Patent Publication Number: US-10329702-B2

Title: Drum washing machine

Description:
The present application is a national stage application submitted under 35 USC § 371 for International Patent Application No. PCT/CN2015/088808, entitled “DRUM WASHING MACHINE”, filed Sep. 2, 2015, which claims the priority date of Japanese Patent Application No. 2014-177623, filed Sep. 2, 2014. 
     TECHNICAL FIELD 
     The present disclosure relates to a drum washing machine, which not only can be continuously operated from washing to drying, but also can carry out washing without drying. 
     BACKGROUND 
     In the past, a drum washing machine rotates a horizontal shaft drum in an outer tank storing water at a bottom thereof, thus washings are lifted up and dropped down by baffles arranged in the drum, and the washings are thrown to an inner circumferential surface of the drum to be washed (with reference to patent literature 1). 
     In this way, in a structure of stirring the washings by the baffles, the washings are difficult to twine or rub against each other. Therefore, compared with an automatic washing machine in which the washings are washed through rotation of a pulsator in a washing and spin-drying tank, the drum washing machine has a small mechanical force acted on the washings, and the detergency is reduced. 
     Therefore, the drum washing machine may adopt the following structure: a rotating body, the surface of which is provided with a projection, is arranged at a rear surface of the drum, and the drum and the rotating body can rotate at different rotating speeds during washing and rinsing. The washing performance can be improved by rubbing and stirring the washings through the rotating body. 
     EXISTING TECHNICAL LITERATURE 
     Patent Literature 
     Patent Literature 1: Japanese Laid-Open Patent Publication No. 2013-240577 
     SUMMARY 
     Problems to be Solved 
     Under a condition of adopting the above structure, when the washings are not near the rotating body, the washings fail to contact the rotating body and a washing effect brought by the rotating body cannot be thoroughly obtained. 
     Therefore, the present disclosure aims to provide a drum washing machine capable of thoroughly obtaining the washing effect brought by the rotating body. 
     Solution for Solving the Problems 
     A drum washing machine in a main embodiment of the present disclosure includes: an outer tank arranged in a housing; a drum, which is arranged in an outer tank and capable of rotating about a horizontal shaft; a rotating body, which is arranged at a rear part of the drum, and a surface of the rotating body being provided with a projection for contacting washings; and a driving part, configured to drive the drum and the rotating body to coaxially rotate at different rotating speeds. Herein, the drum has a moving unit configured to move the washings in the drum towards the rotating body. 
     With the above structure, since the washings can be positioned near the rotating body, the washings are easy to contact the rotating body and a washing effect brought by the rotating body can be thoroughly given to the washings. 
     In the drum washing machine of the present embodiment, a structure that the moving unit includes a baffle can be adopted, in which the baffle is arranged on an inner circumferential surface of the drum, and has gathering surfaces for gathering the washings through a rotation of the drum, the gathering surfaces are inclined so that the side of the rotating body is lagged in a rotation direction of the drum. 
     Through the above structure, since the gathering surfaces are inclined so that the side of the rotating body is lagged in the rotation direction of the drum, the side of the rotating body becomes lower in a period of gathering the washings. As a result, the washings can be moved towards the rotating body along the gathering surfaces when being gathered by the gathering surfaces. 
     In this way, through the above structure, the washings can be moved to approach the rotating body while being rolled through the baffles, so that the washings can be easily contacted the rotating body, and the washings can be sufficiently imparted with a washing effect brought by the rotating body. 
     Further, under a condition of adopting the above structure, the baffle can be configured into a structure with two gathering surfaces which respectively correspond to a right rotation and left rotation of the drum. 
     If such a structure is adopted, the washings can approach the rotating body regardless of whether the drum rotates in a right direction or a left direction. 
     In the drum washing machine of the present embodiment, a structure that the moving units include the baffle can be adopted, in which the baffle is arranged on the inner circumferential surface of the drum, and can rotate about a rotating shaft arranged on an end part opposite to the side of the rotating body, so that the baffle can incline to two sides from being parallel to the horizontal shaft. 
     Through the above structure, if the drum respectively rotates to the right and the left, the baffle is inclined due to weight of the washings when the washings are folded, so that the side of the rotating body becomes lower. Thus, the washings are moved towards the side of the rotating body along inclination of the baffle. 
     In this way, through the above structure, the washings can be moved to approach the rotating body while being rolled through the baffle, so that the washings can be easily brought into contacting the rotating body, and the washings can be sufficiently imparted with the washing effect brought by the rotating body. Further, the washings can approach the rotating body regardless of whether the drum rotates in the right direction or the left direction. 
     In the drum washing machine of the present embodiment, the moving unit can be configured as a structure including the inner circumferential surface of the drum, which is inclines so that a diameter of the inner circumferential surface of the drum becomes larger when approaching the rear part of the drum. 
     Through the above structure, when the washings rolled along with the rotation of the drum fall onto the inner circumferential surface of the drum, the washings are moved towards the side of the rotating body in the rear along the downward inclination of the inner circumferential surface. 
     In this way, through the above structure, the washings can approach the rotating body through the inclination of the inner circumferential surface of the drum, so that the washings can be easily brought into contacting the rotating body, and the washings can be sufficiently imparted with the washing effect brought by the rotating body. 
     Effects of the Disclosure 
     Through the present disclosure, a drum washing machine, which is capable of thoroughly obtaining a washing effect brought by a rotating body, can be provided. 
     Effects and significances of the present disclosure are further clarified by embodiments shown below. However, the following embodiments are just an illustration when the present disclosure is implemented, and the present disclosure is not limited by any content described in the following embodiments. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a side sectional view illustrating a structure of a drum washing machine according to embodiments. 
         FIG. 2  is a sectional view illustrating a structure of a driving part according to embodiments. 
         FIG. 3  is a sectional view illustrating a structure of a driving part according to embodiments. 
         FIG. 4  is a rotor front view illustrating a structure of a rotor of a driving motor according to embodiments. 
         FIG. 5  is an enlarged perspective view illustrating a rear part of a bearing unit formed with a rack according to embodiments. 
         FIG. 6 &#39;s ( a )˜( c ) are diagrams illustrating a structure of a clutch body of a clutch mechanism part according to embodiments. 
         FIG. 7 &#39;s ( a )˜( d ) are diagrams illustrating a structure of a baffle according to embodiments. 
         FIG. 8 &#39;s ( a )˜( b ) are diagrams schematically illustrating a moving direction of the washings that are rolled through baffles during a washing or rinsing process according to embodiments. 
         FIG. 9  is a sectional view illustrating a structure of a drum of modification I. 
         FIGS. 10( a ) ˜( e ) are diagrams illustrating a structure of a baffle unit of modification I. 
         FIGS. 11( a ) ˜( b ) are diagrams schematically illustrating a tendency of washings that are rolled through baffles during a washing or rinsing process in modification I. 
         FIG. 12  is a sectional view illustrating a structure of a drum of modification II. 
         FIGS. 13( a ) ˜( b ) are sectional views illustrating a structure of a drum of other modifications. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, a drum washing machine without a drying function as an embodiment of the drum washing machine of the present disclosure is described by referring to drawings. 
       FIG. 1  is a side sectional view illustrating a structure of a drum washing machine  1 . 
     The drum washing machine  1  includes a housing  10  forming an appearance. A throwing inlet  11  for the washings is formed in a front surface of the housing  10 . The throwing inlet  11  is covered by a door  12  which is freely opened and closed. 
     An outer tank  20  is elastically supported by a plurality of vibration dampers  21  in the housing  10 . A horizontal shaft drum  22  is rotatably provided in the outer tank  20 . The drum  22  rotates about a horizontal shaft H. An opening part  20   a  in the front surface of the outer tank  20  and an opening part  22   a  in the front surface of the drum  22  are opposite to the throwing inlet  11 , and are closed by the door  12 , together with the throwing inlet  11 . A plurality of spin-drying holes  22   b  are substantially formed throughout a surface of a circumferential wall of the drum  22 . Further, three baffles  23  are arranged in the circumferential direction at roughly equal intervals on the inner circumferential surface of the drum  22 .  FIG. 1  only shows one of the baffles  23 . The baffles  23  are not limited to three as long as at least one baffle is arranged in the drum  22 . A detailed structure of the baffles  23  is described later. 
     A rotating body  24  is rotatablely provided at the rear of the drum  22 . The rotating body  24  has a roughly disc shape and coaxially rotates with the drum  22 . A plurality of projections  24   a  are formed on the surface of the rotating body  24 . Further, an annular retainer  25  which encircles the rotating body  24  is arranged at the rear part of the drum  22 . The retainer  25  prevents the washings from being clamped into a gap generated between the rotating body  24  and the drum  22 . 
     An annular fluid balancer  26  is arranged on the front surface of the drum  22 . The fluid balancer  26  inhibits a rotation of the drum  22  generated in spin-drying. 
     A driving part  30  for generating a torque for driving the drum  22  and the rotating body  24  is arranged behind the outer tank  20 . In a washing process and a rinsing process, the driving part  30  enables the drum  22  and the rotating body  24  to rotate at different rotating speeds in a same direction. Specifically, the driving part  30  enables the drum  22  to rotate at a rotating speed through which centrifugal force applied to the washings in the drum  22  is smaller than gravity, and enables the rotating body  24  to rotate at a rotating speed greater than that of the drum  22 . On the other hand, in a spin-drying process, the driving part  30  enables the drum  22  and the rotating body  24  to integrally rotate at a rotating speed through which the centrifugal force applied to the washings in the drum  22  is much greater than the gravity. A detailed structure of the driving part  30  is described later. 
     A drainage outlet part  20   b  is formed at the bottom of the outer tank  20 . The drainage outlet part  20   b  is provided with a drainage valve  40 . The drainage valve  40  is connected with a drainage hose  41 . When the drainage valve  40  is opened, water stored in the outer tank  20  is discharged out of the machine through the drainage hose  41 . 
     A detergent box  50  is arranged on the upper part of the front in the housing  10 . A detergent container  50   a  containing detergents is held in the detergent box  50  in a manner of being withdrawn from the front freely. The detergent box  50  is connected with, through a water feeding hose  52 , a water feeding valve  51  disposed on the upper part at the rear in the housing  10 . In addition, the detergent box  50  is connected with the upper part of the outer tank  20  through a water injection pipe  53 . When the water feeding valve  51  is opened, water from a faucet is supplied into the outer tank  20  by virtue of the water feeding hose  52 , the detergent box  50  and the water injection pipe  53 . At this moment, the detergents contained in the detergent container  50   a  are supplied into the outer tank  20  along with a water flow. 
     Next, the structure of the driving part  30  is described in detail. 
       FIG. 2  and  FIG. 3  are sectional views illustrating the structure of the driving part  30 .  FIG. 2  shows a state in which a driving form of the driving part  30  is switched to a biaxial driving form.  FIG. 3  shows a state in which the driving form of the driving part  30  is switched to a uniaxial driving form.  FIG. 4  is a front view of a rotor  110  of a driving motor  100 , in which a structure of the rotor  110  is illustrated.  FIG. 5  is an enlarged perspective diagram of a rear part of a bearing unit  500  formed with a rack  514 .  FIGS. 6( a ) ˜( c ) are diagrams illustrating a structure of a clutch body  610  of a clutch mechanism part  600 , i.e., a front view, a right view and a back view of the clutch body  610 . 
     The driving part  30  includes: the driving motor  100 , a wing shaft  200 , a drum shaft  300 , a planetary gear mechanism  400 , the bearing unit  500  and the clutch mechanism part  600 . The driving motor  100  is configured to generate a torque for driving the rotating body  24  and the drum  22 . The wing shaft  200  rotates by utilizing the torque of the driving motor  100 , and transmits the rotation thereof to the rotating body  24 . The planetary gear mechanism  400  is configured to decelerate the rotation of the wing shaft  200 , namely rotation of the rotor  110  of the driving motor  100 , and transmit the rotation to the drum shaft  300 . The drum shaft  300  coaxially rotates with the wing shaft  200  at a rotating speed being decelerated through the planetary gear mechanism  400 , and transmits the rotation to the drum  22 . The wing shaft  200  and the drum shaft  300  are rotatablely supported by the bearing unit  500 . The clutch mechanism part  600  is configured to switch the driving part  30  between the biaxial driving form and the uniaxial driving form. The biaxial driving form is a form in which the rotating body  24 , namely the wing shaft  200 , is enabled to rotate at a rotating speed the same as that of the driving motor  100 , and the drum  22 , namely the drum shaft  300 , is enabled to rotate at the rotating speed being decelerated through the planetary gear mechanism  400 . The uniaxial driving form is a form in which the rotating body  24  and the drum  22  (namely the wing shaft  200 , the drum shaft  300 ) as well as the planetary gear mechanism  400  integrally rotate at a rotating speed the same as that of the driving motor  100 . 
     The driving motor  100  is an external rotor type direct current (DC) brushless motor, including the rotor  110  and a stator  120 . The rotor  110  is formed as a cylinder with a bottom, and is provided with permanent magnets  111  on the inner circumferential surface thereof throughout the circumference. As shown in  FIG. 4 , a circular shaft sleeve part  112  is formed at the central part of the rotor  110 . The shaft sleeve part  112  is formed with a shaft sleeve hole  113  for fixing the wing shaft  200 , and an annular engaged recess  114  is formed at a periphery of the shaft sleeve hole  113 . Uneven parts  114   a  are arranged at a periphery of the engaged recess  114  throughout the periphery. 
     The stator  120  is provided with a coil  121  at a periphery thereof. The rotor  110  rotates when driving current is supplied from a motor driving part not shown to the coil  121  of the stator  120 . 
     The drum shaft  300  has a hollow shape in which is provided with the wing shaft  200  and the planetary gear mechanism  400 . The central part of the drum shaft  300  protrudes outward to form a receiving part for the planetary gear mechanism  400 . 
     The planetary gear mechanism  400  includes: a sun gear  410 ; an annular internal gear  420  surrounding the sun gear  410 ; a plurality of groups of planetary gears  430  between the sun gear  410  and the internal gear  420 ; and a planetary gear carrier  440  through which the planetary gears  430  are rotatablely retained. 
     The sun gear  410  is fixed on the wing shaft  200 , and the internal gear  420  is fixed on the drum shaft  300 . A group of planetary gears  430  includes a first gear and a second gear which are engaged with each other and reversely rotate. The planetary gear carrier  440  includes a planet carrier shaft  441  extending backward. The planet carrier shaft  441  and the drum shaft  300  are coaxial, and the planet carrier shaft  441  is hollow so as to be inserted by the wing shaft  200 . 
     The rear end of the wing shaft  200  protrudes backward from the planet carrier shaft  441  and is fixed at the shaft sleeve hole  113  in the rotor  110 . 
     A cylindrical bearing part  510  is arranged at the central part of the bearing unit  500 . In the bearing part  510 , a rolling bearing  511  and a rolling bearing  512  are arranged at the front part and rear part, and a mechanical seal  513  is arranged at the front end part. The peripheral surface of the drum shaft  300  is supported by the rolling bearings  511  and  512  so that the drum shaft  300  smoothly rotates inside the bearing part  510 . In addition, water is prevented from intruding between the bearing part  510  and the drum shaft  300  through the mechanical seal  513 . As shown in  FIG. 5 , racks  514  are formed on an inner surface of the rear end part of the bearing part  510  throughout a periphery thereof. 
     A securing flange part  520  is formed around the bearing part  510  of the bearing unit  500 . A mounting protrusion  521  is formed at a lower end of the securing flange part  520 . 
     The bearing unit  500  is fixed on a rear surface of the outer tank  20  through the securing flange part  520  by fastening screws and other securing methods. The wing shaft  200  and the drum shaft  300  enter into the interior of the outer tank  20  in a state that the driving unit  30  is mounted on the outer tank  20 . The drum  22  is fixed on the drum shaft  300 , and the rotating body  24  is fixed on the wing shaft  200 . 
     The clutch mechanism part  600  includes: the clutch body  610 , a clutch spring  620 , a clutch lever  630 , a lever supporting part  640 , a clutch driving apparatus  650 , a relaying rod  660  and a mounting plate  670 . 
     As shown in  FIGS. 6( a ) ˜( c ), the clutch body  610  has an approximately disc shape. An annular rack  611  is formed on an outer circumferential surface of a front end of the clutch body  610 . The rack  611  is formed to be engaged with the rack  514  in the bearing unit  500 . In addition, a flange part  612  is formed on a peripheral surface of the clutch body  610 , and the flange part  612  is behind the rack  611 . Further, an annular engaging flange part  613  is formed at the rear end of the clutch body  610 . The engaging flange part  613  has the same shape as that of the engaged recess  114  of the rotor  110 , and is provided with uneven parts  613   a  throughout the periphery thereof. When the engaging flange part  613  is inserted into the engaged recess  114 , the uneven parts  613   a  and  114   a  are engaged with one another. 
     The planet carrier shaft  441  is inserted into a shaft hole  614  of the clutch body  610 . A rack  614   a  formed on an inner circumferential surface of the shaft hole  614  is engaged with the rack  441   a  formed in an outer circumferential surface of the planet carrier shaft  441 . Therefore, the clutch body  610  is in the following state: relative to the planet carrier shaft  441 , movement in the front and rear directions is allowed and rotation in the circumferential direction is limited. 
     An annular receiving groove  615  is formed on an outer side of the shaft hole  614  in the clutch body  610 . The clutch spring  620  is received in the receiving groove  615 . One end of the clutch spring  620  abuts the rear end of the bearing part  510 , and the other end of the clutch spring  620  abuts a bottom surface of the receiving groove  615 . 
     The upper end of the clutch lever  630  is provided with a pressing part  631  which contacts the rear surface of the flange part  612  in the clutch body  610  and pushes the flange part  612  forward. The clutch lever  630  is rotatablely supported by a fulcrum  641  provided in the lever supporting part  640 . A mounting shaft  632  is formed at a lower end of the clutch lever  630 . 
     The clutch driving apparatus  650  is arranged below the clutch lever  630 . The clutch driving apparatus  650  includes a torque motor  651  and a disc-shaped cam  652  which rotates about a horizontal axis by virtue of a torque from the torque motor  651 . A camshaft  653  is arranged on a periphery of the cam  652 . A rotating center of the cam  652  is consistent with a center of the mounting shaft  632  of the clutch lever  630  in the front and rear directions. 
     The relaying rod  660  extends up and down and connects the clutch lever  630  and the cam  652 . An upper end of the relaying rod  660  is mounted on the mounting shaft  632  of the clutch lever  630 , and a lower end of the relaying rod  660  is mounted on the camshaft  653  of the cam  652 . A spring  661  is integrally formed in a middle position of the relaying rod  660  and is an extension spring. 
     The lever supporting part  640  and the clutch driving apparatus  650  are fixed on the mounting plate  670  by fastening screws and other securing methods. The mounting plate  670  is fixed on a mounting protrusion  521  of the bearing unit  500  by screws. 
     In the case that the driving form of the driving part  30  is switched from the uniaxial driving form to the biaxial driving form, the torque motor  651  drives the cam  652  to rotate, so that the camshaft  653  is positioned at the lowest part, as shown in  FIG. 2 . Along with the rotation of the cam  652 , the lower end of the clutch lever  630  is pulled downward by the relaying rod  660 . The clutch lever  630  rotates forward with respect to the fulcrum  641 , and the pressing part  631  pushes the clutch body  610  forward. The clutch body  610  moves forward against an elastic force of the clutch spring  620 , and the rack  611  of the clutch body  610  is engaged with the rack  514  of the bearing unit  500 . 
     The rack  611  of the clutch body  610  reaches a position where the rack  611  is engaged with the rack  514  when the camshaft  653  is moved to a specified middle position. Then, the spring  661  of the relaying rod  660  is in a natural length state. Since the clutch body  610  will not moved to a position in front of the engaging position, the spring  661  extends downward when the camshaft  653  is moved from the specified position to the lowest position, as shown in  FIG. 2 . In this way, since the clutch lever  630  is pulled by the spring  661  to rotate forward, a pressing force is applied to the clutch body  610  positioned at the engaging position by the pressing part  631 . Thus, the rack  611  can be tightly engaged with the rack  514 . 
     When the rack  611  is engaged with the rack  514 , a rotation of the clutch body  610  relative to the bearing unit  500  in the circumferential direction is limited, that is, the clutch body  610  is in a non-rotatable state, thus the planet carrier shaft  441  of the planetary gear mechanism  400  (namely the planetary gear carrier  440 ) is fixed to be non-rotatable. In such a state, when the rotor  110  rotates, the wing shaft  200  rotates at a rotating speed equal to that of the rotor  110 , and the rotating body  24  connected with the wing shaft  200  also rotates at a rotating speed equal to the rotating speed of the rotor  110 . As for the planetary gear mechanism  400 , the sun gear  410  rotates along with the rotation of the wing shaft  200 . As mentioned above, the planetary gear carrier  440  is in a fixed state, thus the first gear and second gear of the planetary gears  430  rotate in a direction opposite to that of the sun gear  410  and the same direction with that of the sun gear  410  respectively, and the internal gear  420  and the sun gear  410  rotate in the same direction. As a result, the drum shaft  300  fixed on the internal gear  420  rotates at a rotating speed lower than that of the wing shaft  200  in the same direction as that of the wing shaft  200 , so that the drum  22  fixed on the drum shaft  300  rotates at a rotating speed lower than that of the rotating body  24  in the same direction as that of the rotating body  24 . In other words, the rotating body  24  rotates at a rotating speed greater than that of the drum  22  in the same direction as that of the drum  22 . 
     On the other hand, in the case that the driving form of the driving unit  30  is switched from the biaxial driving form to the uniaxial driving form, the torque motor  651  drives the cam  652  to rotate so that the camshaft  653  is positioned at the uppermost part, as shown in  FIG. 3 . When the cam  652  rotates to enable the camshaft  653  to move upward, the spring  661  contracts firstly. After the spring  661  returns to the natural length, the relaying rod  660  moves upward along with the movement of the camshaft  653 , so that the lower end of the clutch lever  630  is pushed by the relaying rod  660  to move upward. The clutch lever  630  rotates backward about the fulcrum  641 , so that the pressing part  631  is separated from the flange part  612  of the clutch body  610 . The clutch body  610  moves backward by the elastic force of the clutch spring  620 , so that the engaging flange part  613  of the clutch body  610  is engaged with the engaged recess  114  of the rotor  110 . 
     When the engaging flange part  613  is engaged with the engaged recess  114 , a rotation of the clutch body  610  relative to the rotor  110  in the circumferential direction is limited, so that the clutch body  610  is capable of rotating with the rotor  110 . In such a state, when the rotor  110  rotates, the wing shaft  200  and the clutch body  610  rotate at a rotating speed equal to the rotating speed of the rotor  110 . At this moment, as for the planetary gear mechanism  400 , the sun gear  410  and the planetary gear carrier  440  rotate at a rotating speed equal to that of the rotor  110 . Thus, the internal gear  420  rotates at a rotating speed equal to that of the sun gear  410  and the planetary gear carrier  440 , so that the drum shaft  300  fixed on the internal gear  420  rotates at a rotating speed equal to that of the rotor  110 . That is, in the driving part  30 , the wing shaft  200 , the planetary gear mechanism  400  and the drum shaft  300  rotate integrally. Therefore, the drum  22  and the rotating body  24  rotate integrally. 
     Next, the structure of the baffle  23  is described in detail. 
       FIG. 7  is a diagram illustrating the structure of the baffle  23 .  FIGS. 7( a ), ( b ) and ( c )  are a top view, a front view and a rear view of the baffle  23  respectively.  FIG. 7( d )  is a sectional view along A-A′ in  FIG. 7( a ) . 
     With reference to  FIG. 1  and  FIG. 7 , a bottom surface  23   a  of the baffle  23  is an approximate isosceles triangle, and the baffle  23  is an approximate triangular pyramid in which vertex P opposite to the bottom surface  23   a  is located near a bottom edge on a central line of the isosceles triangle. The baffle  23  is a hollow body of which the bottom surface is opened, and includes an approximate triangular right gathering surface  23 R for gathering the washings when the drum  22  rotates to the right and an approximate triangular left gathering surface  23 L for gathering the washings when the drum  22  rotates to the left. As shown in  FIG. 1 , when the baffle  23  is mounted on the inner circumferential surface of the drum  22 , an edge  23 R 1 , which is abutted against the inner circumferential surface of the drum  22 , of the right gathering surface  23 R is inclined rather than being parallel to a horizontal axis H. The right gathering surface  23 R per se is inclined so that the side of the rotating body  24  is lagged in the right rotation direction of the drum  22 . In addition, an edge  23 L 1 , which is abutted against the inner circumferential surface of the drum  22 , of the left gathering surface  23 L is inclined rather than being parallel to the horizontal axis H. The left gathering surface  23 L per se is inclined so that the side of the rotating body  24  is lagged in the left rotation direction of the drum  22 . 
     The drum washing machine  1  performs a washing operation of various operation modes. A washing process, an intermediate spin-drying process, a rinsing process and a final spin-drying process are sequentially performed in the washing operation. It should be noted that the intermediate spin-drying process and the rinsing process may be performed more than twice sometimes according to the operation mode. 
     In the washing process and rinsing process, the driving form of the driving part  30  is switched to the biaxial driving form. In the case that the washings in the drum  22  is soaked in water, and the water accumulated in the outer tank  20  does not reach a specified water level of the lower edge of the throwing inlet  11 , the driving motor  100  alternately performs right rotation and left rotation. As a result, the drum  22  and the rotating body  24  alternately performs the right rotation and the left rotation with the rotating speed of the rotating body  24  being greater than that of the drum  22 . At this time, the drum  22  rotates at a rotating speed so that the centrifugal force exerted on the washings is smaller than the gravity. The washings in the drum  22  are lifted up and down by the baffles  23  (i.e., rolling in the drum  22 ), and are thrown onto the inner circumferential surface of the drum  22 . In addition, at the rear part of the drum  22 , the washings contact the projections  24   a  of the rotating body  24  which is rotating, and are rubbed and stirred by the projections  24   a . Thus, the washings are washed or rinsed. 
     In this way, not only a mechanical force generated by the rotation of the drum  22  but also an mechanical force generated by the rotating body  24  are exerted on the washings during the washing and rinsing process, thus the improvement of the cleaning performance can be expected. The driving form of the driving part  30  is switched to the uniaxial driving form in the intermediate spin-drying process and the final spin-drying process. The driving motor  100  (that is to say, the drum  22 ) and the rotating body  24  integrally rotate at a rotating speed so that the centrifugal force acted on the washings in the drum  22  is far larger than the gravity. Due to the action of the centrifugal force, the washings are pressed on the inner circumferential surface of the drum  22  for spin-drying. 
     In this way, the drum  22  and the rotating body  24  integrally rotate in the spin-drying process, the washings attached to the drum  22  can be well spin-dried without being stirred by the rotating body  24 . 
       FIG. 8  is a diagram schematically illustrating a tendency of the washings which are rolled through the baffles  23  during the washing or rinsing process.  FIG. 8( a )  schematically illustrates the tendency of the washings when the drum  22  is rotated to the right; and  FIG. 8( b )  schematically illustrates the tendency of the washings when the drum  22  is rotated to the left. 
     As mentioned above, the right gathering surface  23 R is inclined so that the side of the rotating body  24  is lagged in the right rotation direction of the drum  22 , thus the side of the rotating body  24  becomes lower in a period of gathering the washings. Therefore, when being gathered by the right gathering surface  23 R, the washings move to the side of the rotating body  24  along the right gathering surface  23 R. Similarly, the left gathering surface  23 L is inclined so that the side of the rotating body  24  is lagged in the left rotation direction of the drum  22 , thus the side of the rotating body  24  becomes lower in the period of gathering the washings. As a result, when being gathered by the left gathering surface  23 L, the washings are moved to the side of the rotating body  24  along the left gathering surface  23 L. In this way, even if the washings are placed at a front side of the drum  22 , i.e., a position away from the rotating body  24 , the washings are moved to a rear side of the drum  22 , i.e., the vicinity of the rotating body  24 , in a period of repeatedly rolling the washings through the left rotation and right rotation of the drum  22 , as shown in dotted arrows of  FIGS. 8( a ) and ( b ) . 
     In this way, in the present embodiment, the drum  22  has the baffles  23  which constitute a moving unit. The washings can move to the rear part of the drum  22  equipped with the rotating body  24  while being rolled through the baffles  23 . Thus, for example, even if a small amount of washings are thrown to the vicinity of the front side of the drum  22 , the washings can also be moved towards the side of the rotating body  24  and contact the rotating body  24 . Therefore, the washings can be well imparted with the washing effect brought by the rotating body  24  without being affected by the amount of the washings and the like. 
     Further, in the present embodiment, the moving unit configured to enable the washings to move to the side of the rotating body  24  can be easily realized by considering the shape of the baffle  23 . Specifically, the baffle  23  is formed into an approximate triangular pyramid in which the right gathering surface  23 R is inclined so that the side of the rotating body  24  is lagged in the right rotation direction of the drum  22 , and the left gathering surface  23 L is inclined so that the side of the rotating body  24  is lagged in the left rotation direction of the drum  22 . 
     Although embodiments of the present disclosure are described above, the present disclosure is not limited to the above embodiments. In addition, embodiments of the present disclosure may be subjected to various modifications in addition to the description above. 
     &lt;Modification I&gt; 
       FIG. 9  is a sectional view illustrating the structure of the drum  22  of the modification I.  FIG. 10  is a diagram illustrating the structure of a baffle unit  27  of the modification I.  FIGS. 10( a ), ( b ), ( c ) and ( d )  are a top view, a right view, a front view and a rear view of the baffle unit  27  respectively.  FIG. 10( e )  is a sectional view along B-B′ of  FIG. 10( a ) . 
     In the present modification, instead of the baffles  23 , baffle units  27  are arranged on the inner circumferential surface of the drum  22 . Although only one baffle unit  27  is shown in  FIG. 9 , three baffle units  27  are arranged in the drum  22  like the above embodiment. It should be noted that the baffle units  27  are not limited to three as long as at least one baffle unit is arranged in the drum  22 . 
     With reference to  FIG. 9  and  FIG. 10 , the baffle unit  27  includes a baffle  271 , a base body  272 , a right displacement restrictor  273  and a left displacement restrictor  274 . 
     The baffle  271  is a hollow body having an approximate triangular shape viewed from the front, an approximate trapezoidal shape viewed from the side, and a bottom surface of which is opened. The baffle  271  includes: an approximate trapezoidal right gathering surface  271 R for gathering the washings when the drum  22  is rotated to the right; and an approximate trapezoidal left gathering surface  271 L for gathering the washings when the drum  22  is rotated to the left. Further, a bearing sleeve  275  is formed in a front end of the baffle  271 , and a recess  271   a  is formed in an outer part side. A shaft hole  275   a  formed in the bearing sleeve  275  penetrates into the bottom surface of the recess  271   a.    
     The base body  272  is in an approximate rectangular shape as viewed from the top. The size of an upper surface of the base body  272  is slightly greater than the size of the bottom surface of the baffle  271 . A rotating shaft  276  is formed in the base body  272 , and the rotating shaft  276  is inserted into the shaft hole  275   a  of the bearing sleeve  275  so that the front end of the baffle  271  is rotatablely supported on the base body  272 . An anti-dropping member  277 , which drops from the side of the recess  271   a , is mounted at the upper end of the rotating shaft  276  through a screw  278 . Since a diameter of a head part  277   a  of the anti-dropping member  277  is greater than a diameter of the shaft hole  275   a , the bearing sleeve  275  of the baffle  271  will not drop from the rotating shaft  276 . As shown in  FIG. 9 , the base body  272  equipped with the baffle  271  is fixed on the inner circumferential surface of the drum  22  by a fixing method such as the screw, with the base body being parallel to the horizontal axis H. 
     The right displacement restrictor  273  is arranged on the inner circumferential surface of the drum  22  at a position where the rear part of the baffle  271  is touched when the baffle  271  is inclined for a predetermined angle from being parallel to the horizontal axis H in the right rotation direction of the drum  22 . The left displacement restrictor  274  is arranged on the inner circumferential surface of the drum  22  at a position where the rear part of the baffle  271  is touched when the baffle  271  is inclined for a predetermined angle from being parallel to the horizontal axis H in the left rotation direction of the drum  22 . The predetermined angle may be an angle of several degrees to tens of degrees. 
     The distance between the bottom surface of the baffle  271  and the inner circumferential surface of the drum  22  is about a height of the base body  272 . Therefore, when the baffle  271  is inclined to both sides, the bottom surface of the baffle  271  will not touch the inner circumferential surface of the drum  22  until the left displacement restrictor  273  and the right displacement restrictor  274  are touched. It should be noted that the height of the base body  272  can also be adjusted so that the bottom surface of the baffle  271  touches the inner circumferential surface of the drum  22  and cannot be further inclined when the baffle  271  is inclined for the predetermined angle from being parallel to the horizontal axis H. In this case, the left displacement restrictor  273  and the right displacement restrictor  274  may be omitted. 
       FIG. 11  is a diagram schematically illustrating the tendency of the washings when being rolled by the baffle  271  during the washing or rinsing process.  FIG. 11( a )  schematically illustrates the tendency of the washings when the drum  22  is rotated to the right; and  FIG. 11( b )  schematically illustrates the tendency of the washings when the drum  22  is rotated to the left. 
     When the drum  22  rotates to the right, the washings are gathered by the right gathering surface  271 R. Meanwhile, the baffle  271  is inclined to the left rotation direction of the drum  22  due to the weight of the washings, and a side adjacent to the rotating body  24  of the right gathering surface  271 R becomes lower. Therefore, the washings gathered by the right gathering surface  271 R are moved to the side of the rotating body  24  along the right gathering surface  271 R. On the other hand, when the drum  22  rotates to the left, the washings are gathered by the left gathering surface  271 L. Meanwhile, the baffle  271  is inclined to the right rotation direction of the drum  22  due to the weight of the washings, and a side adjacent to the rotation body  24  of the left gathering surface  271 L becomes lower. Therefore, the washings gathered by the left gathering surface  271 L are moved to the side of the rotating body  24  along the left gathering surface  271 L. In this way, even if the washings are placed at the front side of the drum  22 , i.e., a position away from the rotating body  24 , the washings are moved to the rear side of the drum  22 , i.e., a position where the washings contact the rotating body  24 , in the period of repeatedly rolling the washings through the left rotation and the right rotation of the drum  22 , as shown in the dotted arrows of  FIGS. 11( a ) and ( b ) . 
     In this way, in the present modification, the washings can be moved to the rear part of the drum  22  equipped with the rotating body  24  while being rolled through the baffles  271  constituting the moving units. Therefore, similar to the above-mentioned embodiment, the washings can be well imparted with the washing effect brought by the rotating body  24  without being affected by the amount of the washings and the like. 
     Further, in the present modification, the right gathering surface  271 R and the left gathering surface  271 L can automatically incline according to the rotation direction of the drum  22 , thus the shapes of the right gathering surface  271 R and the left gathering surface  271 L may not be set as the triangular shape as described in the above-mentioned embodiment, but may be set as a quadrilateral shape such as a trapezoidal shape. As a result, areas of the right gathering surface  271 R and the left gathering surface  271 L can be increased, so that the washings can be rolled well through the baffles  271 . 
     &lt;Modification II&gt; 
       FIG. 12  is a sectional view illustrating a structure of a drum  22 A of the modification II. 
     In the present modification, a drum  22 A is configured in the outer tank  20  for replacing the drum  22 . The drum  22 A is formed in such a manner that an inner diameter of a peripheral wall  22 A 1 , i.e., a diameter D 1  of an inner circumferential surface  22 A 2 , gradually increases toward the rear. As a result, the inner circumferential surface  22 A 2  of the drum  22 A is inclined downward on the bottom side of the outer tank  20 . 
     Three baffles  28  are arranged on the inner circumferential surface  22 A 2  of the drum  22 A in the circumferential direction at substantively equal intervals.  FIG. 12  shows only one baffle  28 . The baffle  28  has the same structure as that of the baffle  271  of modification I, except that the baffle  28  is directly fixed on the drum  22  rather than being supported by the base body  272 . 
     When the drum  22 A is rotated to the left and the right, the washings are rolled by the baffles  28 . When being fallen onto the inner circumferential surface  22 A 2  of the drum  22 A, the rolled washings move backward along a downward slope of the inner circumferential surface  22 A 2 . In this way, the washings can be easily moved towards the rear part of the drum  22 A during a process of rolling, and contact the rotating body  24 . 
     In the present modification, the moving unit has an inclination on the inner circumferential surface  22 A 2  of the drum  22 A in such a manner that the diameter becomes larger gradually when approaching the rear of the drum, thus the rolled washings can be moved towards the rear part of the drum  22 A, and the washings can be well imparted with the washing effect brought by the rotating body  24 . 
     Further, in the present modification, the moving unit, which has an inclination on the inner circumferential surface  22 A 2  of the drum  22 A in such a manner that the diameter becomes larger gradually when approaching the rear of the drum and can move the washings to the side of the rotating body  24 , can be realized easily. 
     It should be noted that, in the present modification, the baffles  28  can be replaced with the baffles  23  or the baffle units  27 . In this way, the washings can move to the side of the rotating body  24  more easily. 
     &lt;Other Modifications&gt; 
     Embodiments of the present disclosure can also be subjected to various changes, besides the above-mentioned modifications. 
     For example, in the modification II, the peripheral wall  22 A 1  of the drum  22 A has an inclination. However, the drum  22 A can also be replaced with the drum  22 B shown in  FIG. 13 . 
       FIG. 13( a )  is a sectional view illustrating the structure of the drum  22 B, and  FIG. 13( b )  is a perspective diagram of an inner member  222  as viewed from the rear. 
     The drum  22 B is formed by accommodating the inner member  222  inside a drum body  220 , in which the peripheral wall  221  of the drum body  220  is not inclined, while the inner member  222  has an inner circumferential surface  224   a  with an inclination. 
     A plurality of spin-drying holes  223  are formed substantively throughout the whole surface of the peripheral wall  221  of the drum body  220 . In addition, the drum body  220  can be opened from the entire front surface in such a manner that the inner member  222  can be accommodated from the front. 
     The inner member  222  includes: a body part  224 ; and an annular flange part  225  formed at the front end of the body part  224 . The body part  224  is formed in such a manner that a diameter D 2  of the inner circumferential surface  224   a  becomes larger gradually when approaching the rear. A plurality of spin-drying holes  226  are formed substantively throughout the entire surface of the body part  224 . When an outer diameter of the flange part  225  is the same as that of the rear end of the body part  224  and the inner member  222  is accommodated in the drum body  220 , an outer circumferential surface of the flange part  225  and the outer circumferential surface of the rear end of the body part  224  are abutted against the inner circumferential surface of the drum body  220 . 
     In this way, similar to modification II, in the case of using the drum  22 B, since the rolled washings can move towards the rear part of the drum  22 B due to a downward inclination of the inner circumferential surface  224   a  of the body part  224 , the washings can also be well imparted with the washing effect brought by the rotating body  24 . 
     Further, in the above-mentioned embodiment, the right gathering surface  23 R and the left gathering surface  23 L of the baffles  23  are formed as flat surfaces. However, the right gathering surface  23 R and the left gathering surface  23 L are not limited to flat surfaces, and can also be, e.g., convex curved surfaces or concave curved surfaces. Similarly, the right gathering surfaces  271 R and the left gathering surfaces  271 L of the baffles  271  of the modification I are not limited to flat surfaces, and can also be, e.g., convex curved surfaces or concave curved surfaces. 
     Further, although the drum washing machine  1  in the above embodiment does not have a drying function, the present invention also can be applied to a drum washing machine with the drying function, that is, a drum washing and drying machine. 
     In addition, embodiments of the present disclosure can be subjected to various changes within the scope of a technical idea shown in claims. 
     LIST OF REFERENCE NUMERALS 
       10 : housing;  20 : outer tank;  22 : drum;  23 : baffle;  23 R: right gathering surface;  23 L: left gathering surface;  24 : rotating body;  24   a : projection;  27 : baffle unit;  271 : baffle;  272 : base body;  276 : rotating shaft;  22 A: drum;  22 A 2 : inner circumferential surface;  22 B: drum;  220 : drum body;  222 : inner member;  224 : body part; and  224   a : inner circumferential surface.