Drum-type washing machine

Abstract

To provide a drum-type washing machine in which vibration amplitude of an outer tank is reduced and the outer tank or a weight suppresses occurrence of noise by preventing collision of a housing in a resonance rotation speed range of the outer tank when a drum and the outer tank are enlarged.SOLUTION: A drum-type washing machine 100 comprises: a housing 1; an outer tank 17 that is supported in the housing 1 and can store liquid inside; a drum 21 capable of rotating in the outer tank 17; and a motor 22 to rotate the drum 21. The outer tank 17 has ribs 17c protruding to the outside of a back face. A weight 42 is disposed on the back face of the outer tank 17. The weight 42 disposed on the back face of the outer tank 17 is built between the ribs 17c disposed on the back face of the outer tank 17. Height of the weight 42 disposed between the ribs on the back face of the outer tank 17 is lower than the ribs 17c disposed on the back face of the outer tank 17.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a drum-type washing machine for dehydrating clothes and the like. [Background technology]

[0002] In the spin-drying operation of a drum-type washing machine, it is necessary to reduce the vibration of the washing tub (hereinafter referred to as the "outer tub") itself. The vibration of the outer tub is reduced by providing a weight on the outer tub. Patent Document 1 is an example of a document relating to vibration reduction during spin-drying operation by providing a weight on the outer tub. In Patent Document 1, the front adjustment weight (referred to as the "weight" in this invention) is fixed to the front lower part of the outer tub. It is also described that the rear adjustment weight (referred to as the "weight" in this invention) is fixed to the rear lower part of the outer tub. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-6006 A (paragraph 0028, Figure 3) Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been an increasing need to wash large amounts of clothes at once, and washing capacity has been increased (hereinafter referred to as "large capacity"). In order to increase capacity, it is necessary to enlarge the drum into which the clothes are put and the outer tub that contains the drum. On the other hand, if the width of the washing machine body is also increased to enlarge the drum and outer tub, the washing machine body will become larger, making it difficult to transport and install. Therefore, it is necessary to increase the capacity while maintaining the width of the washing machine body.

[0005] If the outer tub is enlarged while maintaining the width of the washing machine body, the gap between the housing constituting the washing machine body and the outer tub is reduced, and when the vibration amplitude of the outer tub becomes excessive, the outer tub is likely to come into contact with the housing, which may cause abnormal noise. In addition, since clothes are put into the drum from the front to the rear, clothes are likely to be distributed at the rear of the drum, and clothes are likely to be unevenly distributed at the rear of the drum. When clothes are unevenly distributed at the rear of the drum, it becomes a vibration force that vibrates the rear of the outer tub. Therefore, the vibration amplitude at the rear of the outer tub is likely to be larger than the vibration amplitude at the front of the outer tub, and the rear of the outer tub is likely to come into contact with the housing when the capacity is increased. In order to prevent the rear of the outer tub from colliding with the housing, a weight is provided at the rear of the outer tub, and the mass at the rear of the outer tub due to the weight is increased, thereby reducing the vibration amplitude at the rear of the outer tub.

[0006] The drum-type washing machine of Patent Document 1 has a weight at the rear lower part of the outer tub. When the drum and outer tub are enlarged in this configuration to increase the capacity, in addition to reducing the gap between the outer tub and the housing, the gap between the weight and the housing also decreases because the weight protrudes from the outer tub. When the gap between the weight and the housing decreases, there is a risk that the weight and the housing will come into contact with each other and generate abnormal noise when the vibration amplitude of the outer tub becomes excessive. In addition, generally, when the weight of a weight is increased, the effect of reducing the vibration amplitude of the outer tub increases, but in order to increase the weight of the weight, the shape of the weight needs to be enlarged. When the shape of the weight is enlarged, the gap between the weight and the housing is further reduced, so that the weight and the housing are more likely to collide with each other, which may cause abnormal noise. Furthermore, when the shape of the weight is enlarged, the cost increases because the material cost increases.

[0007] The object of the present invention is to provide a drum-type washing machine which, when the drum and outer tub are enlarged, reduces the vibration amplitude of the outer tub in the resonant rotation speed range of the outer tub, and suppresses the generation of abnormal noise caused by preventing the outer tub or weight from colliding with the housing. [Means for solving the problem]

[0008] In order to achieve the above object, the drum type washing machine of the present invention comprises a housing, an outer tub supported within the housing and capable of storing liquid therein, a drum rotatable in the outer tub, and a motor for rotating the drum, the outer tub having a rib protruding outward from the rear surface thereof, a weight provided on the rear surface of the outer tub, and the weight provided on the rear surface of the outer tub being built in between the ribs provided on the rear surface of the outer tub. Other aspects of the present invention will be described in the embodiments described later. Effect of the Invention

[0009] According to the present invention, a drum-type washing machine can be provided in which, when the drum and outer tub are enlarged, the vibration amplitude of the outer tub is reduced in the resonant rotation speed range of the outer tub, and the generation of abnormal noise caused by the outer tub or weight preventing collision with the casing is suppressed. [Brief description of the drawings]

[0010] [Figure 1] 1 is a perspective view of a drum-type washing machine according to a first embodiment. [Diagram 2] 1 is a cross-sectional view of an internal structure of a drum-type washing machine according to a first embodiment, as viewed from the right side. [Figure 3A] 11A to 11C are diagrams illustrating an example of the drum rotation operation in the dehydration process. [Figure 3B] 13A to 13C are diagrams illustrating another example of the drum rotation operation in the dehydration process. [Figure 4A] FIG. 2 is a view of the outer tank according to the first embodiment, seen from the rear side. [Figure 4B] 4B is a cross-sectional view taken along line AA in FIG. 4A. [Diagram 5] 11 is a cross-sectional view of an internal structure of a drum-type washing machine according to a second embodiment, as viewed from the right side. FIG. [Figure 6A] FIG. 11 is a view of the outer tank according to the second embodiment, seen from the rear side. [Figure 6B] FIG. 11 is a view of the outer tub with weights arranged therein according to the second embodiment, seen from the rear side. [Figure 7A] FIG. 11 is a view of the outer tank according to the third embodiment, seen from the rear side. [Figure 7B]FIG. 11 is a rear view of the outer tub with weights arranged therein according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a drum type washing machine according to the present invention will be described with reference to the drawings. The drum type washing machine according to the present invention also includes a drum type washing and drying machine having a drying function.

[0012] <<First embodiment>> A drum type washing machine 100 according to a first embodiment will be described with reference to Figs. 1 to 3B. Fig. 1 is a perspective view of a drum type washing machine 100 according to the first embodiment. Fig. 2 is a cross-sectional view of the internal structure of the drum type washing machine 100 according to the first embodiment, seen from the right side. As shown in both figures, the outer shell of the drum type washing machine 100 is covered with a housing 1, which is composed of left and right side panels 1a, a front cover 1b, a rear cover 1c, a top cover 1d, and a bottom cover 11. The top cover 1d is provided with a water supply hose connection port 30 for supplying water from a water faucet to the drum type washing machine 100.

[0013] The door 2 is for closing an opening (not shown) for inserting and removing clothes, which is provided at approximately the center of the front cover 1b, and is supported by a hinge (not shown) provided on the front cover 1b so that it can be opened and closed. The door 2 opens when a door opening handle 2a is pulled to release a locking mechanism (not shown), and closes when the door 2 is pressed against the front cover 1b, locking the locking mechanism. The front cover 1b has a circular opening 1ba for inserting and removing clothes, which is approximately concentric with the opening 9a of the front stay 9 and the opening 17a of the outer tub 17.

[0014] An operation / display panel 3 provided on the upper part of the housing 1 includes a power switch 4 and an operation switch 5. The operation / display panel 3 is electrically connected to a control device 13 provided inside the housing 1.

[0015] An outer tub 17 for storing water (liquid) is provided inside the housing 1. Ribs 17b protruding out of the surface of the outer tub 17 are provided on the outer periphery of the outer tub 17, and ribs 17c protruding out of the surface of the outer tub 17 are provided on the back surface of the outer tub 17. The ribs 17b and 17c are integrally formed with the outer tub 17 and serve as strength members for the outer tub 17.

[0016] The lower part of the outer tub 17 is supported by a damper 29 fixed to the housing 1. The damper 29 is composed of four parts: a front first damper 25, a front second damper 26, a rear first damper 27, and a rear second damper 28. The upper part of the outer tub 17 is connected to the upper stay 7 by a suspension device 12, so that the outer tub 17 is supported in a state where it is suspended from the housing 1. The suspension device 12 is composed of, for example, a coil spring.

[0017] A weight 40 is provided at the lower front (front side) of the outer tub, a weight 41 is provided at the upper front (front side) of the outer tub 17, and a weight 42 is provided at the rear surface of the outer tub 17. The arrangement of the weight 42 according to the present invention will be described in detail later.

[0018] The outer tub 17 contains a drum 21 for storing clothes. A motor 22 for rotating the drum 21 is disposed behind the outer tub 17. The motor 22 has a shaft 22a, which serves as a rotation axis, penetrating the outer tub 17 and coupled to the drum 21. The motor 22 also includes a Hall element for detecting the motor rotation speed, and outputs the motor rotation speed detected by the Hall element to the control device 13. By enlarging the drum 21 and the outer tub 17 in the front-rear direction, the capacity is increased while maintaining the width of the housing 1.

[0019] A vibration sensor 24 for detecting vibration of the outer tub 17 is fixed to the lower part of the outer tub 17. The value of the vibration sensor 24 is output to the control device 13.

[0020] The control device 13 appropriately controls the opening and closing of the water supply valve 31, the opening and closing of the drain valve 34a, the rotation of the motor 22, the heat generation of the heater (not shown), etc., according to commands input by the user via the operation / display panel 3, detection values ​​of various sensors, control programs, etc., to perform each process such as washing, rinsing, spin-drying, and drying. Of these processes, the spin-drying process according to this embodiment will be described in detail later. Based on the motor rotation speed input from the motor 22, the control device 13 calculates the rotation speed of the drum 21 corresponding to the motor rotation speed. Based on the vibration value input from the vibration sensor 24, the control device 13 also calculates the outer tub vibration value in any direction.

[0021] When motor 22 is driven, drum 21 is driven to rotate in both forward (counterclockwise when viewed from the front of drum type washing machine 100) and reverse (clockwise when viewed from the front of drum type washing machine 100). Rotation axis Az of drum 21 is horizontal from the front to the rear of drum type washing machine 100 or inclined so that the back side faces downward. Fig. 2 shows a state in which it is inclined so that the back side faces downward.

[0022] Drum 21 is provided with a plurality of dewatering holes 21b for draining the wash water in drum 21 into outer tub 17, and is provided with a plurality of baffles 23 (only one is shown in FIG. 2) on its inner circumferential surface. The baffles 23 are provided at intervals in the circumferential direction of drum 21 and lift up clothes placed in drum 21 as drum 21 rotates. Baffles 23 extend in the front-to-rear direction of drum 21.

[0023] A cylindrical fluid balancer 21c is provided at the front end (front side) of the drum 21. The outer tub 17 is an approximately cylindrical shape with an opening at the front and a closed rear, with a bottom. The opening of the outer tub 17 and the loading port of the housing 1 are connected by a bellows 19 that easily expands and contracts in the front-rear direction. The bellows 19 is made of a ring-shaped elastic member, and the drum 21 is water-sealed by closing the door 2. The loading port of the housing 1, the opening of the outer tub 17, and the opening of the drum 21 are connected to each other, and clothes can be put in and taken out of the drum 21 by opening the door 2. The outer tub 17 can be divided into a side including the opening and a side to which the motor 22 is attached.

[0024] A water supply valve 31 is disposed below the water supply hose connection port 30. One end of a water supply pipe 32 for supplying water to the outer tub 17 is connected to the water supply valve 31. When the water supply valve 31 is opened, water flows from the water supply hose connection port 30 through the water supply pipe 32 into the detergent container 33, and water is supplied into the outer tub 17 from a front water supply hose 35 or a rear water supply hose 36.

[0025] A drain valve 34a is provided in the drain path of a drain hose 34 provided at the bottom of the outer tub 17. When the drain valve 34a is closed, the water supplied to the outer tub 17 accumulates in the outer tub 17, and when the drain valve 34a is opened, the washing water in the outer tub 17 is drained from the drain hose 34 to the outside of the drum type washing machine 100.

[0026] <Basic operation of drum washing machine 100> Next, a basic operation of the drum type washing machine 100 will be described. First, the user presses the power switch 4 to start the drum type washing machine 100. The user then pulls the door opening handle 2a to open the door 2 and places clothes in the drum 21. After closing the door 2, the user operates the operation switch 5 to set up the operation and start the operation.

[0027] When operation starts, drum 21 rotates under the control of control device 13, and the laundry volume before water is poured is calculated. The laundry volume is calculated based on the current value of motor 22 when motor 22 is rotated. At this time, the greater the laundry volume, the greater the load on motor 22 and the greater the current value, so the laundry volume can be determined from the current value. Then, the amount of detergent to be dispensed is displayed on operation and display panel 3 based on the laundry volume. At this time, the greater the calculated laundry volume, the greater the amount of detergent to be dispensed. The user checks the display on operation and display panel 3 and dispenses a predetermined amount of detergent into detergent container 33. Control device 13 then starts the washing process.

[0028] In the washing step, the controller 13 opens the water supply valve 31, and supplies water supplied from the water supply hose connection port 30 into the outer tub 17 together with detergent via the water supply pipe 32, the detergent container 33, and the front water supply hose 35 or the rear water supply hose 36. At this time, the larger the calculated laundry volume, the larger the amount of water supplied in the washing step. After performing this operation for a predetermined time, the controller 13 performs a washing operation for a predetermined time in which the drum 21 is rotated forward, stopped, reversed, and stopped repeatedly. At this time, the laundry is lifted up by the baffle 23 and dropped repeatedly, thereby enhancing the washing power of the clothes.

[0029] After the washing step, the control device 13 executes the spin-drying step. Fig. 3A is a diagram showing an example of the drum rotation operation in the spin-drying process (an example of the drum rotation operation when unbalance is not detected), and Fig. 3B is a diagram showing another example of the drum rotation operation in the spin-drying process (an example of the drum rotation operation when unbalance is detected).

[0030] In the spin-drying process shown in FIG. 3A, the drum 21 is rotated at a low rotation speed (for example, less than 100 r / min) at which the clothes do not stick to the drum 21. At the low rotation speed, the clothes soaked in water in the washing process are lifted by the baffle 23 when the drum 21 rotates, and are spread on the inner circumferential surface of the drum 21 as the clothes fall. When the clothes start to spread, the rotation speed of the drum 21 is gradually increased to make the clothes stick to the drum 21. When the clothes stick to the drum 21, the rotation speed of the drum 21 is increased to pass through the resonance rotation speed range of the outer tub 17 (for example, 100 to 400 r / min) and reach a steady rotation speed (for example, 900 r / min), thereby centrifugally spinning out the water contained in the clothes. The resonance rotation speed of the outer tub 17 is a value obtained by converting the natural frequency (Hz) at which the outer tub 17 resonates into a rotation speed (rpm).

[0031] In the resonant rotation speed range of outer tub 17, the vibration amplitude of outer tub 17 becomes large, so when the outer tub vibration value calculated by control device 13 exceeds a predetermined value (hereinafter referred to as "imbalance detection"), the rotation speed of drum 21 shown in Fig. 3B is stopped and spin-drying is restarted (hereinafter referred to as "retry"). When the number of imbalance detections or retry counts exceeds a predetermined number, the spin-drying process after the washing process is skipped and the process moves to the next process.

[0032] After the spin cycle, the control device 13 executes the rinsing cycle. In the rinsing cycle, the water supply valve 31 is opened, and water supplied from the water supply hose connection port 30 is supplied into the outer tub 17 via the water supply pipe 32, the detergent container 33, and the front water supply hose 35 or the rear water supply hose 36. As in the washing cycle, the greater the calculated laundry volume, the greater the amount of water supplied. In the rinsing cycle, as in the washing cycle, the drum 21 is rotated forward, stopped, reversed, and stopped repeatedly. At this time, an agitation operation is performed for a predetermined period of time, in which the clothes lifted by the baffle 23 fall.

[0033] Thereafter, the controller 13 repeats the spin-drying and rinsing steps a predetermined number of times, and then proceeds to the final spin-drying step. If the number of unbalance detections or the number of retries in the final spin-drying step exceeds a predetermined number, an error is notified.

[0034] If the drum type washing machine has a drying function, the control device 13 executes a drying process after the final spin-drying process. The rotation speed of the drum 21 in the drying process is set to be slower than that in the washing process. In the drying process, the drum 21 is rotated at a slow speed and hot air is blown from an air blowing unit (not shown) onto the clothes in the drum 21 to dry the clothes while reducing wrinkles in the clothes.

[0035] <Vibration amplitude of outer tank 17> Next, the vibration amplitude of the outer tub 17 in the resonance rotation speed range of the outer tub 17 will be described. Since clothes are fed from the front to the rear of the drum 21, they are likely to be distributed behind the drum 21. If the clothes become tangled and unevenly distributed, the uneven distribution of the clothes is added to the vibration force due to the centrifugal force of the drum 21, and the vibration amplitude of the outer tub 17 increases in the resonant rotation speed range of the outer tub 17. Since the clothes are distributed behind the drum 21, uneven distribution of the clothes is likely to occur behind the drum 21. If uneven distribution of the clothes occurs behind the drum 21, the vibration amplitude of the rear of the outer tub 17 increases in the resonant rotation speed range of the outer tub 17. Therefore, in the resonant rotation speed range of the outer tub 17, the vibration amplitude of the rear becomes larger than the vibration amplitude of the front of the outer tub 17, and the rear of the outer tub 17 comes closest to the housing 1.

[0036] <Weight 42 placement> Next, the arrangement of the weight 42 provided on the rear surface of the outer tub 17 will be described with reference to Figs. 4A and 4B. Fig. 4A is a view of the outer tub 17 according to the first embodiment as seen from the rear side. Fig. 4B is a cross-sectional view taken along line AA in Fig. 4A. The weight 42 is provided between the ribs 17c (between the ribs) provided on the rear side of the outer tub 17. By providing the weight 42 between the ribs 17c, the weight 42 is disposed inside the outer tub 17.

[0037] By providing the weight 42 on the back surface of the outer tub 17, the vibration amplitude behind the outer tub 17 can be reduced by the mass effect, and abnormal noise caused by contact between the outer tub 17 and the housing 1 in the resonant rotation speed range of the outer tub 17 can be suppressed. When the capacity is increased, the outer tub 17 is enlarged, and the gap between the outer tub 17 and the housing 1 is reduced, so that the outer tub 17 and the housing 1 come into contact with each other, easily generating abnormal noise.

[0038] By providing the weight 42 between the ribs 17c, as shown in the AA cross section of FIG. 4B, the weight 42 can be prevented from protruding from the outer tub 17, and thus the reduction in the gap between the outer tub 17 and the housing 1 can be suppressed as in Patent Document 1. Moreover, the height of the weight 42 provided between the ribs 17c on the back surface of the outer tub 17 is lower than the height of the ribs 17c on the back surface of the outer tub 17. That is, the weight 42 is a dimension that does not protrude from the ribs 17c. In this way, by suppressing the reduction in the gap between the outer tub 17 and the housing 1 due to the weight 42, it is possible to prevent the generation of abnormal noise caused by contact between the outer tub 17 and the housing 1 when the washing tub formed by the outer tub 17 and the like is enlarged to increase the capacity.

[0039] The drum type washing machine 100 of the first embodiment includes a housing 1, an outer tub 17 supported within the housing 1 and capable of storing liquid therein, a drum 21 that can rotate around the outer tub 17, and a motor 22 that rotates the drum 21, the outer tub 17 is provided with a rib 17c that protrudes outward from the rear surface thereof, and a weight 42 is provided on the rear surface of the outer tub 17, and the weight 42 provided on the rear surface of the outer tub 17 is built in between the ribs 17c provided on the rear surface of the outer tub 17. The drum type washing machine 100 also includes weights (weights 40, 41) on the upper and lower front portions of the outer tub 17.

[0040] As described above, by providing the weights 42 between the ribs 17c on the back surface of the outer tub 17, it is possible to reduce the vibration amplitude at the rear of the outer tub 17 in the resonant rotation speed range of the outer tub 17 while suppressing the reduction in the gap between the outer tub 17 and the housing 1, thereby preventing abnormal noise caused by contact between the outer tub 17 and the housing 1 when the capacity is increased.

[0041] <<Second embodiment>> Next, a second embodiment will be described with reference to Figures 5, 6A, and 6B. In the second embodiment, the shape of the back surface of the outer tub 17 is changed from that of the first embodiment. In the second embodiment, the arrangement of the weight 42 when the shape of the back surface of the outer tub 17 is changed from that of the first embodiment will be described. Note that the drum type washing machine 100 has a basically similar configuration to that of the first embodiment, so the following will describe the different parts.

[0042] First, a drum type washing machine 100 according to a second embodiment will be described with reference to FIG. 5 is a cross-sectional view of the internal structure of a drum type washing machine 100 according to the second embodiment, seen from the right side. In the second embodiment, an air passage 46 for blowing hot air from the blower motor 43 to the clothes in the drum 21 is provided on the left side of the drum type washing machine 100. A duct 17d for sucking the hot air blown into the drum 21 into the blower motor 43 and circulating it is provided on the left side of the rear surface of the outer tub 17. In the figure, the arrow (→) indicates the route of the air blowing.

[0043] FIG. 6A is a view of the outer tub 17 according to the second embodiment, seen from the rear side. FIG. 6B is a view of the outer tub 17 with the weight 42 according to the second embodiment, seen from the rear side. FIG. 6A shows the rear side of the outer tub. When the duct 17d is provided on the left side of the outer tub 17, the center of gravity G1 of the outer tub 17 is on the left side as shown in FIG. 6A, and the center of gravity G1 of the outer tub 17 is separated from the rotation axis G2 of the drum 21. When the center of gravity G1 of the outer tub 17 is separated from the rotation axis G2 of the drum 21, the centrifugal force increases when the drum 21 rotates, so that the vibration amplitude of the rear of the outer tub 17 becomes excessive in the resonance rotation speed range of the outer tub 17, and the outer tub 17 and the housing 1 are easily brought into contact with each other, which may cause abnormal noise.

[0044] As shown in Fig. 6B, the weight 42 provided on the back surface of the outer tub 17 in the second embodiment is provided between the ribs 17c on the opposite side of the duct 17d with respect to the rotation axis G2 of the drum 21. By providing the weight 42 on the opposite side of the duct 17d with respect to the rotation axis G2 of the drum 21, the center of gravity G1 of the outer tub 17 is located on the right side.

[0045] Therefore, by providing the duct 17d, the center of gravity G1 of the outer tub 17, which was previously on the left side, is moved to the right side by the weight 42, and the center of gravity G1 of the outer tub approaches the rotation axis G2 of the drum 21. By moving the center of gravity G1 of the outer tub closer to the rotation axis G2 of the drum 21, it is possible to suppress an increase in centrifugal force when the drum 21 rotates, and to prevent the vibration amplitude behind the outer tub 17 from becoming excessive in the resonance rotation speed range of the outer tub 17, and to prevent abnormal noise caused by contact between the outer tub 17 and the housing 1 when the capacity is increased.

[0046] As described above, when the rear surface of the outer tub 17 is provided with a duct 17d for blowing warm air onto the clothes in the drum 21, by providing a weight 42 between the ribs 17c on the opposite side of the duct 17d relative to the rotation axis G2 of the drum 21, the center of gravity G1 of the outer tub 17 and the rotation axis G2 of the drum 21 can be prevented from moving away from each other. This prevents the vibration amplitude at the rear of the outer tub 17 from becoming excessive in the resonant rotation speed range of the outer tub 17, and prevents abnormal noise caused by contact between the outer tub 17 and the housing 1 when the capacity is increased.

[0047] In the second embodiment, the duct 17d is provided on the left side of the outer tub 17 and the weight 42 is provided on the right side of the outer tub 17. However, when the duct 17d is provided on the right side of the outer tub 17, the weight 42 is provided on the left side of the outer tub 17, thereby preventing the vibration amplitude of the outer tub 17 described in the second embodiment from becoming excessive.

[0048] <<Third embodiment>> Next, a third embodiment will be described with reference to FIG. 7. In the third embodiment, the position of the motor 22 provided on the back surface of the outer tub 17 is changed from that of the first and second embodiments. In the third embodiment, the motor 22 in the first and second embodiments is changed to a belt driving motor 22A. In the third embodiment, the arrangement of the weight 42 when the motor 22 is changed to the belt driving motor 22A will be described. Note that the drum type washing machine 100 has a basically similar configuration to the first embodiment, so the following will describe the different parts.

[0049] Fig. 7A is a view of the outer tub 17 according to the third embodiment, seen from the rear side. Fig. 7B is a view of the outer tub 17 with the weight 42 according to the third embodiment, seen from the rear side. Fig. 7A shows the rear side of the outer tub 17, and includes a belt drive motor 22A at the lower left of the rear side of the outer tub 17, and a pulley 44 on the rear side of the outer tub 17. The pulley 44 is connected to the shaft 22a. The belt drive motor 22A and the pulley 44 are connected by a belt 45. When the belt drive motor 22A rotates, the pulley 44 rotates via the belt 45, and the drum 21 rotates.

[0050] When the belt drive motor 22A is provided at the lower left of the back surface of the outer tub 17, as shown in Fig. 7A, the center of gravity G1 of the outer tub 17 is on the left side, and the center of gravity G1 of the outer tub 17 is separated from the rotation axis G2 of the drum 21. When the center of gravity G1 of the outer tub 17 is separated from the rotation axis G2 of the drum 21, the centrifugal force increases when the drum 21 rotates, so that the vibration amplitude behind the outer tub 17 becomes excessive in the resonance rotation speed range of the outer tub 17, making it easier for the outer tub 17 to come into contact with the housing 1, which may cause abnormal noise.

[0051] As shown in Fig. 7B, the weight 42 provided on the back surface of the outer tub 17 in the third embodiment is provided between the ribs 17c on the opposite side of the belt drive motor 22A with respect to the rotation axis G2 of the drum 21. By providing the weight 42 on the opposite side of the belt drive motor 22A with respect to the rotation axis G2 of the drum 21, the center of gravity G1 of the outer tub 17 is located on the right side.

[0052] Therefore, by providing the belt drive motor 22A, the center of gravity G1 of the outer tub 17, which was previously on the left side, is moved to the right side by the weight 42, and the center of gravity G1 of the outer tub approaches the rotation axis G2 of the drum 21. By moving the center of gravity G1 of the outer tub closer to the rotation axis G2 of the drum 21, it is possible to suppress an increase in centrifugal force when the drum 21 rotates, and to prevent the vibration amplitude behind the outer tub 17 from becoming excessive in the resonance rotation speed range of the outer tub 17, and to prevent the generation of abnormal noise caused by contact between the outer tub 17 and the housing 1 when the capacity is increased.

[0053] As described above, when the belt drive motor 22A is provided at the bottom left of the back surface of the outer tub 17, by providing a weight 42 between the ribs 17c in the opposite direction of the belt drive motor 22A relative to the rotation axis G2 of the drum 21, the center of gravity G1 of the outer tub 17 and the rotation axis G2 of the drum 21 can be prevented from moving away from each other, preventing the vibration amplitude at the rear of the outer tub 17 from becoming excessive in the resonant rotation speed range of the outer tub 17 and preventing abnormal noise caused by contact between the outer tub 17 and the housing 1 when the capacity is increased.

[0054] In the third embodiment, the belt drive motor 22A is provided at the bottom left of the back surface of the outer tub 17 and the weight 42 is provided on the right side of the outer tub 17. However, when the belt drive motor 22A is provided at the bottom right of the back surface of the outer tub 17, the weight 42 can be provided on the left side of the outer tub 17 to prevent the vibration amplitude of the outer tub 17 described in the third embodiment from becoming excessive. [Explanation of symbols]

[0055] 1 Case 17 Outer tank 17b Rib 17c Rib 17d Duct 21 Drums 22 Motor 22A belt drive motor 40 Weight (front lower weight) 41 Weight (upper front weight) 42 Weight (rear weight) 43 Blower motor 44 Pulley 45 Belt 46 Wind path 100 Drum type washing machine

Claims

1. A housing and an outer tank supported within the housing and capable of storing a liquid therein; A rotatable drum in the outer tank; A motor is provided to rotate the drum, The outer tub is provided with a rib protruding outward from the rear surface thereof, and a weight is provided on the rear surface of the outer tub. The weight provided on the rear surface of the outer tub is built between the ribs provided on the rear surface of the outer tub. A drum type washing machine characterized by the above.

2. In the drum type washing machine according to claim 1, A duct is provided on the rear surface of the outer tank, The weights built in between the ribs on the back surface of the outer tub are provided on the opposite side of the duct with respect to the drum rotation axis. A drum type washing machine characterized by the above.

3. In the drum type washing machine according to claim 1, The motor is provided at the lower part of the rear surface of the outer tub, The weight built in between the ribs on the back surface of the outer tub is provided in the opposite direction to the motor with respect to the drum rotation axis. A drum type washing machine characterized by the above.

4. In the drum type washing machine according to claim 1, The weight is provided at the upper and lower parts of the front side of the outer tank. A drum type washing machine characterized by the above.

5. In the drum type washing machine according to any one of claims 1 to 4, The height of the weight built in between the ribs on the back surface of the outer tub is lower than the height of the ribs. A drum type washing machine characterized by the above.

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