DISHWASHER

The present disclosure relates to a dishwasher. The dishwasher of the present disclosure includes a tub forming a washing space, a sump disposed below the tub and storing washing water flowing from the tub, a pump configured to supply the washing water stored in the sump to the washing space, and a spray arm configured to discharge the washing water flowing from the pump into the washing space. A channel is formed inside the spray arm to spray the washing water into the washing space or discharge the washing water containing microbubbles into the washing space. The spray arm includes an upper cover and a lower cover coupled to a lower side of the upper cover, a flat surface is formed on a surface facing each other in one of the upper cover and the lower cover, and a pair of inner ribs protruding toward the flat surface to form the channel to be in contact with the flat surface is formed in the other of the upper cover and the lower cover.

TECHNICAL FIELD

The present disclosure relates to a dishwasher, and more specifically, to a dishwasher that washes dishes with washing water including microbubbles.

BACKGROUND

A dishwasher is a device that removes dirt from dishes by spraying washing water. For example, the dishwasher sprays washing water into the washing space through a spray arm placed inside a tub. In some cases, a spray channel through which the washing water flows may be formed inside the spray arm.

In a couple process of the spray arm, it may be difficult to perform the coupling at the same position between ribs, and errors may occur at certain intervals.

In some cases, when a cross-sectional area of the channel defined inside the spray arm is very small, the size or shape of the channel may be deformed due to errors caused by the fusion coupling. When the channel is relatively small, changes in the size or shape of the channel may impede the function of the channel.

SUMMARY

The present disclosure describes a dishwasher that improves dishwashing performance by using washing water including microbubbles.

The present disclosure further describes a dishwasher that can secure a size and cross-sectional area of the channel formed inside the spray arm.

The present disclosure further describes a dishwasher that maintains the flow of washing water sprayed from the spray arm and generates microbubbles using a part of the washing water.

According to one aspect of the subject matter described in this application, a dishwasher includes a tub that defines a washing space, a sump disposed below the tub and configured to store washing water received from the tub, a pump configured to supply the washing water stored in the sump to the washing space, and a spray arm configured to discharge the washing water from the pump into the washing space, where the spray arm defines a channel therein configured to carry the washing water received from the pump, the spray arm being configured to spray the washing water or the washing water including microbubbles into the washing space. The spray arm includes an upper cover and a lower cover that have inner surfaces facing each other, the lower cover being coupled to a lower side of the upper cover. The spray arm has (i) a flat surface that is defined at one of the inner surfaces of the upper cover and the lower cover, and (ii) a pair of inner ribs that protrude from the other of the inner surfaces of the upper cover and the lower cover to the flat surface, the pair of inner ribs being in contact with the flat surface to thereby define the channel between the pair of inner ribs.

Implementations according to this aspect can include one or more of the following features. For example, the upper cover and the lower cover can be coupled to each other by fusion in a state in which the pair of inner ribs are in contact with the flat surface. In some implementations, the flat surface is disposed above and spaced apart from a bottom surface of the lower cover, and the pair of inner ribs protrude downward from the upper cover. In some examples, the upper cover further includes a pair of support ribs that are spaced apart from the pair of inner ribs and protrude toward the lower cover. In some examples, the pair of support ribs protrude from the upper cover to the bottom surface of the lower cover and are in contact with the bottom surface of the lower cover.

In some implementations, the channel defined by the pair of inner ribs and the flat surface has a rectangular cross section. In some examples, a cross section of the channel has (i) a first side that is defined by a straight line and (ii) a second side that is defined by a curved line, bent lines, or a plurality of straight lines. In some implementations, the spray arm includes a first blade configured to spray the washing water into the washing space, and a second blade configured to supply the washing water including the microbubbles to the washing space, where the channel includes (i) a spray channel defined inside the first blade and (ii) a bubble generating channel defined inside the second blade. The upper cover can include an upper rib that protrudes downward, and the lower cover can include a lower rib that protrudes upward to the upper rib to thereby define the spray channel between the upper cover and the lower cover, where the flat surface and the pair of inner ribs are disposed in the second blade and define at least a portion of the bubble generating channel.

In some examples, the spray arm defines (i) an intake hole that is in fluid communication with an outside of the spray arm and configured to provide air to the bubble generating channel and (ii) a supply channel configured to supply the washing water discharged from the pump to at least one of the spray channel or the bubble generating channel. The bubble generating channel can include (i) a connection channel connected to the supply channel, the connection channel being defined by the flat surface and the pair of inner ribs, (ii) a buffer chamber connected to the connection channel and the intake hole, the buffer chamber having a cross-sectional area that increases and then decreases along a direction away from the connection channel, (iii) an air intake channel configured to receive the air from the intake hole via the buffer chamber, and (iv) a discharge channel connected to the air intake channel, the discharge channel having a cross-sectional area that increases in a direction away from the air intake channel. The spray arm can further define a discharge hole configured to discharge the washing water from the discharge channel to the outside of the spray arm.

In some examples, a cross-sectional area of the connection channel is smaller than a cross-sectional area of an inlet end of the supply channel. In some examples, a cross-sectional area of the connection channel is smaller than a cross-sectional area of the air intake channel.

In some implementations, the flat surface is defined at the inner surface of the lower cover, and the pair of inner ribs protrude downward from the inner surface of the upper cover toward the lower cover. In some examples, the flat surface protrudes upward from a bottom surface of the lower cover to the pair of inner ribs of the upper cover. In some examples, a channel height of the channel between the flat surface and the inner surface of the upper cover is less than a height of the flat surface protruding from the bottom surface of the lower cover. In some examples, the flat surface extends laterally outward relative to the pair of inner ribs, and a channel width of the channel between the pair of inner ribs is less than a lateral width of the flat surface.

In some implementations, by placing a bubble generating channel in the spray arm, washing water including generated microbubbles can be supplied to the washing water discharged into the tub. The washing water including the generated microbubbles supplied to the tub can be circulated through the sump and sprayed onto the dishes. The washing water containing the microbubbles has the advantage of effectively cleaning contamination from dishes.

In some implementations, a flat surface is formed on one cover, and a pair of ribs protruding from one cover is disposed on the other cover, which has the advantage of securing the desired shape and size of the channel.

In some implementations, the connection channel formed in the second blade has a small cross-sectional area, so that a flow rate of washing water supplied to the spray channel can be secured. Therefore, it has the advantage of securing the amount of washing water sprayed from the spray arm and generating microbubbles at the same time.

The effects of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned may be clearly understood by those skilled in the art from the description of the claims.

DETAILED DESCRIPTION

Hereinafter, the present disclosure will be described with reference to drawings for explaining the dishwasher according to the one or more implementations of the present disclosure.

In some implementations, a dishwasher of the present disclosure includes a cabinet that defines an outer appearance of the dishwasher, a tub2that is disposed inside the cabinet and forms a washing space2s, a sump3that is disposed below the tub2and temporarily stores washing water, a spray arm10that sprays washing water into the washing space2s, and a washing pump that supplies washing water stored in the sump3to the spray arm10. The spray arm10may be rotatably placed in the tub2or sump3.

The washing water stored in the sump3may flow to the washing space2sof the tub2through the washing pump and spray arm10, and the washing water sprayed into the washing space2sof the tub2may flow to the sump3again.

FIG.1illustrates one spray arm10, for example. In some implementations, additional spray arms may be disposed in the washing space2s.

Referring toFIGS.2and3, the spray arm10includes first blades12aand12bthat spray the washing water into the washing space2sinside the tub2, a second blade18that supplies microbubbles to the washing space2s, and a hub82that supplies washing water supplied from the washing pump to the first blades12aand12bor the second blade18.

The first blades12aand12bhave spray channels14aand14bthrough which the washing water flows. The first blades12aand12bmay have a structure extending centrifugally from the hub82. Inside the first blades12aand12b, the spray channels14aand14bare formed in a direction extending centrifugally from the hub82. A plurality of spray nozzles16aand16bspaced apart in the radial direction may be disposed on an upper surface13of the first blades12aand12b. The plurality of spray nozzles16aand16bdisposed on the upper surface13of the first blades12aand12bare spaced apart in the radial direction. The first blades12aand12bare configured to spray washing water supplied from the washing pump to the washing space.

The second blade18has a bubble generating channel40forming microbubbles inside. In the second blade18, discharge holes108a,108b, and118are formed to discharge the microbubbles generated through the bubble generating channel40. A discharge channel70through which the microbubbles generated through the bubble generating channel40flow to the discharge holes108a,108b, and118is formed inside the second blade18. The internal channel of the second blade18is described in detail below.

Additional spray channels28aand28bwhich spray the washing water into the washing space2smay be formed inside the second blade18. The additional spray channels28aand28bmay be disposed on one side of a buffer chamber44of the bubble generating channel40. Additional spray nozzles30aand30bwhich spray the washing water flowing through the additional spray channels28aand28binto the washing space2smay be disposed on an upper surface13of the second blade18. There may be differences between distances11and12at which the additional spray nozzles30aand30bare separated from the center of the hub82and distances13and14at which the spray nozzles16aand16bare separated from the center of the hub82. Referring toFIG.4, the distance11,12at which the additional spray nozzles30aand30bare spaced from the center of the hub82are smaller than the distances13and14at which the spray nozzles16aand16bare separated from the center of the hub82.

The spray arm10may include at least one first blades12aand12b. The spray arm10may include a plurality of first blades12aand12b. The spray arm10may include one second blade18. The spray arm10may include two second blades18.

Referring toFIGS.2and3, the spray arm10has a pair of first blades12aand12barranged in opposite directions and a pair of second blades18disposed to intersect the pair of first blades12aand12b. However, unlike the drawing, the number or arrangement of the first blades12a,12band the second blade18may be set differently.

The first blades12aand12bhave a spray channel formed therein and includes a1-1blade12aand a1-2blade12bextending in opposite directions. The second blade18has a bubble generating channel formed inside and includes a second-1 blade18aand a second-2 blade18bextending in opposite directions.

Referring toFIGS.2and3, the spray arm10includes the hub82, the1-1blade12aextending in one direction from the hub82, the1-2blade12bextending in the direction opposite to the1-1blade12afrom the hub82, the2-1blade18aextending in a direction between the1-1blade12aand the1-2blade12bfrom the hub82, and the2-2blade18bextending in the direction opposite to the2-1blade18afrom the hub82.

A first spray channel14ais formed inside the1-1blade12a. A second spray channel14bis formed inside the1-2blade12b. A plurality of first injection nozzles16a1,16a2,16a3,16a4, and16a5are disposed on the upper surface of the1-1blade12a. A plurality of second injection nozzles16b1,16b2,16b3,16b4, and16b5are disposed on the upper surface of the1-2blade12b. Distances at which the plurality of first injection nozzles16a1,16a2,16a3,16a4, and16a5are spaced apart from a rotation center axis10cof the spray arm10and distances at which the plurality of second injection nozzles16b1,16b2,16b3,16b4, and16b5are spaced apart from the rotation center axis10cof the spray arm10may be different from each other.

A first bubble generating channel40and a first additional spray channel28aare formed inside the2-1blade18a. A second bubble generating channel40and a second additional spray channel28bare formed inside the2-2blade18b. A first additional spray nozzle30ais disposed on the upper surface of the2-1blade18a. A second additional spray nozzle30bis disposed on the upper surface of the2-2blade18b. A distance at which the first additional spray nozzle30ais spaced apart from the rotation center axis10cof the spray arm and a distance at which the second additional spray nozzle30bis spaced apart from the rotation center axis10cof the spray arm10may be different from each other.

A supply channel84extending in an up-down direction is formed inside the hub82. The supply channel84may have a structure in which the upper end is closed and the lower end is open. Therefore, the washing water flowing from the washing pump is supplied to the lower side.

The spray channels14aand14bof the first blades12aand12bmay be connected to the upper end portion of the supply channel84. The bubble generating channel40of the second blade18may be connected to the upper end portion of the supply channel84. Therefore, the washing water flowing upward along the supply channel84may flow into the spray channels14aand14bor the bubble generating channel40.

Referring toFIG.3, the spray arm10may include an upper cover90and a lower cover100coupled to the lower side of the upper cover90. The upper cover90and lower cover100may be coupled to each other by fusion. Ribs92and102protruding in directions facing each other may be formed on the upper cover90or the lower cover100. An upper rib92protruding downward may be disposed on the lower surface of the upper cover90facing the lower cover100. A lower rib102protruding upward may be disposed on the upper surface of the lower cover100facing the upper cover90.

The ribs92and102disposed on the upper cover90or lower cover100may form a channel formed inside the upper cover90and lower cover100.

The ribs92and102forming the internal channel of the spray arm10may be disposed in at least one of the upper cover90and the lower cover100.

Each of the upper cover90and lower cover100may form a part of each of the first blades12aand12b, the second blade, and the hub82. When the upper cover90and the lower cover100are coupled to each other, the spray channels14aand14binside the first blades12aand12bmay be formed. When the upper cover90and the lower cover100are coupled to each other, the bubble generating channel40inside the second blade18may be formed. When the upper cover90and the lower cover100are coupled to each other, the discharge channel70inside the second blade18can be formed.

The spray arm10includes an inner side wall110in which a vertical hole116penetrating the upper cover90and the lower cover100in the up-down direction is formed. The vertical hole116formed inside the inner side wall110. The vertical hole116is open in the up-down direction so that falling washing water can flow to the bottom surface of the tub2.

The inner side wall110is connected to the upper cover90and the lower cover100, respectively. The inner side wall110may have a plurality of discharge holes108a,108b, and118formed on one side surface. The discharge holes108a,108b, and118discharge washing water containing microbubbles discharged from the bubble generating channel40into the tub2.

The inner side wall110may have a tubular shape extending from the top to the bottom. The inner side wall110may have a tubular shape whose diameter decreases from the top to the bottom. That is, the surface formed by the inner side wall110may be perpendicular to the rotation axis of the spray arm10, or may have a shape inclined upward from the vertical direction. Accordingly, the discharge holes108a,108b, and118may be opened in a direction perpendicular to the rotation axis or above the direction perpendicular to the rotation axis. Accordingly, washing water sprayed through the spray nozzles16aand16bof the first blades12aand12bmay fall into the discharge holes108a,108b, and118of the inner side wall110. This may have the effect of applying pressure to the washing water containing the microbubbles discharged through the discharge holes108a,108b, and118, thereby causing the microbubbles to be additionally broken. The specific structure and shape of the inner side wall110will be described in detail below.

The spray channels14aand14bmay have a shape extending centrifugally from the hub82. The spray channel may be formed so that a channel cross-sectional area thereof decreases in a direction away from the hub82.

The bubble generating channel40allows a portion of the washing water supplied from the hub82to flow, and air is suctioned and crushed into the flowing washing water to discharge the washing water containing microbubbles.

Hereinafter, with reference toFIGS.7to12, the bubble generating channel will be described.

In some implementations, the bubble generating channel40includes a connection channel42connected to the supply channel84of the hub82, a buffer chamber44connected to the connection channel42and having the increasing cross-sectional area in the channel, an air intake channel56which is connected to the buffer chamber44and through which external air flows in, and a discharge channel70connected to the air intake channel56and discharging washing water having the generated microbubbles.

Referring toFIGS.7to12, in some examples, the bubble generating channel40may have a rectangular cross-section in the channel.

The connection channel42is connected to the supply channel84of the hub82. The connection channel42may supply the washing water flowing from the supply channel84to the buffer chamber44. The channel cross-sectional area of the connection channel42is smaller than the channel cross-sectional area at inlet ends of the spray channels14aand14b.

The buffer chamber44includes an expansion portion50in which the cross-sectional area of the channel increases, a maintenance portion52in which the cross-sectional area of the channel is maintained, and a reduction portion54in which the cross-sectional area of the channel is reduced.

The cross-sectional area of the channel formed in the expansion portion50is larger than the cross-sectional area of the connection channel42. Referring toFIGS.8and11, the cross-sectional area of the channel at the inlet end portion of the expansion portion50is larger than the cross-sectional area of the discharge end portion of the connection channel42. Accordingly, when the washing water flowing through the connection channel42flows into the buffer chamber44, the flow rate may rapidly decrease. Additionally, as the expansion portion50moves in a flow direction of the washing water, the cross-sectional area of the channel rapidly expands, so the flow rate of the washing water may decrease. That is, the pressure of the washing water flowing into the buffer chamber44through the connection channel42may be lowered.

A length501of the expansion portion50extending in the flow direction of the washing water is shorter than a length521of the maintenance portion52extending in the flow direction of the washing water. The length501of the expansion portion50in a longitudinal direction is formed to be shorter than a length (t1+t2) of the expansion portion50expanding in a width direction. Accordingly, the flow rate of washing water flowing from the connection channel42into the buffer chamber44may be rapidly reduced.

The maintenance portion52may maintain the cross-sectional area of the channel expanded in the expansion portion50. The length521of the maintenance portion52extending in the longitudinal direction may be longer than the length501of the expansion portion50extending in the longitudinal direction.

The reduction portion54extends from the end portion of the maintenance portion52in the flow direction of the washing water. The channel formed inside the reduction portion54is connected to the air intake channel56at a discharge end. Here, the discharge end of the reduction portion54may be an outlet48of the buffer chamber44.

Since the cross-sectional area of the channel of the washing water flowing along the reduction portion54is reduced in the flow direction of the washing water, the pressure of the flowing washing water is lowered. Since the cross-sectional area of the channel of the washing water flowing along the reduction portion54decreases in the flow direction of the washing water, the flow speed of the flowing washing water increases. A length541of the reduction portion54extending in the flow direction of the washing water is shorter than a length521of the maintenance portion52extending in the flow direction of the washing water. The length541of the reduction portion54in the longitudinal direction is shorter than a length t3+t4 by which the reduction portion54is reduced in the width direction. The length541of the reduction portion54extending in the flow direction of the washing water may be similar to the length501of the expansion portion50extending in the flow direction of the washing water. That is, the length541of the reduction portion54in the longitudinal direction may be 0.8 to 1.2 times the length501of the expansion portion50in the longitudinal direction.

Here, the longitudinal direction may be the direction in which the second blade18extends. Additionally, the width direction may be perpendicular to the longitudinal direction.

Referring toFIGS.8and11, the channel formed inside the buffer chamber44may be formed to have the same length in the up-down direction over the entire area. Referring toFIGS.9and12, the channel formed inside the buffer chamber44may form the channel that expands, maintains, and contracts in the width direction.

An inlet46connected to the connection channel42and an outlet48connected to the air intake channel56may be formed in the buffer chamber44. The inlet46may be a hole or channel formed at the inlet end of the buffer chamber44. The outlet48may be a hole or channel formed at the discharge end of the buffer chamber44.

The positions of the centers of the inlet46and the outlet48formed in the buffer chamber44may be different. Here, a center46cof the inlet46may refer to the center of the hole or channel formed by the inlet46. Likewise, a center48cof the outlet48may refer to the center of the hole or channel formed by the outlet48.

Referring toFIG.8, the center46cof the inlet46of the buffer chamber44may be formed above the center48cof the outlet48of the buffer chamber44. Referring toFIG.11, in some examples, the center46cof the inlet46of the buffer chamber44may also be formed above the center48cof the outlet48of the buffer chamber44.

In some examples, unlike the examples ofFIGS.8and11, the center46cof the inlet46of the buffer chamber44and the center48cof the outlet48of the buffer chamber44may be spaced apart in the width direction.

The sizes of the inlet46and the outlet48formed in the buffer chamber44may be different from each other. The size of the inlet46formed in the buffer chamber44may be smaller than the size of the outlet48.

The size of the outlet48formed in the buffer chamber44may be formed in a size corresponding to the air intake channel56. The size of the outlet48formed in the buffer chamber44may be formed at a level where the pressure of the washing water flowing through the air intake channel56can form negative pressure.

The size of the inlet46formed in the buffer chamber44may be formed to correspond to the channel cross-sectional area of the connection channel42. The size of the inlet46formed in the buffer chamber44can be formed so that the flow rate of washing water flowing into the connection channel42can be adjusted. The flow rate of washing water flowing through the connection channel42may be relatively lower than the flow rate of washing water flowing through the spray channels14aand14b.

An inner protrusion58protruding from one side of the outlet48is disposed in the spray arm10to change the center48cof the outlet48. The inner protrusion58protrudes to one side of the outlet48to change the center of the outlet48. Referring toFIG.8, the inner protrusion58may be formed on the upper side of the outlet48. The inner protrusion58can move the center of the outlet48of the buffer chamber44downward. Accordingly, the separation distance between the center46cof the inlet46of the buffer chamber44and the center48cof the outlet48may increase.

In the buffer chamber44of the present disclosure, the positions of the centers of the inlet46and the outlet48are different from each other, so that the flow rate of the washing water flowing into the buffer chamber44through the inlet46is reduced inside the buffer chamber44, and thereafter, the flow rate of washing water passing through the outlet48through the reduction portion54may increase. In other words, the change in flow rate of washing water flowing into the inlet46of the buffer chamber44and flowing to the outlet48can be changed to decrease and then increase. When the positions of the centers of the inlet46and the outlet48formed in the buffer chamber44are the same, there will be little change in the flow rate of the washing water flowing through the inlet46to the outlet48, which may cause the pressure of the washing water flowing through the air intake channel56to be higher than the negative pressure. That is, microbubbles may not be actively formed because the rate at which external air is suctioned into the air intake channel56is low.

In some implementations, the positions of the centers of the inlet46and the outlet48of the buffer chamber44are formed differently from each other, so that the flow rate of the washing water flowing through the buffer chamber44is reduced and increased, and thus, a negative pressure may be formed in the washing water flowing through the air intake channel56.

The expansion portion50may begin with a channel area larger than the inlet46. Referring toFIGS.8and11, the expansion portion50may begin with the expansion portion50expanded downward beyond the inlet46of the buffer chamber44connected to the connection channel43.

The air intake channel56is connected to the buffer chamber44. The washing water flowing in the buffer chamber44may flow to the air intake channel56. The channel cross-sectional area of the air intake channel56may be smaller than the channel cross-sectional area of the buffer chamber44. The channel cross-sectional area of the air intake channel56may be smaller than the channel cross-sectional area of the channel formed in the maintenance portion52. Accordingly, the washing water flowing through the air intake channel56may form negative pressure.

The air intake channel56is connected to an air flow channel60on one side. External air may flow into the air flow channel60through the intake hole64formed on one side of the spray arm10.

The air flow channel60may be connected to the downstream end portion of the air intake channel56. The air flow channel60may be connected to a peripheral surface of the air intake channel56. The air flow channel60may be disposed on the peripheral surface of the air intake channel56at a portion where the discharge end portion of the air intake channel56is formed. Therefore, it is possible to prevent air introduced into the air intake channel56from flowing into the buffer chamber44.

The intake hole64may be formed on the lower surface of the spray arm10. Referring toFIG.6, the intake hole64may be formed in the lower cover100. Therefore, it is possible to prevent washing water falling from the upper side from flowing into the air flow channel60through the intake hole64. The air flow channel60may include at least one bending portion62through which the flow direction of the channel changes.

The air flow channel60may be connected perpendicularly to the air intake channel56. Accordingly, the air flowing into the air intake channel56from the air flow channel60may flow perpendicular to the flow direction of the washing water flowing through the air intake channel56. Since the air flowing into the air intake channel56flows perpendicular to the flow direction of the washing water flowing through the air intake channel56, the air may be primarily crushed due to friction with the flowing washing water.

The discharge channel70is connected to the air intake channel56. The cross-sectional area of the discharge channel70may increase from the inlet end connected to the air intake channel56toward the flow direction of the washing water. The channel cross-sectional area of the inlet end70aof the discharge channel70is larger than the channel cross-sectional area of the discharge end56aof the air intake channel56. The channel cross-sectional area of the inlet end70aof the discharge channel70may be 1.5 to 2.5 times the channel cross-sectional area of the discharge end56aof the air intake channel56. Accordingly, pressure is temporarily applied to the washing water discharged from the air intake channel56and flowing into the discharge channel70, and the air contained in the washing water may be secondarily destroyed.

The discharge channel70may have a cross-sectional area that increases toward the flow direction of the washing water. Accordingly, the air contained in the washing water flowing along the discharge channel70may be additionally crushed. The discharge channel70includes a pressurized portion72in which the cross-sectional area of the channel increases in the flow direction of the washing water.

Below, with reference toFIG.13, the bubble generating channel will be described.

In some implementations, referring toFIG.13, the bubble generating channel40may include the connection channel42which is connected to the supply channel84of the hub82, the buffer chamber44which is connected to the connection channel42and of which a cross-sectional area of the channel increases, the air intake channel56which is connected to the buffer chamber44and through which external air flows in, and the discharge channel70which is connected to the air intake channel156and through which the washing water having the generated microbubbles is discharged. In addition, the bubble generating channel40may include the downstream end portion of the air intake channel56and the air flow channel60that supplies the external air introduced through the intake hole64to the air intake channel56.

The buffer chamber44includes the expansion portion50in which the cross-sectional area of the channel increases, the maintenance portion52in which the cross-sectional area of the channel is maintained, and the reduction portion54in which the cross-sectional area of the channel is reduced. The positions of the inlet and outlet of the buffer chamber44may be different from each other.

Referring toFIG.13, in some examples, the bubble generating channel40may have a circular or oval cross-sectional shape.

Hereinafter, with reference toFIG.14, a bubble generating channel will be described.

Referring toFIG.14, in some examples, the bubble generating channel40includes the connection channel42which is connected to the supply channel84of the hub82, the air intake channel56which is connected to the connection channel42and through which external air flows in, and the discharge channel70which is connected to the air intake channel156and through which the washing water having the generated microbubbles is discharged. In addition, the bubble generating channel40may include the downstream end portion of the air intake channel56and the air flow channel60that supplies the external air introduced through the intake hole64to the air intake channel56.

The bubble generating channel40may include the downstream end portion of the air intake channel56and the air flow channel60that supplies the external air introduced through the intake hole64to the air intake channel56.

Referring toFIG.14, in some examples, the bubble generating channel40may not include a separate buffer chamber. The connection channel42may have a reduced cross-sectional area to reduce the pressure of the flowing washing water.

Hereinafter, with reference toFIGS.3to6andFIGS.15to18, the structure of the channel formed inside the spray arm will be described.

In some implementations, protruding inner ribs94aand94bare disposed on the upper cover90or lower cover100and define a channel through which the washing water flows.

In the spray arm10of the present disclosure, a flat surface may be formed in one of the upper cover90and lower cover100, and the ribs94aand94bprotruding to the flat surface and coming into contact with the flat surface may be formed in the other of the upper cover90and lower cover100. The ribs94aand94bmay come into contact with the flat surface104to form the channel through which washing water flows.

Referring toFIG.15, the lower cover100forms the flat surface104, and the pair of ribs94aand94bextending to the flat surface104of the lower cover100protrudes from the upper cover90. The pair of ribs94aand94bextend downward from the upper cover90. The pair of ribs94aand94bis arranged to be in contact with the flat surface104of the lower cover100. In a state where the pair of ribs94aand94bin contact with the flat surface104of the lower cover100, the upper cover90and the lower cover100may be fused.

Specifically, in the connection channel42formed in the spray arm10, the pair of ribs94and94bprotruding from the other of the upper cover90and the lower cover100is in contact with the flat surface104formed in one of the upper cover90and the lower cover100, and thus, the connection channel42is formed. Referring toFIG.15, the pair of ribs94aand94bprotruding from the upper cover90is in contact with the flat surface104formed in the lower cover100, and thus, the connection channel42may be formed.

The connection channel42may have a small diameter so that only a portion of the washing water flowing through the supply channel84of the hub82flows into the bubble generating channel40. As in the present disclosure, one cover forms a flat surface, and the channel may be formed by a coupling of the pair of ribs protruding from the other cover. In this structure, the area of the channel or the center of the channel can be maintained even when there is some error due to the fusion of the upper cover90and the lower cover100.

The flat surface104of the lower cover100may be disposed to be spaced upward from the bottom surface106formed by the lower cover100. The support ribs96aand96bmay be disposed in the upper cover90to support the arrangement of the pair of ribs94aand94bforming the connection channel42. The support ribs96aand96bmay be provided as a pair disposed outside each of the pair of ribs94aand94b. That is, referring toFIG.15, each of the pair of support ribs96aand96bmay be spaced apart from the outside of each of the pair of ribs94aand94band disposed to be in contact with the bottom surface106of the lower cover100. The pair of support ribs96aand96bmay be fused to each other in a state of being in contact with the bottom surface106of the lower cover100.

Referring toFIG.15, the connection channel42may be a channel having a rectangular cross-section. The rectangular cross-sectional channel shape according toFIG.15is just an example. In some implementations, various channel shapes are possible in the channel structure defined by a flat surface and a pair of ribs in contact with the flat surface. For instance, a semicircular cross-sectional structure as inFIG.16, a triangular cross-sectional structure as inFIG.17, and a trapezoidal cross-sectional structure as inFIG.18may be provided.

The discharge channel70is connected to the air intake channel56, and can discharge the washing water discharged from the air intake channel56into the tub2through the discharge holes108a,108b, and118.

The discharge channel70can additionally pulverize the air contained in the washing water discharged from the air intake channel56. The cross-sectional area of the discharge channel70may increase from the inlet end toward the flow direction of the washing water. Accordingly, pressure is applied to the washing water flowing from the inlet end of the discharge channel70in the flow direction of the washing water, and thus, the air contained in the washing water may be additionally crushed.

The discharge channel70includes the pressurized portion72which is connected to the air intake channel56and in which the channel is expanded, and a discharge portion74which is disposed downstream of the pressurized portion72and in which the discharge holes108a,108b,118are formed.

The pressurized portion72connects the air intake channel56and the discharge portion74, the cross-sectional area of the channel increases in the direction away from the rotation axis of the spray arm10, and thus, the pressure on the flowing washing water may increase. Accordingly, the air contained in the washing water flowing along the pressurized portion72may be additionally crushed. The air contained in the washing water discharged from the air intake channel56and flowing through the pressurized portion72may be additionally crushed to form microbubbles.

The discharge portion74is formed in the direction in which the second blade18extends, and is configured to discharge the washing water having the generated microbubbles into the tub2through the discharge holes108a,108b,118formed on one side. The discharge holes108a,108b, and118are disposed on the channel formed by the discharge portion74, so that the washing water flowing through the discharge portion74may be discharged to the outside of the second blade18through the discharge holes108a,108b, and118.

The discharge holes108a,108b, and118are the first discharge hole118disposed on the side walls24and110of the second blade18and the second discharge hole108aand108bdisposed on the lower surface of the second blade18.

The first discharge hole118is formed on the side walls24and110of the second blade18. Here, the side walls24and110of the second blade18may face a direction perpendicular to the rotation axis of the spray arm10. For example, the side walls24and110define a vertical surface. In some implementations, the side walls24and110may face a direction inclined upward from the direction perpendicular to the rotation axis of the spray arm10. The side walls24and110may be defined at the upper cover90. The side walls24and110may be formed in the inner side wall110.

The first discharge hole118may be opened in a direction perpendicular to the rotation center axis10cof the spray arm10or in a direction inclined upward from the vertical direction to the rotation center axis10cof the spray arm10. The washing water that is sprayed into the washing space through the spray nozzles16aand16bof the first blades12aand12band falls may fall into the first discharge hole118. The washing water sprayed and dropped from the first blades12aand12bmay hit the washing water discharged from the first discharge hole118, thereby further pulverizing the microbubbles.

The second discharge holes108aand108bmay be formed in the lower cover100. The second discharge holes108aand108bcan discharge the washing water remaining in the bubble generating channel40to the tub2. The second discharge holes108aand108bcan discharge the washing water remaining in the discharge channel70into the tub2. That is, when the operation of the washing pump stops, the washing water can be prevented from remaining in the bubble generating channel40.

Hereinafter, with reference toFIGS.19to22, the arrangement of the first discharge hole118and the structure of the discharge channel70will be described.

Referring toFIG.19, in some implementations, the second blade18includes an upper wall20disposed to face upward, a lower wall22disposed to face downward, and side walls24and110connecting the upper wall20and the lower wall22. The side walls24and110may form a surface facing in a direction perpendicular to the rotation center axis10cof the spray arm10, or form a surface facing upward from the direction perpendicular to the rotation center axis10cof the spray arm10.

The side walls24and110include an outer side wall24that connects the upper wall20and the lower wall22and forms the outer perimeter of the second blade18, and an inner side wall110that connects the upper wall20and the lower wall22and is formed around the vertical hole116formed in the second blade18.

Referring toFIG.19, the upper wall20and the outer side wall24are disposed in the upper cover90. The lower wall22is disposed in the lower cover100. The outer side wall24may be disposed in the lower cover100. Referring toFIG.19, the first discharge hole118is formed in the inner side wall110. In some implementations, the first discharge hole may be formed in the outer side wall24.

The first discharge hole118is formed in the inner side wall110. The inner side wall110forms the vertical hole116that is open in the up-down direction. The inner side wall110may form a peripheral wall around the vertical hole116. The inner side wall110may form a surface facing in a direction perpendicular to the rotation center axis10cof the spray arm10, or form a surface facing upward from the direction perpendicular to the rotation center axis10cof the spray arm10.

The inner side wall110is formed such that the cross-sectional area of the inner peripheral surface of the upper end portion is larger than the cross-sectional area of the inner peripheral surface of the lower end portion. The inner side wall110has an oval pillar shape. The inner side wall110has a shape inclined toward the upper side. The inner side wall110may be disposed in the second blade18and may be the side wall24or110on which the first discharge hole118is formed.

The inner side wall110may include a pair of long walls114aand114bformed in the direction in which the second blade18extends and a pair of short walls112aand112bconnecting both end portions of the pair of long walls114aand114b. The pair of short walls112aand112bincludes a first short wall112adisposed adjacent to the air intake channel56and a second short wall112bdisposed adjacent to an end portion of the second blade18.

A plurality of first discharge holes118are formed in the pair of short walls112aand112b. Referring toFIGS.21and22, an inclination angle θ1 formed between the short walls112aand112bwhere the first discharge hole118is formed and a virtual horizontal line v1 is smaller than an inclination angle θ2 formed between the long walls114aand114band the virtual horizontal line v1. Accordingly, the short walls112aand112bin which the plurality of first discharge holes118are formed may form an inclined surface inclined more upward than the long walls114aand114b.

A length1141of the long walls114aand114bin the direction in which the second blade18extends is longer than a length1121of the short wall112aand112bin the direction perpendicular to the long walls114aand114b. Referring toFIG.19, the long walls114aand114bmay have the shape of straight surfaces. Referring toFIG.19, the short wall112aand112bmay have a curved shape.

In the discharge portion74, the washing water flowing from the pressurized portion72is branched from the first short wall112a. Therefore, the flow of the washing water may temporarily stagnate around the first short wall112a, and the stagnant washing water may flow into the tub2through the first discharge hole118formed in the first short wall112a.

The discharge portion74includes a pair of extension channels78aand78bformed outside the pair of long walls114aand114b, a branch channel76that is connected to the pressurized portion72and branches from each of the pair of extension channels78aand78b, and a combined channel80in which a pair of extension channels78aand78bare combined.

The pair of extension channels78aand78bare formed outside the pair of long walls114aand114b. The pair of extension channels78aand78bextend along each of the pair of long walls114aand114b. Each of the pair of extension channels78aand78bconnects the branch channel76and the combined channel80to each other.

The second discharge holes108aand108bare formed in the lower portions of each of the branch channel76and the combined channel80.

Referring toFIG.23, the first discharge hole118may be formed along the inner peripheral surface of the inner side wall110. That is, the first discharge hole118may be formed in each of the short wall112aand112band the long walls114aand114bof the inner side wall110.

Referring toFIG.24, the first discharge hole118may be disposed in the outer side wall24. The plurality of first discharge holes118may be spaced apart in the direction in which the second blade18extends.

Referring toFIG.25, the bubble generating channel40may be formed around the side walls24and110. That is, the bubble generating channel40includes the connection channel42which is connected to the hub82, the buffer chamber44which is connected to the connection channel42and in which the cross-sectional area of the channel increases or decreases, the air intake channels56aand56bwhich are connected to the buffer chamber44and in which a reduced channel cross-sectional area is maintained, and the discharge channel170which is connected to the air intake channels56aand56b, has an expanded channel cross-sectional area, and discharges the washing water to the discharge hole118.

Referring toFIG.25, the bubble generating channel40includes a pair of air intake channels56aand56b. A pair of air flow channels60a,60bthrough which external air flows in are connected to each of the pair of air intake channels56aand56b. Each of the pair of air flow channels60aand60bsupplies external air flowing in from a pair of intake holes64aand64bformed on one side to each of the pair of air intake channels56aand56b.

The buffer chamber44may be connected to each of the pair of air intake channels56aand56b. That is, the washing water flowing into the buffer chamber44can flow into each of the pair of air intake channels56aand56b. Referring toFIG.25, the connection channel42may be connected to the buffer chamber44at the center of the second blade18in the width direction. The pair of air intake channels56aand56bmay be connected at both end portions of the buffer chamber44in the width direction. That is, the centers of the inlet and outlet of the buffer chamber44may be spaced apart in the width direction of the second blade18.

In the above, one or more implementations of the present disclosure have been illustrated and described, but the present disclosure is not limited to the specific embodiments described above. That is, the present disclosure can be modified in various ways by a person with ordinary knowledge in the technical field to which the disclosure belongs without departing from the gist of the present disclosure as claimed in claims, and these modified implementations should not be understood individually from the technical ideas or perspectives of this disclosure.