JP5184678B2 - Stirring blade, stirrer using the same, and washing machine - Google Patents

Description

  The present invention relates to a stirring blade that stirs a fluid, a stirring device using the blade, and a washing machine.

  A conventional washing machine is disclosed in Patent Document 1. This washing machine is a type of washing machine in which a dewatering tank and a water tank are used as a stirring tank, and the stirring tank is a non-hole type stirring tank having a dewatering hole only in the upper part. A stirring blade is rotatably disposed at the bottom of the stirring tank. At the time of washing, water is stored in an agitation tank containing the laundry, and the laundry, which is a fluid, is agitated by the rotation of the agitation blade to wash the laundry.

Japanese Patent Application Laid-Open No. 61-9878 Japanese Patent Publication No. 6-296794

  However, according to the conventional washing machine, the surface of the stirring blade is formed smoothly, and there is a problem that a large frictional resistance is generated between the surface of the stirring blade and the fluid. For this reason, there has been a problem that the torque applied to the rotation of the stirring blades increases and the power consumption of the washing machine increases.

  An object of this invention is to provide the stirring blade which can reduce the frictional resistance with a fluid, and the stirring apparatus and washing machine which can aim at reduction of power consumption using it.

  In order to achieve the above object, the present invention comprises an agitating blade that is provided with a blade portion that is arranged on at least one surface and protrudes in the axial direction, and a concave portion adjacent to the blade portion in the circumferential direction, and stirs fluid by rotation. In the present invention, a plurality of ribs arranged side by side in the fluid flow direction and extending in the direction are provided in at least one of the blade portion and the concave portion.

  According to this configuration, a fluid flow is generated by the rotation of the stirring blade, and a part of the fluid becomes a vortex and stagnates between the ribs on the surface of the stirring blade.

  Moreover, the stirring blade of the present invention is characterized in that, in the above configuration, the interval between the ribs in the region where the average fluid speed is large is narrower than the interval between the ribs in the small region. According to this configuration, the Reynolds number on the surface of the stirring blade in the region where the average speed of the fluid is large and the region where the fluid is small is constant. Thereby, the effect | action with respect to the stirring blade of a fluid is homogenized. Therefore, the frictional resistance reduction effect on the surface of the stirring blade is homogenized.

  The stirring blade of the present invention is characterized in that, in the above configuration, a plurality of the blade portions are provided radially, and the ribs arranged on the blade portions extend in the radial direction.

  The stirring blade of the present invention is characterized in that, in the above configuration, the interval between the ribs on the outer peripheral side is narrower than that on the inner peripheral side.

  Further, the stirring blade of the present invention has the above-described configuration in which a plurality of the blade portions are provided radially, the ribs arranged on the recesses extend in the circumferential direction, and the distance from the rotation center is small at a position close to the blade portions. The distance from the center of rotation is large at a distant position.

  Moreover, the stirring blade of the present invention is characterized in that, in the above configuration, the interval between the ribs at a position close to the blade portion is narrower than the interval between the ribs at a position away from the blade portion.

  The stirring blade of the present invention is characterized in that, in the above configuration, a plurality of small holes are provided between the adjacent ribs. According to this configuration, when the stirring blade rotates, the fluid is sucked into the space behind the stirring blade, which has become negative pressure, through the small hole.

  Moreover, the stirring blade of this invention is characterized by the ratio of the space | interval of the said adjacent rib, and the height of the said rib being in the range of 100: 1-5: 1 in the said structure.

  Moreover, the stirring blade of this invention is characterized by the ratio of the space | interval of the said adjacent rib and the height of the said rib being in the range of 50: 1-15: 1 in the said structure.

  Moreover, the stirring device of the present invention is characterized by including the stirring blade having the above-described configuration and a stirring tank in which the stirring blade is rotatably arranged to store a fluid.

  The washing machine of the present invention is characterized by including the stirring device having the above-described configuration.

  According to the present invention, since the plurality of ribs extending parallel to the fluid flow direction and extending across the direction are provided in at least one of the blade portion and the concave portion adjacent to the circumferential direction of the stirring blade, A fluid flow is generated, and a part of the fluid becomes a vortex and stagnates between the ribs on the surface of the stirring blade. The fluid flowing above the ribs flows through the upper surface of the ribs and the vortex stagnating between the ribs. At this time, in addition to the small contact area with the upper surface of the rib, the frictional resistance of the fluid can be reduced by the bearing effect due to the vortex. Thereby, the power consumption of the stirring apparatus and washing machine provided with the stirring blade can be reduced.

Front sectional drawing which shows schematic structure of the washing machine which concerns on embodiment of this invention The perspective view which shows the stirring blade which concerns on embodiment of this invention The top view which shows the stirring blade which concerns on embodiment of this invention Schematic cross-sectional view schematically showing a phenomenon that occurs on the surface of a stirring blade according to an embodiment of the present invention A graph showing the relationship between the rib spacing and height ratio and the drive efficiency of the stirring blades Graph showing the relationship between rib height and the degree of cloth damage on the laundry Graph showing the relationship between rib height and the degree of cloth damage on the laundry

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front sectional view showing a schematic structure of a washing machine 1 according to the present embodiment. In addition, the near side of FIG. 1 is the front of the washing machine 1, and the back side is a back surface.

  The washing machine 1 is a fully automatic type and includes an outer box 10 made of metal or synthetic resin. The outer box 10 is formed in a rectangular parallelepiped shape, and the upper surface and the bottom surface are openings. A synthetic resin upper surface plate 11 provided with an operation panel or the like is fixed to the upper surface opening of the outer box 10. A synthetic resin base 12 is fixed to the bottom opening of the outer box 10 with screws. Legs 13 for supporting the outer box 10 on the floor are provided at the four corners of the base 12.

  The upper surface plate 11 is provided with a laundry loading port 14 for loading laundry into the washing machine 1. The upper lid 15 is pivotally supported on the upper surface plate 11 by a horizontal rotation shaft on the heel side of the washing machine 1. By rotating the upper lid 15 up and down to open and close the laundry input port 14, the laundry can be input into the agitation tank 30 described later, and the laundry can be taken out from the agitation tank 30.

  Inside the outer box 10, a water tank 20 that houses the stirring tank 30 and the stirring tank 30 is housed. The stirring tank 30 stores water in which detergent is dissolved or rinsing water (hereinafter collectively referred to as “washing water”). Both the water tank 20 and the stirring tank 30 have a shape of a bottomed cylindrical cup having an open upper surface, and are arranged concentrically with the water tank 20 on the outside and the stirring tank 30 on the inside, with the axis line vertical. The

  The water tank 20 is suspended from the outer box 10 by a suspension member (not shown). Suspension members are provided at a total of four locations in such a manner that the lower part of the outer surface of the water tank 20 and the inner corner part of the outer box 10 are connected to support the water tank 20 so that it can swing within the horizontal part.

  The agitation tank 30 has a peripheral wall 30b that tapers upward from the bottom wall 30a, and the peripheral wall 30b has an opening for allowing liquid to pass therethrough except for a plurality of dewatering holes 31 arranged in an annular shape at the top. There is no part. That is, the stirring tank 30 is formed in a so-called “no hole” type. At the edge of the upper opening of the agitation tank 30, an annular balancer 32 that functions to suppress vibration when the dehydration tank 30 is rotated at a high speed for dehydrating the laundry is attached. On the inner bottom surface of the dewatering tank 30, a stirring blade 70 for causing the washing water to flow in the tank is rotatably disposed.

  A drive unit 40 is attached to the lower surface of the water tank 20. The drive unit 40 includes a motor 41, a belt transmission mechanism 42 that transmits the rotational output of the motor 41, and a clutch / brake mechanism 43, and a dehydrating shaft 44 and a stirring blade shaft 45 that are arranged coaxially from the center thereof Protruding. The dewatering shaft 44 and the stirring blade shaft 45 have a double shaft structure in which the dewatering shaft 44 is disposed outside and the stirring blade shaft 45 is disposed inside. The dehydrating shaft 44 penetrates the bottom surface of the water tank 20 from below to above and supports the stirring tank 30. The stirring blade shaft 45 passes through the water tank 20 from the bottom to the top and further passes through the bottom wall 30a of the stirring tank 30 to support the stirring blade 70.

  The stirring blade 70 rotates at 55 to 300 rpm and performs washing or rinsing. At the time of dehydration, the dehydration is performed by rotating at 0 to 1200 rpm together with the stirring tank 30. Seal members for preventing water leakage are arranged between the dehydrating shaft 44 and the water tank 20 and between the dewatering shaft 44 and the stirring blade shaft 45, respectively.

  A water supply valve (not shown) that opens and closes electromagnetically is disposed in the space in the top plate 11. A water supply hose (not shown) for supplying tap water such as tap water is connected to the connection pipe 51 connected to the upstream side of the water supply valve and protruding upward through the upper surface plate 11. The downstream side of the water supply valve is connected to a container-like water supply port (not shown) arranged at a position facing the inside of the agitation tank 30.

  A control unit (not shown) is provided in the upper surface plate 11. The control unit receives an operation command from the user through an operation display unit (not shown) provided on the upper surface of the upper surface plate 11, and issues an operation command to the drive unit 40, the water supply valve and the drain valve 68. In addition, the control unit issues a display instruction for the operation content such as the operation course and the time required for each process to the operation display unit.

  A drain hose 60 for draining the water in the water tank 20 and the stirring tank 30 out of the outer box 10 is attached to the bottom of the water tank 20. Water flows into the drain hose 60 from a drain port 61 that opens to the bottom of the water tank 20. The water discharged to the outside of the agitation tank 30 at the time of dehydration flows into the drainage hose 60 through a water distribution pipe (not shown).

  A packing (not shown) is sandwiched between the agitation tank 30 and the water tank 20 to prevent water leakage from the center. A seal holder 63 is attached to the center of the bottom surface of the water tank 20, and a drainage path is formed between the water tank 20 and the drain outlet 61. Four drain holes 67 are provided on the circumference of the bottom of the stirring tank 30, and the drain holes 67 guide water in the stirring tank 30 from the drain port 61 to a drain valve 68 that electromagnetically opens and closes. An oil seal (not shown) is press-fitted inside the seal holder 63, and the oil seal seals the stirring tank 30, so that the stirring tank 30 is rotatable and has a watertight structure. An independent drainage space 66 is formed between the two.

  With the structure described above, the water in the agitation tank 30 is stopped by the drain valve 68 during washing in which the agitation blade 70 rotates, and the water is stored only in the agitation tank 30. At this time, water does not accumulate between the stirring tank 30 and the water tank 20. Thereby, water saving at the time of washing is realized. When performing dehydration, the drain valve 68 is opened, and the water in the agitation tank 30 is drained to the outside. At this time, the dehydrating shaft 44, the stirring blade shaft 45, and the stirring tank 30 are rotated by driving the motor 41, but the stirring tank 30 and the seal holder 63 can be relatively rotated by the oil seal described above and can continue to have a watertight structure. .

  Next, the stirring blade 70 will be described. FIG. 2 is a perspective view of the stirring blade 70, and FIG. 3 is a top view of the stirring blade 70. The stirring blade 70 has a disk shape, and the surface of the stirring blade 70 is formed in a tray shape that becomes deeper toward the center with respect to the peripheral edge portion 70a. On the surface of the stirring blade 70, four blade portions 71 that are radially arranged at a central angle of 90 ° are formed so as to protrude. Further, a recess 72 adjacent to the blade portion 71 in the circumferential direction is provided. At the time of washing, the blade part 71 generates a flow of washing water as a fluid in the stirring tank 30 by the rotation of the stirring blade 70.

  When the stirring blade 70 is rotated, a water flow is generated in the circumferential direction on the surface of the blade portion 71. Further, a water flow is generated in the recess 72 toward the outside in the radial direction along the wall surface of the blade portion 71 at the rear in the rotation direction.

  A plurality of ribs 73 a and 73 b are provided on the surface of the stirring blade 70. The ribs 73a and 73b are juxtaposed in the direction in which the washing water flows on the surface of the stirring blade 70 and extend so as to cross the direction. Further, on the surface of the stirring blade 70, the interval between the ribs 73a and 73b in the region where the average speed of the washing water flow is large is formed narrower than the interval between the ribs 73a and 73b in the region where the average water flow rate is low. Yes.

  Specifically, a plurality of ribs 73 a extending in the radial direction of the stirring blade 70 are arranged in parallel on the upper surface of the blade portion 71 in the circumferential direction. At this time, the interval between the ribs 73a on the outer peripheral side is formed narrower than that on the inner peripheral side. On the upper surface of the recess 72, a plurality of ribs 73b extending in the circumferential direction of the stirring blade 70 are arranged in parallel in the radial direction. At this time, the rib 73b is curved with respect to an arc centered on the rotation center, and the distance from the rotation center is small at a position close to the blade portion 71, and the distance from the rotation center is large at a remote position. In addition, the rib 73b at a position close to the blade portion 71 is formed to be narrower than the position where the interval is away.

  FIG. 4 is a schematic cross-sectional view schematically showing a phenomenon that occurs on the surface of the stirring blade 70. When the flow of the washing water, which is a fluid, is generated by the rotation of the stirring blade 70, a boundary layer of the washing water is generated on the surface of the stirring blade 70, and a highly viscous region exists in the boundary layer. Therefore, by arranging the ribs 73 in parallel on the surface of the stirring blade 70, the boundary layer can be broken and the frictional resistance can be reduced. As shown in FIG. 4, a part of the washing water becomes a vortex between the ribs 73 on the surface of the stirring blade 70 and stagnates to form a stagnation portion (vortex) 75. The fluid (arrow A) flowing above the rib 73 flows through the upper surface of the rib 73 and the stagnant portion 75 stagnating between the ribs 73. At this time, in addition to the small contact area between the fluid and the upper surface of the rib 73, the frictional resistance of the fluid can be reduced by the bearing effect of the stagnant portion 75.

  Further, the spacing between the ribs 73 in the region where the average speed of the washing water flow is large on the surface of the stirring blade 70 is narrower than the spacing between the ribs 73 in the region where the average speed of the water flow is slow. 70 The Reynolds number on the surface becomes constant. Thereby, the effect | action with respect to the stirring blade 70 of a fluid is homogenized. Therefore, the frictional resistance reducing effect on the fluid on the surface of the stirring blade 70 is homogenized. Therefore, by designing the arrangement and shape of the ribs 73 so that the Reynolds number is constant in a plurality of regions on the surface of the stirring blade 70, it is possible to maximize the friction reducing effect on the surface of the stirring blade 70 over a wide range. it can.

  Further, the ratio of the interval between the adjacent ribs 73 and the height of the ribs 73 is formed in the range of 100: 1 to 5: 1, and more preferably in the range of 50: 1 to 15: 1. If the interval between the ribs 73 is too wide with respect to the height of the rib 73, a stagnant portion (vortex) 75 is difficult to be formed between the ribs 73 on the surface of the stirring blade 70, and the frictional resistance of the stirring blade 70 cannot be sufficiently reduced. . On the other hand, if the height of the rib 73 is too high with respect to the interval between the ribs 73, the rib 73 and the laundry collide with each other and the laundry is damaged.

  A large number of small holes 74 penetrating the stirring blade 70 are provided between the adjacent ribs 73. The small hole 74 is also provided in the blade portion 71. The small hole 74 generates a water flow that is sucked into the space behind the stirring blade 70 that becomes negative pressure when the stirring blade 70 rotates.

  When the washing machine configured as described above puts laundry into the agitation tank 30 and instructs the controller to start operation, the water supply valve is controlled to supply water to a predetermined water level. When the washing process is started, the power of the motor 41 is transmitted to the stirring blade 70 through the belt transmission mechanism 42 and the stirring blade shaft 45, and the stirring blade 70 is operated alternately in the clockwise and counterclockwise directions. In accordance with the operation of the stirring blade 70, the laundry and the washing water in the stirring tank 30 are stirred, and washing of the laundry proceeds.

  Next, the ratio between the spacing and height of the ribs 73 provided on the stirring blade 70 and the driving efficiency of the stirring blade 70 were evaluated. FIG. 5 shows the relationship between the ratio between the spacing and height of the ribs 73 and the driving efficiency of the stirring blade 70. The vertical axis represents the driving efficiency η of the stirring blade 70, and the driving efficiency of the stirring blade 70 without the rib 73 is 1. The horizontal axis represents the ratio r (r = d / h) of the interval d between the adjacent ribs 73 and the height h of the ribs. The driving efficiency η was calculated from the power consumption consumed during the cleaning until the same cleaning effect appeared. When the driving efficiency η is high, it means that the frictional resistance between the stirring blade 70 and the fluid is low.

  The driving efficiency η was greater than 1 when 5 ≦ r ≦ 100. In particular, the driving efficiency η at 15 ≦ r ≦ 30 is improved by about 10% as compared with the case where the rib 73 is not provided. This is presumably because the frictional resistance on the entire surface of the stirring blade 70 was reduced by the adjacent rib 73 provided on the surface of the stirring blade 70. When r <5, the driving efficiency η decreased from 1. Further, when r> 100, there was no change in the performance of the stirring blade 70 due to the provision of the rib 73.

  Next, the relationship between the height of the rib 73 provided on the stirring blade 70 and the degree of cloth damage on the laundry was evaluated. FIG. 6 shows the rib height h and the degree of fabric damage on the laundry when the ratio r (r = d / h) of the distance d between the ribs 73 and the rib height h is r = 3, r = 30, and r = 75. Show the relationship. The vertical axis indicates the degree of cloth damage, and the horizontal axis indicates the height h of the rib. FIG. 7 is an enlarged view of a region where the rib height h is low in FIG. The degree of cloth damage was calculated from the weighted average of the MA value (Mechanical Action: damage value), which is a damage evaluation value of the laundry, and the weight reduction value of the laundry.

  When the rib 73 is not provided, the height of the rib is set to 0, and the degree of cloth damage at this time is set to 1. In addition, when r = 30 and r = 75 and the height h of each rib exceeds h = 20 mm and h = 8 mm, the rib 73 cannot be formed adjacent to the rib h, so that the evaluation is not performed. The diameter of the stirring blade 70 was 410 mm, and the starting point of the rib 73 formed on the surface of the stirring blade 70 was provided on the inner side from the middle in the radial direction.

  When r = 3, the degree of fabric damage monotonously increased as the rib height h increased. When r = 30, the fabric damage decreased until the rib height h was about 2 mm, and when the rib height h was higher than 2 mm, the degree of fabric damage increased compared to the case where the rib 73 was not provided. When r = 75, the degree of fabric damage monotonously increased as the rib height h increased.

  Therefore, as the height h of the rib increases, the cloth and the rib 73 collide with each other, and the fabric damage increases. On the other hand, if the rib height h is constant, the greater the gap between the ribs 73, the lower the degree of fabric damage. The relationship between the rib height h and the degree of fabric damage when r = 3 showed the same tendency when r <15. The relationship between the height h of the rib and the degree of fabric damage when r = 30 showed the same tendency when 15 ≦ r ≦ 50. Further, the relationship between the rib height h and the degree of fabric damage when r = 75 was the same when r> 50. From the above, it has been found that fabric damage can be reduced when 0 <h ≦ 2 and 15 ≦ r ≦ 50.

  According to this embodiment, the plurality of ribs 73 that are arranged in parallel in the direction in which the fluid flows and extend across the direction are provided in at least one of the blade portion 71 and the recess 72, so that the rotation of the stirring blade 70 causes the fluid to flow. A flow is generated, and part of the fluid becomes a vortex between the ribs 73 on the surface of the stirring blade 70 to form a stagnant portion 75. The fluid flowing above the rib 73 flows through the upper surface of the rib 73 and the stagnant portion 75 stagnating between the ribs 73. At this time, in addition to the small contact area between the fluid and the upper surface of the rib 73, the frictional resistance of the fluid can be reduced by the bearing effect of the stagnant portion 75. Thereby, power saving of the stirring device and the washing machine 1 can be achieved.

  Further, by reducing the interval between the ribs 73 in the region where the average fluid speed is large compared to the interval between the ribs 73 in the small region, the Reynolds on the surface of the stirring blade 70 in the region where the average fluid velocity is large and in the small region. The number becomes constant, and the action of the fluid on the stirring blade 70 in the region where the average speed of the fluid is large and the region where the fluid is small is homogenized. Thereby, the friction resistance with respect to the fluid of the surface of the stirring blade 70 in the region where the average speed of the fluid is large and the region where the fluid is small is homogenized.

  Further, by providing a plurality of blade portions 71 radially and the ribs 73a arranged on the blade portions 71 extending in the radial direction, the frictional resistance of fluid on the upper surface of the blade portions 71 can be reduced.

  Further, since the interval between the outer peripheral side ribs 73a is narrower than that on the inner peripheral side, the Reynolds number on the outer peripheral side and the inner peripheral side becomes constant on the upper surface of the blade part 71, and the fluid blades on the outer peripheral side and the inner peripheral side The action on the upper surface of the portion 71 is homogenized. Thereby, in the upper surface of the blade | wing part 71, the frictional resistance reduction effect of an outer peripheral side and an inner peripheral side is homogenized.

  Further, a plurality of blade portions 71 are provided radially, ribs 73b arranged on the recesses 72 extend in the circumferential direction, the distance from the rotation center is small at a position close to the blade portion 71, and the distance from the rotation center is at a remote position. Since it is formed large, the frictional resistance of the fluid on the upper surface of the recess 72 can be reduced.

  Further, the distance between the ribs 73b near the blades 71 is narrower than the distance between the ribs 73b near the blades 71, so that the upper surface of the recess 72 is separated from the blades 71 and the positions close to the blades 71. Thus, the Reynolds number at the position becomes constant, and the action of the fluid on the upper surface of the recess 72 at a position close to the blade 71 and a position away from the blade 71 is homogenized. Thereby, the frictional resistance reduction effect at a position close to the blade portion 71 and a position away from the blade portion 71 on the upper surface of the recess 72 is homogenized.

  Further, by providing a plurality of small holes 74 penetrating between the adjacent ribs 73, fluid is sucked into the space behind the stirring blade 70 that has become negative pressure through the small holes 74 when the stirring blade 70 rotates. It is.

  Further, by setting the ratio of the distance d between the adjacent ribs 73 and the height h of the ribs 73 within the range of 100: 1 to 5: 1, the frictional resistance between the stirring blade 70 and the fluid can be further reduced. .

  Further, the ratio of the distance d between the adjacent ribs 73 and the height of the ribs 73 is set within the range of 50: 1 to 15: 1, thereby suppressing the collision between the laundry and the ribs 73 stirred by the stirring blade 70. , Can prevent the laundry from being damaged.

  The present invention can be used in a washing machine.

DESCRIPTION OF SYMBOLS 1 Washing machine 10 Outer box 11 Top plate 11a Entrance / exit 12 Base 13 Leg part 14 Laundry insertion port 15 Upper cover 16 Extension part 16a Vertical part 16b Horizontal part 20 Water tank 30 Stirring tank 31 Dehydration hole 32 Balancer 40 Drive unit 41 Motor 42 Belt Conduction mechanism 43 Clutch / brake mechanism 44 Dehydration shaft 45 Stirring blade shaft 51 Connection tube 60 Drain hose 61 Drain port 63 Seal holder 66 Drain space 67 Drain hole 68 Drain valve 70 Stir vane 71 Blade portion 72 Recess 73a, 73b Rib 74 Small hole 75 Stagnation

Claims (8)

A stirrer blade that is disposed on at least one surface and protrudes in the axial direction, and a recess that is adjacent to the blade portion in the circumferential direction, and is arranged in parallel in the fluid flow direction in a stirring blade that stirs fluid by rotation. A plurality of ribs extending across the direction are provided on at least one of the blade portion and the recess ,
A stirring blade characterized in that a plurality of the blade portions are provided radially, the ribs arranged on the blade portions extend in the radial direction, and the interval between the ribs on the outer peripheral side is narrower than that on the inner peripheral side. A stirrer blade that is disposed on at least one surface and protrudes in the axial direction, and a recess that is adjacent to the blade portion in the circumferential direction, and is arranged in parallel in the fluid flow direction in a stirring blade that stirs fluid by rotation. A plurality of ribs extending across the direction are provided on at least one of the blade portion and the recess,
A plurality of the blade portions are provided radially, the ribs arranged on the recesses extend in the circumferential direction, the distance from the rotation center is small at a position close to the blade portions, and the distance from the rotation center is large at a remote position. A stirring blade characterized by The stirring blade according to claim 2 , wherein a distance between the ribs at a position close to the blade part is narrower than a distance between the ribs at a position away from the blade part . The stirring blade according to any one of claims 1 to 3, wherein a plurality of small holes are provided between the adjacent ribs . The stirring blade according to any one of claims 1 to 4, wherein a ratio between the interval between the adjacent ribs and the height of the ribs is in a range of 100: 1 to 5: 1 . The stirring blade according to claim 5, wherein a ratio of a distance between adjacent ribs to a height of the ribs is in a range of 50: 1 to 15: 1 . A stirring device comprising: the stirring blade according to any one of claims 1 to 6; and a stirring tank in which the stirring blade is rotatably arranged to store a fluid. A washing machine comprising the stirring device according to claim 7.

Images