Dishwasher

A dishwasher includes a tub. The dishwasher further includes a spray arm that includes a main arm and an auxiliary arm. The dishwasher further includes a fixed gear part that is connected to the tub, that is configured to rotatably support the main arm, and that includes teeth along an outer circumferential surface of the fixed gear part. The dishwasher further includes a rotating gear part that is connected to the main arm and that is configured to rotate and engage the teeth of the fixed gear part based on rotation of the main arm. The dishwasher further includes a link unit that is connected to the rotating gear part, the main arm, and the auxiliary arm, that is configured to move based on rotation of the rotating gear part, and that is configured to guide reciprocation of the auxiliary arm through the predetermined arc.

This application claims the benefit of Korean Patent Applications No. 10-2015-0104240, filed on Jul. 23, 2015, and No. 10-2015-0104242, filed on Jul. 23, 2015, which are both hereby incorporated by reference as if fully set forth herein.

FIELD

The present application relates to a dishwasher.

BACKGROUND

In general, a dishwasher is an appliance that washes dishes, cookware, etc. (hereinafter referred to as an “object to be washed”) by removing foreign substances such as food waste from an object to be washed using a detergent and wash water.

Typically, a dishwasher includes a tub defining a washing compartment, a dish rack provided in the tub, in which an object to be washed is accommodated, a spray arm for spraying wash water to the dish rack, a sump for retaining wash water, and a supply passage, through which the wash water retained in the sump is supplied to the spray arm.

Recently, a dishwasher capable of spraying wash water evenly toward an object to be washed through rotation of the spray arm has been developed. Further, in order to improve washing performance, the spray arm is structured such that a portion thereof performs a reciprocating movement (rolling) along a predetermined circular arc path using the rotating force of the spray arm.

SUMMARY

According to an innovative aspect of the subject matter described in this application, a dishwasher includes a tub that defines a compartment that is configured to receive an object; a spray arm that includes: a main arm that is configured to rotate, that is located in the tub, and that is configured to spray wash water toward the object, and an auxiliary arm that is coupled to the main arm, that is configured to reciprocate through a predetermined arc, and that is configured to spray wash water toward the object; a fixed gear part that is connected to the tub, that is configured to rotatably support the main arm, and that includes teeth along an outer circumferential surface of the fixed gear part; a rotating gear part that is connected to the main arm and that is configured to rotate and engage the teeth of the fixed gear part based on rotation of the main arm; a link unit that is connected to the rotating gear part, the main arm, and the auxiliary arm, that is configured to move based on rotation of the rotating gear part, and that is configured to guide reciprocation of the auxiliary arm through the predetermined arc; and a foreign substance blocking part that is configured to receive the fixed gear part and the rotating gear part and that is configured to block the fixed gear part and the rotating gear part from being exposed to wash water.

This and other implementations may include one or more of the following optional features. The link unit includes a ring-shaped rim portion that is configured to receive the fixed gear part; and a plurality of connection portions that each extend from the rim portion in a radial direction and that are each connected to the spray arm. The link unit defines a recessed portion in one of the connection portions, the recessed portion being configured to receive the rotating gear part and prevent interference by the rotating gear part. The foreign substance blocking part includes a first rib that protrudes from an outer circumferential surface of the rim portion and that is configured to receive the fixed gear part, and a second rib that protrudes from the recessed portion and that is configured to receive the rotating gear part. The foreign substance blocking part includes one or more protruding ribs that each protrude toward the fixed gear part from branched portions of the main arm and the auxiliary arm and that are configured to receive the fixed gear part and the rotating gear part. The one or more protruding ribs each protrude perpendicular to a bottom surface of the main arm and a bottom surface of the auxiliary arm. The one or more protruding ribs are inclined at a predetermined acute angle relative to a bottom surface of the main arm and a bottom surface of the auxiliary arm. The one or more protruding ribs have a predetermined curvature. The foreign substance blocking part includes spray arm ribs (i) that are located in a plane that is defined by the main arm and the auxiliary arm and (ii) that are located at branched portions of the main arm and the auxiliary arm. The ribs include a mesh material.

According to an innovative aspect of the subject matter described in this application a dishwasher includes a tub that defines a compartment that is configured to receive an object; a spray arm that includes a main arm that is configured to rotate, that is located in the tub, and that is configured to spray wash water toward the object, and an auxiliary arm that is coupled to the main arm, that is configured to reciprocate through a predetermined arc, and that is configured to spray wash water toward the object; a fixed gear part that is connected to the tub, that is configured to rotatably support the main arm, and that includes teeth along an outer circumferential surface of the fixed gear part; a rotating gear part that is connected to the main arm and that is configured to rotate and engage the teeth of the fixed gear part based on rotation of the main arm; a link unit that is connected to the rotating gear part, the main arm, and the auxiliary arm, that is configured to move based on rotation of the rotating gear part, and that is configured to guide reciprocation of the auxiliary arm through the predetermined arc, where the spray arm further includes a nozzle that defines a spray hole and is configured to spray wash water toward the fixed gear part and the rotating gear part.

This and other implementations may include one or more of the following optional features. The nozzle is located on a bottom surface of the spray arm and is configured to spray wash water toward at least one of a region where the fixed gear part engages the rotating gear part, an outer circumferential surface of the fixed gear part where the fixed gear part does not engage the rotating gear part, or an outer circumferential surface of the rotating gear part where the fixed gear part does not engage the rotating gear part. The spray arm further includes one or more additional nozzles. The nozzle and the one or more additional nozzles are configured to spray wash water toward a region where the fixed gear part engages the rotating gear part, an outer circumferential surface of the fixed gear part where the fixed gear part does not engage the rotating gear part, and an outer circumferential surface of the rotating gear part where the fixed gear part does not engage the rotating gear part. The nozzle is located on a bottom surface of the auxiliary arm and is configured to spray wash water toward the outer circumferential surface of the rotating gear part, the bottom surface of the auxiliary arm being connected to a portion of the main arm that is connected to rotating gear part.

The nozzle has a plurality of spray holes and is configured to spray wash water toward the region where the fixed gear part engages the rotating gear part, an outer circumferential surface of the fixed gear part where the fixed gear part does not engage the rotating gear part, and an outer circumferential surface of the rotating gear part where the fixed gear part does not engage the rotating gear part. The nozzle is configured to spray wash water at a predetermined spray angle that aligns with a plane that is defined by the rotating gear part while engaged with the fixed gear part. The spray arm defines a supply flow passage that is configured to guide wash water to the object, and a wash flow passage that is configured to guide, to the fixed gear part and the rotating gear part, wash water that is supplied to the supply flow passage. The nozzle is connected to an end portion of the wash flow passage. The link unit includes a ring-shaped rim portion that is configured to receive the fixed gear part; and a plurality of connection portions that each extend from the rim portion in a radial direction and that are each connected to the spray arm. The link unit defines a recessed portion in one of the connection portions, the recessed portion being configured to receive the rotating gear part and prevent interference by the rotating gear part. The link unit further includes an insertion portion that is located in the recessed portion and that guides the rotating gear part into the link unit.

The main arm defines first spray holes that are defined by a portion of the main arm, that extend in a first direction from a center of the spray arm, and that are configured to spray wash water toward the object, and second spray holes that are defined by a portion of the main arm, that extend in a second direction opposite the first direction from the center of the spray arm, and that are configured to spray wash water toward the object. The main arm includes guide protrusions that are located on a bottom surface of the main arm and that are coupled to a first group of the connection portions. The auxiliary arm includes third spray holes that are defined by a portion of the auxiliary arm, that extend in a third direction from the center of the spray arm, and that are configured to spray wash water toward the object, and fourth spray holes that are defined by a portion of the auxiliary arm, that extend in a fourth direction opposite the third direction from the center of the spray arm, and that are configured to spray wash water toward the object. The auxiliary arm includes a force transmission part that is located on a bottom surface of the auxiliary arm and that is coupled a second group of the connection portions that are not included in the first group. An angle defined by the main arm and the auxiliary arm is a right angle or an acute angle. The rim portion is configured to reciprocate between the first spray holes and the second spray holes defined in the main arm based on the rotating gear part revolving along an outer circumferential surface of the fixed gear part. The force transmission part is configured to reciprocate the auxiliary arm by moving in a direction of the rim portion based on the rim portion reciprocating.

An object of the subject matter described in this application lies in a dishwasher, which is capable of preventing foreign substances from adhering to gear parts for rotating a spray arm, thereby ensuring stable rotation of the spray arm.

Another object of the subject matter described in this application lies in a dishwasher, which is capable of rapidly removing adhered foreign substances from gear parts for rotating a spray arm, thereby ensuring stable rotation of the spray arm.

A further object of the subject matter described in this application lies in a dishwasher, which is capable of preventing water leakage from occurring at a spray arm, thereby improving washing efficiency.

Another further object of the subject matter described in this application in a dishwasher, in which an auxiliary arm connection unit is formed integrally with a spray arm, thereby simplifying a manufacturing process.

Still another further object of the subject matter described in this application lies in a dishwasher, in which an auxiliary arm connection unit is formed integrally with a spray arm, thereby preventing water leakage from occurring at a connection portion between the auxiliary arm connection unit and the spray arm.

DETAILED DESCRIPTION

As shown inFIG. 1, a dishwasher1may include a tub2defining a washing compartment therein, a door3for selectively opening and closing the washing compartment, a dish rack4provided in the tub2so as to accommodate an object to be washed therein, a sump5provided in the tub1so as to retain wash water therein, and a spray arm assembly10provided in the tub1so as to spray wash water toward the object to be washed, which is accommodated in the dish rack4.

The dish rack4may be mounted so as to be drawn out forward from the tub2. Therefore, a user may put an object to be washed in the dish rack4after pulling the dish rack4out and forward from the tub2.

As shown inFIG. 2, the dishwasher may include a sump cover20, which serves as a top surface of the sump5, and a sump discharge part30, which is provided at the sump cover20. The wash water sprayed into the tub2may be collected in the sump5through the sump discharge part30. In some implementations, a water supply pump may be provided in the sump5to transfer the wash water retained in the sump5to the spray arm assembly10.

The wash water collected in the sump5may be supplied again to the spray arm assembly10by the water supply pump provided in the sump5.

The spray arm assembly10may be mounted to the sump cover20, and may function to spray the wash water retained in the sump5to the object to be washed accommodated in the dish rack. The spray arm assembly10may include a spray arm100for spraying wash water, and a fixed gear part200and an arm holder300, which are mounted to the sump cover20so as to rotatably support the spray arm100.

The wash water may flow into the spray arm assembly10via the sump5, and may be then sprayed toward an object to be washed through the spray arm100.

Unlike the structure illustrated inFIG. 1, the spray arm assembly10may not be disposed below the dish rack4, but may be disposed above the dish rack4. In some implementations, the spray arm assembly10may be provided in a plural number such that the spray arm assemblies10spray wash water toward the regions above and below the dish rack4. The spray arm assembly10may be coupled to the sump cover20.

Hereinafter, the structure of the spray arm assembly10will be explained in detail with reference to the attached drawings.

Referring toFIG. 3, the spray arm assembly10may include a spray arm100, a fixed gear part200, an arm holder300, a flow passage switching part400, a rotating gear part500, and a link unit600.

An arm holder coupling part180may be provided on the bottom surface of the spray arm100, and the arm holder300, which is coupled to the arm holder coupling part180, may be provided on the sump cover20(refer toFIG. 2). The arm holder300may be rotatably coupled to the sump cover20. That is, the arm holder300may be rotated together with the spray arm100, and may also serve as a rotating shaft of the spray arm100. Here, the wash water supplied from the sump5flows into the arm holder300, and is then supplied to the spray arm100.

The flow passage switching part400may be accommodated in the arm holder300. When the water pressure in the arm holder30is increased as the wash water flows into the arm holder300, the flow passage switching part400may move upwards, and when the inflow of the wash water into the arm holder300is stopped, the water pressure in the arm holder300may be decreased, and thus the flow passage switching part400may move downwards.

The spray arm100may include a main arm130, on the bottom surface of which the arm holder coupling part180, which is coupled with the arm holder300, is disposed, and an auxiliary arm150, which is rotatably coupled to the main arm130.

The main arm130and the auxiliary arm150may be formed with a plurality of flow passages, through which the wash water supplied from the sump5flows. The main arm130may have spray holes133and134formed in the top surface thereof, through which the wash water introduced into the main arm130is sprayed. The wash water introduced into the main arm130from the sump5may be sprayed upwards from the main arm130through the spray holes133and134.

The spray holes in the main arm130may include first spray holes133, which are formed in a portion of the main arm130extending in one direction from the rotational center, positioned to correspond to the fixed gear part200, so as to spray wash water toward an object to be washed, and second spray holes134, which are formed in a portion of the main arm130extending in the opposite direction from the rotational center, positioned to correspond to the fixed gear part200, so as to spray wash water toward an object to be washed.

The auxiliary arm150may be coupled to the main arm130so as to perform a reciprocating movement (rolling) along a predetermined circular arc path. In detail, the main arm130may have an extension portion120formed to extend in a radial direction, and the auxiliary arm150may be coupled to the extension portion120so as to perform a reciprocating movement along a predetermined circular arc path.

The auxiliary arm150may have auxiliary spray holes153and154formed so as to spray the wash water introduced into the main arm130. The auxiliary spray holes in the auxiliary arm150may include third spray holes153, which are formed in a portion of the auxiliary arm150extending in one direction from the rotational center, positioned to correspond to the fixed gear part200, so as to spray wash water toward an object to be washed, and fourth spray holes154, which are formed in a portion of the auxiliary arm150extending in the opposite direction from the rotational center, positioned to correspond to the fixed gear part200, so as to spray wash water toward an object to be washed.

The main arm130and the auxiliary arm150may extend radially from the rotational center, positioned to correspond to the fixed gear part200, and may be angularly spaced apart from each other at a predetermined angle. For example, the portion of the main arm130, in which the first spray holes133are formed, and the portion of the auxiliary arm150, in which the third spray holes153are formed, may be angularly spaced apart from each other at an acute angle or a right angle.

The portion of the main arm130, in which the first spray holes133are formed, and the portion of the auxiliary arm150, in which the fourth spray holes154are formed, may be angularly spaced apart from each other at an obtuse angle or a right angle.

In some implementations, the extension portion120may have a transfer flow passage formed therein, through which the wash water supplied from the sump5flows. The wash water flowing through the transfer flow passage may be introduced into an auxiliary flow passage formed in the auxiliary arm150. Therefore, the wash water introduced into the auxiliary flow passage formed in the auxiliary arm150may be sprayed through the auxiliary spray holes153and154.

The spray arm100may be rotated by a separate driving device. In some implementations, the spray arm100may be rotated by the repulsive force that is generated when wash water is sprayed through the spray holes133and134or the auxiliary spray holes153and154. That is, the spray arm100may be rotated by the repulsive force that is generated when wash water is sprayed, without the use of a separate driving device such as a motor or the like.

Referring toFIG. 4, the main arm130may include a gear-rotating shaft135, which is inserted into the rotating gear part500and serves as the rotating shaft of the rotating gear part500. The gear-rotating shaft135may be formed to protrude from a lower frame of the main arm130. The gear-rotating shaft135may be disposed on the bottom surface of the main arm130, as illustrated in the drawings, but the position of the gear-rotating shaft135is not limited to the bottom surface of the main arm130.

The main arm130may have guide protrusions136formed so as to guide the movement of the link unit600.

The auxiliary arm150may have force transmission parts156formed so as to receive force from the link unit600. The force transmission parts156may be protrusions, which protrude downwards from the bottom surface of the auxiliary arm150.

As illustrated inFIG. 5, the arm holder300may include an inlet portion310, through which the wash water retained in the sump5is introduced, and a coupling portion330, which is coupled to the spray arm100.

The inlet portion310may be formed with a hole, through which the wash water retained in the sump5is supplied. Therefore, the wash water retained in the sump5may flow into the arm holder300through the hole formed in the inlet portion310.

The inlet portion310may have a separation-prevention portion315, formed to prevent the arm holder300from being separated from the sump cover20. The separation-prevention portion315may be formed by expanding an end portion of the inlet portion310. The separation-prevention portion315may be connected to the sump cover20. Accordingly, the inlet portion310may be rotatably coupled to the sump cover20. The arm holder300may be received in the arm holder coupling part180, which is provided on the bottom surface of the spray arm100(refer toFIG. 3).

FIG. 6illustrates an example fixed gear part.

Referring toFIG. 6, the fixed gear part200may be coupled to the sump cover20in a manner such that fastening portions223provided at the fixed gear part200are fastened to the sump cover20. Unlike the arm holder300, the fixed gear part200may be non-rotatably secured to the arm holder300.

The fixed gear part200may include a rim portion210, which is provided with a plurality of teeth213, and support portions220, which extend downwards from the rim portion210. The arm holder coupling part180may be inserted into the rim portion210.

The rim portion210may have gap-reducing protrusions215formed to reduce the gap between the rim portion210and the arm holder coupling part180. The gap-reducing protrusions215may be provided in a plural number, and may protrude toward the center of the rim portion210.

The support portions220may be disposed at two opposing positions on the rim portion210. Each of the support portions220may be provided with the fastening portion223, which is fastened to the sump cover20. Each of the fastening portions223may be a protrusion protruding from the side surface of the corresponding support portion220. The fixed gear part200may be secured to the sump cover20via the fastening of the fastening portions223to the sump cover20.

Each of the support portions220may be further provided with a knob portion225, which a user grabs to couple or remove the fixed gear part200to/from the sump cover20. The knob portions225may be formed to extend in the radial direction of the fixed gear part200. Further, each of the knob portions225may be formed such that at least a portion of the surface thereof is convex or concave so that a user can grab the knob portions225.

The rotating gear part500may be rotatably mounted to the bottom surface of the spray arm100, and may be engaged with the fixed gear part200.

Referring toFIG. 7, the rotating gear part500may include a rim portion510, which is provided with a plurality of teeth513formed along the outer circumferential surface thereof, a rotating shaft insertion portion530, into which the gear-rotating shaft135is inserted, and an eccentric protrusion520, which is inserted into the link unit600so as to make the link unit600perform a reciprocating movement. The eccentric protrusion520may be disposed eccentrically from the center of the rim portion510. The gear-rotating shaft135may be inserted into the rotating shaft insertion portion530. The eccentric protrusion520may have a recess formed in a portion thereof into which the rotating shaft insertion portion530is inserted.

The eccentric protrusion520may protrude and extend in the direction of the rotational axis S of the rotating gear part500. The rotational axis S corresponds to the rotational center of the rotating gear part500. In some implementations, unlike the structure illustrated in the drawings, the eccentric protrusion520may be disposed on the outer circumferential surface of the rim portion510.

When the spray arm100rotates, the rotating gear part500may revolve along the circumference of the fixed gear part200, which is secured to the sump cover20, and may also rotate in engagement with the fixed gear part200at the same time. The rotating gear part500may be coupled to the gear-rotating shaft135, which is provided at the main arm130, in an insertion manner. Accordingly, the rotating gear part500may be coupled to the main arm100, and may be capable of rotating about the gear-rotating shaft135.

The link unit600may be connected to the main arm130and the auxiliary arm150by the guide protrusions136and the force transmission parts156(refer toFIG. 4). That is, the link unit600may be connected to 4 points of the spray arm100.

The link unit600may include a ring-shaped rim portion610, and a plurality of extension portions620,630,640and650, which extend from the rim portion610in the radial direction.

The rim portion610may be formed with an insertion hole612, into which the arm holder coupling part180is inserted. The insertion hole612may be formed to have an elliptical shape. Therefore, the arm holder coupling part180may move in the direction of the long axis612aof the insertion hole612.

The rim portion610may be further provided with a reinforcement rib617for increasing the rigidity of the rim portion610. The reinforcement rib617may be formed along the circumferential direction of the rim portion610, and may protrude upwards.

The first extension portions620and630may be coupled to the main arm130, and the second extension portions640and650may be coupled to the auxiliary arm150. In detail, the first extension portions620and630may be provided with guide portions623and633, into which the guide protrusions136of the main arm130are fitted, and the second extension portions640and650may be provided with transmission portions643and653, into which the force transmission parts156of the auxiliary arm150are fitted. Therefore, the movement of the link unit600may be transmitted to the auxiliary arm150through the force transmission parts156.

Any one of the extension portions620,630,640and650may be further provided with a recessed portion624in order to avoid interference with the rotating gear part500. The recessed portion624may be provided with an insertion portion625, into which the eccentric protrusion520of the rotating gear part500is inserted. The insertion portion625, as illustrated in the drawings, may be formed in an elongated hole shape.

As the link unit600transmits the force supplied from the rotating gear part500to the force transmission parts156, the auxiliary arm150may perform a reciprocating movement (rolling) along a predetermined circular arc path. That is, the reciprocating movement of the link unit600may be converted into the reciprocating movement (rolling) of the auxiliary arm150along the circular arc path.

FIGS. 9(a)-9(d)illustrate an example auxiliary arm by an example link unit.

Referring toFIGS. 9(a)-9(d), the constitution in which the auxiliary arm150is rotated as the link unit600is rotated by the rotating gear part500will be explained. In some implementations,FIGS. 9(a), 9(b), 9(c), and 9(d)are views showing the bottom surface of the spray arm assembly10when the rotating gear part500rotates 0 degrees, 90 degrees, 180 degrees and 270 degrees, respectively.

Referring toFIG. 9(a), when the rotating gear part500is in an initial state, i.e., a non-rotated state, the eccentric protrusion520is located at one end portion of the insertion portion625. Referring toFIG. 9(b), when the rotating gear part500rotates 90 degrees counterclockwise, the link unit600is moved in the direction A of the long axis612aof the insertion hole612by the eccentric protrusion520.

That is, since the rim portion610is formed in an elliptical shape, the rim portion610moves linearly toward the main arm130as the rotating gear part500revolves around the fixed gear part200. At this time, since the main arm130and the auxiliary arm150are angularly spaced apart from each other at a right angle or an acute angle, as the link unit600moves in the direction of the long axis612a, the extension portion640applies force to the force transmission part156in the moving direction of the link unit600.

Accordingly, the auxiliary arm150is moved upwards (in the drawing) along a circular arc path at a predetermined angle. The angle at which the auxiliary arm150reciprocates may be about 40 degrees.

Referring toFIG. 9(c), when the rotating gear part500rotates 90 degrees further counterclockwise, the link unit600is moved in the direction B of the long axis612a, which is opposite the direction A.

Accordingly, the link unit600returns to the same position as illustrated inFIG. 9(a). At the same time, the auxiliary arm150returns to its original position while being moved along the circular arc path in the reverse direction by the extension portion640.

Referring toFIG. 9(d), when the rotating gear part500rotates 90 degrees further counterclockwise, the link unit600is moved in the direction B of the long axis612aby the eccentric protrusion520.

Since the rim portion610is formed in an elliptical shape, the rim portion610moves linearly in the reverse direction as the rotating gear part500revolves around the fixed gear part200. At this time, the auxiliary arm150is moved along the circular arc path at a predetermined angle.

The angle at which the auxiliary arm150reciprocates may be about 40 degrees. In other words, as the rim portion610of the link unit600reciprocates linearly toward the first spray holes133and the second spray holes134of the main arm130, the force transmission part156reciprocates linearly through the extension portion640, thereby making the auxiliary arm150perform a reciprocating movement along the circular arc path.

The reciprocating movement of the auxiliary arm150along the circular arc path may be considered as vibration movement, and may particularly be considered to correspond to rolling, among the several types of vibrations including rolling, yawing and pitching.

Hereinafter, the structure of preventing the adherence of foreign substances to the spray arm assembly will be explained with reference toFIG. 10.

The spray arm100is rotated by the repulsive force that is generated when wash water is sprayed through the spray holes133,134,153and154formed in the main arm130and the auxiliary arm150.

However, the foreign substances removed from an object to be washed may adhere to the teeth213of the fixed gear part200or the teeth513of the rotating gear part500. In this case, the foreign substances may move to the region of engagement between the fixed gear part200and the rotating gear part500, and may even make it impossible for the rotating gear part500to revolve around the fixed gear part200.

If the foreign substances adhere to the teeth213and513, the spray arm100may not be rotated, and thus wash water may be sprayed toward a limited region rather than being sprayed evenly toward an object to be washed. Further, if the rotating gear part500does not revolve along the circumference of the fixed gear part200, the link unit600cannot make the auxiliary arm150perform a rolling movement. As a result, the washing efficiency of the dishwasher is deteriorated.

In addition, a load due to the torque generated at the spray arm100may be applied to the fixed gear part200and the rotating gear part500, which may cause damage to the components.

Therefore, there is a need to prevent foreign substances from adhering to the fixed gear part200and the rotating gear part500or to remove the adhered foreign substances rapidly.

FIG. 10illustrates an example link unit600having an example foreign substance blocking part700.

The rim portion610of the link unit600is a portion through which the fixed gear part200passes, and the recessed portion624is a portion in which the rotating gear part500is received. Therefore, the foreign substance blocking part700may include a first rib710, which is formed along the outer circumferential surface of the rim portion610so as to surround the outer circumferential surface of the fixed gear part200, and a second rib720, which is formed on the recessed portion624so as to surround the outer circumferential surface of the rotating gear part500.

The ribs710and720function to prevent the fixed gear part200and the rotating gear part500from being exposed to foreign substances generated during the washing process. Accordingly, the rotating gear part500is capable of continually revolving along the circumference of the fixed gear part200, thereby resolving the aforementioned problems.

FIG. 11illustrates an example spray arm100having an example foreign substance blocking part700.

The foreign substance blocking part700may include protruding ribs730, which protrude in the downward direction of the spray arm100. The protruding ribs730may protrude from one surface of the extension portion120toward the sump cover20, and the distance between the protruding ribs730may be equal to the width between the outer peripheral surfaces of the extension portion120. That is, the protruding ribs730may extend radially from the rotational center of the main arm130.

In addition, since the end portions of the protruding ribs730that are directed toward the end of the main arm130are spaced apart from each other and the end portions of the protruding ribs730that are directed toward the end of the auxiliary arm150are spaced apart from each other, interference with the link unit600may be avoided.

That is, since the fixed gear part200and the rotating gear part500are disposed on the bottom surface of the extension portion120, they may be surrounded by the protruding ribs730. Therefore, the protruding ribs730may prevent foreign substances from adhering to the fixed gear part200or to the rotating gear part500.

In some implementations, first and second ribs710and720disposed at the link unit and the protruding ribs730disposed at the spray arm may be inclined at a predetermined acute angle relative to the vertical plane of the dishwasher, or may be formed with a predetermined curvature. The inclination of the ribs may prevent the fixed gear part200and the rotating gear part500from being exposed to wash water more effectively than ribs extending in the vertical direction.

The ribs formed with a predetermined curvature may contain the fixed gear part200and the rotating gear part500more effectively than ribs that extend in the vertical direction or ribs that are inclined at a certain angle, thereby improving space utilization.

FIG. 12illustrates an example spray arm having an example foreign substance blocking part.

Referring toFIG. 12, the foreign substance blocking part700may include spray arm ribs740, which lie in substantially the same plane as the main arm130and the auxiliary arm150and are located at regions at which the auxiliary arm150branches from the main arm130.

That is, the spray arm ribs740may have a flange shape that is capable of preventing the wash water falling to the spray arm100from directly contacting the fixed gear part200or the rotating gear part500. In some implementations, the ribs720,730and740constituting the foreign substance blocking part700may be a mesh member.

The mesh-type ribs may prevent foreign substances from approaching the fixed gear part200and the rotating gear part500, but may allow the fixed gear part200and the rotating gear part500to be exposed to the wash water so as to be washed.

In some implementations, the foreign substance blocking part700may have a configuration that is capable of preventing foreign substances from adhering to the fixed gear part200and the rotating gear part500and of also preventing the fixed gear part200and the rotating gear part500from being exposed to the wash water so as to prevent corrosion.

Hereinafter, the constitution of removing the adhered foreign substances from the fixed gear part200and the rotating gear part500will be explained with reference toFIG. 13.

It may be important not only to prevent foreign substances from adhering to the fixed gear part200or to the rotating gear part500, but also to remove such adhered foreign substances rapidly.

FIG. 13illustrates an example spray arm, which illustrates a nozzle for removing the adhered foreign substances from the fixed gear part200and the rotating gear part500.

The nozzle800may be disposed on the bottom surface of the spray arm100. The nozzle800may spray wash water toward at least any one of the region of engagement between the fixed gear part200and the rotating gear part500, the outer circumferential surface of the fixed gear part200in the non-engaged region, and the outer circumferential surface of the rotating gear part500in the non-engaged region.

In some implementations, one or more nozzles800may be provided in order to spray wash water toward all of the region of engagement between the fixed gear part200and the rotating gear part500, the outer circumferential surface of the fixed gear part200in the non-engaged region, and the outer circumferential surface of the rotating gear part500in the non-engaged region.

In some implementations, the nozzle800may have a plurality of spray holes in order to spray wash water toward all of the region of engagement between the fixed gear part200and the rotating gear part500, the outer circumferential surface of the fixed gear part200in the non-engaged region, and the outer circumferential surface of the rotating gear part500in the non-engaged region.

The nozzle800may be disposed on at least any one of the bottom surface of the main arm130and the bottom surface of the auxiliary arm150. If the nozzle800is disposed on the bottom surface of the main arm130at a position near the region of engagement between the fixed gear part200and the rotating gear part500, the nozzle800may be capable of spraying wash water toward the region of engagement between the fixed gear part200and the rotating gear part500, thereby removing the adhered foreign substances therefrom.

That is, the nozzle800may be capable of rapidly removing the adhered foreign substances from the region of engagement between the fixed gear part200and the rotating gear part500by spraying wash water toward the engaged region, thereby ensuring smooth revolution of the rotating gear part500around the fixed gear part200.

The nozzle800may be disposed on the bottom surface of the auxiliary arm150, which is connected to the portion of the main arm130to which the rotating gear part500is mounted, in order to spray wash water toward the outer circumferential surface of the rotating gear part500.

Further, the nozzle800may prevent foreign substances from approaching the region of engagement between the fixed gear part200and the rotating gear part500by spraying wash water toward the outer circumferential surface of the fixed gear part200and the outer circumferential surface of the rotating gear part500.

Furthermore, the nozzle800may prevent foreign substances from adhering to the region of engagement between the fixed gear part200and the rotating gear part500by spraying wash water toward the outer circumferential surface of the fixed gear part200and the outer circumferential surface of the rotating gear part500.

Referring toFIG. 14, the nozzle800may spray wash water at a predetermined angle relative to the plane in which the rotating gear part500rotates.

That is, the wash water sprayed from the nozzle800may be directed toward the teeth213of the fixed gear part200or the teeth513of the rotating gear part500from the region above or below the fixed gear part200and the rotating gear part500at a predetermined angle of inclination.

When the nozzle800sprays wash water toward the rotating gear part500at a predetermined angle of inclination, the adhered foreign substances may be removed from the teeth213and513.

The angle between the wash water sprayed from the nozzle800and the plane in which the fixed gear part200and the rotating gear part500are engaged may be 90 degrees. In this case, the nozzle800may spray wash water in substantially the same plane as the fixed gear part200and the rotating gear part500.

However, if the nozzle800sprays wash water in substantially the same plane as the fixed gear part200and the rotating gear part500, more foreign substances may be directed toward the region between the fixed gear part200and the rotating gear part500. For this reason, in some implementations, the nozzle800to spray wash water at a predetermined angle of inclination from above to below, or from below to above, the gear parts200and500in order to remove the adhered foreign substances from the teeth213and513.

The nozzle800may be supplied with some of the wash water from the flow passage through which the wash water in the main arm130flows. However, if the nozzle800is supplied with wash water from the aforementioned flow passage, this may be very wasteful of wash water.

FIG. 15illustrates an example flow passage that is located in an example spray arm.

Referring toFIG. 15, the spray arm100may include a main flow passage131, through which wash water is supplied to the main arm130and the extension portion120, and a wash flow passage810, which is branched from the main flow passage131and has a smaller diameter than the main flow passage131.

The nozzle800may communicate with an end portion of the wash flow passage810. Since the diameter of the wash flow passage810can be set to supply the water quantity and the water pressure suitable for removing foreign substances from the fixed gear part200and the rotating gear part500, the consumption of wash water may be reduced.

FIG. 16illustrates an example auxiliary arm connection unit. Referring toFIG. 16, a conventional auxiliary arm connection unit160may include an extension pipe162, which is inserted into the main arm130, a flow pipe164, which communicates with the extension pipe162and through which wash water discharged from the extension pipe162flows, a shaft166, which is connected to the flow pipe164, and a projection168, which protrudes from the shaft166.

The shaft166is inserted into an auxiliary flow passage152, which is formed in the auxiliary arm150. The wash water discharged from the extension portion120flows through the auxiliary flow passage152, and the wash water flowing through the auxiliary flow passage152is sprayed outside through the auxiliary spray holes153and154.

The projection168, as illustrated in the drawings, may be formed in a column shape. The auxiliary flow passage152may have a connection portion, which is formed around the inner circumferential surface of the auxiliary flow passage152and which is connected with the main arm130through contact with the flow pipe164. The connection portion of the auxiliary flow passage152may function to support the weight of the flow pipe164through contact with the flow pipe164.

In the above-described conventional structure, the wash water discharged from the main arm130may be supplied to the auxiliary arm150through the auxiliary arm connection unit160.

However, there is a problem in that a gap may be formed in the connection portion between the main arm130and the auxiliary arm150in the event of a manufacturing error of the auxiliary arm connection unit160. That is, a large amount of wash water may leak through the gap when it is discharged from the main arm130.

In some implementations, wash water primarily leaks through the coupling portion between the extension pipe162and the main arm130, and flows backward and secondarily leaks through the connection portion of the auxiliary flow passage152, which connects the main arm130and the auxiliary arm150.

Because wash water is not smoothly supplied to the auxiliary arm150due to the above-described water leakage, washing efficiency is deteriorated. This water leakage becomes more severe when the pressure of the wash water is relatively high.

FIG. 17illustrates an example auxiliary arm connection unit. In order to solve the water leakage problem afflicting the conventional structure, as illustrated inFIG. 17, the auxiliary arm connection unit170may be formed integrally with the main arm130.

The auxiliary arm connection unit170may include an extension pipe172, which is formed integrally with the main arm130and extends therefrom, and a shaft176, which extends from the extension pipe172and is inserted into the auxiliary flow passage152of the auxiliary arm150.

The auxiliary arm connection unit170has the same constitution as the conventional auxiliary arm connection unit160, except for the integral formation of the extension pipe172with the main arm130. Therefore, the auxiliary arm connection unit170may be capable of preventing wash water from leaking between the main arm130and the extension pipe172.

Further, since the main arm130and the auxiliary arm connection unit170are formed integrally with each other, it may be possible to produce these components using an injection molding method or the like. Accordingly, an additional assembly process may be obviated, which leads to an improvement in manufacturing efficiency.

FIG. 18illustrates an example auxiliary arm connection unit.

The structure capable of preventing wash water from leaking through the connection portion of the auxiliary flow passage152connecting the main arm130and the auxiliary arm150will be explained with reference toFIG. 18. A sealing unit900may be provided in the connection portion of the auxiliary flow passage152connecting the main arm130and the auxiliary arm150, in order to prevent wash water from flowing backward.

The sealing unit900may include a plurality of first sealing members910,920,930and940, which protrude from the outer circumferential surface of the extension pipe172and have a ring shape. The first sealing members910,920,930, and940may be in contact with the inner circumferential surface of the auxiliary flow passage152of the auxiliary arm150. That is, the first sealing members910,920,930, and940may function to seal the connection portion of the auxiliary flow passage152connecting the main arm130and the auxiliary arm150.

The first sealing members910,920,930, and940may prevent the wash water discharged from the extension pipe172from leaking through the connection portion of the auxiliary flow passage152. The sealing unit900may further include a second sealing member950, which is disposed between two of the first sealing members910,920,930, and940.

One or more second sealing members950may be provided in a manner such that every second sealing member950is disposed in the respective region between two adjacent ones among the first sealing members910,920,930, and940. The second sealing member950may be attached on the outer circumferential surface of the extension pipe172. The second sealing member950may include a body portion951, which is secured to the extension pipe172, and a bent portion952, which extends from the body portion951and is capable of contacting the connection portion of the auxiliary flow passage152. The second sealing member950may be formed of an elastic material.

The operation of the second sealing member950will now be explained with reference toFIG. 18. The body portion951of the second sealing member950may be secured to the extension pipe172, and the bent portion952may be in a state of being separated from the connection portion of the auxiliary flow passage152.

When a large amount of wash water is discharged from the extension pipe172, some of the wash water flows toward the spray holes153and154in the auxiliary arm150, and the remainder of the wash water flows backward to the connection portion of the auxiliary flow passage152. At this time, if the pressure of the wash water is increased, the amount of wash water flowing backward to the connection portion of the auxiliary flow passage152is also increased.

If the wash water flows backward to the connection portion of the auxiliary flow passage152, the backflowing wash water pressurizes the bent portion952. Accordingly, the bent portion952comes into contact with the connection portion of the auxiliary flow passage152.

If the pressure of the wash water is increased, the bent portion952is further pressurized toward the connection portion of the auxiliary flow passage152. Accordingly, the second sealing member950may prevent wash water from leaking through the outer circumferential surface of the extension pipe172and the inner circumferential surface of the auxiliary flow passage152. As a result, all of the wash water supplied to the spray arm100may be sprayed toward an object to be washed without leakage, thereby improving washing efficiency.

As is apparent from the above description, the subject matter described above provides a dishwasher that is capable of preventing foreign substances removed from an object to be washed from adhering to a fixed gear part and a rotating gear part.

In addition, since smooth rotation of the spray arm is ensured without the adherence of foreign substances to the fixed gear part or to the rotating gear part, the fixed gear part and the rotating gear part may be prevented from being damaged.

In addition, adhered foreign substances may be removed rapidly by spraying wash water to a region of engagement between the fixed gear part and the rotating gear part.

In addition, it may be possible to prevent foreign substances from approaching a region of engagement between the fixed gear part and the rotating gear part by spraying wash water toward the outer circumferential surface of the fixed gear part and the outer circumferential surface of the rotating gear part.

In addition, foreign substances may be removed effectively by spraying wash water from above or below the fixed gear part and the rotating gear part.

In addition, washing efficiency may be improved by ensuring the smooth rotation of the spray arm.

In addition, washing efficiency may be improved by enabling the rotating gear part to revolve smoothly along the outer circumferential surface of the fixed gear part.

In addition, it may be possible to prevent components from being damaged by preventing an excessive load from being applied to the fixed gear part or to the rotating gear part due to the presence of foreign substances

In addition, it may be possible to prevent corrosion and propagation of bacteria due to the adherence of foreign substances to the fixed gear part and the rotating gear part.