DRUM-TYPE WASHING MACHINE

Abstract

In a drum-type washing machine, a plurality of dampers include a first damper and a second damper, the second damper is provided in such a manner that compression force on the second damper from a rotary drum rotated in the forward direction is larger than that on the first damper, the second damper and a vibration detection portion are arranged posterior to a gravity center of a water tank in the front and rear direction, and the first damper is arranged anterior to the second damper. Thus, precise imbalance determination is performed, so that low vibration is realized.

Description

TECHNICAL FIELD

The present invention relates to a drum-type washing machine for controlling vibration of its entire water tank.

BACKGROUND ART

Conventionally, a configuration in this type of drum-type washing machine is proposed that a vibration detector is provided in a water tank and an imbalance amount of a laundry (such as clothes) is determined by an output of the vibration detector in order to control vibration (for example, refer to Patent Literature 1).

FIG. 6 shows a configuration diagram of the conventional drum-type washing machine described in Patent Literature 1.

As shown in FIG. 6, a drum 101 for accommodating and rotating a laundry is rotatably arranged in a water tank 103. In a bottom part of the water tank 103, a motor 105 for driving and rotating the drum 101 is provided. In an opening part of the drum 101, a lid body 108 is openably and closably provided. Between the water tank 103 and a housing 109, spring bodies 110 are provided. By the spring bodies 110, a posture of the water tank 103 is retained. The water tank 103 is supported by an anti-vibration damper 111 in such a manner that vibration of the water tank 103 is not transmitted to the housing 109 at the time of a spin-drying operation. In order to prevent that a user feels anxiety due to transmission of the vibration of the water tank 103 to the housing 109, a seal packing 107 is provided between a laundry inlet on a front surface of the water tank 103 and the housing 109.

On the front side of an upper part of the water tank 103, a vibration detector 106 using an acceleration sensor is arranged. In accordance with an output of the vibration detector 106, an imbalance determining portion 113 determines an imbalance state (unstable state) in the drum 101. In a case where the imbalance state in the drum 101 is detected, a control portion 116 controls an action of the motor 5 and the like, so that the vibration is controlled.

As well as shown in Patent Literature 1, a configuration that a vibration detector is provided in a water tank and an imbalance amount of a laundry is determined by an output of the vibration detector is proposed in order to control vibration (for example, refer to Patent Literature 2).

FIG. 7 is a vertical sectional view of the conventional drum-type washing machine described in Patent Document 2. FIG. 8 is an internal front view of major parts of the same drum-type washing machine.

As shown in FIGS. 7 and 8, a drum 121 accommodated in a water tank 120 is driven and rotated taking a horizontal shaft 122 attaching to the drum 121 as a rotation center axis. The water tank 120 is hanged down from an upper part of a main body 118 by two pairs of spring bodies 126. The water tank 120 is supported from a bottom part of the main body 118 by a pair of anti-vibration dampers 127. In a front part of the water tank 120, a weight 128 for suppressing vibration of the water tank 120 is provided. In the water tank 120, a vibration detector 130 for detecting the vibration of the water tank 120 by utilizing an acceleration sensor is provided. As shown in FIG. 8, the vibration detector 130 is provided at a symmetrical position to a motor 124 arranged in the vicinity of a lower corner part of the main body 118 taking a center shaft 134 of the water tank 120 as a center. When the laundry becomes imbalanced, the vibration detector 130 detects a maximum vibration value of the water tank 120 vibrated taking the heavy motor 124 as a substantial revolution center.

• Patent Literature 1: JP 2010-277 A
• Patent Literature 2: JP 6-233890 A

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

However, in the conventional configurations, in a case where the laundry exists so as to be leaned to the front surface side or the center side of the rotary drum at the time of a spin-drying step, vibration on the front surface side of the water tank becomes larger than vibration on the back surface side of the water tank. Meanwhile, the seal packing provided between the front surface side of the water tank and the housing is generally made of an anti-vibration rubber material. When the vibration detector is arranged on the front side of the upper part of the water tank, even in a case of abnormal vibration of the water tank, the vibration is damped by an anti-vibration effect of the seal packing. Therefore, there is a problem that a vibration state of the water tank is not easily precisely detected by the vibration detector.

In a case where the laundry exists so as to be leaned to the back surface side of the drum, the vibration of the water tank is damped by the anti-vibration damper. Thus, a vibration value is decreased. Therefore, even when vibration components in plural directions are to be detected by the acceleration sensor of the vibration detector arranged on the front side of the upper part of the water tank, a determining method becomes complicated. In such a way, there is also a problem that the imbalance state is not easily determined.

The present invention is to solve the above conventional problems, and an object thereof is to provide a low-vibration drum-type washing machine for performing precise imbalance determination by an arrangement balance between a support damper and an anti-vibration damper, an arrangement position and an arrangement direction of the anti-vibration damper, an arrangement position of an acceleration sensor, and the like.

Means to Solving the Issue

In order to solve the above conventional problems, a drum-type washing machine of the present invention includes a rotary drum having a substantially horizontal axis of rotation;

a water tank incorporating the rotary drum;

a motor for rotating the rotary drum;

a washing machine housing elastically-supporting the water tank from underneath by a plurality of dampers; and

a vibration detector for detecting vibration of the water tank,

wherein the plurality of dampers comprise a first damper and a second damper,

the second damper is provided in such a manner that compression force on the second damper from the rotary drum rotating in a forward direction is larger than that on the first damper,

the second damper and the vibration detector are arranged posterior to a gravity center of the water tank in a front and rear direction, and

the first damper is arranged anterior to the second damper.

Effect of the Invention

According to the drum-type washing machine of the present invention, precise imbalance determination is performed and low vibration is realized.

BRIEF DESCRIPTION OF THE DRAWINGS

These aspects and features of the present invention will become clear from the following description taken in conjunction with the preferred embodiments thereof with reference to the accompanying drawings, in which:

FIG. 1 is a vertical sectional view of a drum-type washing machine according to Embodiment 1 of the present invention;

FIG. 2 is a front view in which an interior of the drum-type washing machine of FIG. 1 is seen;

FIG. 3 is a vertical sectional view of the drum-type washing machine according to a second embodiment of the present invention;

FIG. 4 is a front view in which an interior of the drum-type washing machine of FIG. 3 is seen;

FIG. 5 is a block circuit diagram showing a part of a configuration relating to a control device of the drum-type washing machine of FIG. 3;

FIG. 6 is a configuration diagram of a conventional drum-type washing machine;

FIG. 7 is a vertical sectional view of another conventional drum-type washing machine; and

FIG. 8 is a front view in which an interior of the drum-type washing machine of FIG. 7 is seen from.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to a first aspect of the present invention, there is provided a drum-type washing machine, comprising:

a rotary drum having a substantially horizontal axis of rotation;

a water tank incorporating the rotary drum;

a motor for rotating the rotary drum;

a washing machine housing elastically-supporting the water tank from underneath by a plurality of dampers; and

a vibration detector for detecting vibration of the water tank,

wherein the plurality of dampers comprise a first damper and a second damper,

the second damper is provided in such a manner that compression force on the second damper from the rotary drum rotating in a forward direction is larger than that on the first damper,

the second damper and the vibration detector are arranged posterior to a gravity center of the water tank in a front and rear direction, and

the first damper is arranged anterior to the second damper.

According to the second aspect of the present invention, there is provided the drum-type washing machine according to the first aspect, wherein the vibration detector and the motor are arranged symmetrically about the axis of rotation of the rotary drum.

According to the third aspect of the present invention, there is provided the drum-type washing machine according to the first aspect or the second aspect, wherein the second damper and the vibration detector are arranged in a substantially identical perpendicular plane to a perpendicular plane including a gravity center of the motor in the front and rear direction.

According to the forth aspect of the present invention, there is provided the drum-type washing machine according to the first aspect or the second aspect, further comprising a spring suspending the water tank from the washing machine housing, wherein:

the spring is arranged in a substantially identical perpendicular plane to a perpendicular plane including the gravity center of the water tank in the front and rear direction.

Before the description of the present invention proceeds, it is to be noted that like parts are designated by like reference numerals throughout the accompanying drawings. Hereinbelow, embodiments of the present invention will be described with reference to the accompanying drawings.

Embodiment 1

FIG. 1 is a vertical sectional view of a drum-type washing machine according to Embodiment 1 of the present invention. FIG. 2 is a front view in which an interior of the same drum-type washing machine is seen.

As shown in FIGS. 1 and 2, a rotary drum 17 formed in a cylindrical shape with a bottom is rotatably arranged in a water tank 19. In other words, the water tank 19 accommodates (incorporates) the rotary drum 17. On the entire surface of an outer peripheral wall of the rotary drum 17, a large number of water passage holes 18 are provided. In a rotation center of the rotary drum 17, an axis of rotation (rotation center axis) 20 exists. The axis of rotation 20 is substantially horizontal, and the axial direction of the rotary drum 17 is also substantially horizontal. A drum pulley 28 is coupled to a back surface of the water tank 19 positioned on the axis of rotation 20. The drum pulley 28 is connected to a motor 21 via a belt 29. The motor 21 is coupled to the rotary drum 17 by the belt 29 and the drum pulley 28. The motor 21 drives and rotates the rotary drum 17 in the forward direction or the reverse direction. On an inner wall surface of the rotary drum 17, a plurality of protuberances 22 for agitating a laundry is provided.

A water tank unit 37 is configured by the rotary drum 17, the water tank 19, the motor 21, the drum pulley 28, and the like.

As shown in FIG. 2, weight of the water tank 19 is supported by damping and anti-vibration dampers 25 and 26 attached to a base bottom portion 24 of a washing machine housing 23. Spring bodies 27 are provided between an upper surface of the washing machine housing 23 and an upper part of the water tank 19. The water tank 19 is oscillatably and elastically anti-vibration supported by the spring bodies 27. That is, the washing machine housing 23 elastically supports the water tank 19 from the lower side by the plurality of dampers 25 and 26.

As shown in FIG. 2, the dampers 25 and 26 include a pair of support dampers 25 (first dampers) left-right symmetrically arranged when seen from the front side, and one anti-vibration damper 26 (a second damper).

The support dampers 25 support the water tank 19 and suppress vibration of the water tank 19. As shown in FIG. 1, the support dampers 25 are arranged on the more front surface side than (anterior to) a gravity center position G of the water tank unit 37 in the front and rear (front-back) direction.

The anti-vibration damper 26 particularly suppresses the vibration of the water tank 19. As shown in FIG. 1, the anti-vibration damper 26 is arranged on the more back surface side than (posterior to) the gravity center position G. That is, the support dampers 25 are arranged on the more front surface side than the anti-vibration damper 26. The water tank unit 37 is supported by the support dampers 25 and the anti-vibration damper 26 in a favorably balanced state, so that damping and anti-vibration are performed.

As shown in FIG. 2, the anti-vibration damper 26 is provided in such a manner that compression force on the anti-vibration damper 26 from the rotary drum 17 rotated in the forward direction (counterclockwise rotation) A is larger than that on the two support dampers 25. In other words, when seen from a front, the anti-vibration damper 26 is provided in such a manner that a straight line connecting a housing support portion 35 and a water tank support portion 36 is inclined at an angle of α to the upstream side of the forward direction A with respect to a straight line connecting the housing support portion 35 and a center position C of the water tank 19.

It should be noted that in a case where the forward direction and the reverse direction of the rotary drum 17 at the time of a spin-drying step are set to be opposite to each other (that is, in a case where the forward direction of the rotary drum 17 is clockwise when seen from the front), the anti-vibration damper 26 may be arranged at a left-right symmetrical position when seen from the front (that is, in a lower part on the left side).

The anti-vibration damper 26 is provided in such a manner that an inclination angle of the anti-vibration damper 26 with respect to a bottom surface of the washing machine housing 23 extending in the horizontal direction becomes smaller than that of the support dampers 25. Thereby, the anti-vibration damper 26 particularly exerts a larger damping effect on vibration in the horizontal direction (left and right direction of FIG. 2).

It should be noted that damping force of the support dampers 25 and the anti-vibration damper 26 may be the same. Alternatively, damping force of the anti-vibration damper 26 may be slightly weaker than that of the support dampers 25.

As shown in FIG. 1, a seal packing 38 formed of a rubber material or the like is coupled between the front surface side of the water tank 19 and the washing machine housing 23. An opening portion 39 of the washing machine housing 23 is openably and closably covered by a lid body 30. By opening the lid body 30, the laundry can be brought into the rotary drum 17 through the opening portion 39 and taken out from the rotary drum 17.

As shown in FIG. 1, a control device 31 is provided on the upper side of the water tank 19. The control device 31 is configured by a micro computer or the like for controlling a series of steps such as washing, rinsing, and spin-drying, and the like. The control device 31 transmits signals with an input setting portion 32 arranged on the upper side of the lid body 30 and an acceleration sensor (vibration detector) 34 arranged in the upper part of the water tank 19. The control device 31 also controls rotation and the like of the motor 21.

The acceleration sensor 34 detects acceleration and vibration not only in one direction but also in multiaxis (two or three axis) directions such as the front and rear direction, the left and right direction, and the up and down direction. Actual vibration of the water tank unit 37 is not always limited to one direction. Thus, by using the multiaxis acceleration sensor 34, movement of the water tank unit 37 is detected with high precision.

Actions and operations of the drum-type washing machine configured as above will be described.

The lid body 30 is opened and the laundry is brought into the rotary drum 17, so that an operation is started. In a first washing step, the rotary drum 17 is driven and rotated at low speed by the motor 21. By driving and rotating the rotary drum 17, the laundry in the rotary drum 17 is brought up and dropped onto a water surface in the rotary drum 17. By such an action, the washing step is progressed. After the washing step is performed for a predetermined time, washing water in the water tank 19 is drained, and intermediate spin-drying is performed. After that, a rinsing step is performed. Also in the rinsing step, the same action as the washing step is performed. In the spin-drying step, by driving and rotating the rotary drum 17 at high speed, water is centrifugally removed from the laundry.

In a case where the laundry brought in the rotary drum 17 is leaned to one side at the time of the spin-drying step, rotation for spin-drying is preferably performed while absorbing leaning (bias) of the laundry. In order to do so, by oscillatably anti-vibration supporting the water tank 19 by the spring bodies 27 or the like, the vibration is prevented from being transmitted to the washing machine housing 23. However, in a case where the leaning of the laundry is abnormally large, the water tank 19 is abnormally vibrated. Thus, there is a fear that large noise is generated from the washing machine or in the worst case, the washing machine is damaged.

In the first embodiment, the control device 31 controls rotation in accordance with the vibration of the water tank unit 37 in the multiaxis directions detected by the acceleration sensor 34. The control device 31 lowers the rotation number of the motor 21, and stops a spin-drying action of the rotary drum 17 and supplies the water again. In such a way, in accordance with a determination result of the vibration, the actions such as easing the leaning of the laundry are performed by control of the control device 31.

The acceleration sensor 34 is provided on the more back surface side than the gravity center position G of the water tank unit 37. Thus, even when the leaning of the laundry is generated in any place in the rotary drum 17, there is little influence on the acceleration sensor 34 by damping of the seal packing 38. Therefore, the vibration of the water tank unit 37 is determined with favorable precision, so that highly precise vibration detection is realized.

Further, by an arrangement position of the anti-vibration damper 26, the vibration of the rotary drum 17 in the left and right direction in particular is largely damped. Thus, a magnitude of the vibration is determined based on the vibration of the water tank unit 37 mainly in the up and down direction. In such a way, an easier detection method is realized.

It should be noted that a case where the axial direction (axis of rotation 20) of the rotary drum 17 is arranged substantially horizontally from the front surface side toward the back surface side is described in the first embodiment. However, the axial direction may be inclined from a horizontal line.

As described above, in the first embodiment, the support dampers 25, the anti-vibration damper 26, and the acceleration sensor 34 are arranged in a favorably balanced manner relative to the water tank unit 37. Thus, precise and efficient imbalance determination is performed irrespective of a place of the leaning of the laundry. By the determination result thereof, low-vibration and low-noise spin-drying control is performed.

The anti-vibration damper is provided at the position and in the direction so that the compression force on the anti-vibration damper acts in the rotation direction (forward direction A) of the rotary drum 17. Thus, the vibration of the water tank in the left and right direction is efficiently damped.

Further, the arrangement position of the anti-vibration damper 26 in the up and down direction relative to the water tank unit 37 is on the more bottom surface side than the support dampers. Thus, the vibration of the water tank 19 in the left and right direction is more effectively suppressed.

As described above, in the drum-type washing machine according to the first embodiment, by an arrangement balance between the support dampers and the anti-vibration damper, the arrangement position and the direction of the anti-vibration damper, an arrangement position of the acceleration sensor, and the like, low vibration and low noise can be realized. Therefore, the drum-type washing machine according to the first embodiment can be applied to a use for other washing machines and the like having a spin-drying function.

Second Embodiment

FIG. 3 is a vertical sectional view of the drum-type washing machine in a second embodiment of the present invention. FIG. 4 is a front view in which an interior of the drum-type washing machine of FIG. 3 is seen.

As shown in FIGS. 3 and 4, a water tank unit 49 is provided in an interior of a washing machine housing 41. The water tank unit 49 includes a water tank 42, a rotary drum 43, and a motor 45. The water tank 42 is oscillatably arranged in the interior of the washing machine housing 41. The rotary drum 43 is rotatably arranged in the water tank 42. A axis of rotation (rotation center axis) 44 extending in the horizontal direction is provided in a rotation center part of the rotary drum 43. The motor 45 arranged in the vicinity of the back surface side of the water tank 42 is coupled to the axis of rotation 44 via a belt 46. By this motor 45, the rotary drum 43 is driven and rotated in the forward direction or in the reverse direction. On an inner wall surface of the rotary drum 43, a plurality of protuberances 47 for agitating the laundry is provided. On an outer peripheral wall of the rotary drum 43, a large number of water passage holes 48 are provided.

The water tank 42 is supported by two support dampers 51 and one anti-vibration damper 91 attached to a lower part of the washing machine housing 41. As shown in FIGS. 3 and 4, a plurality of spring bodies 50 is provided between an upper part of the washing machine housing 41 and the water tank 42. The spring bodies 50 hang down (suspend) the water tank 42 from the washing machine housing 41. The water tank 42 is oscillatably anti-vibration supported by the plurality of spring bodies 50.

As shown in FIG. 3, the pair of spring bodies 50 is arranged on a substantially identical perpendicular plane to a perpendicular plane including a gravity center position Gs of the water tank unit 49 in the front and rear direction.

The two support dampers 51 are dampers provided for a purpose of supporting the water tank 42 and suppressing vibration of the water tank 42. As shown in FIG. 4, the two support dampers 51 are left-right symmetrically arranged when seen from the front. As shown in FIG. 3, the two support dampers 51 are arranged on the more front surface side than the gravity center position Gs of the water tank unit 49. The anti-vibration damper 91 is a damper provided for a purpose of mainly suppressing the vibration of the water tank 42. As shown in FIG. 3, the anti-vibration damper 91 is arranged on the more back surface side than the gravity center position Gs. The anti-vibration damper 91 is connected to the washing machine housing 41 at a housing support portion 93 and connected to the water tank 42 at a water tank support portion 94. It should be noted that the anti-vibration damper 91 may be indirectly connected to the washing machine housing 41 and the water tank support portion 94 via other members. The water tank 42 is supported by the respective dampers in a favorably balanced manner, so that the damping and the anti-vibration of the water tank 42 are performed.

It should be noted that in the second embodiment, friction dampers are used as the dampers 51 and 91. In an interior of the friction damper, a friction pad (not shown) is accommodated. Friction force is generated by rubbing this friction pad and a tube (not shown), and the friction force serves as damping force for suppressing the vibration of the water tank 42.

As shown in FIG. 4, the anti-vibration damper 91 is provided in such a manner that compression force on the anti-vibration damper 91 from the rotary drum 43 rotated in the forward direction (counterclockwise rotation) A is larger than that on the two support dampers 51. In other words, when seen from the front, the anti-vibration damper 91 is provided in such a manner that a straight line connecting the housing support portion 93 and the water tank support portion 94 is inclined at an angle of α to the upstream side of the forward direction A with respect to a straight line connecting the housing support portion 93 and a center position C of the water tank 42.

As shown in FIG. 4, the anti-vibration damper 91 is provided in such a manner that an inclination angle of the anti-vibration damper 91 with respect to a bottom surface of the washing machine housing 41 extending in the horizontal direction becomes smaller than that of the support dampers 51. Thereby, the anti-vibration damper 91 particularly exerts a larger damping effect on the vibration in the horizontal direction (left and right direction of FIG. 4).

It should be noted that damping force of the support dampers 51 and the anti-vibration damper 91 may be the same. Alternatively, the damping force of the anti-vibration damper 91 may be slightly weaker than the damping force of the support dampers 51.

As shown in FIG. 3, a vibration detector 78 is arranged in an upper part on the rear surface side of the water tank 42. As shown in FIG. 4, the vibration detector 78 is arranged at a substantially symmetrical position to the motor 45 with respect to the axis of rotation (rotation center axis) 44. The vibration detector 78 utilizing an acceleration sensor for detecting vibration of the water tank unit 49 detects not only acceleration in one direction but also vibration in the three-dimensional directions of the front and rear direction (X axis direction), the left and right direction (Y axis direction), and the up and down direction (Z axis direction). Based on a detection result of the vibration by the vibration detector 78, an operation is controlled. Actual vibration of the water tank unit 49 is not always limited to one direction. Thus, by using the multiaxis acceleration sensor, the vibration is detected with high precision.

As shown in FIG. 3, the vibration detector 78, a gravity center position Gm of the motor 45, and the anti-vibration damper 91 are arranged on a substantially identical perpendicular plane in the front and rear direction.

A housing opening portion is provided at a position facing a laundry outlet/inlet 53 of the rotary drum 43 in the washing machine housing 41. A lid body 52 is provided so as to openably and closably cover this housing opening portion. By opening the lid body 52, the laundry can be taken out and brought into the rotary drum 43 through the laundry outlet/inlet 53. A front part of the water tank 42 and the housing opening portion are coupled by a seal packing 92. The seal packing 92 is provided so as to suppress the vibration of the water tank unit 49 and to watertightly seal in such a manner that water does not come into a space between the washing machine housing 41 and the water tank 42. When the lid body 52 is closed, the lid body 52 and the seal packing 92 are closely attached, so that the washing machine housing 41 is sealed.

A control device 81 is provided in an upper part in the washing machine housing 41. The control device 81 is configured by a micro computer or the like. In accordance with mode setting and a control program, the control device 81 controls the motor 45, a first electromagnetic valve 57, a second electromagnetic valve 58, a drainage pump 63, and a circulation pump 67, so as to execute cleaning steps including a washing step, a rinsing step, and a spin-drying step.

In the interior of the washing machine housing 41, a water supply passage 54 for supplying washing water (such as tap water) into the water tank 42, a drainage passage 55 for draining the washing water in the water tank 42 to an exterior of the washing machine housing 41, and a water circulation passage 56 for circulating the washing water in the water tank 42 are provided.

The water supply passage 54 is configured by a first water supply hose 59, a second water supply hose 60, a detergent accommodating portion 61, and a water supply passage 62.

The first electromagnetic valve 57 is provided in the first water supply hose 59. The second electromagnetic valve 58 is provided in the second water supply hose 60. The detergent accommodating portion 61 accommodates a drawer (not shown) storing detergent and softener in such a manner that the drawer can be pulled out by touch from the exterior. By opening the first electromagnetic valve 57 or the second electromagnetic valve 58, the washing water flows into the first water supply hose 59 or the second water supply hose 60. The washing water flowing into the first water supply hose 59 or the second water supply hose 60 passes through the detergent accommodating portion 61 and the water supply passage 62, and is supplied into the water tank 42.

The drainage passage 55 is configured by a drainage tube 64, a filter case 88, the drainage pump 63, and a drainage hose 66.

The drainage tube 64 is connected to a drainage port 95 provided in a recessed portion 71 in a bottom part of the water tank 42 and connected to the filter case 88. In an interior of the filter case 88, a lint filter 65 for collecting lint in the washing water is provided. The lint filter 65 is configured so as to be detached by pulling outwardly a filter grip 89 provided in a lower part on a front surface of the washing machine housing 41.

The drainage pump 63 is connected to the filter case 88 and the drainage hose 66. The drainage hose 66 is provided so as to extend upward in the exterior of the washing machine housing 41 from the interior of the washing machine housing 41. By driving the drainage pump 63 at a predetermined timing such as a time of finishing the washing step and a time of finishing the rinsing step, the washing water in the water tank 42 passes through the drainage tube 64, the filter case 88, the drainage pump 63, and the drainage hose 66 in this order, and is drained to the exterior.

It should be noted that in the second embodiment, the filter case 88 is arranged in a right lower part on the front surface of the washing machine housing 41 in order to improve handleability of the filter grip 89. In the second embodiment, the drainage port 95 is provided on the more right side than a horizontal center of the water tank 42 when seen from the front in order to efficiently arrange the drainage tube 64.

The water circulation passage 56 is provided so as to circulate the washing water in the water tank 42 at a predetermined timing such as a time of a pre-washing step, the time of the washing step, and the time of the rinsing step. By this water circulation passage 56, the detergent can be quickly dissolved into the washing water, and imbalance of the detergent is prevented. As a result, washing and rinsing abilities of the drum-type washing machine are improved.

This water circulation passage 56 is configured by the drainage tube 64, the filter case 88, an inflow side passage 68, the circulation pump 67, a discharge side passage 69, and jet ports 70. The inflow side passage 68 is a passage connecting the filter case 88 and the circulation pump 67. The discharge side passage 69 is a passage connecting the circulation pump 67 and the jet ports 70. The jet ports 70 are provided in the front part of the water tank 42 so as to discharge the washing water passing through the discharge side passage 69 into the rotary drum 43.

By driving the circulation pump 67, the washing water in the water tank 42 passes through the drainage tube 64, the filter case 88, the inflow side passage 68, the circulation pump 67, the discharge side passage 69, and the jet ports 70 in this order, and is discharged into the rotary drum 43 as circulated water shown by a solid arrow. It should be noted that the plurality of jet ports 70 is provided in line in the circumferential direction of the rotary drum 43. Thereby, the circulated water is sprinkled toward the laundry in the rotary drum 43 from plural directions.

A heater 72 including a sheathed heater or the like is provided in the recessed portion 71 formed in the bottom part of the water tank 42 and connected to the drainage tube 64 in order to heat the washing water. The heater 72 is arranged in such a manner that the longitudinal direction thereof matches or substantially matches with the horizontal direction. By this heater 72, the washing water in the water tank 42 is heated.

The washing water heated by the heater 72 is circulated via the water circulation passage 56, discharged into the rotary drum 43, and sprinkled on the laundry. After that, the washing water sprinkled on the laundry is moved into the water tank 42 through the water passage holes 48 and heated by the heater 72. These actions are repeated. By heating the washing water, molecule activities of the washing water are activated, and the detergent is activated. As a result, a washing ability of the washing water is improved, so that washing non-uniformity of the laundry can be reduced. In the vicinity of the heater 72, a temperature detector 73 for detecting a water temperature such as a thermistor is provided.

An air trap 74 is formed in a side wall on the rear side of the bottom part of the water tank 42 so as to communicate with the drainage tube 64. The air trap 74 is connected to an air tube 75. The air tube 75 is connected to a water level detector 76 provided in the upper part in the washing machine housing 41. The water level detector 76 is configured by for example a pressure sensor or the like. The water level detector 76 detects a water level of the washing water in the water tank 42 based on water pressure of the washing water in the interior of the water tank 42, that is, pressure in the corresponding air trap 74.

In the upper part in the washing machine housing 41, a coupling hose 77 for coupling an upper part on a rear surface of the detergent accommodating portion 61 and the upper part of the water tank 42 is provided. The coupling hose 77 functions to remove the air in the water tank 42 pressurized during the washing steps.

An operation display portion 79 is provided in the upper part on the front surface of the washing machine housing 41. In the operation display portion 79, an input setting portion 80 to which modes such as an operation course and various functions can be set (selected), and a display portion 96 (refer to FIG. 5) for displaying information inputted to the input setting portion 80 are provided. A user can set the modes such as the operation course and the various functions by inputting to the input setting portion 80.

FIG. 5 is a block circuit diagram showing a part of a configuration relating to the control device of the drum-type washing machine in the embodiment of the present invention.

As shown in FIG. 5, the control device 81 includes a control portion 82 and a load drive portion 86. When a power switch 84 is turned on, electric power is supplied from a commercial power source 83, and the control portion 82 starts controlling each portion. The control portion 82 controls the load drive portion 86 based on output signals of the water level detector 76, the temperature detector 73, a cloth amount detector 85, the vibration detector 78, and a rotation speed detector 90. The load drive portion 86 is configured by a bidirectional thyristor, a relay, or the like. Upon control by the control portion 82, the load drive portion 86 activates the motor 45, the heater 72, the first electromagnetic valve 57, the second electromagnetic valve 58, the drainage pump 63, the circulation pump 67, and the like. Thereby, the washing step, the rinsing step, and the spin-drying step are performed. It should be noted that the cloth amount detector 85 is to detect an amount of the laundry in the rotary drum 43. A notification portion 87 is to display information to be given to the user. The rotation speed detector 90 detects rotation speed of the rotary drum 43 by detecting the rotation number of the rotary drum 43 per unit time.

Actions and operations of the drum-type washing machine configured as above will be described.

In the spin-drying step, in general, the vibration of the water tank 42 is anti-vibration damped in a favorably balanced manner by one pair of spring bodies 50, one pair of support dampers 51, one anti-vibration damper 91, weights provided in each part in the water tank unit 49 (not shown), and the like.

However, particularly when water is removed from a small amount of laundry and an imbalance state is detected, the laundry is easily gathered in a mass in a rear part of the rotary drum 43 because an operation of the protuberances 47 in the rotary drum 43 also exert influence. Meanwhile, the support dampers 51 are arranged on the more front side than a gravity center of the water tank unit 49, and the spring bodies 50 are arranged on the substantially identical perpendicular plane to the perpendicular plane including the gravity center of the water tank unit 49 in the front and rear direction. When the amount of the laundry is small, weight of the water tank unit 49 is decreased. Therefore, an anti-vibration property of the seal packing 92 effectively acts on the front surface side of the water tank 42, so that the rear surface side of the water tank 42 is largely vibrated.

On the rear surface side of the bottom part of the water tank 42, the heavy motor 45 is attached to a left lower part when seen from the front. Thus, the water tank 42 is to be vibrated taking the motor 45 as a substantial revolution center. In a case of a small amount of laundry, the laundry is easily brought up at once to the right upper side when seen from the front by the rotary drum 43. Therefore, the water tank 42 is largely vibrated from the right upper direction to the left upper direction when seen from the front.

As described above, the rear surface side of the water tank 42 is largely vibrated, and the water tank is largely vibrated from the right upper direction to the left upper direction when seen from the front. With respect to such two movements of the water tank 42, the vibration detector 78 is provided at the substantially symmetrical position to the motor 45 when seen from the front, and arranged on a substantially identical perpendicular plane to a perpendicular plane including the gravity center position Gm of the motor 45 in the front and rear direction. Therefore, the vibration detector 78 detects a maximum vibration value, so that the imbalance state of the water tank unit 49 can be detected with favorable precision. After being largely vibrated from the right upper direction to the left upper direction when seen from the front, the water tank 42 is vibrated from the left lower direction to the right lower direction. With respect to such a water tank 42, the anti-vibration damper 91 is arranged on the substantially identical perpendicular plane to the perpendicular plane including the gravity center position Gm of the motor 45 in the front and rear direction. When seen from the front, the anti-vibration damper 91 is provided in such a manner that the straight line connecting the housing support portion 93 and the water tank support portion 94 is inclined at the angle of α to the upstream side of the forward direction A with respect to the straight line connecting the housing support portion 93 and the center position C of the water tank 42. Thereby, the compression force effectively acts on the anti-vibration damper 91. Thus, the vibration of the water tank unit 49 in the up and down direction and the left and right direction is efficiently damped.

As described above, in the second embodiment, the anti-vibration damper and the vibration detector are arranged on the more back surface side than a gravity center of the water tank in the front and rear direction, the support dampers are arranged on the more front surface side than the anti-vibration damper, and the vibration detector and the anti-vibration damper are arranged on the substantially identical perpendicular plane to the perpendicular plane including a gravity center of the motor in the front and rear direction. Thereby, particularly when water is removed from a small amount of laundry, the vibration is detected with favorable precision, so that the spin-drying rotation is controlled. The vibration is suppressed in such a way. Thus, a situation that spin-drying cannot be started due to an imbalance state and the steps are stopped in the middle is eliminated. Therefore, the steps are progressed till the end.

As described above, the drum-type washing machine according to the second embodiment can suppress the vibration by detecting the vibration with favorable precision and controlling the spin-drying rotation. Therefore, the drum-type washing machine according to the second embodiment can be applied to a use for other washing machines and the like having the spin-drying function.

It is to be noted that, by properly combining the arbitrary embodiments of the aforementioned various embodiments, the effects possessed by them can be produced.

Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.

The entire disclosure of Japanese Patent Application No. 2011-036733 filed on Feb. 23, 2011 and Japanese Patent Application No. 2011-036756 filed on Feb. 23, 2011, including specification, drawings, and claims are incorporated herein by reference in its entirety.

Claims

1. A drum-type washing machine, comprising:

a rotary drum having a substantially horizontal axis of rotation;

a water tank incorporating the rotary drum;

a motor for rotating the rotary drum;

a washing machine housing elastically-supporting the water tank from underneath by a plurality of dampers; and

a vibration detector for detecting vibration of the water tank,

wherein the plurality of dampers comprise a first damper and a second damper,

the second damper is provided in such a manner that compression force on the second damper from the rotary drum rotating in a forward direction is larger than that on the first damper,

the second damper and the vibration detector are arranged posterior to a gravity center of the water tank in a front and rear direction, and

the first damper is arranged anterior to the second damper.

2. The drum-type washing machine according to claim 1, wherein:

the second damper and the vibration detector are arranged in a substantially identical perpendicular plane to a perpendicular plane including a gravity center of the motor in the front and rear direction.

3. The drum-type washing machine according to claim 1, wherein:

the vibration detector and the motor are arranged symmetrically about the axis of rotation of the rotary drum.

4. The drum-type washing machine according to claim 1, further comprising a spring suspending the water tank from the washing machine housing, wherein:

the spring is arranged in a substantially identical perpendicular plane to a perpendicular plane including the gravity center of the water tank in the front and rear direction.

5. The drum-type washing machine according to claim 2, wherein:

the vibration detector and the motor are arranged symmetrically about the axis of rotation of the rotary drum.

6. The drum-type washing machine according to claim 2, further comprising a spring suspending the water tank from the washing machine housing, wherein:

the spring is arranged in a substantially identical perpendicular plane to a perpendicular plane including the gravity center of the water tank in the front and rear direction.