JP7538785B2 - Drum type washing machine - Google Patents

Description

The present invention relates to a drum-type washing machine that performs washing and spin-drying.

As a drum-type washer-dryer belonging to this technical field, there is a drum-type washing machine described in Patent Document 1. The drum-type washing machine in Patent Document 1 has a configuration in which a water tub unit (outer tub) is supported by two vibration dampers (suspensions, vibration-proofing members) at a position lower toward the front side than the position of the center of gravity G. In this configuration, based on output signals FFR, FLR, and FUD of vibration components in multiple directions related to the front-rear direction (FFR), front-left direction (FLR), and front-upward direction (FUD), if the magnitude relationship between the output signal FFR related to the vibration component in the front-rear direction and the output signal FLR related to the vibration component in the front-upward direction at a predetermined rotation speed R1, R2 point (R1<R2) is FFR>FUD at the predetermined rotation speed R1 and FFR<FUD at the predetermined rotation speed R2, it is determined that a rear imbalance has occurred and corresponds to a rear imbalance abnormality (see paragraph 0019 of the specification). Unbalance refers to a state in which clothes are unevenly distributed inside the rotating drum, which causes the drum to vibrate when it rotates.

JP 2010-125250 A

In recent years, the trend in the market has been toward larger washing capacity. When increasing capacity, it is necessary to increase capacity while maintaining the dimensions of the washing machine body so as not to impair the installation and transportability of the washing machine. If the dimensions of the outer tub are enlarged to increase capacity while maintaining the dimensions of the washing machine body, the gap between the body and the outer tub becomes smaller, and the outer tub and the body are more likely to collide when the outer tub vibrates strongly.
It is possible to reduce the vibration of the outer tub by providing four suspensions to the outer tub. The vibration state of the outer tub differs between two suspensions and four suspensions due to the imbalance caused by uneven distribution of clothes. For this reason, it is necessary to detect the vibration of the outer tub according to the number of suspensions.

However, in the drum-type washing machine of Patent Document 1, while it describes the detection of vibration of two suspensions, it makes no mention of changes in the vibration of the outer tub due to changes in the number of suspensions associated with larger capacity. In addition, while it can detect rear imbalance when judging imbalance, it makes no mention of the detection of vibration of opposing imbalance, which causes the outer tub to vibrate back and forth. If it is not possible to detect the vibration of opposing imbalance, there is a risk that the elastic member will be damaged during high-speed rotation. Furthermore, if it is not possible to detect opposing imbalance, it may erroneously detect rear imbalance and opposing imbalance, causing the operation to end before the spin-drying is completed.

The present invention was made in consideration of this background, and aims to provide a drum-type washing machine with high accuracy in detecting imbalance when the outer tub is supported by four vibration-proof members.

In order to solve the above-mentioned problems, the drum-type washing machine of the present invention comprises a housing, an outer tub supported by a member including four vibration-damping members within the housing and capable of storing liquid inside, a rotatable drum provided inside the outer tub, a vibration detection means installed in the outer tub and detecting vibration displacement, and a control means, wherein the control means, during the process of increasing the rotational speed of the drum in the dehydration operation, judges it to be an in-phase imbalance if the vertical displacement of the outer tub is greater than a predetermined first threshold, and judges it to be an opposite imbalance or balance if the vertical displacement of the outer tub is smaller than the predetermined first threshold , and when it is determined to be the in-phase imbalance, judges it to be unbalanced if the left-right displacement of the outer tub is greater than a predetermined second threshold, and when it is determined to be the opposite imbalance or balance, judges it to be unbalanced if the front-to-back displacement of the outer tub is greater than the predetermined second threshold .

The present invention provides a drum-type washing machine that has high accuracy in detecting imbalance when the outer tub is supported by four vibration-proof members. Problems, configurations, and effects other than those described above will become clear from the description of the following embodiment.

1 is an external view of a drum-type washing machine according to an embodiment of the present invention; 1 is a cross-sectional view of a drum-type washing machine according to an embodiment of the present invention, as viewed from the right side. In a conventional drum-type washing machine, a graph is shown of the front-to-rear displacement of the outer tub due to in-phase imbalance when there is a 1000g weight on the rear side of the drum, and a graph is shown of the front-to-rear displacement of the outer tub due to opposing imbalance when there are 600g weights on the front and rear sides of the drum. In a drum-type washing machine according to this embodiment, a graph is shown of the front-to-rear displacement of the outer tub in an in-phase imbalance when there is a weight of 1000 g on the rear side of the drum, and a graph is shown of the front-to-rear displacement of the outer tub in an opposing imbalance when there are weights of 600 g on both the front and rear sides of the drum. Graphs of front-to-back displacement, up-down displacement, and left-to-right displacement are shown for an in-phase imbalance (weight 1000 g at the rear of the drum) in the drum-type washing machine of this embodiment. Graphs showing front-to-back displacement, up-down displacement, and left-to-right displacement due to opposing unbalance (weights of 600 g on the front and rear sides of the drum) in the drum-type washing machine of this embodiment are shown. 10 is a flowchart of an imbalance determination process in a spin-drying process according to the present embodiment. 13 is a flowchart of an imbalance determination process in a spin-drying process according to a modified example of the embodiment.

<Overview of drum washing machines>
The outer tub of the drum type washing machine in this embodiment is supported by four suspensions. The control means of the drum type washing machine determines whether or not an in-phase imbalance has occurred based on the magnitude of the up-down displacement of the outer tub. If an in-phase imbalance has been determined, the control means determines whether or not an imbalance exists based on the magnitude of the left-right displacement of the outer tub. If an in-phase imbalance has not occurred, the control means determines whether or not an imbalance exists based on the magnitude of the front-rear displacement (displacement in the front-rear direction) of the outer tub.

By doing this, when the number of suspensions is four, it is possible to improve the accuracy of detecting rear imbalance and opposing imbalance, which in turn makes it possible to prevent damage to the elastic member during high-speed rotation and to prevent operation from ending before the spin-drying is completed.
The amount of imbalance is actually a numerical value that indicates the degree to which clothes are unevenly distributed, but it is difficult to actually measure it. For this reason, the amount of imbalance is sometimes indicated by the vibration displacement of the outer tub.

<Exterior of drum-type washing machine>
Fig. 1 is an external view of a drum type washing machine 100 according to this embodiment. A housing 101 constituting the outer shell of the drum type washing machine 100 includes left and right side plates 101A, a front cover 101B, a rear cover 101C (see Fig. 2 described later), a top cover 101D, and a lower stay 111 (see Fig. 2). Note that Fig. 1 shows only the right side plate 101A, and the left side plate 101A is formed in the same manner as the right side plate.

The side plate 101A is provided with a convex portion 106 that creates an uneven surface on the side plate 101A in order to increase the rigidity of the side plate 101A itself and the rigidity of the housing 101. The housing 101 also has a sufficient strength due to an outer frame (not shown) that is made up of the side plate 101A, the back cover 101C, and a reinforcing member. The top cover 101D that constitutes the housing 101 is provided with a water supply hose connection port 130 for supplying water from a water tap to the drum washing machine 100.

The door 102 is provided approximately in the center of the front cover 101B and serves to close an opening (not shown) for inserting and removing clothes. The door 102 is supported so as to be openable and closable by a hinge (not shown) provided on the front cover 101B. The door 102 opens when the door opening handle 102A is pulled to release a locking mechanism (not shown), and closes when the door is pressed against the front cover 101B, locking the locking mechanism. The front cover 101B has a circular opening 101BA (see FIG. 2) for inserting and removing clothes, which is approximately concentric with the opening of the front stay (not shown) and the opening 117A of the outer tub 117 (see FIG. 2).

The operation/display panel 103 provided on the top of the housing 101 includes a power switch, an operation switch, and a display panel. The operation/display panel 103 is electrically connected to a control device 113 (see FIG. 2) provided inside the housing 101.

<Internal structure of a drum washing machine>
Fig. 2 is a cross-sectional view of the drum type washing machine 100 according to this embodiment as seen from the right side. The internal configuration of the drum type washing machine 100 will be described with reference to Fig. 2. The outer frame includes a side plate 101A, a rear cover 101C, an upper stay 107, a front upper stay (not shown), a front stay (not shown), a lower front stay (not shown), and a lower stay 111. The reinforcing member described above includes the upper stay 107, the front upper stay, the front stay, the lower front stay, and the lower stay 111.

An outer tub 117 for storing water is provided inside the housing 101. The lower part of the outer tub 117 is supported in an anti-vibration manner by a total of four suspensions (anti-vibration members): two suspensions 126A fixed to the left and right sides of the front of the lower stay 111 and two suspensions 126B fixed to the left and right sides of the rear of the lower stay 111. The upper part of the outer tub 117 is connected to the upper stay 107 by a suspension device 112 (e.g., a coil spring), so that the outer tub 117 is supported in a state of being suspended from the outer frame.
The outer tub 117 contains a drum 121 for storing clothes. A motor 122 for rotating the drum 121 is disposed behind the outer tub 117. The motor 122 has a shaft 122A, which serves as a rotation axis, passing through the outer tub 117 and coupled to the drum 121.

The control device 113 (control means) acquires the measured value of the vibration sensor 128 provided in the outer tub 117 and controls the rotation speed (rpm) of the motor 122. When the vibration amplitude (displacement) of the outer tub 117 exceeds a predetermined threshold due to an imbalance in the clothes placed in the drum 121 during the spin-drying process, the control device 113 temporarily suspends the spin-drying process and rotates the drum 121 forward and backward (loosening operation). When the imbalance in the clothes is corrected by rotating the drum 121 forward and backward, the control device 113 restarts the spin-drying process (retry).

When the motor 122 is driven, the drum 121 is driven to rotate in both the forward direction (clockwise when viewed from the front of the drum-type washing machine 100) and the reverse direction. The rotation axis Az of the drum 121 is horizontal from the front to the rear of the drum-type washing machine 100, or is inclined so that the rear is downwards. Figure 2 shows the state in which it is inclined so that the rear is downwards.

The drum 121 is provided with a plurality of dewatering holes 121B for draining the wash water in the drum 121 into the outer tub 117, and is provided with a plurality of baffles 123 (only one is shown in FIG. 2) on its inner circumferential surface. The baffles 123 are provided at intervals around the circumference of the drum 121 and extend in the front-to-rear direction of the drum 121. The baffles 123 lift up the clothes placed in the drum 121 as the drum 121 rotates.

A cylindrical fluid balancer 121C is provided at the front end (front side) of the drum 121. The outer tub 117 is generally cylindrical with an opening at the front and a closed rear. The opening 117A of the outer tub 117 and the loading port of the housing 101 are connected by a bellows 119 that easily expands and contracts in the front-to-rear direction. The bellows 119 is made of a ring-shaped elastic material, and the drum 121 is sealed with water by closing the door 102. The loading port of the housing 101, the opening 117A of the outer tub 117, and the opening of the drum 121 are connected, and clothes can be put in and taken out of the drum 121 by opening the door 102. The outer tub 117 can be divided into a side including the opening 117A and a side to which the motor 122 is attached.

A water supply valve 131 is disposed below the water supply hose connection port 130. One end of a water supply hose 132 for supplying water to the outer tub 117 is connected to the water supply valve 131. When the water supply valve 131 is opened, water flows from the water supply hose connection port 130 to the water supply hose 132, and is supplied into the outer tub 117 via the detergent container 133.
A drain valve 134A is provided in the drain path of a drain hose 134 provided at the bottom of the outer tub 117. When the drain valve 134A is closed, the water supplied to the outer tub 117 accumulates in the outer tub 117, and when the drain valve 134A is opened, the washing water in the outer tub 117 is drained from the drain hose 134 to the outside of the drum type washing machine 100.

<Overview of drum washing machine operation>
The drum type washing machine 100 starts when the user presses the power switch on the operation and display panel 103. Next, the user pulls the door opening handle 102A to open the door 102 and places clothes into the drum 121. After closing the door 102, the user operates the operation switch on the operation and display panel 103 to instruct the washing machine to start operation.

When an instruction to start operation is received, the control device 113 rotates the drum 121 to calculate the laundry volume before water is poured in. The laundry volume is calculated based on the current value of the motor 122 when it is rotated. The larger the laundry volume, the greater the load on the motor 122 and the larger the current value, so the laundry volume can be determined based on the current value. The control device 113 displays the amount of detergent based on the laundry volume on the operation and display panel 103. At this time, the larger the calculated laundry volume, the greater the amount of detergent to be poured in. The user checks the display on the operation and display panel 103 and pours a specified amount of detergent into the detergent container 133. The control device 113 then starts the washing process.

During the washing process, the control device 113 opens the water supply valve 131 and supplies water supplied from the water supply hose connection port 130 into the outer tub 117 together with detergent via the water supply hose 132 and detergent container 133. At this time, the greater the calculated volume of clothes, the greater the amount of water supplied. After performing this operation for a predetermined time, the control device 113 performs a washing operation for a predetermined time in which the drum 121 is rotated forward, stopped, reversed, and stopped repeatedly. At this time, the clothes are lifted up by the baffle 123 and dropped repeatedly, thereby enhancing the cleaning power of the clothes.

After the washing process, the control device 113 executes the spin-drying process. In the spin-drying process, the control device 113 first rotates the drum 121 at a low speed so that the clothes do not stick to the drum 121. At the low speed, the clothes that have absorbed water in the washing process are lifted by the baffle 123 as the drum 121 rotates, and are spread out on the inner surface of the drum 121 as the clothes fall. When the clothes start to spread, the control device 113 gradually increases the rotation speed of the drum 121 to make the clothes stick to the drum 121. When the clothes stick to the drum 121, the rotation speed of the drum 121 is increased, and the water contained in the clothes is centrifugally dehydrated by passing through the resonant rotation speed range of the outer tub 117 where the vibration of the outer tub 117 increases, until it reaches the target rotation speed.

After the spin cycle, the control device 113 executes the rinsing cycle. In the rinsing cycle, the water supply valve 131 is opened, and water supplied from the water supply hose connection port 130 is supplied into the outer tub 117 via the water supply hose 132 and detergent container 133. As with the washing cycle, the larger the laundry volume, the greater the amount of water supplied. In the rinsing cycle, as with the washing cycle, the drum 121 repeats the cycle of forward rotation, stop, reverse rotation, and stop. At this time, an agitation operation is performed for a predetermined period of time, in which the clothes lifted by the baffle 123 fall.

Thereafter, the control device 113 repeats the dehydration step and the rinsing step a predetermined number of times, and then proceeds to the final dehydration step. The operation time in the target rotation speed range in the final dehydration step is set longer than that in the dehydration step.
After the final spin-drying step, the control device 113 executes the drying step. The rotation speed of the drum 121 in the drying step is set to be slower than that in the washing step. In the drying step, the drum 121 is rotated at a slow speed and hot air is blown onto the clothes in the drum 121 from an air blowing unit (not shown) to dry the clothes while reducing wrinkles in the clothes.

<Imbalance detection in conventional drum-type washing machines>
Next, an example of unbalance determination by the vibration sensor 128 provided in the outer tub 117 will be described. In the dehydration process, the control device 113 gradually increases the rotation speed of the drum 121, passes through the resonant rotation speed range where the vibration of the outer tub 117 increases, and reaches the target rotation speed. In the resonant rotation speed range of the outer tub 117, the vibration of the outer tub 117 is detected by the vibration sensor 128, and the control device 113 increases the rotation speed of the drum 121 while performing unbalance determination. In the resonant rotation speed range of the outer tub 117, when the vibration (vibration amplitude) of the outer tub 117 is smaller than a preset threshold, the control device 113 increases the rotation speed of the drum 121 toward the target rotation speed. In the resonant rotation speed range of the outer tub 117, when the vibration of the outer tub 117 is larger than the threshold, the control device 113 stops the rotation of the drum 121 and performs a retry (loosening operation).

Imbalance can be divided into in-phase imbalance and counter-phase imbalance. In-phase imbalance occurs when clothes are unevenly distributed at either the front or rear of the drum 121. Counter-phase imbalance occurs when clothes are unevenly distributed at the front and rear of the drum 121. Counter-phase imbalance occurs when clothes are unevenly distributed at the front and rear of the drum 121. In counter-phase imbalance, clothes are unevenly distributed at the front and rear of the outer tub 117, which generates a couple of forces in the outer tub 117, making the outer tub 117 more likely to vibrate back and forth at the target rotation speed than in-phase imbalance, and making the bellows 119 more likely to be damaged. To avoid this, the vibration amplitude threshold for detecting imbalance when passing through the resonant rotation speed range of the outer tub 117 is set so that the counter-phase imbalance threshold is smaller than the in-phase imbalance threshold.

In conventional drum-type washing machines, two suspensions are provided near the approximate center of the outer tub. When clothes are shifted to a position away from the approximate center of the suspension and outer tub, causing an imbalance, the front-to-back displacement becomes large in the resonant rotation speed range of the outer tub. In conventional drum-type washing machines, both in-phase and counter-phase imbalance occur when clothes are shifted to a position away from the position of the suspension near the center of the outer tub. When this occurs, the displacement becomes large when the outer tub resonates in the front-to-back direction in the resonant rotation speed range of the outer tub.

Figure 3 shows graph 211 of the front-to-rear displacement of the outer tub in an in-phase imbalance when there is a 1000g weight on the rear side of the drum in a conventional drum-type washing machine, and graph 212 of the front-to-rear displacement of the outer tub in an opposed imbalance when there are 600g weights on the front and rear sides of the drum. In a conventional drum-type washing machine, the outer tub passes through the resonant rotation speed range in the front-to-rear direction at around 300 rpm. At this time, the maximum displacement values for the in-phase imbalance and opposed imbalance are approximately the same. Therefore, in a conventional drum-type washing machine, the allowable imbalance amounts for the in-phase imbalance and opposed imbalance can be set by setting a threshold value for the front-to-rear displacement at around 300 rpm.

The "displacement (mmP-P)" on the vertical axis in Figure 3 and Figure 4 described below indicates that the vertical axis is the numerical value in millimeters of both amplitudes (Peak to Peak). Of course, the vertical axis may be the numerical value of one amplitude (0-Peak), or it may be any other numerical value as long as it can be used for control.

<Problems with conventional unbalance detection for drum-type washing machines>
4 shows a graph 221 of the front-rear displacement of the outer tub 117 in the drum type washing machine 100 according to this embodiment in the case of an in-phase imbalance when there is a weight 1000g on the rear side of the drum 121, and a graph 222 of the front-rear displacement of the outer tub 117 in the case of an opposed imbalance when there are weights 600g on the front and rear sides of the drum 121. The drum type washing machine 100 according to this embodiment has a vibration-proof structure including four suspensions 126A, 126B on the front and rear of the outer tub 117 in order to increase the capacity of the drum 121.

In-phase imbalance occurs when clothes are shifted to the front or rear side from approximately the center of the outer tub 117, generating a couple of forces in the outer tub 117. As for opposing imbalance, the suspensions 126A, 126B are provided on the front and rear sides of the outer tub 117, which can suppress the front-to-rear vibration of the outer tub 117 more than in-phase imbalance. Therefore, the front-to-rear displacement of the outer tub 117 is greater in in-phase imbalance than opposing imbalance. In other words, compared to a vibration-proof structure with two suspensions, a vibration-proof structure with four suspensions 126A, 126B produces a large difference in front-to-rear displacement between in-phase imbalance and opposing imbalance.

In a drum-type washing machine 100 equipped with four suspensions 126A, 126B, the threshold for the front-rear displacement is set at approximately 300 rpm, as in a conventional drum-type washing machine. If the threshold is set based on the same-phase imbalance, the front-rear displacement of the opposing imbalance will exceed the allowable amount of imbalance. As a result, the front-rear displacement of the outer tub 117 at the target rotation speed becomes large, and the bellows 119 will be damaged.

On the other hand, if the threshold is set based on the counter imbalance, the allowable amount of in-phase imbalance becomes smaller. Even if the imbalance is such that the forward/backward displacement at the target rotation speed is allowable, the threshold will be exceeded, and the drum-type washing machine 100 may repeatedly retry, increasing the operating time and ending without spin-drying.

As explained above, the same imbalance judgment as for the vibration isolation structure with two suspensions cannot be applied to the vibration isolation structure with four suspensions 126A, 126B. Unlike the vibration isolation structure with two suspensions, the vibration isolation structure with four suspensions 126A, 126B sets a threshold value by distinguishing between in-phase imbalance and opposing imbalance.

<Unbalance determination according to this embodiment>
Fig. 5 shows a graph 231 of front-rear displacement, a graph 232 of up-down displacement, and a graph 233 of left-right displacement in the case of in-phase imbalance (weight 1000g on the rear side of drum 121) in drum type washing machine 100 of this embodiment. Graphs 221 and 231 are graphs of front-rear displacement in the case of in-phase imbalance. Fig. 6 shows a graph 241 of front-rear displacement, a graph 242 of up-down displacement, and a graph 243 of left-right displacement in the case of opposing imbalance (weights 600g on the front and rear sides of drum 121) in drum type washing machine 100 of this embodiment. Graphs 222 and 241 are graphs of front-rear displacement in the case of opposing imbalance.

In-phase imbalance and opposing imbalance pass through the resonant rotation speed range of the outer tub 117 at around 300 rpm, resulting in large left-right and front-back displacement. In-phase imbalance and opposing imbalance differ in the rotation speed of the drum 121 at which the vertical displacement increases. With in-phase imbalance, the vertical displacement of the outer tub 117 increases at 300 rpm to 400 rpm (see graph 232). With opposing imbalance, the vertical displacement of the outer tub 117 increases at 200 rpm to 300 rpm (see graph 242).

Regarding the vertical vibration of the outer tub 117, in-phase unbalance causes the outer tub 117 to vibrate while pulling the suspension 112, whereas in counter-phase unbalance, the outer tub 117 vibrates while pulling the bellows 119, which has a lower spring constant than the suspension 112. Generally, the higher the spring constant, the higher the rotation speed at which the vertical displacement increases. In other words, the rotation speed of the drum 121 at which the vertical displacement of the outer tub 117 increases differs between in-phase unbalance and counter-phase unbalance. For this reason, in-phase unbalance and counter-phase unbalance can be distinguished by looking at the magnitude of the vertical displacement at a rotation speed of around 300 rpm. In addition, in-phase unbalance and counter-phase unbalance can be distinguished by looking at whether the vertical displacement at around 300 rpm is increasing or decreasing.

<Imbalance determination process>
7 is a flowchart of the unbalance determination process in the spin-drying step according to the present embodiment. In the following description, the rotation speed of the drum 121 will be simply referred to as the rotation speed.
In step S11, the control device 113 increases the rotation speed to 300 rpm.

In step S12, if the vertical displacement at a rotation speed of around 300 rpm is equal to or greater than a predetermined threshold (step S12→YES), the control device 113 proceeds to step S15, and if it is less than the threshold (step S12→NO), the control device 113 proceeds to step S13. The control device 113 proceeds to step S15 in the case of in-phase imbalance, and to step S13 in the case of opposite-phase imbalance or balance. Note that the control device 113 may proceed to step S15 if the rate of change of the vertical displacement relative to an increase in rotation speed at a rotation speed of around 300 rpm is equal to or greater than a predetermined threshold, and proceed to step S13 if it is less than the threshold.
In addition, the "predetermined threshold value" for the vertical displacement and the "predetermined threshold value" (first threshold value) for the rate of change of the vertical displacement herein are values in millimeters or percentages that are determined, for example, for each model of drum-type washing machine.

In step S13, if the longitudinal displacement is equal to or greater than a predetermined threshold value (step S13→YES), the control device 113 proceeds to step S16, and if the longitudinal displacement is less than the threshold value (step S13→NO), the control device 113 proceeds to step S14.
In step S14, the control device 113 increases the rotation speed to the target rotation speed and continues the dehydration for a predetermined period of time.
In step S15, if the left/right displacement is equal to or greater than a predetermined threshold value (step S15→YES), the control device 113 proceeds to step S16, and if it is less than the threshold value (step S15→NO), the control device 113 proceeds to step S14.

In step S16, the control device 113 stops the rotation of the drum 121.
In step S17, the control device 113 executes the loosening operation and returns to step S11 (retry).

<Features of the imbalance determination process>
The drum type washing machine 100 uses the vertical displacement of the outer tub 117 at a rotation speed of about 300 rpm to distinguish between in-phase imbalance and counter imbalance (including balance) (see step S12), and then judges whether or not imbalance has occurred (see steps S13 and S15). In this way, the control device 113 can optimize the judgment of whether in-phase imbalance and counter imbalance are correct (the direction of displacement and the threshold value), and optimize the passing imbalance amount, which is the amount of imbalance when passing through the resonance rotation speed range. In addition, the front-rear displacement of the outer tub 117 at the target rotation speed is prevented from becoming excessive, and the bellows 119 can be prevented from being damaged. In addition, by optimizing the passing imbalance amount, the drum type washing machine 100 can suppress an increase in the number of retries, prevent an increase in the operation time, and prevent the operation from ending without completing the spin cycle. The imbalance judgment process shown in this embodiment can also be applied to a drum type washing and drying machine.

<<Modification: Unbalance determination process taking water leakage into account>>
When water is drained from the clothes, the in-phase imbalance may change to the opposite phase imbalance, or the opposite phase imbalance may change to the in-phase imbalance. The imbalance determination process taking the drainage of water into consideration will be described below.

FIG. 8 is a flowchart of an imbalance determination process in the spin-drying process according to a modified example of this embodiment.
Steps S31 to S39, excluding steps S34 and S35, are respectively similar to steps S11 to S17 shown in Fig. 7. Steps S34 and S35 will be described below.

In step S34, the control device 113 increases the rotation speed.
In step S35, if the rotation speed reaches 400 rpm, the control device 113 proceeds to step S36 (step S35→YES), and if not (step S35→NO), the control device 113 returns to step S32 and repeats the unbalance determination.

In this way, by repeating the unbalance judgment when the rotation speed is between 300 rpm and 400 rpm, even if in-phase unbalance changes to opposite-phase unbalance or opposite-phase unbalance changes to in-phase unbalance due to water leakage, the judgment of whether the in-phase unbalance and opposite-phase unbalance are correct or not can be optimized, and the amount of passing unbalance can be optimized.

<Modification: Unbalance determination process after same-phase/opposite-phase unbalance determination>
In the above embodiment, the control device 113 determines the imbalance by the left-right displacement (step S15) after determining the in-phase imbalance, and by the front-rear displacement (see step S13) after determining the opposite-phase imbalance. Alternatively, the control device 113 may determine the imbalance by the front-rear displacement after determining the in-phase imbalance, and by the left-right displacement after determining the opposite-phase imbalance.

Other Modifications
Although several embodiments of the present invention have been described above, these embodiments are merely illustrative and do not limit the technical scope of the present invention. The present invention can take various other embodiments, and various modifications such as omissions and substitutions can be made without departing from the gist of the present invention. These embodiments and modifications are included in the scope and gist of the invention described in this specification, etc., and are included in the scope of the invention described in the claims and their equivalents.

100 Drum type washing machine 101 Housing 113 Control device (control means)
117 Outer tank 121 Drum 126A, 126B Suspension (vibration-proof member)
128 Vibration sensor (vibration detection means)

Claims (5)

A housing and
an outer tank supported by a member including four vibration isolating members in the housing and capable of storing liquid therein;
A rotatable drum disposed inside the outer tub;
A vibration detection means is provided in the outer tank and detects a vibration displacement.
and a control means.
The control means
During the dehydration operation, the rotation speed of the drum is increased.
When the vertical displacement of the outer tank is greater than a predetermined first threshold, it is determined that an in-phase imbalance occurs;
When the vertical displacement of the outer tub is smaller than the first threshold, it is determined that there is an opposing imbalance or balance .
When it is determined that the in-phase imbalance exists, if the left-right displacement of the outer tank is greater than a predetermined second threshold value, it is determined that the imbalance exists;
When it is determined that the outer tub is in a counter imbalance state or in a balanced state, if the forward/backward displacement of the outer tub is greater than a predetermined second threshold value, it is determined that the outer tub is in a counter imbalance state or in a balanced state.
A drum type washing machine characterized by the above. A housing and
an outer tank supported by a member including four vibration isolating members in the housing and capable of storing liquid therein;
A rotatable drum disposed inside the outer tub;
A vibration detection means is provided in the outer tank and detects a vibration displacement.
and a control means.
The control means
During the dehydration operation, the rotation speed of the drum is increased.
When the rate of change of the vertical displacement of the outer tank is greater than a predetermined first threshold, it is determined that an in-phase imbalance occurs;
When the rate of change of the vertical displacement of the outer tub is smaller than the first threshold, it is determined that the outer tub is in a counter imbalance or a balance state .
When it is determined that the in-phase imbalance exists, if the left-right displacement of the outer tank is greater than a predetermined second threshold value, it is determined that the imbalance exists;
When it is determined that the outer tub is in a counter imbalance state or in a balanced state, if the forward/backward displacement of the outer tub is greater than a predetermined second threshold value, it is determined that the outer tub is in a counter imbalance state or in a balanced state.
A drum type washing machine characterized by the above. A housing and
an outer tank supported by a member including four vibration isolating members in the housing and capable of storing liquid therein;
A rotatable drum disposed inside the outer tub;
A vibration detection means is provided in the outer tank and detects a vibration displacement.
and a control means.
The control means
During the dehydration operation, the rotation speed of the drum is increased.
When the vertical displacement of the outer tank is greater than a predetermined first threshold, it is determined that an in-phase imbalance occurs;
When the vertical displacement of the outer tub is smaller than the first threshold, it is determined that there is an opposing imbalance or balance .
When it is determined that the in-phase imbalance exists, if the forward/backward displacement of the outer tank is greater than a predetermined second threshold value, it is determined that the imbalance exists;
When the opposite imbalance or balance is determined, if the lateral displacement of the outer tub is greater than a predetermined second threshold, the outer tub is determined to be unbalanced.
A drum type washing machine characterized by the above. A housing and
an outer tank supported by a member including four vibration isolating members in the housing and capable of storing liquid therein;
A rotatable drum disposed inside the outer tub;
A vibration detection means is provided in the outer tank and detects a vibration displacement.
and a control means.
The control means
During the dehydration operation, the rotation speed of the drum is increased.
When the rate of change of the vertical displacement of the outer tank is greater than a predetermined first threshold, it is determined that an in-phase imbalance occurs;
When the rate of change of the vertical displacement of the outer tub is smaller than the first threshold, it is determined that the outer tub is in a counter imbalance or a balance state .
When it is determined that the in-phase imbalance exists, if the forward/backward displacement of the outer tank is greater than a predetermined second threshold value, it is determined that the imbalance exists;
When the opposite imbalance or balance is determined, if the lateral displacement of the outer tub is greater than a predetermined second threshold, the outer tub is determined to be unbalanced.
A drum type washing machine characterized by the above. The control means
The drum type washing machine according to any one of claims 1 to 4, characterized in that, when it is not determined that there is an imbalance and the rotation speed of the drum is lower than a predetermined rotation speed threshold, the determination of whether there is an in-phase imbalance, an opposite-phase imbalance, or the balance is performed again.

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