Patent Publication Number: US-2023147162-A1

Title: Robot cleaner

Description:
TECHNICAL FIELD 
     The present disclosure relates to a robot cleaner, and more particularly, to a robot cleaner that does not cause damage to an obstacle or a side brush even when the obstacle is caught on the side brush during travel. 
     BACKGROUND ART 
     Generally, a vacuum cleaner is an appliance that sucks air containing a foreign substance from outside by driving an air suction apparatus, which is disposed inside a cleaner main body to generate an air suction force, and separates and collects the foreign substance. 
     The vacuum cleaner performing the above function is classified into a manual vacuum cleaner that is directly manipulated by a user and a robot cleaner that performs cleaning by itself without the user manipulation. A robot cleaner sucks various foreign substances lying on a face to be cleaned while autonomously travelling on the face-to-be cleaned. 
     Korean Patent Application Publication No. 10-2006-0111788 discloses a technology in which a robot cleaner includes a side brush to clean various faces of a floor during cleaning. According to the prior art, when the side brush hits an obstacle, the obstacle may move closer to a suction portion and may be sucked into the cleaner. However, in the prior art, when the obstacle does not move when the side brush hits the obstacle, the side brush may be caught by the obstacle and may be damaged, or a strong rotation force may be transmitted to the obstacle and the obstacle may be damaged. In particular, when the obstacle corresponds to an electric wire, the electric wire may be cut and a phenomenon such as an electric leakage and the like may occur. 
     DISCLOSURE OF INVENTION 
     Technical Problem 
     The present disclosure is to solve the problem as described above. The present disclosure is to provide a robot cleaner with improved stability during travel. 
     In addition, the present disclosure is to provide a robot cleaner in which a rotation of a side brush changes when an obstacle is caught on the side brush, thereby preventing damage of the obstacle or the side brush. 
     Solution to Problem 
     In order to achieve the above objectives, the present disclosure includes a main body including a suction portion disposed thereon, main wheels for moving the main body, and a side brush assembly disposed on the main body and rotating with a rotation shaft perpendicular to a rotation shaft of the main wheels, wherein the rotation of the side brush assembly may change based on whether an obstacle is hit. 
     In the present embodiment, two transmitters are connected to each other by a belt, so that operation of a side brush assembly may be maintained in a situation in which a change in a rotational force occurs between the two transmitters when the side brush assembly hits an obstacle. In addition, disclosed is a configuration of connecting the two transmitters with each other by the belt having a constant vertical dimension such that the rotational force may be transmitted between the two transmitters again when the side brush assembly returns to a situation of not hitting the obstacle. 
     The present disclosure provides a robot cleaner including a main body including a suction portion disposed thereon, main wheels for moving the main body, and a side brush assembly disposed on the main body and rotating with a rotation shaft perpendicular to a rotation shaft of the main wheels, wherein the side brush assembly includes a housing for forming an exterior of the side brush assembly, a first force transmitter disposed in the housing and rotating by receiving a driving force, a belt connected to the first force transmitter, a second force transmitter connected to the first force transmitter by the belt to receive a rotational force of the first force transmitter, and a side brush coupled to the second force transmitter. 
     The present disclosure discloses a structure in which, when slip occurs between the belt and one of the first force transmitter and the second force transmitter, a rotation angular speed of the first force transmitter and a rotation angular speed of the second force transmitter may become different from each other. 
     Further, the present disclosure discloses a technology capable of providing the rotational force to both the side brush and agitator using one motor assembly. Different rotational speeds may be transmitted to the side brush and the agitator depending on respective coupling schemes and gear ratios. 
     The second force transmitter includes a pulley to which the belt is coupled, and a rotation shaft to be coupled to a rotation center of the pulley. In this connection, the side brush is rotated at the same rotational angular speed with the rotation shaft. 
     Because the motor assembly and the first force transmitter are coupled to each other through a plurality of gear-coupling, a rotational speed is changed, but a rotational force is constantly transmitted from the motor assembly to the first force transmitter. However, because the rotational force is transmitted by the belt from the first force transmitter to the second force transmitter, even when a rotation is consistent in the first force transmitter, a rotation of the second force transmitter may change based on circumstances of the second force transmitter. In one example, when a factor that changes the rotation of the second force transmitter is removed after the rotation of the second force transmitter is changed, the rotational force of the first force transmitter is stably transmitted to the second force transmitter again by the belt. 
     Advantageous Effects of Invention 
     According to the present disclosure, even when the side brush hits an obstacle that is not moved by the side brush, no damage occurs to the side brush or the obstacle, so that the robot cleaner may travel stably. 
     That is, according to the present disclosure, when a rotational force having a magnitude equal to or greater than a certain magnitude is applied to the side brush, the rotational force of the side brush may be changed such that the side brush no longer hits the obstacle. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a view illustrating a bottom face of a robot cleaner according to the present disclosure. 
         FIG.  2    is a view illustrating main components according to an embodiment. 
         FIG.  3    is a view illustrating an exploded perspective view in  FIG.  2   . 
         FIG.  4    is a view illustrating a cross-section of some of main components in  FIG.  2   . 
         FIG.  5    is a view illustrating an operation of a side brush assembly. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Hereinafter, a preferred embodiment of the present disclosure that may specifically realize the above objects will be described with reference to the accompanying drawings. 
     In this process, a size, a shape, or the like of a component shown in the drawings may be exaggerated for clarity and convenience of the description. In addition, terms specifically defined in consideration of a configuration and an operation of the present disclosure may vary depending on a user or an operator&#39;s intention or practice. Definitions of such terms should be made based on the contents throughout this specification. 
       FIG.  1    is a view illustrating a bottom face of a robot cleaner according to the present disclosure. Hereinafter, a description will be achieved with reference to  FIG.  1   . 
     The present disclosure includes a main body  10  for forming an exterior, main wheels  40  arranged on the main body  10  and rotating such that the main body  10  may be moved back and forth or may turn, and a front auxiliary wheel  20  for supporting one side of the main body  10  and assisting the turning of the main body  10  by the main wheels  40 . 
     In this connection, the main wheels  40  are arranged on left and right sides of the main body  10  independently of each other. The main wheels  40  on the left and right sides may be driven independently of each other. 
     The main body  10  includes a suction portion  14  for sucking a foreign substance and the like. The suction portion  14  may include an agitator  60  disposed on the main body  10  and being brought into contact with a floor face on which cleaning is performed while rotating, a suction hole defined in the main body  10  and capable of sucking the external foreign substance by a suction force generated inside the main body  10 , and the like. 
     In one example, a rear auxiliary wheel  30  may be disposed rearward of the main wheels  40  to support the other side of the main body  10 . 
     The front auxiliary wheel  20  and the rear auxiliary wheel  30  are arranged to be freely rotatable in a horizontal direction with respect to the main body  10 . In one example, the front auxiliary wheel  20  and the rear auxiliary wheel  30  are arranged to have a fixed height with respect to the main body  10 . 
     In one example, although the main wheels  40  are not rotatable in the horizontal direction with respect to the main body  10 , the main wheels  40  are composed of two wheels on both sides and the wheels on the both sides rotate at different rotational speeds or in different directions, so that the main body  10  may turn left or right. 
     Especially, unlike the front auxiliary wheel  20 , the main wheels  40  have a height varying with respect to the main body  10 . The main wheels  40  may be moved to a desired location or rotated in a desired direction by a rotational force of the wheel in a state in which a rotation shaft is disposed substantially parallel to the floor face or a face to be cleaned where the robot cleaner is moved. 
     A side brush assembly  100  is disposed on one side of the main body  10 . In the side brush assembly  100 , as a brush rotates, the brush moves an obstacle located away from a bottom of the main body  10  or an obstacle in contact with a wall to be sucked into the suction portion  14 . The side brush assembly  100  may be driven together with the suction portion  14  when the robot cleaner is driven. 
     In the side brush assembly  100 , as a driving force for rotating the brush, a suction force generated in the suction portion  14  or a driving force for rotating the main wheels  40  may be used. In one example, the side brush assembly  100  may include a separate motor to generate a separate rotational force. 
       FIG.  2    is a view illustrating main components according to an embodiment. 
     In  FIG.  2   , a motor assembly  200 , a gear box  300 , and a side brush assembly  100  are represented together. 
     The motor assembly  200  has a motor therein, so that a rotational force by the motor may be generated. 
     The motor assembly  200  is coupled to the gear box  300 , so that the rotational force generated by the motor assembly  200  is transmitted to the gear box  300 . The gear box  300  is coupled to the side brush assembly  100 , so that the rotational force of the motor assembly  200  is transmitted to the side brush assembly  100  through the gear box  300 . 
     The side brush assembly  100  includes a housing that forms an exterior of the side brush assembly  100 , a first force transmitter  130  disposed on the housing and rotating by receiving a driving force, a belt  150  connected to the first force transmitter  130 , a second force transmitter  170  connected to the first force transmitter  130  by the belt  150  to receive a rotational force of the first force transmitter, and a side brush  190  coupled to the second force transmitter  170 . 
     That is, the rotational force transmitted to the side brush assembly  100  is transferred to the side brush  190  through the first force transmitter  130 , the belt  150 , and the second force transmitter  170 . 
       FIG.  3    is a view illustrating an exploded perspective view in  FIG.  2   , and  FIG.  4    is a view illustrating a cross-section of some of main components in  FIG.  2   . 
     Referring to  FIGS.  3  and  4    below, the housing forming the exterior of the side brush assembly  100  includes an upper housing  112  disposed on an upper side and a lower housing  114  coupled to a lower side of the upper housing  112 . A space may be defined inside by the upper housing  112  and the lower housing  114 , and a plurality of components may be arranged in the space. 
     The first force transmitter  130  is rotatably coupled to the upper housing  112  and the lower housing  114 . The first force transmitter  130  has a first coupling groove  134  defined therein to which the belt  150  is coupled. First coupling ribs  136  for preventing the belt  150  from being removed from the first coupling groove  134  are respectively arranged on a top face and a bottom face of the first coupling groove  134 . The first coupling ribs  136  may be arranged to protrude from a portion where the first coupling groove  134  is recessed to respectively surround upper and lower ends of the belt  150 . Therefore, even when the belt  150  momentarily slips, the belt  150  may be prevented from leaving the first coupling groove  134 . The first coupling ribs  136  are entirely arranged along a circumference of the first coupling groove  134 . 
     The second force transmitter  170  is rotatably coupled to the upper housing  112  and the lower housing  114 . The second force transmitter  170  has a second coupling groove  174  defined therein to which the belt  150  is coupled. Second coupling ribs  176  are respectively arranged on a top face and a bottom face of the second coupling groove  174  to prevent the belt  150  from being removed from the second coupling groove  174 . The second coupling rib  176  may be arranged to protrude from a portion where the second coupling groove  174  is recessed to respectively surround the upper and lower ends of the belt  150 . Therefore, even when the belt  150  momentarily slips, the belt  150  may be prevented from leaving the second coupling groove  174 . The first coupling ribs  136  are entirely arranged along a circumference of the second coupling groove  174 . 
     The belt  150  may be an endless belt. In addition, the endless belt may have a constant vertical dimension. The endless belt may have an O-shaped section constantly. 
     Each of the first coupling groove  134  and the second coupling groove  174  may have a circular shape in which a central portion thereof is more recessed than an outer portion thereof so as to be coupled to the circular cross-section of the belt  150 . In one example, the coupling groove may be defined such that recessed depths of the central portion and the outer portion thereof are the same. 
     Each of the first coupling groove  134  and the second coupling groove  174  has a shape in which a groove is not defined in the middle and has a shape of being recessed along the circumference that is kept constant. That is, the first coupling groove  134  and the second coupling groove  174  are defined to maintain a smooth shape without intermittently protruding portions. Therefore, even when the slip occurs on the belt  150  and locations at which the belt  150  is coupled to the first coupling groove  134  and the second coupling groove  174  are changed, a state in which the belt  150  is coupled to the first coupling groove  134  and the second coupling groove  174  may be maintained. 
     The second force transmitter  170  includes a pulley  172  to which the belt  150  is coupled, and a rotation shaft  180  coupled to a rotation center of the pulley  172 . In this connection, the second coupling groove  174  and the second coupling rib  176  are respectively defined in and formed on the pulley  172 . 
     The rotation shaft  180  is coupled to a central portion of the pulley  172 , so that when the pulley  172  is rotated, the rotation shaft  180  is rotated together. The rotation shaft  180  is formed such that upper and lower sides thereof have a polygonal shape rather than a circular shape. Therefore, because a central through-hole of the pulley  172  is coupled to the upper side of the rotation shaft  180 , the pulley  172  is rotated with the same rotational angular speed as the rotation shaft  180 . The central through-hole of the pulley  172  is defined to have the same polygonal shape as the polygonal shape formed at the upper side of the rotation shaft  180 , so that the pulley  172  may be coupled to the rotation shaft  180  so as not to be idle. 
     The side brush  190  is coupled to the lower side of the rotation shaft  180 . A through-hole is also defined in a center of the side brush  190  and is coupled to a polygonal portion formed at the lower side of the rotation shaft  180 . The through-hole defined in the side brush  190  is also defined in the same polygonal shape as the rotation shaft  180 , so that the side brush  190  and the rotation shaft  180  may be rotated at the same rotational angular speed without idling. 
     The side brush  190  includes a plurality of brushes  194 . The brushes  194  may be distributed to be spaced apart from each other and hit a floor portion where the robot cleaner is moving. The brush  194  is made of a material that may be deformed when a force is applied from the outside. Specifically, because the brush  194  is made of a rubber material, so that a deformation of the brush  194 , such as bending, may occur when the brush  194  hits an obstacle made of a relatively strong material. In addition, when the brush  194  does not hit the obstacle by moving away from the obstacle, the brush  194  may be restored into an original shape, that is, a straight extended shape. 
     The side brush assembly  100  includes a reduction gear  116  for reducing a speed of the rotational force transmitted from the gear box  300 . The rotational force transmitted to the reduction gear  116  is transmitted to the first force transmitter  130  through another gear  117 . The rotational force transmitted from the gear box  300  is transmitted to the first force transmitter  130  through the plurality of gears. Therefore, when a gear of the gear box  300  is rotated, the first force transmitter  130  is always rotated. However, a rotation speed and the like may be changed by a gear ratio. 
     The motor assembly  200  includes a motor that is rotated by receiving current from the battery. As the motor is rotated, the motor assembly  200  may generate he rotational force. 
     The gear box  300  is disposed to engage a rotation shaft of the motor disposed in the motor assembly  200 . The gear box  300  includes a first cover  304  that forms an exterior of the gear box  300  and a second cover  306  coupled to the first cover  304 . When the first cover  304  and the second cover  306  are coupled to each other, a space is defined therebetween, and a plurality of gears  310  and  320  are arranged to be engaged with each other in the corresponding space. The plurality of gears  310  and  320  are rotated based on the rotational force supplied from the motor assembly  200 . Specifically, the gear  310  disposed at one end of the gear box  300  may be coupled to and rotated together with the rotation shaft of the motor disposed in the motor assembly  200 . In addition, a center of the gear  320  disposed at the other end of the gear box  300  is coupled to the reduction gear  116 , so that, as the gear  320  is rotated, the reduction gear  116  may be rotated together. The gear  320  may transmit the rotational force to a rotation shaft of the agitator. Therefore, when the gear  320  is rotated, the rotational force may be simultaneously transmitted to the side brush assembly  100  and the agitator  60 . 
       FIG.  5    is a view illustrating an operation of a side brush assembly. 
     As shown in  FIG.  5   , the rotational force generated in the motor assembly  200  may be transmitted to both the side brush assembly  100  and the agitator  60 . Because the gear box  300  is disposed between the side brush assembly  100  and the agitator  60 , the rotational force of the motor assembly  200  may be simultaneously transmitted to the side brush assembly  100  and the agitator  60 . 
     In one example, the agitator  60  is disposed in a horizontal direction in  FIG.  5   , and the rotation shaft of the agitator  60  is parallel to the direction in which the agitator  60  is disposed. On the other hand, because the rotation shaft of the side brush assembly  100  is in a normal direction of  FIG.  5   , the rotation shaft for rotating the agitator  60  and the rotation shaft of the side brush assembly  100  are arranged perpendicular to each other. In one example, the rotation shaft of the agitator  60  and the rotation shaft of the motor assembly  200  may be arranged parallel to each other. All of the plurality of gears arranged in the gear box  300  may be rotated with rotation shafts in a direction parallel to the direction of the rotation shaft of the agitator  60 . 
     In one example, the side brush assembly  100  may also be disposed on a left side of the agitator  60 , so that the rotational force generated by one motor assembly  200  may be transmitted to the two side brush assemblies  100 . Because the agitator  60  is elongated in the main body  10 , the agitator  60  may perform a function of transmitting the rotational force to the side brush assembly positioned on the opposite side. 
     The rotational force generated by the motor assembly  200  is transmitted to the agitator  60  and the side brush assembly  100  through the gear box  300 . In this connection, because the gear box  300  is coupled to the agitator  60  and the side brush assembly  100  in different forms, a rotation speed may be transmitted differently. In one example, in the side brush assembly  100 , a rotation direction is vertically changed through the reduction gear  116  and the rotation speed may be reduced. The gear  117  coupled with the reduction gear  116  is gear-coupled to the first force transmitter  130 . Therefore, when the reduction gear  116  is rotated, the first force transmitter  130  must be rotated together, and when the rotation of the reduction gear  116  is stopped, the rotation of the first force transmitter  130  must also be stopped. 
     In one example, when the first force transmitter  130  is rotated, as the second force transmitter  170  coupled to the belt  150  is also rotated, the side brush  190  is also rotated to hit the floor or a side face. In this connection, when a relatively large object such as an electric wire is caught on the brush  194 , the brush  194  may be deformed. In addition, a situation in which the rotation of the side brush  190  is slowed or stopped may occur. 
     In this connection, the slip may occur between the belt  150  and the second force transmitter  170 , so that the rotation of the first force transmitter  130  may be continued. For example, when the second force transmitter  170  should be constantly rotated while the first force transmitter  130  is rotated, the side brush  190  should be rotated constantly even when the side brush  190  hits any obstacle. When the side brush  190  is continuously rotated even while twisting occurs by the object such as the electric wire, damage may occur to the robot cleaner as well as the side brush  190 . Therefore, in the present embodiment, because a situation in which, even though the rotational force is continuously transmitted from the first force transmitter  130 , the second force transmitter  170  does not rotate constantly based on the rotational force of the first force transmitter  130  may occur, the side brush may be prevented from being damaged. In the present embodiment, disclosed is a structure in which a rotation angular speed of the first force transmitter and a rotation angular speed of the second force transmitter may be different when the slip occurs between the belt  150  and the first force transmitter  130  or the second force transmitter  170 . 
     In one example, when the brush  194  is out of a moment of hitting the obstacle, the brush  194  may rotate by the rotational force transmitted from the first force transmitter  130  again by the rotational force by the belt  150 . 
     The present disclosure is not limited to the above-described embodiments. As may be seen from the appended claims, the present disclosure is able to be modified by those of ordinary skill in the field to which the present disclosure belongs, and such modifications are within the scope of the present disclosure.