speed during the spin process. In addition, a proximity switch 55 is provided near one of the pulleys 52, which can detect the passage of a mark 52a formed on the pulley 52.

Figure 4 is a block diagram showing the electrical configuration of the washing machine 1 of this embodiment. The operation of the washing machine 1 is controlled by a control means 60 including a microcomputer. The control means 60 has a central control unit (CPU) 61 that controls the entire system, and a memory 62 is connected to the central control unit 61. The control means 60 causes the microcomputer to execute a program stored in the memory 62, thereby performing a predetermined operation, and the memory 62 temporarily stores data, etc., used when executing the program.

The memory 62 stores values, each of which will be described in detail below, such as a predetermined rotation speed (N1) lower than the resonance point (resonance rotation speed) CP of the dehydration tub 2, a water injection threshold (ma), an acceleration threshold (mc) as an acceleration threshold ( _mc0 ), a first acceleration threshold ( _mc1 ), a second acceleration threshold ( _mc2 ), and a third acceleration threshold ( _mc3 ), a steady-state dehydration rotation speed, and a predetermined dehydration time for which the dehydration operation continues. Note that in this embodiment, the resonance point (resonance rotation speed) CP of the dehydration tub 2 is set lower than the resonance rotation speed of the outer tub 3 itself.

(Water injection threshold)
The water injection threshold (ma) is a threshold of the amount of eccentricity in the dehydration tub 2 for determining whether or not to start injecting adjustment water from the water injection nozzles 30a, 30b, and 30c into the three baffles 8. Therefore, when the amount of eccentricity in the dehydration tub 2 exceeds the water injection threshold (ma), an injection process is performed. In this embodiment, a predetermined water injection threshold (ma) is set as the water injection threshold (ma) regardless of whether the rotation speed of the dehydration tub 2 is lower than the resonant rotation speed or higher than the resonant rotation speed, and regardless of the eccentricity position in the dehydration tub 2.

(Acceleration Threshold)
The acceleration threshold (mc) is a threshold for the amount of eccentricity in the dehydration tub 2 when water injection is terminated after the start of injection of adjustment water from the water injection nozzles 30a, 30b, and 30c into the three baffles 8. Therefore, after the start of the water injection process, when the amount of eccentricity in the dehydration tub 2 becomes equal to or less than the predetermined acceleration threshold (mc), the water injection process is terminated.

In this embodiment, as shown in Fig. 5, when the rotation speed of the dehydration tub 2 is smaller than the resonant rotation speed, the acceleration threshold ( _mc0 ) is set as the acceleration threshold (mc), regardless of the eccentric position in the dehydration tub 2. When the rotation speed of the dehydration tub 2 is greater than the resonant rotation speed, the first acceleration threshold ( _mc1 ) is set when the eccentric position in the dehydration tub 2 is in the upper part of the dehydration tub 2, the second acceleration threshold ( _mc2 ) is set when the eccentric position in the dehydration tub 2 is in the center in the height direction of the dehydration tub 2, and the third acceleration threshold ( _mc3 ) is set when the eccentric position in the dehydration tub 2 is in the lower part of the dehydration tub 2. The third acceleration threshold ( _mc3 ) is a value greater than the first acceleration threshold ( _mc1 ), and the second acceleration threshold ( _mc2 ) is a value less than the first acceleration threshold ( _mc1 ).

When water is supplied to the baffle 8 at medium speed (e.g., 500 to 600 rpm), the height of the center of gravity of the water supplied to the baffle 8 is approximately the same as the height of the center of the spin tub 2 in the vertical direction, and is considered to change very little regardless of the amount of water supplied to the baffle 8.

In this embodiment, when the eccentric load position in the dehydration tub 2 is at the bottom of the dehydration tub 2, the moment A1 with which the eccentric load tries to tip the dehydration tub 2 is relatively small, so that even if less water is supplied to the baffle 8 than necessary, high-speed rotation is possible with low vibration. In contrast, when the eccentric load position in the dehydration tub 2 is at the top of the dehydration tub 2, the moment A1 with which the eccentric load tries to tip the dehydration tub 2 is relatively large, so that if less water is supplied to the baffle 8 than necessary, the vibration of the dehydration tub 2 becomes very large. Therefore, the third acceleration threshold (mc ₃ ) when the eccentric load position in the dehydration tub 2 is at the bottom of the dehydration tub 2 is set to a value larger than the first acceleration threshold (mc ₁ ) when the eccentric load position in the dehydration tub 2 is at the top of the dehydration tub 2.

As described above, when the eccentric load position in the dehydration tank 2 is at the bottom of the dehydration tank 2, and when the eccentric load position in the dehydration tank 2 is at the top of the dehydration tank 2, the vertical deviation between the eccentric load position in the dehydration tank 2 and the center of gravity of the water supplied to the baffle 8 is large, and the difference between the moment A1 at which the eccentric load tries to tilt the dehydration tank 2 toward the eccentric load with the support part as a fulcrum, and the moment A2 at which the water supplied to the baffle tries to tilt the dehydration tank 2 toward the center of gravity of the water supplied to the baffle with the support part as a fulcrum, becomes large.

In contrast, when the eccentric position in the dehydration tank 2 is in the center of the height of the dehydration tank 2, the vertical deviation between the eccentric load position in the dehydration tank 2 and the center of gravity of the water supplied to the baffle 8 is very small or nonexistent, and the difference between the moment A1, which the eccentric load exerts on the support portion as a fulcrum to tilt the dehydration tank toward the eccentric load side, and the moment A2, which the water supplied to the baffle exerts on the support portion as a fulcrum to tilt the dehydration tank toward the center of gravity of the water supplied to the baffle side, is very small.

Therefore, when the eccentric position within the dehydration tank 2 is in the center of the height of the dehydration tank 2, even if too much water is supplied to the baffle 8, the moment difference between moments A1 and A2 is unlikely to become significantly large, so the second acceleration threshold ( _mc2 ) is set to a value smaller than the first acceleration threshold ( _mc1 ).

In the washing machine 1 of this embodiment, if the vibration detected by the acceleration sensor 5 attached to the upper end of the outer tub 3 is greater than the vibration detected by the acceleration sensor 6 attached to the lower end of the outer tub 3 by a specified value or more, the eccentric load position in the dehydration tub 2 is determined to be at the upper part of the dehydration tub 2. Also, if the vibration detected by the acceleration sensor 6 attached to the lower end of the outer tub 3 is greater than the specified value or more than the vibration detected by the acceleration sensor 5 attached to the upper end of the outer tub 3, the eccentric load position in the dehydration tub 2 is determined to be at the lower part of the dehydration tub 2. Therefore, if the difference between the vibration detected by the acceleration sensor 5 attached to the upper end of the outer tub 3 and the vibration detected by the acceleration sensor 6 attached to the lower end of the outer tub 3 is smaller than a specified value, the eccentric position in the dehydration tub 2 is determined to be at the center of the height of the dehydration tub 2. The above specified value is set so that the upper region of the dehydration tub 2, the center region of the height of the dehydration tub 2, and the lower region of the dehydration tub 2 are approximately equal (are approximately the same height).

The central control unit 61 outputs a control signal to the rotation speed control unit 63, which in turn outputs the control signal to the motor control unit (motor control circuit) 64 to control the rotation of the motor 51. The rotation speed control unit 63 receives a signal indicating the rotation speed of the motor 51 from the motor control unit 64 in real time, which serves as a control element.

Two acceleration sensors 5 and 6 are connected to the unbalance amount detection unit 65. An acceleration sensor 5 and a proximity switch 55 are connected to the unbalance position detection unit 66. In this embodiment, the unbalance amount detection unit 65 and the unbalance position detection unit 66 constitute the eccentricity detection means.

As a result, when the proximity switch 55 detects the marker 52a (see Figure 2), the unbalance amount detection unit 65 calculates the amount of eccentricity (M) of the spin tub 2 from the magnitude of the acceleration in the left-right, up-down, and front-back directions obtained from the two acceleration sensors 5 and 6, and outputs the amount of eccentricity (M) to the unbalance amount determination unit 67.

The unbalance position detection unit 66 calculates the angle of the unbalance direction from the signal indicating the position of the marker 52a input from the proximity switch 55, and outputs an unbalance position signal indicating the eccentric position (N) to the water injection control unit 68. Here, the angle of the unbalance direction is the relative angle with respect to the baffle 8 in the circumferential direction of the axis S1. In this embodiment, as shown in FIG. 8, as an example, the midpoint between the three baffles 8(B) and 8(C) arranged at equal angular intervals around the axis S1 is set to 0° to indicate the relative angle between the eccentric position and the three baffles 8(A), 8(B), and 8(C).

When the water injection control unit 68 receives signals indicating the eccentricity amount (M) and eccentricity position (N) from the unbalance amount determination unit 67 and the unbalance position detection unit 66, it determines the baffle 8 to which water should be supplied and the amount of water to be supplied based on a pre-stored control program. The water injection control unit 68 then opens the selected water supply valves 31a, 31b, and 31c to start injecting the adjustment water W. When the eccentricity amount (M) in the spin tub 2 is greater than or equal to a predetermined standard, the water injection control unit 68 starts injecting the adjustment water W into at least one of the baffles 8 from the water injection nozzle 30a selected based on the calculation of the eccentricity amount (M), and stops injecting the adjustment water W when the eccentricity amount (M) falls below the predetermined standard.

As shown in FIG. 6, for example, when the laundry clump D(X) causing the eccentricity is between baffles 8(B) and 8(C) of the spin tub 2, the water injection control unit 68 controls the nozzle unit 30 to supply adjustment water W to baffle 8(A). When the laundry clump D(Y) is near baffle 8(A), the water injection control unit 68 controls the nozzle unit 30 to supply adjustment water W to both baffles 8(B) and 8(C).

The central control unit 61 opens the water supply valves X and Z as shown in the parameter table of FIG. 7. In this embodiment, the eccentric position (N) is determined by dividing the spin tub 2 into six equal parts in the circumferential direction as shown in FIG. 8, and is classified into two cases: an eccentric position (N) that determines one baffle 8 to which water should be poured, and an eccentric position (N) that determines two baffles 8 to which water should be poured.

The area Y of the eccentric position (N) that identifies one baffle 8 to which water should be injected is the area (P(A)), (P(B)), and (P(C)). The area Y of the eccentric position (N) required to eliminate the eccentricity is the area (P(AB)), (P(BC)), and (P(CA)). The angles of the areas (P(A)), (P(B)), and (P(C)) centered on the axis S1 are set to 20°, and the angles of the areas (P(AB)), (P(BC)), and (P(CA)) centered on the axis S1 are set to 100°.

(Calculation of eccentricity amount and eccentricity position)
The procedure for calculating the amount of eccentricity (M) and the eccentricity position θ1 in the washing machine 1 of this embodiment will be described with reference to FIGS.

In this embodiment, during the spin-drying process, the time difference t1 between any point in the signal related to acceleration indicating at least one period t2 of the spin-drying tub 2 transmitted from the acceleration sensor 5 and the timing at which the pulse signal ps is transmitted from the proximity switch 55 is calculated, and the eccentric position θ1 in the circumferential direction within the spin-drying tub 2 is calculated from the relationship between the time difference t1 and the rotation speed of the spin-drying tub 2, and control is performed to reduce the amount of eccentricity (M) based on the calculated eccentric position θ1. In this embodiment, of the signals from the two acceleration sensors 5 and 6, the signal from the acceleration sensor 5 is used to calculate the eccentric position θ1.

In contrast, to calculate the amount of eccentricity (M), a signal from acceleration sensor 5 attached to the upper end of outer tub 3 and a signal from acceleration sensor 6 attached to the lower end of outer tub 3 are used, but the signal from acceleration sensor 5 is considered to be more important in detecting vibrations of spin tub 2 than the signal from acceleration sensor 6. Therefore, if the signal from acceleration sensor 5 is a and the signal from acceleration sensor 6 is b, then the signal c calculated by (2 x a + b) / 3 is used to calculate the amount of eccentricity (M).

Figure 9 is a graph showing the relationship between information indicating the change in acceleration over time calculated based on the acceleration sensor 5 and the pulse signal ps obtained from the proximity switch 55. For convenience, in Figure 9, the eccentric position θ1 is calculated from the time difference t1 between the maximum value (Ymax) of the acceleration in the vertical direction obtained from the acceleration sensor 5 and the pulse signal ps. Note that in the present embodiment shown in Figure 9, as an example, a mode in which the eccentric position θ1 is calculated from the maximum value (Ymax) and minimum value (Ymin) of the acceleration is shown, but in other embodiments of the present invention, the eccentric position θ1 may be calculated from one or more of the zero point of acceleration, the maximum value (Ymax), and the minimum value (Ymin) of the acceleration.

Figure 10 is a flowchart showing the processing steps for measuring the amount of eccentricity and the eccentricity position.

<Step S1>
In step S1, the central control unit 61 detects acceleration data (MX, MY, MZ) relating to the left-right direction, the up-down direction, and the front-rear direction from the two acceleration sensors 5, 6.

<Step S2>
In step S2, the central control unit 61 performs a calculation process to determine the maximum values (Xmax, Ymax, Zmax) and minimum values (Xmin, Ymin, Zmin) of the acceleration data (MX, MY, MZ) from the acceleration data (MX, MY, MZ) obtained from the acceleration sensors 5 and 6 and the pulse signal ps, which is an interrupt signal from the proximity switch 55.

<Step S3>
In step S3, the central control unit 61 calculates and determines the value of one cycle t2, which is the time it takes for the spin tub 2 to make one rotation, from the interval between multiple pulse signals ps, which are interrupt signals from the proximity switch 55.

<Step S4>
In step S4, the central control unit 61 calculates and determines the time difference t1 from the multiple pulse signals ps, which are interrupt signals from the proximity switch 55, and the maximum values (Xmax, Ymax, Zmax) of the acceleration data (MX, MY, MZ) obtained in step S2. In step S4, the central control unit 61 calculates time differences t1X and t1Z relating to the left-right direction and the front-rear direction in addition to the time difference t1Y, which is the time difference t1 relating to the up-down direction shown in Figure 9.

<Step S5>
In step S5, the central control unit 61 calculates and determines the eccentricity amounts Mx, My, Mz in the left-right direction, up-down direction, and front-rear direction, which are the eccentricity amount (M), from the maximum value (Xmax, Ymax, Zmax) and minimum value (Xmin, Ymin, Zmin) of the acceleration data (MX, MY, MZ) obtained in step S2. In this embodiment, the eccentricity amounts Mx, My, Mz are determined from the difference between the maximum value (Xmax, Ymax, Zmax) and the minimum value (Xmin, Ymin, Zmin).

<Step S6>
In step S6, the central control unit 61 calculates and determines the eccentric positions θX1, θY1, and θZ1 in the left-right, up-down, and front-rear directions, respectively, using the one period t2 obtained in step S3 and the time difference t1 obtained in step S4, using the following equations.
θX1=t1X×360÷t2
θY1=t1Y×360÷t2
θZ1=t1Z×360÷t2

The procedure for the dehydration process will be described with reference to Figures 11 and 12. Figures 11 and 12 are flow charts showing the procedure for the dehydration process.

In this embodiment, the central control unit 61 starts the spin-drying process when it receives an input signal from a spin-drying button (not shown) or a signal indicating that the spin-drying process should be started during the operation of a washing course.

<Step S101>
In step S101, central control unit 61 loosens and inverts dehydration tub 2, and then increases the rotation speed of dehydration tub 2 to a predetermined rotation speed (N1) that is lower than the resonance point CP of dehydration tub 2, which is about 250 to 260 rpm.

<Step S102>
In step S102, the central control unit 61 determines whether the amount of eccentricity (M) in the spin tub 2 is equal to or greater than the water supply threshold (ma). If the central control unit 61 determines that the amount of eccentricity (M) is equal to or greater than the water supply threshold (ma), the process proceeds to step S103. If the central control unit 61 determines that the amount of eccentricity (M) is smaller than the water supply threshold (ma), the process proceeds to step S105.

Therefore, in step S102, the central control unit 61 first executes control to have the eccentricity detection means calculate the amount of eccentricity (M) and the eccentricity position θ1 based on the acceleration signals provided by the two acceleration sensors 5 and 6. Specifically, the central control unit 61 calculates the amount of eccentricity (M) for each direction based on the acceleration signals related to the left-right, up-down, and front-back directions obtained from the two acceleration sensors 5 and 6, and calculates the eccentricity position θ1 for each direction based on the acceleration signal obtained from the acceleration sensor 5. The central control unit 61 then compares the calculated amount of eccentricity (M) with the water injection threshold (ma) stored in the memory 62, and determines whether the amount of eccentricity (M) is equal to or greater than the water injection threshold.

<Step S103>
In step S104, the central control unit 61 injects water into the baffle 8 that faces the eccentric position θ1 in the dehydration tub 2.

<Step S104>
In step S104, the central control unit 61 determines whether the amount of eccentricity (M) in the spin tub 2 is equal to or less than the acceleration threshold (mc). If the central control unit 61 determines that the amount of eccentricity (M) is equal to or less than the acceleration threshold (mc), the process proceeds to step S105. If the central control unit 61 determines that the amount of eccentricity (M) is greater than the acceleration threshold (mc), the process returns to step S103 and water injection is continued.

<Step S105>
In step S105, if water is being poured, the central control unit 61 stops pouring water and increases the rotation speed of the spin tub 2. Note that if the central control unit 61 determines in step S102 that the eccentricity amount (M) is smaller than the water pouring threshold value (ma) and the process proceeds to step S105, water is not being poured, so the rotation speed of the spin tub 2 is increased.

<Step S106>
In step S106, the central control unit 61 determines whether the rotation speed of the dehydration tub 2 has reached 500 rpm, which is higher than the resonance point CP of the dehydration tub 2. In this embodiment, the rotation speed of 500 rpm of the dehydration tub 2 is higher than the resonance point CP of the dehydration tub 2, and is the highest possible rotation speed at which water is properly supplied to the baffle 8 without making a mistake when water is supplied to the baffle 8. If the central control unit 61 determines that the rotation speed of the dehydration tub 2 has reached 500 rpm, the process proceeds to step S107. If the central control unit 61 determines that the rotation speed of the dehydration tub 2 has not reached 500 rpm, the process returns to step S102.

<Step S107>
In step S107, the central control unit 61 determines whether the eccentric load position in the spin tub 2 is located at the bottom of the spin tub 2. Specifically, if the vibration detected by the acceleration sensor 6 attached to the lower end of the outer tub 3 is greater than the vibration detected by the acceleration sensor 5 attached to the upper end of the outer tub 3 by a specified value or more, the central control unit 61 determines that the eccentric load position in the spin tub 2 is located at the bottom of the spin tub 2. If the central control unit 61 determines that the eccentric load position is located at the bottom of the spin tub 2, the process proceeds to step S108. If the central control unit 61 determines that the eccentric load position is not located at the bottom of the spin tub 2, the process proceeds to step S109.

<Step S108>
In step S108, the central control unit 61 sets the acceleration threshold (mc) to the third acceleration threshold (mc ₃ ) After that, the process proceeds to step S112.

<Step S109>
In step S109, the central control unit 61 determines whether the eccentric load position in the dehydration tub 2 is at the upper part of the dehydration tub 2. Specifically, if the vibration detected by the acceleration sensor 5 attached to the upper end of the outer tub 3 is greater than the vibration detected by the acceleration sensor 6 attached to the lower end of the outer tub 3 by a specified value or more, the central control unit 61 determines that the eccentric load position in the dehydration tub 2 is at the upper part of the dehydration tub 2. If the central control unit 61 determines that the eccentric load position is at the upper part of the dehydration tub 2, the process proceeds to step S110. If the central control unit 61 determines that the eccentric load position is not at the lower part of the dehydration tub 2, the process proceeds to step S111.

<Step S110>
In step S110, the central control unit 61 sets the acceleration threshold (mc) to a first acceleration threshold (mc ₁ ) After that, the process proceeds to step S112.

<Step S111>
In step S111, the central control unit 61 sets the acceleration threshold (mc) to the second acceleration threshold (mc ₂ ) After that, the process proceeds to step S112.

<Step S112>
In step S112, the central control unit 61 determines whether the amount of eccentricity (M) in the spin tub 2 is equal to or greater than the water supply threshold (ma). If the central control unit 61 determines that the amount of eccentricity (M) is equal to or greater than the water supply threshold (ma), the process proceeds to step S113. If the central control unit 61 determines that the amount of eccentricity (M) is less than the water supply threshold (ma), the process proceeds to step S115. The processing method in step S112 is the same as the processing method in step S102.

<Step S113>
In step S114, the central control unit 61 injects water into the baffle 8 that faces the eccentric position θ1 in the dehydration tub 2.

<Step S114>
In step S114, the central control unit 61 determines whether the amount of eccentricity (M) in the spin tub 2 is equal to or less than the acceleration threshold (mc) set in any one of steps S108, S110, and S111. If the central control unit 61 determines that the amount of eccentricity (M) is equal to or less than the acceleration threshold (mc), the process proceeds to step S115. If the central control unit 61 determines that the amount of eccentricity (M) is greater than the acceleration threshold (mc), the process returns to step S113 and water injection is continued.

<Step S115>
In step S115, the central control unit 61 stops pouring water and increases the rotation speed of the spin tub 2. Note that if the central control unit 61 determines in step S112 that the eccentricity amount (M) is smaller than the water pouring threshold value (ma) and proceeds to step S115, water is not being poured, so the rotation speed of the spin tub 2 is increased.

<Step S116>
In step S116, the central control unit 61 determines whether the rotation speed of the spin tub 2 has reached 800 rpm. If the central control unit 61 determines that the rotation speed of the spin tub 2 has reached 800 rpm, the process proceeds to step S117. If the central control unit 61 determines that the rotation speed of the spin tub 2 has not reached 800 rpm, the process returns to step S112.

<Step S117>
In step S117, the central control unit 61 increases the rotation speed of the dehydration tub 2 until the rotation speed of the dehydration tub 2 reaches 1200 rpm.

<Step S118>
In step S118, the central control unit 61 repeatedly determines whether or not a predetermined dehydration time has elapsed since the start of dehydration. If the central control unit 61 determines that the predetermined dehydration time has elapsed since the start of dehydration, the dehydration process is terminated.

The washing machine 1 of this embodiment is arranged in an outer tub 3, and includes a spin tub 2 with a pulsator 4 arranged at the bottom, three or more baffles 8 arranged at equal intervals in the circumferential direction on the inner surface 2a of the spin tub 2, a water injection device 30 for injecting water into each of the baffles 8, acceleration sensors 5 and 6 which are acceleration detection means for detecting vibrations of the spin tub 2, a proximity switch 55 which is a position detection device that transmits a pulse signal in response to the rotation of the spin tub 2, and an imbalance amount detection unit which is an eccentricity detection means for detecting the amount of eccentricity and the eccentricity position in the spin tub 2. 65, an unbalanced position detection unit 66, and a control means 60 that controls the water injection device 30 to start injecting water into the baffle 8 facing the eccentric position when the amount of eccentricity becomes equal to or greater than a water injection threshold (ma) during the spin-drying process, and to stop injecting water into the baffle 8 when the amount of eccentricity becomes equal to or less than an acceleration threshold (mc). When the rotation speed of the spin-drying tub 2 is greater than the resonant rotation speed, the greater the deviation in the height direction between the eccentric position in the spin-drying tub and the center of gravity of the water supplied to the baffle, the greater the acceleration threshold is set to.

According to the washing machine 1 of this embodiment, when the deviation in the height direction between the eccentric position in the spin tub 2 and the center of gravity of the water supplied to the baffle 8 is large, the acceleration threshold (mc) is set large so as not to add more water than necessary when the deviation in the height direction between the eccentric position in the spin tub 2 and the center of gravity of the water supplied to the baffle 8 is large. Therefore, it is possible to prevent the spin tub 2 from vibrating significantly during high-speed rotation while minimizing vibration of the spin tub 2. Therefore, regardless of the deviation in the height direction between the eccentric position in the spin tub 2 and the center of gravity of the water supplied to the baffle 8, the spin tub 2 can be rotated at high speed with low vibration to perform spin drying.

In the washing machine 1 of this embodiment, the acceleration threshold (mc ₃ ) when the eccentric position in the dehydration tub 2 is below the center of gravity of the water supplied into the baffle 8 is greater than the acceleration threshold (mc ₁ ) when the eccentric position in the dehydration tub 2 is above the center of gravity of the water supplied into the baffle 8, and the acceleration threshold (mc ₂ ) when the eccentric position in the dehydration tub 2 is at approximately the same height as the center of gravity of the water supplied into the baffle 8 is smaller than the acceleration threshold (mc ₁ ) when the eccentric position in the dehydration tub 2 is above the center of gravity of the water supplied into the baffle 8.

The washing machine 1 of this embodiment can prevent the spin tub from vibrating significantly during high-speed rotation while minimizing vibrations of the spin tub, regardless of the eccentric position of the spin tub 2 relative to the center of gravity of the water supplied to the baffle 8.

The above describes an embodiment of the present invention, but the configuration of this embodiment is not limited to the above, and various modifications are possible.

For example, in the above embodiment, the acceleration threshold (mc) is set to three levels when the rotation speed of the dehydration tank 2 is greater than the resonant rotation speed: an acceleration threshold (mc 1 ) when the eccentric position is at the top of the dehydration tank 2 (when the eccentric position in the dehydration tank 2 is above the center of gravity of the water supplied into the baffle 8); an acceleration threshold (mc ₂ ) when the eccentric position is at the center of the height of the dehydration tank 2 (when the eccentric position in the dehydration tank 2 is at approximately the same height as the center of gravity of the water supplied into the baffle 8); and an acceleration threshold (mc ₃ ) when the eccentric position is at the bottom of the dehydration tank 2 (when the eccentric position in the dehydration tank 2 is below the center of gravity of the water supplied into the baffle ₈ ). However, this is not limited to this.

Therefore, when the rotation speed of the dehydration tub 2 is higher than the resonant rotation speed, the acceleration threshold (mc) may be set to two stages: an acceleration threshold (mc ₁ ) when the eccentric position is above the height center of the dehydration tub 2, and an acceleration threshold (mc ₃ ) when the eccentric position is below the height center of the dehydration tub 2. Furthermore, when the rotation speed of the dehydration tub 2 is higher than the resonant rotation speed, the acceleration threshold (mc) may be set in multiple stages or continuously so as to gradually change according to the amount of deviation in the height direction (the amount of deviation in the upward direction, the amount of deviation in the downward direction, respectively) between the eccentric position in the dehydration tub 2 and the center of gravity of the water supplied to the baffle 8.

In this case, the acceleration threshold (mc) is set to different values when the eccentric position in the dehydration tank 2 is above the center of gravity of the water supplied into the baffle 8 and when the eccentric position in the dehydration tank 2 is below the center of gravity of the water supplied into the baffle 8, and it is preferable that the increase in the acceleration threshold (mc ₃ ) when the eccentric position in the dehydration tank 2 is below the center of gravity of the water supplied into the baffle 8 is greater than the increase in the acceleration threshold (mc ₁ ) when the eccentric position in the dehydration tank 2 is above the center of gravity of the water supplied into the baffle 8.

Specifically, assuming that the acceleration threshold value when the eccentric position in the dehydration tub 2 is at substantially the same height as the center of gravity of the water supplied into the baffle 8 is a reference value _mc2 , the acceleration threshold value ( _mc3 ) when the eccentric position in the dehydration tub 2 is below the center of gravity of the water supplied into the baffle 8 is set so that the difference from the reference value _mc2 increases as the downward deviation of the eccentric position from the center of gravity of the water increases. Also, the acceleration threshold value ( _mc1 ) when the eccentric position in the dehydration tub 2 is above the center of gravity of the water supplied into the baffle 8 is set so that the difference from the reference value _mc2 increases as the upward deviation of the eccentric position from the center of gravity of the water increases.

At that time, the acceleration threshold value ( _mc3 ) when the eccentric position in the dehydration tank 2 is below the center of gravity of the water supplied into the baffle 8 is set to increase by a larger amount when the difference between the acceleration threshold value (mc3) and the reference value _mc2 increases in accordance with the amount of downward deviation, compared to the acceleration threshold value ( _mc1 ) when the eccentric position in the dehydration tank ₂ is above the center of gravity of the water supplied into the baffle 8.

In addition, in the washing machine 1 of this embodiment, when there is a first state in which the amount of vertical deviation between the eccentric position in the spin tub 2 and the center of gravity of the water supplied to the baffle 8 is greater than a predetermined value, and a second state in which the above-mentioned deviation is smaller than a predetermined value, the effect of the present invention can be obtained if there is at least one of the first state and the second state in which the acceleration threshold of the first state is set to a value greater than the acceleration threshold of the second state.

In the above embodiment, the determination is made as to whether the eccentric load position in the dehydration tub 2 is at the top, the center in the height direction, or the bottom of the dehydration tub 2 based on the vibrations of the upper end of the dehydration tub 2 detected by the acceleration sensor 5 and the vibrations of the lower end of the dehydration tub 2 detected by the acceleration sensor 6, but this is not limited to the above. In the washing machine according to the present invention, any method can be used to determine at what height in the dehydration tub 2 the eccentric load position is located.

In the above embodiment, the specified value is set so that the upper region of the dehydration tank 2, the heightwise central region of the dehydration tank 2, and the lower region of the dehydration tank 2 are uniform, but the heights of these regions are not limited to being uniform. For example, the height of at least one of the upper region of the dehydration tank 2, the heightwise central region of the dehydration tank 2, and the lower region of the dehydration tank 2 may be different.

In the above embodiment, the height of the center of gravity of the water supplied into the baffle 8 is approximately the same as the height of the center of the height of the dehydration tank 2, but this is not limited to the above. For example, depending on the shape of the baffle 8 provided on the inner peripheral surface of the dehydration tank 2, the height of the center of gravity of the water supplied into the baffle 8 may be located above the height of the center of the height of the dehydration tank 2, or may be located below the height of the center of the height of the dehydration tank 2.

In the above embodiment, of the signals from the two acceleration sensors 5 and 6, the signal from the acceleration sensor 5 is used to calculate the eccentricity position θ1, and the signals from the two acceleration sensors 5 and 6 are used to calculate the eccentricity amount (M), but this is not limited to the above. For example, the method of calculating the eccentricity amount (M) and the eccentricity position θ1 may be any method that uses at least one of the signals from the two acceleration sensors 5 and 6.

Other configurations may also be modified in various ways without departing from the spirit of the present invention.

1 Washing machine 2 Dehydration tub 2a Inner surface of dehydration tub 2c Bottom of dehydration tub 3 Outer tub 4 Pulsator 5 Acceleration sensor (first acceleration sensor, acceleration detection means)
6 Acceleration sensor (second acceleration sensor, acceleration detection means)
8 Baffle (water passage pipe section)
30 Water injection device 55 Proximity switch (position detection device)
60 Control means 65 Unbalance amount detection section (eccentricity detection means)
66 Unbalanced position detector (eccentricity detector)

Claims (2)

A dehydration tub is disposed in the outer tub and has a pulsator disposed at the bottom thereof;
Three or more baffles are disposed at equal intervals in a circumferential direction on an inner peripheral surface of the dehydration tub;
a water injection device for injecting water into each of the baffles;
an acceleration detection means for detecting vibration of the dehydration tub;
a position detection device that transmits a pulse signal in response to rotation of the dehydration tub;
an eccentricity detection means for detecting an amount and position of eccentricity in the dehydration tub;
a control means for controlling the water injection device so as to start injecting water into the baffle facing the eccentric position when the amount of eccentricity becomes equal to or greater than a water injection threshold value in a dewatering process, and stop injecting water into the baffle when the amount of eccentricity becomes equal to or less than an acceleration threshold value;
When the rotation speed of the dehydration tank is greater than the resonance rotation speed,
The washing machine, characterized in that the acceleration threshold is set to a larger value as the amount of deviation in the height direction between an eccentric position in the spin tub and a center of gravity position of water supplied to the baffle increases. the acceleration threshold value when the eccentric position in the dehydration tub is below the center of gravity of the water supplied into the baffle is greater than the acceleration threshold value when the eccentric position in the dehydration tub is above the center of gravity of the water supplied into the baffle;
The washing machine according to claim 1, characterized in that the acceleration threshold when the eccentric position in the spin tub is at approximately the same height as the center of gravity of the water supplied into the baffle is smaller than the acceleration threshold when the eccentric position in the spin tub is above the center of gravity of the water supplied into the baffle.

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