Patent Publication Number: US-11382468-B2

Title: Cleaner

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority under 35 U.S.C. 119 and 35 U.S.C. 365 to Korean Patent Application No. 10-2019-0089625, filed on Jul. 24, 2019, which is hereby incorporated by reference in its entirety. 
     BACKGROUND 
     The present disclosure relates to a structure that is capable of improving suction performance of a vacuum cleaner. 
     The vacuum cleaner refers to a device that suctions dust and air by using suction power generated by a suction motor mounted inside a cleaner body and separates the dust from the air to collect the dust. 
     Such vacuum cleaners are classified into a canister cleaner, an upright cleaner, a stick cleaner, a handy cleaner, and a robot cleaner. In the case of the canister cleaner, a suction nozzle for suctioning dust is provided separately from a cleaner body, and the cleaner body and the suction nozzle are connected to each other by a connection device. In the case of the upright cleaner, a suction nozzle is rotatably connected to a cleaner body. In the case of the stick cleaner and the handy cleaner, the stick cleaner and the handy cleaner are used in a state in which a user grips a cleaner body by his/her hand. However, in the case of the stick cleaner, a suction motor is disposed close to a suction nozzle (a lower center), and in the case of the handy cleaner, a suction motor is disposed close to a grip part (an upper center). The robot cleaner cleans itself while traveling by itself through an autonomous driving system. 
     The suction nozzle refers to a portion which touches the floor to directly suction dust and air. Suction force generated by the suction motor mounted inside the cleaner body is transmitted to the suction motor, and the dust and air are suctioned into the suction nozzle by the suction force. 
     The suction nozzle is provided with a rotation cleaning part (or an agitator). The rotation cleaning part rotates to scrape dust from the floor or carpet, thereby improving cleaning performance. 
     In addition, the user allows the suction nozzle to move forward and backward to suction dust on the floor surface. Here, the suction nozzle may be improved in suction performance only when the suction nozzle is maintained in close contact with the floor surface except for a space in which the dust is introduced. 
     In general, the suction nozzle defines a front opening through which dust is introduced. 
     Then, to clean the floor surface, when the suction force is generated in the suction nozzle, dust or the like is introduced through the front opening. 
     Here, a flow of air is generated forward from a rear side, and thus, the front suction force is reduced to deteriorate the cleaning performance. 
     A cleaner head having a rear portion and a side portion, which seals a side surface and a rear side of the cleaner head while moving with respect to the cleaner head is disclosed in Korean Patent Publication No. 10-2018-0044366 (May 2, 2018) among the prior art documents. 
     The patent has a structure in which the rear portion rotates with respect to a hinge axis, and the rear portion and the floor surface linearly contact each other in a straight-line shape. Therefore, when the cleaner performs a suction operation, there is a limit in blocking a flow of air flowing forward from the rear side through a space between the floor surface and the cleaner head. 
     SUMMARY 
     Embodiments provide a vacuum cleaner that is capable of preventing air from flowing forward from a rear side of a suction nozzle when suction force is generated in the suction nozzle. 
     Embodiments also provide a vacuum cleaner that is capable of preventing cleaning performance from being deteriorated while suction performance of a front opening is deteriorated. 
     Embodiments also provide a vacuum cleaner that is capable of preventing a stable time reduction and suction motor overload from occurring due to deterioration of suction performance. 
     Embodiments also provide a vacuum cleaner in which a flow of a fluid flowing forward from a rear side of a suction nozzle when the cleaner operates is not simply blocked, but multi-stage resistance is generated in a passage of the fluid flowing forward from the rear side to reduce a flow velocity and rate of the fluid flowing forward from the rear side, resulting in concentrating the suction force, thereby allowing the front suction force to increase. 
     In one embodiment, a vacuum cleaner includes a sealing part that comes into contact with a floor surface to block a flow of air flowing forward from a rear side when the cleaner operates and is provided with at least one air chamber recessed upward from a bottom surface thereof. 
     The vacuum cleaner may include a cleaner body provided with a suction motor at the inside thereof and a handle at the outside thereof and a suction nozzle connected to the cleaner body. 
     The suction nozzle may include a housing of which at least a portion of a front side is opened, and a rotation cleaning part is installed inside the housing, and at least a portion of the rotation cleaning part may be exposed through the front opening of the housing. 
     The sealing part may protrude downward from a lower end of the housing and be provided in rear of the front opening. 
     The sealing part may include at least one of a groove recessed upward from a lower end thereof or a protrusion protruding downward from the lower end thereof. 
     The sealing part may include a sealing groove recessed upward from the lower end thereof and extending parallel to a longitudinal direction of the suction nozzle. 
     The sealing groove may be provided in plurality, which are spaced apart from each other in a front-rear direction. 
     The sealing groove may have a height (h) in a range of about 0.5 mm to about 2 mm. 
     A sealing protrusion may be disposed between the sealing grooves. 
     A ratio (a/b) of a front-rear length (a) of the sealing protrusion and a front-rear length (b) of the sealing groove may be set in a range of about 0.3 to about 0.8. 
     A ratio (h/b) of a front-rear length (b) of the sealing groove and a height (h) of the sealing groove may be set in a range of about 0.2 to about 0.4. 
     A ratio (h/a) of a front-rear length (a) of the sealing protrusion and a height (h) of the sealing groove may be set in a range of about 0.5 to about 0.8. 
     The sealing part may include a sealing protrusion protruding downward from an upper side and extending parallel to a longitudinal direction of the suction nozzle. 
     The sealing protrusion may be provided in plurality, which are spaced apart from each other in a front-rear direction. 
     The sealing protrusion disposed at a rear side may further protrude than the sealing protrusion disposed at a front side. 
     The sealing part may be elevatably connected to a rear portion of the suction nozzle. 
     At least a portion of a rear side of the housing may be opened to define a rear opening. 
     The housing may include a first side surface configured to define the rear opening and a second side surface spaced backward from the first side surface to face the first side surface, and the sealing part may include a second extension portion and a first extension portion, which extend upward to be contact-supported on the first side surface and the second side surface, respectively. 
     The sealing part may be elevated in the state in which the second extension portion and the first extension portion contact the first side surface and the second side surface, respectively. 
     The sealing part may further include a third extension portion extending backward from a lower end of the second extension portion. 
     The third extension portion may be provided in a curved shape. 
     The sealing part may include a sealing pad configured to connect a lower end of the third extension portion to a lower end of the first extension portion, and a sealing groove recessed upward from a lower end of the sealing pad and extending parallel to a longitudinal direction of the suction nozzle may be defined in the sealing pad. 
     The rear opening may include a first rear opening and a second rear opening disposed behind the first rear opening. 
     The sealing part may include a first extension portion inserted into the first rear opening and a second extension portion inserted into the second rear opening. 
     A hook protrusion extending horizontally from each of both sides of an upper end of the first extension portion may be disposed on the first extension portion. 
     The elevation part may include a fixing hook constituted by a horizontal portion backward from an upper end of the second extension portion and a vertical portion extending downward from an end of the horizontal portion, and a hook groove recessed downward so that the fixing hook may be fitted into an inner surface thereof is defined in the housing. 
     The sealing part may include a sealing pad configured to connect a lower end of the first extension portion to a lower end of the second extension portion, and a sealing groove recessed upward from a lower end of the sealing pad and extending parallel to a longitudinal direction of the suction nozzle may be defined in the sealing pad. 
     The sealing groove may be provided in plurality, which are spaced apart from each other in a front-rear direction. 
     The sealing part may contact the floor surface while descending by a differential pressure when suction force is generated in the suction nozzle. 
     When the sealing part descends, a lower end of the sealing part may be disposed lower than a lower end of the front opening. 
     The sealing part may be made of a material having elasticity or flexibility. 
     The sealing part may be made of a rubber or silicon material. 
     In the suction nozzle, a connection tube connected to the cleaner body may be disposed behind the housing, and the sealing part may be disposed between the front opening and the connection tube. 
     The housing may include: a body part in which the front opening is defined in a front side thereof, and a chamber communicating with the front opening is provided therein and which is configured to cover an upper side of the rotation cleaning part; and a support member provided below the body part. 
     The sealing part may be provided on a bottom surface of the support member. 
     A front end of the body part and a front end of the support member may define the front opening. 
     The sealing part may have unevennesses on the bottom surface that contacts the floor surface. 
     The sealing part may extend in a left-right direction that is perpendicular to the front-rear direction in which the suction nozzle moves. 
     The unevennesses disposed on the bottom surface of the sealing part may alternately disposed in a direction parallel to the front-rear direction in which the suction nozzle moves. 
     The unevennesses disposed on the bottom surface of the sealing part may alternately disposed in a direction parallel to a flow direction of air suctioned into the suction nozzle. 
     The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee. 
         FIG. 1  is a perspective view of a vacuum cleaner according to an embodiment. 
         FIG. 2  is a perspective view of a suction nozzle of  FIG. 1 . 
         FIG. 3  is a plan view of the suction nozzle of  FIG. 2 . 
         FIG. 4  is a side view of the suction nozzle of  FIG. 1 . 
         FIG. 5  is a front view of the suction nozzle of  FIG. 1 . 
         FIG. 6  is a view illustrating a state in which a rotation cleaning part is separated from the suction nozzle of  FIG. 5 . 
         FIG. 7  is a bottom view of the suction nozzle of  FIG. 1 . 
         FIG. 8  is an exploded perspective view of the suction nozzle of  FIG. 1 . 
         FIG. 9  is an exploded perspective view of a housing. 
         FIG. 10  is a cross-sectional view of the suction nozzle, taken along line I-I′ of  FIG. 7 . 
         FIG. 11  is a cross-sectional view taken along line II-II′ of  FIG. 7 . 
         FIG. 12  is a view illustrating a suction nozzle of a vacuum cleaner when viewed from one side according to another embodiment of the present invention. 
         FIG. 13  is a bottom surface of the suction nozzle of  FIG. 12 . 
         FIGS. 14 and 15  are partial cross-sectional views illustrating a sealing part and a housing of the vacuum cleaner according to another embodiment. 
         FIG. 16  is a view obtained by comparing flow analysis results of the suction nozzle depending on whether the sealing part is provided. 
         FIG. 17  is a view obtained by comparing flow analysis results of the suction nozzle depending on whether the sealing part is provided. 
         FIG. 18  is a partial cross-sectional view of a sealing part and a housing of a vacuum cleaner according to further another embodiment. 
         FIG. 19  is a graph obtained by comparing bottom surface pressures when the sealing part of  FIG. 18  is applied. 
         FIG. 20  is a side view of a sealing part that is a main component of the vacuum cleaner according to an embodiment. 
         FIG. 21  is a table obtained by comparing results of measuring a pressure drop depending on a design change of the sealing part. 
         FIG. 22  is a view of a flow analysis result in the sealing part according to a case 1 of  FIG. 21 . 
         FIG. 23  is a view of a flow analysis result in the sealing part according to a case 4 of  FIG. 21 . 
         FIG. 24  is a view of a flow analysis result in the sealing part according to a case 13 of  FIG. 21 . 
         FIG. 25  is a graph of a variation in pressure drop depending on a change in height of a sealing groove. 
         FIG. 26  is a view of a flow analysis result depending on a height of the sealing groove in a first section of  FIG. 25 . 
         FIG. 27  is a view of a flow analysis result depending on a height of the sealing groove in a second section of  FIG. 25 . 
         FIG. 28  is a view of a flow analysis result depending on a height of the sealing groove in a first section of  FIG. 25 . 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, some embodiments of the present invention will be described in detail with reference to the accompanying drawings. Exemplary embodiments of the present invention will be described below in more detail with reference to the accompanying drawings. It is noted that the same or similar components in the drawings are designated by the same reference numerals as far as possible even if they are shown in different drawings. Further, in description of embodiments of the present disclosure, when it is determined that detailed descriptions of well-known configurations or functions disturb understanding of the embodiments of the present disclosure, the detailed descriptions will be omitted. 
     Also, in the description of the embodiments of the present disclosure, the terms such as first, second, A, B, (a) and (b) may be used. Each of the terms is merely used to distinguish the corresponding component from other components, and does not delimit an essence, an order or a sequence of the corresponding component. It should be understood that when one component is “connected”, “coupled” or “joined” to another component, the former may be directly connected or jointed to the latter or may be “connected”, coupled” or “joined” to the latter with a third component interposed therebetween. 
       FIG. 1  is a perspective view of a vacuum cleaner according to an embodiment. 
     Referring to  FIG. 1 , a vacuum cleaner  1  according to an embodiment may include a cleaner body  10  provided with a suction motor (not shown) for generating suction force, a suction nozzle  100  suctioning air that contains dust, and an extension tube  17  connecting the cleaner body  10  to the suction nozzle  100 . 
     Although not shown, the suction nozzle  100  may be directly connected to the cleaner body  10  without the extension tube  17 . 
     The cleaner body  10  may include a dust container  12  in which the dusts separated from the air are stored. Accordingly, the dust introduced through the suction nozzle  100  may be stored in the dust container  12  through the extension tube  17 . 
     A handle  13  to be gripped by a user may be provided outside the cleaner body  10 . The user may perform cleaning while gripping the handle  13 . 
     The cleaner body  10  may include a battery (not shown), and a battery accommodation part  15  in which the battery (not shown) is accommodated may be provided in the cleaner body  10 . The battery accommodation part  15  may be provided below the handle  13 . The battery (not shown) may be connected to the suction nozzle  100  to supply power to the suction nozzle  100 . 
     Hereinafter, the suction nozzle  100  will be described in detail. 
       FIG. 2  is a perspective view of the suction nozzle of  FIG. 1 ,  FIG. 3  is a plan view of the suction nozzle of  FIG. 2 ,  FIG. 4  is a side view of the suction nozzle of  FIG. 1 ,  FIG. 5  is a front view of the suction nozzle of  FIG. 1 ,  FIG. 6  is a view illustrating a state in which a rotation cleaning part is separated from the suction nozzle of  FIG. 5 ,  FIG. 7  is a bottom view of the suction nozzle of  FIG. 1 ,  FIG. 8  is an exploded perspective view of the suction nozzle of  FIG. 1 ,  FIG. 9  is an exploded perspective view of a housing,  FIG. 10  is a cross-sectional view of the suction nozzle, taken along line I-I′ of  FIG. 7 , and  FIG. 11  is a cross-sectional view taken along line II-II′ of  FIG. 7 . 
     Referring to  FIGS. 2 to 11 , the suction nozzle  100  includes a housing  110 , a connection tube  120 , and a rotation cleaning part  130 . 
     Also, the suction nozzle  100  may include a sealing part  200  for sealing a rear side of the suction nozzle  100  on a bottom thereof. 
     The sealing part  200  is provided to block a flow of air flowing forward from the rear side when the suction force is generated in the suction nozzle  100 . 
     The sealing part  200  may have an unevenness on the bottom surface that contacts the floor surface. 
     The sealing part  200  may extend in a left-right direction if it is assumed that the suction nozzle  100  moves in a front-rear direction. 
     Also, the unevenness provided on the bottom surface of the sealing part  200  may be alternately disposed in a direction that is parallel to the front-rear direction in which the suction nozzle  100  moves, and in a flow direction of the air suctioned into the suction nozzle  100 . 
     Due to the configuration of the above-described sealing part  200 , when the suction force is generated in the suction nozzle  100 , if the flow of the air flowing forward from the rear side may be blocked or interrupted, the suction force suctioned forward from the rear side may increase to improve cleaning performance. 
     Description of the sealing part  200  will be described later with reference to  FIGS. 12 to 28 . 
     The housing  110  includes a body part  111  in which a chamber  112  is provided therein. A front opening  111   a  for suctioning air containing contaminants may be defined in the body part  111 . The air introduced through the front opening  111   a  by the suction force generated in the cleaner body  10  may flow to the connection tube  120  via the chamber  112 . 
     The front opening  111   a  may extend in a left-right direction of the housing  110 , i.e., extend up to a front portion of the housing  110  as well as a bottom surface of the housing  110 . Accordingly, since a suction area is secured sufficiently, cleaning may be uniformly performed from the floor surface to a portion adjacent to a wall surface. 
     The housing  110  may further include an inner tube  1112  communicating with the front opening  111   a . Due to the suction force generated in the cleaner body  10 , external air may flow to an inner passage  1112   a  of the inner tube  1112  via the front opening  111   a.    
     The housing  110  may further include a driving part  140  that provides power for allowing the rotation cleaning part  130  to rotate. The driving part  140  may be inserted into one side of the rotation cleaning part  130  to transmit the power to the rotation cleaning part  130 . 
     The rotation cleaning part  130  may be accommodated in the chamber  112  of the body part  111 . At least a portion of the rotation cleaning part  130  may be exposed to the outside through the front opening  111   a . The rotation cleaning part  130  may rotate by driving force transmitted through the driving part  140  to dust the contaminants by friction with the floor surface. Also, an outer circumferential surface of the rotation cleaning part  130  may be made of a fabric or felt material such as cotton flannel. Thus, when the rotation cleaning part  130  rotates, foreign substances such as dust accumulated on the floor surface may be caught in the outer circumferential surface of the rotation cleaning part  130  and thus be effectively removed. 
     The body part  111  may cover at least a portion of an upper side of the rotation cleaning part  130 . Also, an inner circumferential surface of the body part  111  may have a curved shape to correspond to the outer circumferential surface of the rotation cleaning part  130 . Accordingly, the body part  111  may perform a function of preventing the foreign substances, which is dusted from the floor surface of the rotation cleaning part  130 , from ascending. 
     The housing  110  may further include side covers  115  and  116  covering both side surfaces of the chamber  112 . The side covers  115  and  116  may be provided on both side surfaces of the rotation cleaning part  130 . 
     The side covers  115  and  116  include a first side cover  115  provided at one side of the rotation cleaning part  130  and a second side cover  116  provided at the other side of the rotation cleaning part  130 . The driving part  140  may be fixed to the first side cover  115 . 
     The suction nozzle  100  further includes a rotation support part  150  provided on the second side cover  116  to rotatably support the rotation cleaning part  130 . The rotation support part  150  may be inserted into the other side of the rotation cleaning part  130  to rotatably support the rotation cleaning part  130 . 
     The rotation cleaning part  130  may rotate in a counterclockwise direction with respect to the cross-sectional view of  FIG. 10 . That is, the rotation cleaning part  130  rotates to be pushed from a contact point with the floor surface toward the inner tube  1112 . Therefore, the foreign substances dusted from the floor surface of the rotation cleaning part  130  are move toward the inner tube  1112  and then suctioned into the inner tube  1112  by the suction force. The rotation cleaning part  130  may rotate backward with respect to the contact point with the floor surface to improve cleaning efficiency. 
     A partition member  160  may be provided in the chamber  112 . The partition member  160  may extend downward from an upper side of the chamber of the housing  110 . 
     The partition member  160  may be provided between the rotation cleaning part  130  and the inner tube  1112 . Accordingly, the partition member  160  may partition the chamber of the housing  110  into a first region  112   a , in which the rotation cleaning part  130  is disposed, and a second region  112   b , in which the inner tube  1112  is disposed. As illustrated in  FIG. 10 , the first region  112   a  may be provided in the front of the chamber  112 , and the second region  112   b  may be provided in the rear of the chamber  112 . 
     The partition member  160  may include a first extension wall  161 . The first extension wall  161  may extend so that at least a portion thereof contacts the rotation cleaning part  130 . Thus, when the rotation cleaning part  130  rotates, the first extension wall  161  may dust the foreign substances attached to the rotation cleaning part  130  through the friction with the rotation cleaning part  130 . 
     Also, the first extension wall  161  may extend along a rotation axis of the rotation cleaning part  130 . That is, a contact point between the first extension wall  161  and the rotation cleaning part  130  may be defined along a direction of the rotation axis of the rotation cleaning part  130 . Accordingly, the first extension wall  161  may not only dust the foreign substances attached to the rotation cleaning part  130 , but also block the introduction of the foreign substances on the floor surface into the first region  112   a  of the chamber  112 . Since the introduction of the foreign substances into the first region  112   a  of the chamber  112  is blocked, the foreign substances may be prevented from being discharged in the front of the housing  110  through the front opening  111   a  by the rotation of the rotation cleaning part  130 . 
     In addition, the first extension wall  161  may block introduction of hair or yarn attached to the rotation cleaning part  130  into the first region  112   a  of the chamber  112  to prevent the hair or yarn from being tangled with the rotation cleaning part  130 . That is, the first extension wall  161  may perform an anti-tangle function. 
     The partition member  160  may further include a second extension wall  165 . Like the first extension wall  161 , the second extension wall  165  may extend to at least partially contact the rotation cleaning part  130 . Thus, when the rotation cleaning part  130  rotates, the second extension wall  165  may dust the foreign substances attached to the rotation cleaning part  130  through the friction with the rotation cleaning part  130 , like the first extension wall  161 . The second extension wall  165  has the same function as the first extension wall  161 . As a result, since the foreign substances attached to the rotation cleaning part  130  are dusted using only the first extension wall  161  without the second extension wall  165 , the second extension wall  165  may not be included in the configuration of the housing  110 . 
     The second extension wall  165  may be disposed above the first extension wall  161 . Thus, the second extension wall  165  has a function of secondary separation of the foreign substances, which are not separated by the first extension wall  161 , in the rotation cleaning part  130 . 
     Hereinafter, a flow of air in the housing  110  will be described. 
     A plurality of suction passages F 1 , F 2 , and F 3  through which external air flows to the inner tube of the body part  111  are provided in the body part  111  of the suction nozzle  100 . 
     The plurality of suction passages F 1 , F 2 , and F 3  include a lower passage F 1  provided below the rotation cleaning part  130  and upper passages F 2  and F 3  provided above the rotation cleaning part  130 . 
     The lower passage F 1  is provided below the rotation cleaning part  130 . Particularly, the lower passage F 1  is connected to the inner passage  1112   a  from the front opening  111   a  via a lower side of the rotation cleaning part  130  and the second area  112   b.    
     The upper passages F 2  and F 3  are provided above the rotation cleaning part  130 . In detail, the upper passages F 2  and F 3  may be connected to the inner passage  1112   a  via an upper side of the rotation cleaning part  130  and the second area  112   b  in the first area  112   a . Accordingly, the upper passages F 2  and F 3  may be combined with the lower passage F 1  in the second region  112   b.    
     The upper passages F 2  and F 3  include a first upper passage F 2  provided at one side of the housing  110  and a second upper passage F 3  provided at the other side of the housing  110 . In detail, the first upper passage F 2  is disposed adjacent to the first side cover  115 , and the second upper passage F 3  is disposed adjacent to the second side cover  116 . 
     To provide the first upper passage F 2 , a first lower groove  161   a  may be defined in the first extension wall  161 , and a first upper groove  165   a  may be defined in the second extension wall  165 . 
     The first lower groove  161   a  is defined by recessing a portion of the inner circumferential surface of the first extension wall  161 , that is, a portion of a surface contacting the rotation cleaning part  130 . Also, the first lower groove  161   a  may extend along a circumferential direction of the rotation cleaning part  130 . 
     The first upper groove  165   a  is defined by recessing a portion of the inner circumferential surface of the second extension wall  165 , that is, a portion of a surface contacting the rotation cleaning part  130 . Also, the first upper groove  165   a  may extend along the circumferential direction of the rotation cleaning part  130 . 
     The first lower groove  161   a  is connected to the first upper groove  165   a , and the first upper passage F 2  is provided along the first lower groove  161   a  and the first upper groove  165   a . When the second extension wall  165  is not provided in the suction nozzle  100 , the first upper passage F 2  may be provided only by the first lower groove  161   a.    
     Also, the first lower groove  161   a  and the first upper groove  165   a  may be defined to surround the driving part  140 . Thus, the first upper passage F 2  may be provided to surround at least a portion of the driving part  140  along a circumference of the driving part  140 , and the driving part  140  may be cooled by air flowing along the first upper passage F 2 . 
     The first lower groove  161   a  and the first upper groove  165   a  may have the same left-right width A as illustrated in the drawings, but is not limited thereto. The left-right width A of each of the first lower groove  161   a  and the first upper groove  165   a  may have a predetermined size. When the left-right width A is small, a width of the first upper passage F 2  is narrowed, and thus cooling performance of the driving part  140  may be insignificant because a flow rate of air is small, or a flow of air may be blocked. On the other hand, when the left-right width A is large, the flow rate of the air may increase because the width of the first upper passage F 2  increases, but the anti-tangle function for preventing the hair or the like from being tangled with the rotation cleaning part may be deteriorated. Thus, the left-right width A has to be provided to an appropriate size and may be provided to have a width less than a length of the driving part. For example, the left-right width A of the first upper groove  165   a  may be about 5 mm to about 10 mm, but is not limited thereto. 
     As illustrated in  FIG. 11 , a spaced distance between the inner circumferential surface of the chamber  112  and the upper portion of the rotation cleaning part  130  in the first upper passage F 2  may decrease toward the inside of the chamber  112 . Particularly, the spaced distance between the inner circumferential surface of the chamber  112  and the upper portion of the rotation cleaning part  130  is defined as d 1  at the front opening  165   a , d 2  at the first upper groove  165   a , and d 3  at the first lower groove  161   a . The spaced distances gradually decrease from d 1  to d 3  (d 1 &gt;d 2 &gt;d 3 ). For example, d 1  may be about 3 mm, d 2  may be about 2.7 mm, and d 3  may be about 2 mm. Due to the above-described feature, an air velocity of the air may be reduced at the upper side of the rotation cleaning part  130  as being closer to the front opening  111   a . Thus, the discharge of the foreign substances to the front side by the rotation of the rotation cleaning part  130  may be suppressed. 
     Next, the second upper passage F 3  will be described. To provide the second upper passage F 3 , a second lower groove  161   b  is defined in the first extension wall  161 , and a second upper groove  165   b  is defined in the second extension wall  165 . 
     The second lower groove  161   b  is defined at a position adjacent to the second side cover  116  in the inner circumferential surface of the first extension wall  161 , that is, a surface in contact with the rotation cleaning part  130 . The second lower groove  161   b  is different from the first lower groove  161   a  in formation position, and the remaining components are substantially the same. 
     The second upper groove  165   b  is formed at a position adjacent to the second side cover  116  on an inner circumferential surface of the second extension wall  165 , that is, a surface in contact with the rotation cleaning part  130 . The second upper groove  165   b  is connected to the second lower groove  161   b , and the second upper passage F 3  is provided along the second lower groove  161   b  and the second upper groove  165   b . When the second extension wall  165  is not provided in the suction nozzle  100 , the second upper passage F 3  may be provided only by the second lower groove  161   b.    
     Also, the second lower groove  161   b  and the second upper groove  165   b  may be defined to surround the rotation support portion  150 . Thus, the second upper passage F 3  may be provided along the circumference of the rotation support part  150 , and the rotation support part  150  is cooled by air flowing along the second upper passage F 3 . 
     The second lower groove  161   b  and the second upper groove  165   b  may have the same left-right width A as illustrated in the drawings, but is not limited thereto. Each of the left-right width A of the second lower groove  161   b  and the left-right width A of the second upper groove  165   b  may be the same as the left-right width A of each of the first lower groove  161   a  and the first upper groove  165   a.    
     A spaced distance between the inner circumferential surface of the chamber  112  and the upper portion of the rotation cleaning part  130  in the second upper passage F 3  may gradually decrease toward the inside of the chamber  112 , like the first upper passage F 2 . Thus, detailed descriptions thereof will be omitted. 
     The partition member  160  may further include a third extension wall  163  coupled to the first extension wall  161 . The third extension wall  163  may be coupled to a rear surface of the first extension wall  161  to support the first extension wall  161 . Since the first lower groove  161   a  and the second lower groove  161   b  are defined in the first extension wall  161 , a portion of the third extension wall  163  may be exposed to the first region  112   a  of the chamber  112 . 
     As described above, the first upper passage F 2  provided above the rotation cleaning part  130  as well as the lower passage F 1  provided below the rotation cleaning part  130  may be provided in the housing  110  to efficiently cool the driving part  140 . Also, the second upper passage F 3  may be provided to efficiently cool the rotation support part  150 . 
     The connection tube  120  may connect the housing  110  and the extension tube  17  (see  FIG. 1 ). That is, one side of the connection tube  120  is connected to the housing  110 , the other side of the connection tube  120  is connected to the extension tube  17 . 
     A detachable button  122  for manipulating the mechanical coupling with the extension tube  17  may be provided on the connection tube  120 . The user may manipulate the detachable button  122  to couple the connection tube  120  to the extension tube  17 . 
     The connection tube  120  may be rotatably connected to the housing  110 . In detail, the connection tube  120  may be hinge-coupled to the first connection member  113   a  so as to be rotatable in the vertical direction. 
     Connection members  113   a  and  113   b  that is hinge-coupled to the connection tube  120  may be provided on the housing  110 . The connection members  113   a  and  113   b  may be provided to surround the inner tube  1112 . The connection members  113   a  and  113   b  may include a first connection member  113   a  and a second connection member  113   b , which are directly connected to the connection tube  120 . One side of the second connection member  113   b  may be coupled to the first connection member  113   a , and the other side of the second connection member  113   b  may be coupled to the body part  111 . 
     As illustrated in  FIG. 8 , the first connection member  113   a  may include a hinge hole  114 , and the connection tube  120  may include a hinge shaft  124  inserted into the hinge hole  114 . However, unlike shown in the drawings, the hinge hole may be defined in the connection tube  120 , and the hinge shaft may be provided in the first connection member  113   a . The hinge hole  114  and the hinge shaft  124  may be collectively referred to as a “hinge part”. 
     A center  124   a  of the hinge shaft  124  may be disposed above a central axis C of the first connection member  113   a . Accordingly, a rotation center of the connection tube  120  may be defined above the central axis C of the first connection member  113   a.    
     The first connection member  113   a  may be rotatably connected to the second connection member  113   b . Particularly, the first connection member  113   a  may rotate with respect to an axis in the longitudinal direction. 
     The suction nozzle  100  may further include an auxiliary hose  123  connecting the connection tube  120  to the inner tube  1112  of the housing  110 . Thus, the air suctioned into the housing  110  may move to the cleaner body  10  (see  FIG. 1 ) via the auxiliary hose  123 , the connection tube  120 , and the extension tube  17  (see  FIG. 1 ) to the cleaner body  10  (see FIG.  1 ). 
     The auxiliary hose  123  may be made of a flexible material so that the connection tube  120  is rotatable. Also, the first connection member  113   a  may have a shape surrounding at least a portion of the auxiliary hose  123  to protect the auxiliary hose  123 . 
     The suction nozzle  100  may further include front wheels  117   a  and  117   b  for movement during the cleaning. The front wheels  117   a  and  117   b  may be rotatably provided on the bottom surface of the housing  110 . Also, the front wheels  117   a  and  117   b  may be provided in pairs. The pair of front wheels  117  and  117   b  may be respectively provided on both sides of the front opening  111   a  and may be disposed behind the front opening  111   a.    
     The suction nozzle  100  may further include a rear wheel  118 . The rear wheel  118  is rotatably provided on the bottom surface of the housing  110  and may be disposed behind the front wheels  117   a  and  117   b.    
     The housing  110  may further include a support member  119  provided below the body part  111 . The support member  119  may support the body part  111 . The front wheels  117   a  and  117   b  may be rotatably coupled to the support member  119 . 
     An extension portion  1192  extending backward may be provided on the support member  119 . The rear wheels  118  may be rotatably coupled to the extension portion  1192 . Also, the extension portion  1119  may support the first connection member  113   a  and the second connection member  113   b  at the lower side. 
     The rotation shaft  118   a  of the rear wheel  118  may be disposed behind the center  124   a  of the hinge shaft  124 . Thus, since the housing  110  is improved in stability, overturning of the housing  110  may be prevented from occurring during the cleaning. 
       FIG. 12  is a view illustrating a suction nozzle of a vacuum cleaner when viewed from one side according to another embodiment of the present invention.  FIG. 13  is a bottom surface of the suction nozzle of  FIG. 12 . 
     Referring to  FIGS. 12 and 13 , the suction nozzle  100  includes a sealing part  200  in the rear of the front opening  111   a  on a bottom surface thereof. 
     The sealing part  200  protrudes downward from a lower end of the housing  110  and is provided to be spaced apart from the rear of the front opening  111   a.    
     When the floor surface is cleaned using the vacuum cleaner, dust on the floor surface may be suctioned while the suction nozzle  100  moves by a user. 
     Here, the suction nozzle  100  has to be in contact with the floor surface except for a front opening  111   a  into which the dust is suctioned so as to perform suction performance. 
     According to an embodiment, to improve the dust suction performance, when the suction operation is performed, a sealing part  200  that is in contact with the floor surface, is provided. 
     The sealing part  200  is in close contact with the floor surface by a differential pressure during the suction operation of the suction nozzle  100 . Then, when the sealing part  200  is in close contact with the floor surface, introduction of air from a rear side may be prevented. Also, dust suction force through the front opening  111   a  may increase. 
     Referring again to  FIGS. 12 to 13 , a sealing groove  211  that is recessed upward from a lower end and extends in a longitudinal direction of the suction nozzle  100  may be defined in the sealing part  200 . 
     For another example, the sealing groove  211  may be provided in the form of a slit that is defined by vertically cutting the sealing part  200 . 
     Also, the sealing groove  211  may be provided in plurality, which are spaced apart from each other in a front-rear direction. 
     Here, the front-rear direction (with respect to a vertical direction in  FIG. 13 ) may mean a direction in which air is suctioned. 
     As described above, when the plurality of sealing grooves  211  are defined in the bottom surface of the sealing part  200 , a sealing protrusion  212  may be provided between the sealing grooves  211 . 
     The sealing protrusion  212  has a shape that is convex downward. 
     Each of the sealing groove  211  or the sealing protrusion  212  may have a rectangular shape when viewed from one side. Also, an edge portion of each of the sealing groove  211  or the sealing protrusion  212  may be curved. 
     Also, an inclined surface may be disposed on a portion of each of the sealing groove  211  or the sealing protrusion  212 . 
     The sealing groove  211  and the sealing protrusion  212  may extend in a longitudinal direction of the suction nozzle  100  (a left-right direction in  FIG. 13 ). 
     The front opening  111   a  and the sealing part  200  extend in the left and right directions of the housing  110 . 
     Also, the sealing part  200 , i.e., the sealing groove  211  and the sealing protrusion  212  may extend in a direction crossing an air inflow direction. 
     Also, the plurality of sealing grooves  211  and sealing protrusions  212  may be alternately provided in a direction parallel to the air inflow direction. 
     Also, the sealing part  200  may be made of a material having elasticity or flexibility. For example, the sealing part  200  may be made of rubber or silicon. 
     Also, in the suction nozzle  100 , the connection tube  120  connected to the cleaner body  10  may be disposed in the rear of the housing  110 , and the sealing part  200  may be disposed between the front opening  111   a  and the connection tube  120 . 
     Also, the housing  110  may include a body part  111  in which the front opening  111   a  is defined at a front side, and a chamber  112  communicating with the front opening  111   a  is provided therein and which covers an upper side of the rotation cleaning part  130  and a support member  119  provided below the body part  111 . 
     Also, the sealing part  200  may be provided on a bottom surface of the support member  119 . 
     Here, a front end of the body part  111  and a front end of the support member  119  may be spaced apart from each other to define the front opening  111   a.    
     Referring again to  FIG. 12 , in the sealing protrusion  212 , a sealing protrusion  212   b  disposed at a rear side may further protrude than a sealing protrusion  212   a  disposed at a front side. 
     As described above, when the sealing part  200  in which the sealing groove  211  and the sealing protrusion  212  are alternately disposed is provided at the rear of the front opening  111   a , the flow of the air forward from the rear side may be blocked during the operation of the vacuum cleaner. 
     In detail, when an unevenness is provided by the sealing groove  211  and the sealing protrusion  212  on a bottom surface of the sealing part  200 , a pressure difference between the sealing groove  211  and the sealing protrusion  212  is generated. Also, due to the pressure difference, flow resistance occurs, and as a result, the flow of the air flowing forward from the rear side may be disturbed. Also, suction force in the front side may increase to improve cleaning performance. 
     Also, the sealing part  200  may be provided on both sides of the front opening  111   a  as well as the rear of the front opening  111   a.    
     That is, the sealing part  200  may be provided at various positions except for the front of the front opening  111   a.    
     Also, when the sealing member  200  is viewed from the bottom, the sealing member  200  may be provided in a straight line shape or a curved shape. Also, the sealing member  200  may be provided in a bent form. 
     Also, the sealing member  200  may be provided from one end to the other end of the housing  110  or may be provided only in a partial section of the housing  110 . 
     Also, the sealing member  200  may be provided in plurality, which are spaced apart from each other. 
     Also, a second sealing part made of a cushion material may be additionally provided between the sealing member  200  and the front opening  111   a  while contacting the floor surface, thereby removing dust and preventing a flow of air flowing forward from the rear side. 
       FIGS. 14 and 15  are partial cross-sectional views illustrating the sealing part and the housing of the vacuum cleaner according to another embodiment. 
     In detail,  FIG. 14  is a view illustrating a state of the sealing part before the suction force is generated in the suction nozzle, and  FIG. 15  is a view illustrating a state of the sealing part after the suction force is generated in the suction nozzle. 
     Referring to  FIGS. 14 and 15 , the sealing part  200  may be connected to a rear portion of the suction nozzle  100  so as to be elevatable. 
     Here, the elevation operation may mean a case of being elevated vertically in a straight line. Also, the elevation operation may mean all cases of moving vertically while at least a portion of the of the sealing part  200  moves along a straight or curved trajectory. Also, the elevation operation may also mean a case in which at least a portion of the sealing part  200  moves vertically while rotating. 
     In this embodiment, the sealing part  200  may be made of an elastic material. For example, the sealing part  200  may be made of a rubber or silicon material. 
     Referring to  FIGS. 14 to 15 , when the suction force is generated in the suction nozzle  100 , the sealing part  200  contacts the floor surface while descending by the difference pressure. 
     Also, when the sealing part  200  descends as described above, a lower end of the sealing part  200  is disposed lower than a lower end of the front opening  111   a.    
     Referring to  FIGS. 14 to 15 , at least a portion of the rear portion of the housing  110  may be opened to define a rear opening  119 . 
     The housing  110  includes a first side surface  119   b  defining the rear opening  119  and a second side surface  119   c  spaced backward from the first side surface  119   b  to face the first side surface  119   b.    
     Also, the sealing part  200  may include a second extension portion  214  and a first extension portion  215 , which respectively contact the first side surface  119   b  and the second side surface  119   c  to extend upward. 
     The sealing part  200  may be elevated in a state in which the first extension portion  215  and the second extension portion  214  respectively contact the first side surface  119   b  and the second side surface  119   c.    
     Also, the sealing part  200  may further include a third extension portion  216  extending backward from a lower end of the second extension portion  214 . 
     The third extension portion  216  may have a curved surface that is convex upward or backward. 
     Due to the configuration of the third extension portion  216 , a longitudinal length of a sealing pad  213  that will be described later may increase. That is, due to the configuration of the third extension portion  216 , the longitudinal length of the sealing pad  213  that will be described later may be greater than a distance between the first extension portion  215  and the second extension portion  214 . Also, a flow of air flowing forward from the rear side may be more surely blocked. 
     The sealing part  200  includes the sealing pad  213  connecting a lower end of the third extension portion  216  to a lower end of the second extension portion  214 , and a sealing groove  211  that is recessed upward from a lower end thereof and parallel to a longitudinal direction of the suction nozzle  100  may be defined in the sealing pad  213 . 
     The sealing groove  211  and the sealing protrusion  212  extend in a direction crossing the air inflow direction (a left-right direction in  FIG. 14 ). 
     Also, the plurality of sealing grooves  211  and sealing protrusions  212  may be provided alternately in a direction parallel to the air inflow direction (the left-right direction in  FIG. 14 ). 
     Referring to  FIG. 14 , in the suction nozzle  100 , before the suction force is generated, the sealing part  200  may be in an elevated state and be spaced apart from the floor surface. 
     On the other hand, referring to  FIG. 15 , in the suction nozzle  100 , when the suction force occurs, the sealing part  200  may descend to contact the floor surface. 
     Also, when air is introduced forward from the rear side through a space between the floor surface and the bottom surface of the sealing pad  213 , a sudden decrease in flow resistance and a sudden increase in flow resistance alternately occur by the sealing protrusions  212  and the sealing grooves  211 , which are alternately disposed. Also, in each of the sealing grooves  211 , an eddy current may be generated, and a differential pressure may be generated by multiple flow resistance, and as a result, a bottom surface pressure may increase while external air inflow resistance increase. 
     Then, a flow rate of air flowing forward from the rear side may be sharply reduced, and the front suction force through the front opening  111   a  may increase to improve cleaning performance. 
     For reference, (a) of  FIG. 14  is a perspective view illustrating a state of the sealing part before the suction force is generated in the suction nozzle, and (b) of  FIG. 14  is a partial cutaway perspective view illustrating a state of the sealing part before the suction force is generated in the suction nozzle. 
     Also, (a) of  FIG. 15  is a perspective view illustrating a state of the sealing part after the suction force is generated in the suction nozzle, and (b) of  FIG. 15  is a partial cutaway perspective view illustrating a state of the sealing part after the suction force is generated in the suction nozzle. 
       FIG. 16  is a view obtained by comparing flow analysis results of the suction nozzle depending on whether the sealing part is provided. 
     First, (a) of  FIG. 16  is a diagram illustrating flow velocity distribution and pressure distribution analysis result of the suction nozzle in which the sealing part is not installed, and (b) of  FIG. 16  is a diagram illustrating flow velocity distribution and pressure distribution analysis result of the suction nozzle in which the sealing part is installed. 
     Referring to (a) of  FIG. 16 , when the sealing part  200  is not provided, a suction flow velocity and a suction pressure are deflected to the rear side to decrease in front suction force. As a result, it may be confirmed that the suction performance of the foreign substances at the front opening  111   a  is deteriorated. 
     On the other hand, referring to (b) of  FIG. 16 , when the sealing part  200  is not provided, a suction flow velocity and a suction pressure are deflected to the front side to increase in front suction force. As a result, it may be confirmed that the suction performance of the foreign substances at the front opening  111   a  is improved. 
       FIG. 17  is a view obtained by comparing flow analysis results of the suction nozzle depending on whether the sealing part is provided. 
     (a) of  FIG. 17  illustrates results obtained by analyzing a pressure difference between the front side and the rear side of the sealing part in which the sealing groove is not provided, and (b) of  FIG. 17  illustrates results obtained by analyzing a pressure difference between the front side and the rear side of the sealing part in which the sealing groove is provided. 
     First, in the case of (a) of  FIG. 17 , it may be confirmed that the pressure difference between the rear side and the front side of the sealing part hardly occurs. 
     On the other hand, in the case of (b) of  FIG. 17 , it may be confirmed that a pressure difference between the rear side (right side in  FIG. 17 ) and the front side (left side in  FIG. 17 ) occurs to about −200 Pa. 
     In the case of (b) of  FIG. 17 , it may be confirmed that the suction pressure of the rear side (right side in  FIG. 17 ) of the sealing part is lower about 30% than that in the case of (a) of  FIG. 17 . 
     That is, as shown in (b) of  FIG. 17 , when the sealing part in which the sealing groove is defined is applied, it is understood that a suction negative pressure is reduced while passing through the sealing groove in multi-stages, and as a result, a flow of air flowing forward from the rear side is more reliably blocked. 
       FIG. 18  is a partial cross-sectional view of a sealing part and a housing of a vacuum cleaner according to a further embodiment. 
     Referring to  FIG. 18 , at least a portion of the housing  110  may be opened to define rear openings  119   a  and  119   d.    
     Here, the rear openings  119   a  and  119   d  may include a first rear opening  119   a  and a second rear opening  119   d.    
     The first rear opening  119   a  and the second rear opening  119   d  may be spaced apart from each other in a front-rear direction (left-right direction in  FIG. 18 ). The first rear opening  119   a  may be disposed backward (right side in  FIG. 18 ) from the second rear opening  119   d.    
     That is, the second rear opening  119   d  may be disposed between the front opening  111   a  and the first rear opening  119   a.    
     In this embodiment, the sealing part  200  may be made of an elastic material. For example, the sealing part  200  may be made of a rubber or silicon material. 
     Also, the sealing part  200  includes a first extension portion  215  inserted into the first rear opening  119   a  and a second extension portion  214  inserted into the second rear opening  119   d.    
     Also, at least a portion of the sealing part  200  may be elevated in a state in which the first extension portion  215  and the second extension portion  214  are respectively inserted into the first rear opening  119   a  and the second rear opening  119   d.    
     A hook protrusion  217  extending horizontally from each of both sides of an upper end of the first extension portion  215  is disposed on the first extension portion  215 . 
     The first extension portion  215  may be elevated without being separated from the first rear opening  119   a  by the hook protrusion  217 . 
     A front-rear length (left-right length in  FIG. 18 ) of the hook protrusion  217  may be greater than a front-rear length (left-right length in  FIG. 19 ) of the first rear opening  119   a . Accordingly, the hook protrusion  217  may be maintained in a state of being hung on an upper end of both ends defining the first rear opening  119   a . That is, the hook protrusion  217  may be maintained in a state of being hung on a top surface of a support member  119 . 
     Also, a front-rear length (left-right length in  FIG. 18 ) of the extension portion  215  may be less than or equal to a front-rear length (left-right length in  FIG. 18 ) of the first rear opening  119   a.    
     Also, a vertical length of the first extension portion  215  may be longer than a vertical length of the first rear opening  119   a.    
     On the other hand, a fixing hook  218  may be disposed on an upper end of the second extension portion  214 . 
     In detail, the fixing hook  218  may be provided with a horizontal portion  218   a  extending backward (right side in  FIG. 18 ) from the upper end of the second extension portion  214  and a vertical portion  218   b  extending downward from an upper end of the horizontal portion  218   a.    
     Here, the horizontal portion  218   a  may be inclined upward toward the rear side (right side in  FIG. 18 ). 
     Also, the housing  110  may have a hook groove  119   e  having a shape that is concave downward from an upper side so that the fixing hook  218  is fitted into an inner surface thereof. 
     The hook groove  119   e  may be recessed downward from the top surface of the support member  119 . 
     Here, the top surface of the support member  119  may mean an inner surface of the chamber  112 . 
     Also, a support protrusion  119   f  extending upward so that one surface of the vertical portion  218   b  contacts an inner surface thereof may be disposed on an inner surface of the housing  110 . 
     The support protrusion  119   f  may have a flat surface contacting the vertical portion  218   b . A height of the support protrusion  119   f  may be higher than that of the vertical portion  218   b.    
     As described above, when the first extension portion  215  is elevatably connected to the first rear opening  119   a , and the second extension portion  214  is coupled to the second rear opening  119   d  in a hook manner, the second extension portion  214  may be maintained in a state of being coupled to the housing  110  in the hook manner, and the sealing part  200  may contact the floor surface while the first extension portion  215  is elevated or rotates. 
     The sealing part  200  includes a sealing pad  213  connecting a lower end of the first extension portion  215  to a lower end of the second extension portion  214 , and a sealing groove  211  that is recessed upward from a lower end thereof and parallel to a longitudinal direction of the suction nozzle  100  may be defined in the sealing pad  213 . 
     Also, the sealing groove  211  may be provided in plurality, which are spaced apart from each other in a front-rear direction. 
     Due to the configuration of the sealing grooves  211 , a sealing protrusion  212  protruding downward may be disposed between the sealing grooves  211 . 
     The sealing groove  211  and the sealing protrusion  212  extend in a direction crossing the air inflow direction (a left-right direction in  FIG. 18 ). 
     Also, the plurality of sealing grooves  211  and sealing protrusions  212  may be provided alternately in a direction parallel to the air inflow direction (the left-right direction in  FIG. 18 ). 
     (a) of  FIG. 18  is a cross-sectional view of the sealing part  200  in which the sealing groove  211  and the sealing protrusion  212  are not provided in/on the sealing pad  213 , and (b) of  FIG. 18  is a cross-sectional view of the sealing part  200  in which the sealing groove  211  and the sealing protrusion  212  are provided in/on the sealing pad  213 . 
     Referring to (a) of  FIG. 18 , when suction power is generated in the suction nozzle  100 , air is suctioned into the front opening  111   a , and dust on the floor surface is also suctioned. 
     Also, air is introduced forward (right side in  FIG. 18 ) from the rear side through the space between the bottom surface of the sealing pad and the floor surface without large resistance, and the front suction force is reduced. 
     In detail, in the case of (a) of  FIG. 18 , when air is introduced forward from the rear side through the space between the bottom surface of the sealing pad  213  and the floor surface, only flow resistance due to a sudden decrease occurs. 
     On the other hand, referring to (b) of  FIG. 18 , when the air is introduced forward (from the right side to the left side in  FIG. 18 ) from the rear side through the space between the bottom surface of the sealing pad  213  and the floor surface, the air may be introduced while receiving larger resistance by the sealing groove  211  and the sealing protrusion  212 , which are disposed in/on the bottom surface of the sealing pad  213 , and thus, the front suction force may increase. 
     In detail, in the case of (b) of  FIG. 18 , when air is introduced forward from the rear side through a space between the bottom surface and the bottom surface of the sealing pad  213 , a rapid decrease in flow resistance and a rapid increase in flow resistance alternately occur by the sealing protrusions  212  and the sealing grooves  211 , which are alternately disposed. Also, in each of the sealing grooves  211 , an eddy current may be generated, and a differential pressure may be generated by multiple flow resistance, and as a result, a bottom surface pressure may increase while external air inflow resistance increase. 
       FIG. 19  is a graph obtained by comparing bottom surface pressures when the sealing part of  FIG. 18  is applied. 
     First, (a) of  FIG. 19  is a graph illustrating a bottom surface pressure when a flat type sealing part of (a) of  FIG. 18  is applied, and (b) of  FIG. 19  is a graph illustrating a bottom surface pressure when a pocket sealing type sealing part of (b) of  FIG. 18  is applied. 
     Referring to  FIG. 19 , when the flat type sealing part as illustrated in (a) of  FIG. 18  is applied, the bottom surface pressure is about −3492 Pa, and when the pocket sealing type sealing part as illustrated in (b) of  FIG. 18  is applied, the bottom surface pressure is about −4050 Pa. Here, it may be confirmed that the bottom surface pressure increases by about 16% to about 18% when the pocket sealing type sealing part as illustrated in (b) of  FIG. 18  is applied in comparison to the case in which the flat type sealing part as illustrated in (a) of  FIG. 18  is applied. 
       FIG. 20  is a side view of a sealing part that is a main component of the vacuum cleaner according to an embodiment. 
     Referring to  FIG. 20 , the sealing part  200  has a rectangular cross-section as a whole. Also, a sealing groove  211  that is recessed upward from a lower end and extends in a longitudinal direction of the suction nozzle  100  may be defined in the sealing part  200 . 
     Also, the sealing groove  211  may be provided in plurality, which are spaced apart from each other in a front-rear direction. 
     Here, the front-rear direction (left-right direction in  FIG. 20 ) may mean a direction in which air is suctioned. 
     As described above, when the plurality of sealing grooves  211  are defined in the bottom surface of the sealing part  200 , a sealing protrusion  212  may be provided between the sealing grooves  211 . 
     The sealing grooves  211  and the sealing protrusions  212  may be alternately provided in a front-rear direction (left-right direction in  FIG. 20 ). 
     Referring to  FIG. 20 , a height h of the sealing groove  211  may be set in a range of about 0.5 mm to about 2 mm. 
     Also, a front-rear direction b of the sealing groove  211  may be greater than that a of the sealing protrusion  212 . 
     For example, a ratio a/b of the front-rear length a of the sealing protrusion  212  and the front-rear length b of the sealing groove  211  may be set in a range of about 0.3 to about 0.8. 
     As another example, a ratio a/b of the front-rear length a of the sealing protrusion  212  and the front-rear length b of the sealing groove  211  may be set to about 0.5. 
       FIG. 21  is a table obtained by comparing results of measuring a pressure drop depending on a design change of the sealing part. 
     Referring to  FIG. 21 , in cases 1 to 19, a front-rear length L of the sealing part  200  is about 16 mm, a height H of the sealing part  200  is about 2.5 mm, a distance g between the floor surface and a lower end of the sealing protrusion  212  is about 1.5 mm, and a corner curvature R of the sealing protrusion  212  is about 0.4 mm. 
     First, the case 1 is case in which the sealing groove  211  and the sealing protrusion  212  are not provided in/on the sealing part. Here, a pressure drop is measured to about 32.5 Pa. 
     For reference, the pressure drop may mean a difference between pressures measured at the front and rear ends of the sealing part  200  during the suction operation of the suction nozzle  100 . 
     Here, the front end of the sealing part  200  means one side adjacent to the front opening  111   a , and the rear end of the sealing part  200  means the other side adjacent to the connection tube  120 . 
     Therefore, when the pressure drop is large, it is understood that flow resistance of the air introduced forward from the rear side is large, and the rear sealing is more surely performed. 
     Therefore, the cleaning performance and the pressure drop are proportional to each other. 
     Referring to  FIG. 21 , in the cases 4 and 13, the pressure drop is measured to the largest value. 
     First, in the case 4, the number K of sealing protrusions  212  is four, a height h of the sealing groove  211  is about 0.9 mm, a front-rear length a of the sealing protrusion  212  is about 1.6 mm, and a front-rear length b of the sealing groove  211  is about 3.2 mm. 
     Also, in the case 13, the number K of sealing protrusions  212  is five, a height h of the sealing groove  211  is about 0.9 mm, a front-rear length a of the sealing protrusion  212  is about 1.2 mm, and a front-rear length b of the sealing groove  211  is about 2.4 mm. 
     commonly, it may be confirmed that a ratio a/b of a front-rear length a of the sealing protrusion  212  and a front-rear length b of the sealing groove  211  is about 0.5. 
     On the other hand, when the front-rear length b of the sealing groove  211  and the front-rear length a of the sealing protrusion  212  are the same, or the front-rear length b of the sealing groove  211  is less than the front-rear a of the sealing protrusion  212 , it may be confirmed that the pressure drop is rather reduced. 
     Therefore, the front-rear direction b of the sealing groove  211  has to be greater than that a of the sealing protrusion  212 . 
     Also, in the cases 4 and 13, it may be seen that the height h of the sealing groove  211  is about 0.9 mm. 
     On the other hand, when the height h of the sealing groove  211  is about 1.9 mm or about 2.9 mm under the condition in which the front-rear length b of the sealing groove  211  and the front-rear length a of the sealing protrusion  212  are the same, it may be confirmed that the pressure drop is rather reduced. 
     Therefore, the height h of the sealing groove  211  may be set in a range of about 0.5 mm to about 2 mm. 
     Also, referring to  FIG. 21 , a ratio h/b of the front-rear direction b of the sealing groove  211  and the height h of the sealing groove  211  may be set in a range of about 0.2 to about 0.4. 
     Also, referring to  FIG. 21 , a ratio h/a of the front-rear length a of the sealing protrusion  212  and the height h of the sealing groove  211  may be set in a range of about 0.5 to about 0.8. 
       FIG. 22  is a view of a flow analysis result in the sealing part according to the case 1 of  FIG. 21 .  FIG. 23  is a view of a flow analysis result in the sealing part according to the case 4 of  FIG. 21 , and  FIG. 24  is a view of a flow analysis result in the sealing part according to the case 13 of  FIG. 21 . 
     Referring to  FIGS. 22 to 24 , in the case of  FIGS. 23 and 24  in comparison to  FIG. 22 , it may be confirmed that flow resistance occurs while vortex occurs between the sealing part and the floor surface. 
     Particularly, it may be confirmed that the pressure drop occurs while a flow velocity decreases from the front side (left side in  FIG. 23 ) to the rear side (right side in  FIG. 23 ) of the sealing part. 
       FIG. 25  is a graph of a variation in pressure drop depending on a change in height of the sealing groove. Also,  FIG. 26  is a view of a flow analysis result depending on a height of the sealing groove in a first section of  FIG. 25 ,  FIG. 27  is a view of a flow analysis result depending on a height of the sealing groove in a second section of  FIG. 25 , and  FIG. 28  is a view of a flow analysis result depending on a height of the sealing groove in a first section of  FIG. 25 . 
     Referring to  FIGS. 24 and 26 , it may be confirmed that, in the first section, as the height of the sealing groove increases, the pressure drop also increases. 
     In detail, in the first section, it may be confirmed that, in the case of (b) of  FIG. 26 , in which the height of the sealing groove increases in comparison to (a) of  FIG. 26 , in which the height of the sealing groove is relatively low, the flow velocity is reduced. 
     On the other hand, referring to  FIGS. 24 and 27 , it may be confirmed that, after the first section, in the second section, as the height of the sealing groove increases, the pressure drop also increases, and then, the pressure drop is rather reduced. 
     Also, referring to  FIGS. 24 and 28 , in the third section of the second section, even if the height of the sealing groove increases, it may be confirmed that the pressure drop is constantly maintained. 
     In detail, in the third section, it may be confirmed that, in the case of (b) of  FIG. 28 , in which the height of the sealing groove increases in comparison to (a) of  FIG. 28 , in which the height of the sealing groove is relatively low, the flow velocity is hardly changed. 
     Referring to  FIGS. 25 to 28 , in the case of the first region and the second region, it may be confirmed that an unstable flow occurs in all the regions, and as the differential pressure of the sealing groove  211  increases due to the unstable vortex, the frictional resistance increases. As a result, the bottom surface pressure may increase while inflow resistance of external air increases. 
     On the other hand, in the case of the third region, it may be confirmed that the frictional resistance is rather reduced while the surface exchange disappears very quickly. 
     According to the present invention as described above, the flow of the fluid flowing forward from the rear side of the suction nozzle when the cleaner operates may not be simply blocked, but the multi-stage resistance may be generated in the passage of the fluid flowing forward from the rear side to reduce the flow velocity and rate of the fluid flowing forward from the rear side, resulting in concentrating the suction force, thereby allowing the front suction force to increase. 
     The above-described vacuum cleaner is not limited to the constituent and method according to the foregoing embodiments, but the embodiments may be configured such that all or some of the embodiments are selectively combined with each other. 
     Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.