Patent Publication Number: US-11638512-B2

Title: Robot cleaner

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of Korean Patent Application No. 10-2020-0050063, filed on Apr. 24, 2020, which is hereby incorporated by reference as if fully set forth herein. 
     BACKGROUND 
     Field 
     The present disclosure relates to a robot cleaner. 
     Discussion of the Related Art 
     A person cleans a living space thereof for hygiene and cleanliness. There are many reasons for the cleaning. For example, the cleaning may be done to protect a body from disease or to prevent damage to a bronchus. Further, the cleaning may be done for a quality of life, such as, for using the space thereof in a clean state. 
     Dust or foreign substances settle on a floor by gravity. Thus, in order to perform the cleaning, people tend to bend their waists or sit down, so that it is easy to put a strain on the waists or joints. 
     To this end, in recent years, cleaners that help people clean have appeared. The cleaners may be roughly classified into a handy stick cleaner, a bar-type cleaner, a robot cleaner, and the like. 
     Among these, the robot cleaner cleans the space instead of a user in a specific space such as a home, an office, or the like. The robot cleaner generally performs the cleaning by suctioning dust in an area to be cleaned. 
     However, it may not be said that the cleaning is completed by just suctioning the dust. The reason is that there is dust that is not able to be removed only by a suction power of the robot cleaner. For example, a foreign substance attached to a floor surface or dust larger than a suction port of the robot cleaner are difficult to be removed with only the suction power of the robot cleaner. 
     Thus, dust visible to the naked eye is generally removed by being suctioned through a vacuum cleaner or the robot cleaner, and the cleaning is completed through mopping. 
     In order to effectively perform the mopping, it is desirable to contain moisture in a mop, so that invisible or small dust sticks to the mop. However, when the person is mopping, there may be pain in the waist or knees, so that a demand for a cleaner capable of automatically mopping is increasing. 
     Patent Document 1 and Patent Document 2 respectively disclose cleaners that remove or supply the moisture from or to the mop, but both may not be regarded as having great utility because both require a physical force of the person. 
     PRIOR ART DOCUMENTS 
     Patent Documents
     Patent Document 1: US Patent Publication No. 20080010767 (published on Jan. 17, 2008)   Patent Document 2: U.S. Registered Pat. Publication No. 6,655,866 (published on Dec. 12, 2003)   

     SUMMARY 
     According to an embodiment of the present disclosure, it is intended to provide a robot cleaner capable of mopping during cleaning of the robot cleaner. 
     Further, it is indented to provide a robot cleaner that may smoothly guide water to a mop without a motor that supplies the water in addition to a motor that drives the robot cleaner. That is, it is intended to provide a robot cleaner that may smoothly guide water to a mop without a human power. 
     Further, it is indented to provide a robot cleaner that may properly adjust a water consumption by supplying water to a mop only during travel. 
     Further, it is indented to provide a robot cleaner that continuously supplies water such that a mop does not dry during cleaning. 
     As an example for solving the above-mentioned problem, a robot cleaner capable of automatically supplying water to a mop of the robot cleaner traveling by driving a pump without a motor is provided. 
     A robot cleaner that may travel on its own without a human power, properly adjust a water consumption by supplying water automatically only during traveling without a need for a separate motor and the like, and smoothly supply the water is provided. 
     Specifically, a robot cleaner that has a detachable wet-mop module mounted thereon to supply water inside the wet-mop module to the outside is provided. 
     One aspect of the present disclosure proposes a robot cleaner including a main body for forming an exterior of the robot cleaner, a driver coupled to the main body to move the main body, a cleaning module coupled to the main body to suck dust from a traveling surface, a dust collector for removing dust from an air suctioned through the cleaning module, and a wet-mop module coupled to the main body to mop the traveling surface, wherein the wet-mop module includes a wet-mop module housing for surrounding at least a portion of the main body and accommodating water in an internal space thereof, a wet-mop module wheel disposed in the wet-mop module housing, a mop disposed between the wet-mop module housing and the traveling surface, and a wet-mop pump connected to the wet-mop module wheel to supply water to the mop in response to a rotation of the wet-mop module wheel. 
     In one implementation, the robot cleaner may further include a rotation shaft connected to the wet-mop module wheel, and a pump connector eccentric to a center of the rotation shaft and connected to the wet-mop pump is provided. 
     In one implementation, the wet-mop pump may include a first diaphragm curved as the rotation shaft rotates, and a second diaphragm connected to the first diaphragm. 
     In one implementation, the wet-mop module housing may include a first module portion positioned between the main body and the traveling surface, and a second module portion formed integrally with the first module portion and covering at least a portion of an outer surface of the main body. 
     In one implementation, the first module portion may include a first water storage, wherein the first water storage is a space for accommodating water therein. 
     In one implementation, the main body may include a wet-mop module coupling portion, wherein the first module portion is able to be coupled to the wet-mop module coupling portion, and wherein the first module portion may include a main body connector to be accommodated in a space provided by the wet-mop module coupling portion. 
     In one implementation, the wet-mop module coupling portion may extend in a direction in which the first module portion is inserted on a surface of the main body facing the traveling surface. 
     In one implementation, the second module portion may include a dust-collector connector for receiving the dust collector therein. 
     In one implementation, the dust-collector connector may include a handle disposed to be gripped by a user, and each second water storage disposed on each of both sides of the handle to provide a space for accommodating water therein. 
     In one implementation, the driver may include a main wheel for moving the main body, a driver motor for providing a driving force to the main wheel, a first auxiliary wheel for assisting the movement of the main body, and a first auxiliary wheel housing disposed on the main body and coupled to the first auxiliary wheel. 
     In one implementation, the first module portion may include an auxiliary wheel connector opened such that the first auxiliary wheel housing is able to be connected thereto. 
     In one implementation, the wet-mop module housing may include a third module portion including the wet-mop module wheel. 
     In one implementation, the third module portion may include each recess defined therein to be connected to each wet-mop module wheel. 
     In one implementation, each wet-mop module wheel may be disposed on each of both sides of the first module portion, and wherein at least one of the recesses may include the wet-mop pump inserted therein. 
     In one implementation, a water supply passage for flowing water therethrough may be formed in the first module portion, and wherein the water supply passage may be in communication with the wet-mop pump and the mop. 
     According to the embodiments, the spotless cleaning may be performed through the mopping in addition to the dust removal. 
     Further, because a structure for supplying the water is simple, a structure of the wet-mop module may be simplified to have ease of manufacture and competitive price. 
     Further, because the human power is not involved, the spotless cleaning is possible without any extra effort when the user mops. 
     Further, it is economical because the water is not consumed excessively by supplying the water to the mop only during the travel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the disclosed embodiments and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the disclosure and together with the description serve to explain the principle of the disclosed embodiments. In the drawings: 
         FIG.  1    is a perspective view of a robot cleaner according to an embodiment; 
         FIG.  2    is a bottom view of a robot cleaner according to an embodiment; 
         FIG.  3    is a side view of a robot cleaner according to an embodiment; 
         FIGS.  4 A and  4 B  are views showing a robot cleaner according to an embodiment; 
         FIG.  5    is a view showing a wet-mop module according to an embodiment; 
         FIG.  6    is a plan perspective view of a wet-mop module according to an embodiment: 
         FIG.  7    is a side view of a wet-mop module according to an embodiment; 
         FIGS.  8 A and  8 B  are views showing an operating principle of a pump according to an embodiment; and 
         FIGS.  9 A and  9 B  are views showing a coupling structure of a wet-mop module according to an embodiment. 
     
    
    
     DESCRIPTION OF SPECIFIC EMBODIMENTS 
     Hereinafter, specific embodiments of the present disclosure will be described with reference to the drawings. A following detailed description is provided to aid in a comprehensive understanding of a method, an apparatus, and/or a system described herein. However, this is only an example, and the present disclosure is not limited thereto. 
     In describing embodiments of the present disclosure, when it is determined that a detailed description of a known technology related to the present disclosure may unnecessarily obscure the subject matter of the present disclosure, a detailed description thereof will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the present disclosure, which may vary depending on intention of a user or an operator, customs, or the like. Therefore, the definition thereof should be made based on the contents throughout the present specification. The terminology used in the detailed description is for the purpose of describing the embodiments of the present disclosure only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a” and “an” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “includes”, and “including” when used in the description, specify the presence of the certain features, numbers, steps, operations, elements, and portions or combinations thereof, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, elements, and portions or combinations thereof. 
     Prior to the description, when describing embodiments in the present specification, a portion provided with a cleaning module  40  will be described as a front portion, a portion provided with a dust collector  20  will be described as a rear portion, an upper side on the drawing will be described as an upper portion, and a lower side on the drawing will be described as a lower portion. 
     However, this is only a standard prepared for a clear understanding of the disclosed embodiments. That is, a direction may be expressed differently based on the standard. 
       FIG.  1    is a perspective view of a robot cleaner according to an embodiment. 
       FIG.  2    is a bottom view of a robot cleaner according to an embodiment. Further,  FIG.  3    is a side view of a robot cleaner according to an embodiment. 
     Hereinafter, a structure of a robot cleaner will be described with reference to  FIGS.  1  to  3   . 
     A robot cleaner  100  according to an embodiment may include a main body  10 , a driver  30 , a cleaning module housing  41 , and a roller  42 . Further, the robot cleaner  100  may further include a battery (not shown) for providing electric power such that the above-described driver and roller may be electrically driven. 
     The battery may be provided as a secondary battery and may be repeatedly charged and discharged. Thus, a user may use the robot cleaner by repeatedly charging the battery when a battery power level is low without having to replace or add a battery. 
     When the battery is provided as the secondary battery, the robot cleaner may further include a charging device (not shown) that may charge the robot cleaner. 
     In another example, the battery may be provided as a dry battery rather than the secondary battery. In this case, the dry battery may be required to be replaced when the dry battery is dead. 
     That is, there is no restriction on how the robot cleaner is provided with the electric power. 
     The main body  10  may be disposed to form an exterior of the robot cleaner  100 . 
     The main body  10  may include a first housing  101  and a second housing  102 . 
     The first housing  101  may form a portion of the main body  10  and may provide a space in which electronic components required for the robot cleaner  100  or parts required for the robot cleaner are mounted. 
     For example, a controller (not shown) that controls an operation of the robot cleaner  100  may be mounted in the first housing  101 . 
     Further, the first housing  101  may be disposed to provide a flow path (not shown) through which air containing dust is guided to the dust collector  20  to be described later. That is, the air suctioned through the cleaning module  40  to be described later may be guided through an internal space of the first housing  101  to the dust collector  20 . 
     The second housing  102  may be disposed in a form of a cover that covers the first housing  101 . However, the second housing  102  is not limited thereto. 
     A display (not shown) may be disposed on one surface of the second housing  102 . The display may be formed in a shape of a touch panel, so that the user may simply enter a command through the display. 
     It is sufficient that the second housing  102  is disposed to be coupled to the first housing  101 . For example, the second housing  102  may be hinged or integrally formed with the first housing  101 . 
     However, it is preferable that the second housing  102  is separately disposed in consideration of installation convenience of the parts mounted in the first housing  101 . The second housing  102  may prevent the parts mounted in the first housing  101  from being contaminated or damaged by an outside factor. 
     That is, the robot cleaner according to the present embodiment may be disposed such that the parts mounted in the first housing  101  are covered by the second housing  102  and not exposed to the outside. Thus, when the parts are operating, a user&#39;s body may be injured due to user&#39;s carelessness, malfunction, or the like. Thus, the main body  10  may cover the internal parts to prevent a safety accident. Further, because the main body  10  is present, a complex interior is not exposed to the outside, thereby creating a sense of beauty. Thus, the main body  10  may be used as a design element. 
     The cleaning module  40  may be a portion that is coupled to the main body of the robot cleaner  100  to perform the cleaning. 
     The cleaning module  40  may include a cleaning module housing  41  and a roller  42 . 
     The cleaning module  40  may be disposed to clean a traveling surface. Specifically, the cleaning module  40  may be disposed to suck dust present on the traveling surface. 
     The traveling surface may be a floor surface. When a carpet or the like is disposed, the traveling surface may be a top surface of the carpet. 
     The dust may be suctioned into a space provided by the first housing  101  through the cleaning module housing  41 . The suctioned dust may be collected in the dust collector  20  and air from which the dust has been removed may be discharged to the outside of the main body  10 . 
     The cleaning module housing  41  may be disposed to be coupled to the main body  10  to provide a space for accommodating the roller  42  to be described later therein. 
     Further, the cleaning module housing  41  may provide a flow path through which the air containing the dust may be suctioned such that the dust present on the traveling surface may be removed. 
     The cleaning module housing  41  may include a first cleaning module housing  41   a  and a second cleaning module housing  41   b.    
     Specifically, the first cleaning module housing  41   a  may provide the space for accommodating the roller  42  therein as described above or a space for cleaning the traveling surface. 
     More specifically, the roller  42  may be received in a roller receiver  43  connected to the first cleaning module housing  41   a . At least a portion of the roller  42  may protrude toward the traveling surface and may serve to scatter the dust settled on the traveling surface. 
     The second cleaning module housing  41   b  may serve to securely connect the first cleaning module housing  41   a  to the main body  10 . 
     Specifically, an external force may be applied to the robot cleaner  100  or an unexpected shock may occur on the robot cleaner  100  during the travel. 
     In this connection, the first cleaning module housing  41   a  is firmly connected to the main body  10  by the second cleaning module housing  41   b , so that a situation in which the first cleaning housing  41   a  deviates from an original position may be prevented. 
     In the drawing, the second cleaning module housing  41   b  is shown to be disposed at a lower side of the first housing  101 , that is, a surface facing the surface to be cleaned, but is not limited thereto. 
     That is, there is no restriction on a connection relationship between the cleaning module housing  41  and the main body  10 . 
     The roller  42  may serve to scatter the dust on the traveling surface while rotating. 
     When the roller  42  is not disposed, the cleaning may not be performed smoothly because the dust on the traveling surface is suctioned only by an operation of the dust collector  20 . 
     Specifically, the roller  42  may separate the dust on the traveling surface from the traveling surface while rotating inside the cleaning module housing  41 , and the dust separated from the traveling surface may be scattered in the air and suctioned into the main body  10  by air suction of the dust collector  20 . 
     A roller actuator (not shown) for actuating the roller  42  may be disposed in the cleaning module housing. 
     The robot cleaner  100  may include the driver  30 . 
     The driver  30  may be disposed to move the main body  10 . 
     The driver  30  may include a main wheel  31  and a driver motor  32 . 
     The main wheel  31  may be disposed to be rotated by receiving electric power by the driver motor  32 . 
     Each main wheel  31  may be disposed on each of both sides of the main body  10 . 
     The main wheel  31  disposed on one side and the main wheel  31  disposed on the other side may be controlled by different driver motors  32 , respectively. That is, the main wheel  31   a  disposed on one side and the main wheel  31   b  disposed on the other side may be rotated at different rotational speeds. 
     Thus, the robot cleaner  100  may turn in a left or right direction. Further, the robot cleaner  100  may switch directions in combination with going straight or going backward. 
     That is, a travel speed of the robot cleaner  100  may be determined based on the rotational speed of the main wheel  31  and a travel direction may be determined by a difference in rotational speed of the main wheels  31 . 
     For example, when the main wheel  31  on the left remains stationary and the main wheel  31  on the right is rotated, the robot cleaner  100  may turn to the left. 
     When the main wheels  31  on the both sides are operating, but when the main wheel  31  on the right rotates faster than the main wheel  31  on the left, the robot cleaner  100  may switch the direction to the left and continue moving straight. 
     The driver  30  may include an auxiliary wheel. A first auxiliary wheel  33  may be disposed at or adjacent to a center of the robot cleaner  100 . 
     The first auxiliary wheel  33  is positioned adjacent to the center of the robot cleaner  100 , thereby supporting a load of the robot cleaner  100  at the center of the robot cleaner  100  and simultaneously assisting the travel. 
     Specifically, the first auxiliary wheel  33  may be connected to a first auxiliary wheel housing  331  formed on the main body  10 . 
     Thus, even when the first auxiliary wheel  33  is smaller than the main wheel  31 , the first auxiliary wheel housing  331  may support the main body  10 . 
     Further, the first auxiliary wheel housing  331  may be pivotable. Thus, even when the travel direction of the robot cleaner  100  is switched by the main wheel  31 , the first auxiliary wheel  33  may assist the travel of the robot cleaner  100 . 
     That is, the first auxiliary wheel housing  331  is disposed to be pivotable, so that the first auxiliary wheel housing  331  may not interfere with the travel even when the travel direction of the robot cleaner is switched. 
     Because the first auxiliary wheel  33  and the first auxiliary wheel housing  331  are arranged, shaking of the robot cleaner during the travel of the robot cleaner may be minimized. 
     The first auxiliary wheel  33  may be disposed to rotate as the travel direction of the robot cleaner  100  is switched. 
     Thus, the travel may be guided stably even when the robot cleaner  100  switches the direction while cleaning an area to be cleaned. 
     That is, the first auxiliary wheel  33  may assist the rotation of the main wheel  31  while supporting the robot cleaner  100 . 
     A second auxiliary wheel  34  may be disposed in the cleaning module housing  41 . The cleaning module housing  41  is coupled to the main body  10  to perform the cleaning. The cleaning module housing  41  may be supported by the main body  10  while being coupled to the main body  10 . In another example, a portion of the cleaning module housing  41  in contact with the traveling surface (or a surface to be cleaned) may receive a supporting force by the traveling surface. 
     However, because the robot cleaner  100  performs the cleaning while essentially moving in a region to be cleaned, the cleaning module housing  41  may not move smoothly during the travel. 
     As the second auxiliary wheel  34  is disposed, the cleaning module housing  41  may be moved more smoothly during the travel of the robot cleaner  100 . 
     Each second auxiliary wheel  34  may be disposed on each of both sides of the cleaning module housing  41  to perform a function of assisting balancing of the robot cleaner  100 . 
     The dust collector  20  may be a portion where the dust is collected. The dust collector  20  may include a cyclone (not shown). The dust collector  20  may be in communication with the cleaning module  40 . 
     The air may be introduced into the robot cleaner by the dust collector  20 . When the air is suctioned by the dust collector  20  and the air from which the dust has been removed is discharged to the outside, a negative pressure is generated in the robot cleaner  100 , so that the air containing the dust may be introduced through the cleaning module housing  41 . 
     The dust collector  20  may be formed in a form in which relatively large dust is primarily separated and then relatively small dust is secondarily separated. However, the dust collector  20  is not limited thereto and is sufficient when being able to suct the dust present on the traveling surface. 
     The dust collector  20  may be disposed to be detachable from the main body  10 . Thus, when the robot cleaner completes the cleaning or when excessive dust is accumulated in the dust collector  20 , the user may easily separate the dust collector  20  to remove the dust, thereby ensuring convenience. 
     The sensor unit  11  may be disposed on the main body  10 . The sensor unit  11  may provide image information such that the robot cleaner  100  may travel in the region to be cleaned. 
     That is, the sensor unit  11  may be a camera or a photographing sensor. 
     Specifically, the sensor unit  11  may collect information necessary for autonomous travel of the robot cleaner  100 . 
     For example, the sensor unit  11  may include the photographing sensor that creates a travel map by photographing a periphery of the robot cleaner  100 , an obstacle sensor that senses an obstacle, and the like. In another example, additional sensors may be further provided in addition to the above-described sensor. 
     For example, the sensor unit may include a wall sensor (not shown). Thus, information about the region to be cleaned may be input to the robot cleaner  100  through the wall sensor, the photographing sensor, and the like. 
     The robot cleaner  100  may input a shape of a space while traveling, and divide the region to be cleaned through the wall sensor into a plurality of cleaning areas. 
     However, the present disclosure is not limited to the above-described example, and the above-described example is only one embodiment. The photographing sensor and the obstacle sensor may simultaneously perform wall sensing. 
     The photographing sensor may be disposed not only to sense the region to be cleaned, but also to specify a position of the main body  10  in the region to be cleaned that is previously input. Thus, a position of the space where the robot cleaner  100  performs the cleaning may be specified and the position of the robot cleaner  100  is specified, so that movement to a next cleaning area may be guided. 
     A type and the number of sensor units  11  are not limited. That is, a plurality of photographing sensors may be arranged, and when the plurality of photographing sensors are arranged, the plurality of photographing sensors may be photographing sensors of the same type or different types. 
     The robot cleaner  100  may vary a suction strength of the dust collector  20  based on a material of the floor. This is because when the dust collector  20  always suctions the dust at the same strength, it may be difficult to completely perform the cleaning on an unusual floor surface such as the carpet and the like. 
     The robot cleaner  100  may include a floor sensor (not shown) to sense the material of the floor. The floor sensor may be a sensor that senses the material of the floor. The floor sensor may be disposed in the sensor unit  11  described above, or may be disposed at a position different from the sensor unit  11 . 
     The region to be cleaned in which the robot cleaner  100  is used may vary depending on a case. For example, a floor material of the region to be cleaned may be marble or a floor paper. Further, the region to be cleaned may be made of a material other than the above example. 
     Depending on the material of the floor, an intensity at which the dust collector  20  is driven to effectively suction the dust may vary. 
     Specifically, the dust collector  20  must be driven more strongly in a carpeted region than on a general floor paper to effectively perform cleaning. The controller of the robot cleaner  100  may adjust the driving intensity of the dust collector  20  based on the type of floor material. 
     The obstacle sensor may determine whether an obstacle exists in the region to be cleaned. The obstacle sensor may be disposed integrally with the sensor unit  11  described above, or may be disposed separately. That is, the photographing sensor may also serve as the obstacle sensor. 
     As the obstacle sensor senses the obstacle, a travel path of the robot cleaner  100  may be changed. As a moving line becomes complicated, battery consumption may vary. Specifically, when the obstacle is present, the robot cleaner  100  is moved to bypass the obstacle. At this time, the moving line may be lengthened. As the moving line lengthens, a battery consumption for cleaning the corresponding area may increase. 
       FIGS.  4 A and  4 B  are views showing a robot cleaner according to an embodiment. 
     A wet-mop module of a robot cleaner according to an embodiment will be described with reference to  FIGS.  4 A and  4 B . 
     The robot cleaner according to an embodiment of the present disclosure may include a wet-mop module  50 . 
     The wet-mop module  50  may be disposed to be coupled to the main body  10 . Specifically, the wet-mop module  50  may be disposed to surround at least a portion of the main body  10 . The surrounding of the at least a portion of the main body  10  means that the wet-mop module  50  is disposed to surround a portion of at least one of an outer circumferential surface of the main body  10  and lower and upper surfaces of the main body  10 . 
     The wet-mop module  50  is not disposed to cover an entirety of a surface coupled with the main body  10 , and may have an opening defined therein as shown in the drawing. 
     For example, the exterior of the robot cleaner  100  may be determined by the main body  10  and the dust collector  20 . 
     As shown in the drawing, when the dust collector  20  is disposed in a form protruding outward of the main body  10 , the wet-mop module  50  may include a dust-collector connector  5121  in an opened form to provide a space for accommodating the dust collector  20  therein. 
     In another example, the wet-mop module  50  may not include an open face such as the dust-collector connector  5121  as shown in the drawing. However, in this case, a spacing may occur between the wet-mop module  50  and the main body  10 . When the spacing occurs, a user&#39;s preference may be lower than when there is no spacing because of hygiene or aesthetic reasons. 
     Thus, the wet-mop module  50  may be formed in a shape corresponding to a shape of the main body  10 . 
     In the drawing, the wet-mop module  50  is illustrated as being mounted at the rear portion of the robot cleaner  100 , but is not limited thereto. That is, the wet-mop module  50  is sufficient when mounted on the main body  10  and does not have to be mounted in a specific direction. 
     However, as will be described later, the wet-mop module  50  includes a mop  53  for mopping the traveling surface. Thus, it is preferable that the mop  53  is formed in a shape of being toward the ground. Further, the wet-mop module  50  is preferably disposed such that the mop  53  may be positioned on the traveling surface when the wet-mop module  50  is coupled to the main body  10 . 
       FIG.  5    is a view showing a wet-mop module according to an embodiment. Further,  FIG.  6    is a plan perspective view of a wet-mop module according to an embodiment. Further,  FIG.  7    is a side view of a wet-mop module according to an embodiment. 
     The wet-mop module  50  will be described in detail with reference to  FIGS.  5  to  7   . 
     The wet-mop module  50  may include a wet-mop module housing  51 . The wet-mop module housing  51  may be a portion forming an exterior of the wet-mop module  50 . 
     The wet-mop module housing  51  may include a first module portion  511 , a second module portion  512 , and a third module portion  513 . 
     The first module portion  511  may be positioned between the main body  10  and the traveling surface. The first module portion  511  may include therein a first water storage  5113 , which is a space for accommodating water therein. Because the water is accommodated in the first water storage  5113 , the wet-mop module  50  may mop without a separate water tank. 
     A shape of the first water storage  5113  may be determined depending on a shape of the first module portion  511 . Because the first water storage  5113  is an internal space of the first module portion  511 , the shape of the first water storage  5113  may be determined based on the shape of the first module portion  511 . Further, an amount of water accommodated in the first water storage  5113  may also be determined depending on the shape and a size of the first module portion  511 . 
     The first module portion  511  may be disposed to cover at least a portion of a surface of the main body  10  facing the traveling surface. The mop  53  may be coupled to the first module portion  511 . The mop  53  may be made of a material that may mop the traveling surface. 
     There is no restriction on how the mop  53  is detached from the first module portion  511 . 
     The first module portion  511  may be positioned between the main body  10  and the mop  53  to position the mop  53  at a position at which the mop  53  is capable of mopping the traveling surface, and to couple the wet-mop module  50  to the main body  10 . 
     The first module portion  511  may include a main body connector  5112 . The main body connector  5112  may be disposed at an end of the first module portion  511  as a portion that couples the wet-mop module  50  to the main body. The main body connector  5112  of the first module portion  511  may be connected to a module coupling portion  1011  formed on the main body  10  to provide a supporting force to the wet-mop module  50 . 
     Specifically, the main body connector  5112  may be formed in a protruding shape as a portion of the first module portion  511 . The module coupling portion  1011  may protrude from the surface of the main body  10  facing the traveling surface toward the traveling surface and may extend in a direction in which the first module portion  511  is inserted. The main body connector  5112  may be inserted into a space provided by the module coupling portion  1011 . The wet-mop module  50  may be supported by the main body  10  as the main body connector  5112  is coupled with the module coupling portion  1011 . 
     The main body connector  5112  and the module coupling portion  1011  may be formed in corresponding shapes. Thus, when the wet-mop module  50  is coupled to the main body, despite the travel of the robot cleaner  100 , it is possible to prevent the wet-mop module  50  from deviating from the original position thereof or shaking due to a play. 
     A plurality of main body connectors  5112  may be arranged. Preferably, the plurality of main body connectors  5112  are respectively arranged on both sides based on a width direction of the wet-mop module  50 . 
     The first module portion  511  may include an auxiliary wheel connector  5111  into which the first auxiliary wheel housing  331  may be inserted. The auxiliary wheel connector  5111  may be formed in an open shape in the first module portion  511 . The auxiliary wheel connector  5111  may be formed in a shape corresponding to a shape of the first auxiliary wheel housing  331 . 
     As a result, even when the wet-mop module  50  is mounted on the main body  10 , the first auxiliary wheel  33  may be seated on the traveling surface, thereby performing an original function thereof. 
     The second module portion  512  may be integrally formed with the first module portion  511 . The second module portion  512  may also be disposed to cover at least a portion of the main body  10  of the robot cleaner  10 W. 
     The second module portion  512  may include a handle  5122  that provides a space for the user to grip, and a second water storage  5123  that provides a space for accommodating water therein. 
     The second module portion  512  is disposed to have a predetermined angle with the first module portion  511 , so that the second module portion  512  may be formed in a shape corresponding to at least a portion of the shape of the main body  10 . 
     The handle  5122  may be disposed to have predetermined length and width to be gripped by the user. In the drawing, the handle  5122  and the second water storage  5123  are illustrated separately, but are not limited thereto. 
     That is, the handle  5122  may be disposed to provide a space for accommodating water therein like the second water storage  5123 , as well as to be gripped by the user. It may be appropriately selected by the user or a designer. 
     The second water storage  5123  may provide an additional water storage space in case the first water storage  5113  is difficult to accommodate an adequate amount of water for the cleaning. 
     The second water storage  5123  may be in communication with the first water storage  5113 . As the water stored in the first water storage  5113  is flowed to the mop  53 , the water accommodated in the second water storage  5123  may be flowed to the first water storage  5113 . 
     The second water storage  5123  may be extended in a height direction of the wet-mop module  50 . A plurality of second water storages  5123  may be arranged. 
     Specifically, as shown in the drawing, the second water storages  5123  are respectively extended in the height direction from both sides of the first module portion  511  to form the dust-collector connector  5121  to which the dust collector  20  is connected. The handle  5122  may be disposed to connect the second water storages  5123  with each other. 
     Each third module portion  513  may be disposed on each of both sides of the wet-mop module  50 . 
     That is, when the wet-mop module  50  is formed in a shape shown in the drawing, the third module portions  513  may be respectively arranged on both sides of the first module portion  511 . Further, the third module portions  513  may be respectively arranged both sides of the second module portion  512 . 
     Each third module portion  513  may include a wet-mop module wheel  521  that assists the support of the wet-mop module  50  and the travel of the robot cleaner  100  when the wet-mop module  50  is coupled to the main body  10 . 
     Each wet-mop module wheel  521  may be disposed on each of the third module portions  513  on both sides. The third module portion  513  may include a recess  522  in which the wet-mop module wheel  521  may be accommodated. 
     The recess  522  may provide therein a space in which the wet-mop module wheel  521  is accommodated. Further, the recess  522  may be defined to provide a space in which, when a wet-mop pump  52  is disposed at one side, the wet-mop pump  52  is also accommodated. 
     The recess  522  may be defined by being depressed inwardly of the third module portion  513 . Sizes of the recesses  522  respectively defined in the third module portions  513  may be different. This is because when the wet-mop pump  52  is disposed only on one side, the third module portion  513  on the other side does not necessarily need to have the recess  522  of the same size as the recess  522  on one side. 
     The wet-mop pump  52  may be disposed on the third module portion  513 . The wet-mop pump  52  may be connected to the wet-mop module wheel  521 . The wet-mop pump  52  may be disposed to supply water to the mop  53  based on a rotation of the wet-mop module wheel  521 . 
     It is preferable that the wet-mop pump  52  capable of guiding the water to the mop  53  is disposed such that the water accommodated in the first module portion  511  and the second module portion  512  flows into the mop  53 . 
     The second module portion  512  may be disposed in a form extending in the height direction of the wet-mop module  50 , so that water may be flowed to some extent by a self-load of the water. However, the water may not be smoothly delivered when a water level in the second module portion  512  is lowered or when the traveling surface is inclined. Thus, it is preferable that the wet-mop pump is disposed. 
     A type of wet-mop pump  52  is not limited. However, it is desirable that the wet-mop pump  52  is a pump that may supply the water to the mop  53  based on the rotation of the wet-mop module wheel without a motor or a separate driver. 
     The wet-mop pump  52  may be in communication with the first water storage  5113 , and may be in communication with the water supply passage  522  in communication with the mop  53 . That is, the wet-mop pump  52  may guide the water accommodated in the first module portion  511  or the second module portion  512  to the mop  53  through the water supply passage  522 . 
     The water supply passage  522  may have one side connected to the wet-mop pump  52  and the other side connected to the mop  53 . The water supply passage  522  may be disposed in the first module portion  511 . 
     In the drawing, the water supply passage  522  is illustrated of being connected to the mop  53  at one of the first module portions  511 , but is not limited thereto. In order to evenly supply the water to the mop  53 , the water discharged from the wet-mop pump  52  may be spread and supplied to the mop  53 . 
     The water supply passage  522  may be disposed in a form of a nozzle or may be disposed as a space defined separately in the first module portion  511 . 
     The water supply passage  522  may include a communication hole (not shown) defined in one surface of the first module portion  511  to guide the water toward the mop  53 . The water supply passage  522  may guide the water to the mop  53  through the communication hole. 
     The first module portion  511 , the second module portion  512 , and the third module portion  513  may be integrally formed. That is, for convenience of description, the first module portion  511 , the second module portion  512 , and the third module portion  513  have been described by distinguishing names, but are not limited thereto. 
     In other words, the first module portion  511  is sufficient when positioned between the main body  10  and the traveling surface. Further, the second module portion  512  is sufficient when formed integrally with the first module portion  511  and covering at least a portion of an outer surface of the main body  10 . Further, the third module portion  513  is sufficient when including the wet-mop module wheel  521  and the wet-mop pump  52 . 
     Thus, the wet-mop module  50  may be formed in a shape different from the drawing shown in this specification. 
       FIGS.  8 A and  8 B  are views showing an operating principle of a pump according to an embodiment. 
     As described above, the type of wet-mop pump  52  is not limited. However, hereinafter, an embodiment in which the wet-mop pump  52  is disposed as a diaphragm pump will be described. The diaphragm pump is a pump that suctions and discharges fluid by a motion, which may also be referred to as a membrane pump. 
     A rotation shaft  5213  may be connected to the wet-mop module wheel  521 . The rotation shaft  5213  may serve to fix the wet-mop module wheel  521  to the third module portion  513 . 
     The wet-mop pump  52  may include a first diaphragm  520   a  and a second diaphragm  520   b.    
     The first diaphragm  520   a  is a diaphragm connected to the rotation shaft  5213 , and the second diaphragm  520   b  is a diaphragm that provides a space together with the first diaphragm  520   a  through which the water may be introduced and discharged. 
     The first diaphragm  520   a  may be connected to the rotation shaft  5213 . Specifically, the first diaphragm  520   a  may be connected to the rotation shaft  5213  through a pump connector  5214 . 
     As the wet-mop module wheel  521  rotates, the rotation shaft  5213  rotates, and as the rotation shaft  5213  rotates, the first diaphragm  520   a  may be curved or relaxed. When the first diaphragm  520   a  is curved or relaxed, the water accommodated in the first water storage  5113  or the second water storage  5123  may be introduced into the wet-mop pump  52  and then guided to the mop  53 . 
       FIG.  8 A  is a view showing a connection relationship between the rotation shaft and the wet-mop pump according to an embodiment, and  FIG.  8 B  is a view showing a connection relationship between the rotation shaft and the wet-mop pump according to another embodiment. 
     In  FIG.  8 A , the pump connector  5214  may be eccentric to a rotation center of the rotation shaft  5213  in the same direction as the rotation shaft  5213 . Specifically, the pump connector  5214  may have a rotation center eccentric to the rotation shaft  5213 . Thus, when the wet-mop module wheel  521  is rotated, the rotation shaft  5213  is rotated, and the pump connector  5214  may be rotated to revolve relative to the rotation center of the rotation shaft  5213 . Accordingly, when the pump connector  5214  moves away from the first diaphragm  520   a , the first diaphragm  520   a  moves in a direction away from the second diaphragm  520   b  and the wet-mop pump  52  generates a negative pressure, so that the water accommodated in the first module portion  511  flows into the wet-mop pump  52 . 
     When the pump connector  5214  approaches the first diaphragm  520   a , water accommodated between the first diaphragm  520   a  and the second diaphragm  520   b  may flow to the water supply passage  522 . 
     That is, the pump connector  5214  may be disposed as a rotation shaft that is rotated to be eccentric to the rotation center of the rotation shaft  5213 . In this case, a separate component for connecting the wet-mop pump  52  with the pump connector  5214  may be required. 
     Referring to  FIG.  8 B , the rotation shaft  5213  and the wet-mop pump  52  may be directly connected to each other. In this case, the pump connector  5214  may be disposed eccentrically to the rotation center of the rotation shaft  5213 , as in  FIG.  8 A . 
     However, in this case, a position relationship between the rotation shaft  5213 , the pump connector  5214 , and the wet-mop pump  52  may be important. 
     Specifically, even when the pump connector  5214  is connected at a position eccentric to the rotation center of the rotation shaft  5213 , a case in which the wet-mop pump  52  is not able to be operated normally may occur. 
     For example, when the pump connector  5214  is disposed such that a distance between the wet-mop pump  52  and the rotation shaft  5213  is constant despite the rotation of the rotation shaft  5213 , a position of the first diaphragm  520   a  relative to the second diaphragm does not change despite the rotation of the wet-mop module wheel  521 , which makes it difficult for the pump to perform the role thereof. 
     Thus, the pump connector  5214  is preferably disposed such that the distance between the rotation shaft  5213  and the wet-mop pump  52  changes based on the rotation of the rotation shaft  5213 . 
     Thus, as the wet-mop module wheel  521  is rotated, the pump connector  5214  may also be rotated, and the pump connector  5214  may be rotated while revolving around the rotation center of the rotation shaft  5213 . As the pump connector  5214  is rotated, the distance between the wet-mop pump  52  and the rotation shaft  5213  may change. 
     Specifically, when a distance between the first diaphragm  520   a  and the rotation shaft  5213  becomes smaller, the first diaphragm  520   a  moves in the direction away from the second diaphragm  520   b , so that the water flows into the wet-mop pump  52 . Further, when the distance between the first diaphragm  520   a  and the rotation shaft  5213  becomes larger, the first diaphragm  520   a  moves in a direction closer to the second diaphragm  520   b , so that the water may be discharged to the water supply passage  522 . 
       FIGS.  9 A and  9 B  are views showing a coupling structure of a wet-mop module according to an embodiment. 
     As described above, the wet-mop module  50  may be combined with the main body  10 . 
     Specifically, the wet-mop module  50  may include the main body connector  5112 . It is shown in  FIGS.  9 A and  9 B  that the main body connector  5112  is disposed on the first module portion  511  but is not limited thereto. 
     That is, when the main body connector  5112  is disposed on the second module portion  512 , it is sufficient when the main body  10  includes the module coupling portion  1011  corresponding to the main body connector  5112 . 
     The main body connector  5112  and the module coupling portion  1011  are means for coupling the wet-mop module  50  to the main body  10 . It is not important that the main body connector  5112  and the module coupling portion  1011  are respectively arranged at any specific positions of the wet-mop module  50  and the main body  10 . However, it is important that the main body connector  5112  and the module coupling portion  1011  are respectively arranged at positions corresponding to each other to couple the wet-mop module  50  to the main body  10 . 
     In a description of the embodiment shown in  FIG.  9   , the main body connector  5112  may be disposed on the first module portion  511 . The module coupling portion  1011  may be disposed to extend in a direction in which the wet-mop module  50  is inserted to define a space in a portion of the main body  10  facing the traveling surface. 
     When the main body connector  5112  is inserted into the module coupling portion  1011 , the wet-mop module  50  is coupled to the main body  10 , so that the wet-mop module may be stably used during the travel of the robot cleaner  100 . 
     That is, a front side of the wet-mop module  50  may be supported by the module coupling portion  1011  and a rear side of the wet-mop module  50  may be supported by the wet-mop module wheel  521 . 
     Although the exemplary embodiments of the present disclosed embodiments have been described above in detail, those of ordinary skill in the art to which the present disclosure pertains will appreciate that various modifications are possible within the limits without departing from the scope of the present disclosure for the above-described embodiments. Therefore, the scope of the present disclosure should not be limited to the described embodiments, and should be determined not only by the claims to be described later, but also by the equivalents of the claims.