Patent Publication Number: US-2007113373-A1

Title: Vacuum cleaner

Description:
TECHNICAL FIELD OF THE INVENTION  
      The present invention relates to a vacuum cleaner that performs cleaning while running automatically.  
     BACKGROUND ART  
      As a technique for cleaning the corners of wall surfaces in the conventional vacuum cleaner, Japanese Patent Laid-Open No. 2004-350713 has disclosed a self-propelled vacuum cleaner in which a suction port body is provided so as to be movable in the transverse direction with respect to the advancing direction to clean a corner portion using the suction port body projecting from a cleaner body.  
      Also, Japanese Patent Laid-Open No. 2005-6857 has disclosed a vacuum cleaner in which a corner brush that can project and retract from a main suction port toward the direction crossing the running direction of cleaner body is provided, and the corner brush is provided with a corner suction port for sucking dust and dirt on the floor surface. In this vacuum cleaner, the main suction port sucks dust and dirt on the floor surface and the corner suction port sucks dust and dirt on the floor surface at the side of an obstacle, by which the floor surface can be cleaned surely. Also, even if the corner brush comes into contact with the obstacle, the corner brush retracts toward the rear of the cleaner body, so that the obstacle etc. can be prevented from being damaged. Problems to be Solved by the Invention  
      However, the self-propelled vacuum cleaner described in Japanese Patent Laid-Open No. 2004-350713 has a disadvantage that since the suction port body is moved in the transverse direction when a corner portion is cleaned, a part of the floor surface under the cleaner body cannot be cleaned at the time of corner cleaning, so that the surface to be cleaned cannot be cleaned surely.  
      Also, in the vacuum cleaner described in Japanese Patent Laid-Open No. 2005-6857, the corner brush is provided so as to be capable of projecting and retracting with respect to the cleaner body by being turnably supported on the cleaner body. In the projecting and retracting operation, a driving means such as a motor for reeling is necessary, which presents a disadvantage of high cost. Also, since a suction path from the corner brush is provided separately from a suction path from the main suction port, a space required for the suction path increases, which presents a disadvantage of a large equipment size.  
      The present invention has been made in view of the above circumstances, and accordingly an object thereof is to provide a compact vacuum cleaner capable of easily cleaning a portion near a wall or at a corner.  
     SUMMARY OF THE INVENTION  
      To achieve the above-object, in the present invention, a suction port body having a suction port is provided on the front side of a cleaner body, and an expanding means for expanding the suction port body toward the side is provided. Accordingly, the suction port body itself is not moved, and a part of the suction port body is expanded to the side by using the expanding means. By this expansion, the region capable of being cleaned by the suction port body is widened to the side of wall, so that the side of wall can be cleaned.  
      The suction port body has a rotating brush, and the suction port communicating with a dust collection section is formed on a wall surface of a dust suction chamber of the suction port body accommodating the rotating brush. Therefore, the expanding means is configured so that a part of the suction port body is projected from the cleaner body to expand the dust suction chamber to the side. That is to say, a case or a cover of the suction port body constituting the dust suction chamber is made expandable and contractible to the side. The case or the cover is a member constituting a part of the suction port body. When the side of wall is cleaned, the dust suction chamber is expanded by extending this member. At the time of ordinary cleaning such that a central portion of a room is cleaned, this member is contracted, and is not projected from the cleaner body. Therefore, this member does not collide with an obstacle, and therefore does not hinder the running of the cleaner body.  
      A suction port variable means is provided to displace the suction port in the projecting direction in association with the expansion of the suction port body. The suction port variable means displaces the suction port by widening the suction port or by shifting the position thereof. When apart of the suction port body projects to one direction, the suction port is also displaced in one direction, and the suction port comes close to the expanded region. Thereby, a sufficient suction force can be obtained in the expanded region.  
      An obstacle detector is provided to detect an obstacle located at the front and at the side of the cleaner body so that the vacuum cleaner approaching the side of wall or a corner of room can be detected. At the time of this detection, the expanding means projects a part of the suction port body from the cleaner body. Also, when the vacuum cleaner goes away from the side of wall or when cleaning at the side of wall is finished, the expansion means retracts apart of the suction port body into the cleaner body. Therefore, the suction port body does not hinder the running of the cleaner body. The finish of cleaning of the side of wall is judged from a change of running of cleaner body from advance to retreat or from advance to turning.  
      Also, as the expanding means, side suction ports extending from the suction port body toward the side are provided, by which the region capable of being cleaned by the suction port body can be expanded to the side of wall. That is to say, in the present invention, a semicylindrical space which is open to the floor surface and the cylinder center axis of which is directed in the right and left direction is formed, and this space is used as the dust suction chamber. In the front wall surface of the dust suction chamber, a main suction port is formed to suck dust and dirt from the floor surface together with air. Also, the side suction ports are communicatingly formed in both end portions at the right and the left of the dust suction chamber. When the floor at the side of wall or at a corner of room is cleaned, the side suction port is used. At this time, the side suction ports are also communicatingly formed in the right and left end portions of the dust suction chamber. Therefore, a suction system for sucking dust and dirt from the main suction port and a suction system for sucking dust and dirt from the side suction ports join to each other, so that the suction system can be simplified.  
      If the side suction port is formed of a flexible material, even if the side suction port collides with the wall, the wall surface is not damaged. Also, since the side suction port projects to the side from the overall width of the cleaner body, when the vacuum cleaner runs at a corner of room or at the side of wall, dust and dirt at the side can easily be sucked for cleaning. At this time, even in the case where the side suction port collides with the wall, the wall surface is not damaged because the side suction port is formed of a flexible material.  
      In the dust suction chamber, the side suction port is communicatingly formed at the side, and the rotating brush is supported by bearing portions, so that fine dust and dirt having been sucked through the side suction port may intrude into the bearing portion. Therefore, the bearing portions at both ends of the rotating brush each are covered by a dust-proof cover to prevent the dust and dirt having been sucked through the side suction port from intruding into the bearing portion.  
      In the case where a bumper is provided so as to cover the front and the side of the cleaner body, and the bumper is attached to the cleaner body so as to be movable in the front and rear direction and in the right and left direction, the configuration can be made such that the side suction port is provided on the same surface as the side surface of the bumper and is moved in association with the movement in the right and left direction of the bumper. According to this configuration, even if the bumper collides with the wall surface and moves to the inside in the right and left direction, the side suction port follows, and therefore the side suction port is prevented from being left alone and damaging the wall surface.  
      As described above, according to the present invention, a part of the suction port body is projected from the cleaner body to expand the region capable of being cleaned, whereby the side of wall, furniture, or the like can be cleaned. Since only a part of the suction port body has to be moved, a moving mechanism can be made simple as compared with the case where the whole of the suction port body is moved. Also, a space necessary for moving the suction port body is not needed, and the size of the cleaner body can be reduced.  
      Also, since the side suction ports are communicatingly formed in both end portions at the right and the left of the suction port body, dust and dirt at the side of wall or at a corner of room can be sucked for cleaning through the side suction port. At this time, the side suction ports are also communicatingly formed in the right and left end portions of the dust suction chamber. Therefore, the suction system for sucking dust and dirt from the main suction port and the suction system for sucking dust and dirt from the side suction ports join to each other, so that the suction system can be simplified. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a perspective view of a self-propelled vacuum cleaner in accordance with a first embodiment of the present invention;  
       FIG. 2  is a plan view of the self-propelled vacuum cleaner;  
       FIG. 3  is a side sectional view of the self-propelled vacuum cleaner;  
       FIG. 4  shows a suction port body,  FIG. 4 (A) being a side sectional view at the time when an opening/closing body is in an open posture, and  FIG. 4 (B) being a side sectional view at the time when an opening/closing body is in a closed posture;  
       FIG. 5  is a plan view of a vacuum cleaner at the time when a portion near a wall is cleaned;  
       FIG. 6  is views schematically showing the construction of an expanding means of a suction port body,  FIG. 6 (A) showing an ordinary state of the suction port body,  FIG. 6 (B) showing a state in which the suction port body is expanded in the right direction, and  FIG. 6 (C) showing a state in which the suction port body is expanded in the left direction;  
       FIG. 7  is a plan view of a suction port body,  FIG. 7 (A) showing an ordinary state of the suction port body,  FIG. 7 (B) showing a state in which the suction port body is expanded in the right direction, and  FIG. 7 (C) showing a state in which the suction port body is expanded in the left direction;  
       FIG. 8  is a view showing the interior of a suction port body at the time when the suction port body is expanded in the right direction;  
       FIG. 9  is a perspective view of a self-propelled vacuum cleaner in accordance with a second embodiment of the present invention;  
       FIG. 10  is a perspective view of a suction port body;  
       FIG. 11  is a front sectional view of the suction port body shown in  FIG. 10 ; and  
       FIG. 12  is a front sectional view of a suction port body, showing a modification of the second embodiment. 
    
    
     PREFERRED EMBODIMENT OF THE INVENTION  
     First Embodiment  
      FIGS.  1  to  8  show a first embodiment of the present invention. An embodiment of a vacuum cleaner in accordance with the present invention will be explained by taking a self-propelled vacuum cleaner, which moves in a self-standing manner in a surrounded space in which obstacles such as room walls, furniture, and beds are present, as an example.  
      As shown in FIGS.  1  to  3 , this vacuum cleaner includes a cleaner body  1 , a suction port body  2  for sucking dust and dirt on the floor surface, a bumper  3  disposed on the front side of the cleaner body  1 , a dust collector  4  serving as a dust collecting section mounted detachably on the cleaner body  1 , and a steering means for controlling a running means running on the floor surface and the running direction.  
      In the cleaner body  1 , a semicylindrical accommodation concave portion  7  is formed on the upper surface of an oval casing, and a capsule-form dust collector  4  is mounted detachably in the accommodation concave portion  7 . In the accommodation concave portion  7 , an introduction port  8  is formed to introduce dust and dirt sucked together with air from the suction port body  2  to the dust collector side, and also an exhaust port  10  is formed to exhaust the air coming from the dust collector  4  to a motor-driven blower  9  at the rear part of the casing. The dust collector  4  is connected to the introduction port  8  on the upstream side in the air flow direction, and is connected to the exhaust port  10  on the downstream side.  
      The dust collector  4  is housed detachably in the accommodation concave portion  7  formed on the upper surface of the cleaner body  1 . The dust collector  4  is of a cyclone type. Intake air containing dust and dirt that is sucked from the suction port body  2  into a dust collection chamber  4   a  swirls in the dust collection chamber  4   a . Dust and dirt is separated from air by a filter of an exhaust cylinder  4   b . The dust and dirt are accumulated in the dust collection chamber  4   a . The air sucked is exhausted to the outside of the dust collection chamber  4   a.    
      The bumper  3  is attached so as to be moved in the front and rear direction and the right and left direction by a spring (not shown) to ease a shock produced when the front portion of the cleaner body  1  collides with an obstacle, a wall surface, or the like. Thus, the cleaner body  1  including the bumper  3  takes a rectangular front-side shape. The suction port body  2  is disposed on the front side of the cleaner body  1 . The cleaner body  1  can approach the side of a wall, the side of furniture, and the corner of room to facilitate the cleaning of these places.  
      Also, under the accommodation concave portion  7 , there is provided a control section  12  provided with a control circuit board etc. for controlling driving wheels  11  for running the cleaner body  1  and the motor-driven blower  9 . On the front surface and the side surface of the bumper  3 , obstacle detecting sensors  13  are provided to detect an obstacle in the surroundings. Also, on the front side of the dust collector  4  as well, an obstacle detecting sensor  13  is disposed. The obstacle detecting sensor  13  is a reflective type optical sensor or an ultrasonic sensor, and detects the presence of an obstacle in a noncontact manner.  
      A running means for running the cleaner body  1  consists of the driving wheels  11  and motors for turning the driving wheels. The right and left driving wheels  11  turn independently. The motor for each of the driving wheels  11  is controlled by the control section  12 . Therefore, the driving wheels  11  and the control section  12  constitute the steering means for controlling the running direction. The control section  12  controls the driving of the motors while detecting an obstacle at the front and at the side based on a detection signal sent from the obstacle detecting sensor  13 . Therefore, the cleaner body  1  can run straight and turn while keeping away from obstacles. Also, the cleaner body  1  can move along the side of wall.  
      Next, the suction port body  2  is explained. As shown in  FIGS. 3 and 4 , the suction port body  2 , which has a cleaning means for cleaning the floor surface, is disposed in a concave portion  14  formed on the front bottom surface of the cleaner body  1 , and the rear end portion thereof is supported on the cleaner body  1  so as to be swayable around a vertical shaft  15  (refer to  FIG. 10 ). Also, in the rear end portion of the suction port body  2 , shock absorbers  16  (refer to  FIG. 10 ) are provided on both sides, right and left, with the vertical shaft  15  being held there between to ease a shock when the suction port body  2  comes into contact with a rear surface  14   a  of the concave portion  14 . Thereby, the suction port body  2  can sway around the vertical shaft  15  with respect to the cleaner body  1  in the sway range of about 30 degrees. Therefore, the cleaner body  1  can run straight while keeping its balance in the right and left direction.  
      As shown in  FIG. 4 , the suction port body  2  is formed with a suction flow path  17  enclosed by a lower case  2   b  and an upper case  2   a . The front bottom surface of the lower case  2   b  is concaved, and a space having a semicircular cross section is used as a dust suction chamber  18 . In the dust suction chamber  18 , a rotating brush  19 , which serves as the cleaning means, is housed so as to be rotatable around a horizontal shaft  19   a . In the front wall surface of the dust suction chamber  18 , a main suction port  20  is formed to suck dust and dirt from the floor surface together with air. The main suction port  20  is located in the center in the right and left direction of the front wall surface.  
      The rotating brush  19 , in which bristles are arranged in a spiral form on the circumferential surface, is driven by a motor and a belt (neither is shown) provided on the suction port body  2 . The motor may be disposed on the cleaner body side near the vertical shaft  15 , which is the turning center of the suction port body  2 , to drive the rotating brush  19  by transmitting the power on the cleaner body side with a belt. The driving of the rotating brush  19  is controlled so that the direction of rotation thereof is reverse to the advancing direction of the driving wheels  11 . Therefore, the rotating brush  19  strikes the floor surface to cause dust and dirt to float, and the floating dust and dirt are guided to the center side in the right and left direction.  
      Also, a partitioning wall is formed at the central position in the right and left direction of the dust suction chamber  18 , and the main suction port  20  is formed near the partitioning wall. The dust and dirt conveyed to the center side by the rotating brush  19  is sucked into the suction flow path l 7  through the main suction port  20 .  
      The main suction port  20  is formed in the tangential direction on the front upper side of the dust suction chamber  18 , and communicates with the suction flow path  17 . In the dust suction chamber  18 , therefore, a swirl flow is generated by the rotation of the rotating brush  10  so that the dust sucking capability is enhanced along with the suction flow in the tangential direction acting on the main suction port  20  due to the driving of the motor-driven blower  9 .  
      Further, on the front side of the main suction port  20 , a front suction port  22  is formed which is open in the floor surface and communicates with the suction flowpath  17  so that the dust and dirt at the side of a front wall can be sucked. The downstream side of the suction flow path  17  communicates with the introduction port  8  in the accommodation concave portion  7  through a flexible elbow tube  23 . The elbow tube  23  is located on one side in the right and left direction.  
      The dust and dirt having been sucked through the main suction port  20  and the front suction port  22  are introduced together with air from the elbow tube  23  into the dust collector  4  through the introduction port  8  after passing through the suction flow path  17 . The dust and dirt having flown into the dust collector  4  are separated from the air by the swirl flow in the dust collection chamber  4   a , and the dust and dirt are collected in the dust collection chamber  4   a . The air is exhausted to the outside of the chamber by the motor-driven blower  9  after passing through the exhaust cylinder  4   b  and the exhaust port  10 .  
      The front suction port  22  is open in almost the overall width in the right and left direction at the front end of the suction port body  2 , and an opening/closing body  27  for opening and closing the front suction port  22  is provided. As shown in  FIG. 4 , the opening/closing body  27  is formed by a plate-shaped member supported on the suction port body  2  so as to be turnably opened/closed around a horizontal shaft  28 . At the lower end of the opening/closing body  27 , an auxiliary wheel  29  is provided so as to be turnable around a horizontal shaft. The auxiliary wheel  29  rotates in contact with the floor surface and closes the front suction port  22  when the opening/closing body  27  is in a closing posture, and leaves from the floor surface and opens the front suction port  22  when the opening/closing body  27  is in an opening posture. The opening/closing body  27  with the auxiliary wheel  29  makes it possible for the cleaner body  1  to run while going up onto a height difference of floor surface smoothly. Moreover, the auxiliary wheel  29  is utilized as a closing means of the front suction port  22 , so that the number of parts can be reduced.  
      Also, on the front surface of the opening/closing body  27 , a protrusion  30  that comes into contact with the bumper  3  when the bumper  3  retracts is formed in the right and left direction. If the protrusion  30  comes into contact with the bumper  3 , the opening/closing body  27  turns around the horizontal shaft  28  to open the front suction port  22 . Also, the front end surface of the opening/closing body  27  is formed with an inclined surface  31  inclined downward from the front end toward the rear end so that the cleaner body  1  can easily get over a height difference of floor surface.  
      The suction port body  2  is configured so as to be capable of expanding in the right and left direction. Specifically, as shown in  FIG. 5 , a part of the suction port body  2  projects from the cleaner body  1  to either one side in the right and left direction. Thereby, the suction port body  2  is expanded to the side from the cleaner body  1 , so that the suction port body  2  can be brought close to the side of wall or furniture.  
      As an expanding means for expanding the suction port body  2  toward the side, as shown in  FIG. 6 , covers  40  and  41  covering the suction port main body, which consists of the upper case  2   a  and the lower case  2   b  of the suction port body  2 , are provided so as to be movable in the right and left direction, and a moving section  42  for moving the covers  40  and  41  is provided. It is to be noted that the right and left are directions at the time when the cleaner body  1  is viewed from the front side.  
      As shown in  FIG. 7 , the covers  40  and  41  are separated from each other to form the left cover  40  and the right cover  41 . The covers  40  and  41  are supported on the suction port main body so as to be slidable in the right and left direction, and constitutes a part of the suction port body  2 . The covers  40  and  41  cover a portion ranging from the upper surface of the upper case  2   a  to the front surface, the side surface, and the rear surface of the lower case  2   b . Between the covers  40  and  41  and the side surface of the suction port body  2 , a clearance is provided to allow the covers  40  and  41  to move. The lower ends of the covers  40  and  41  are located at a position higher than the floor surface. Also, the upper surfaces of the covers  40  and  41  are located at a position lower than the lower end of the bumper  3  so that the covers  40  and  41  can move in a clearance between the bumper  3  and the floor surface. The left cover  40  is formed with an elongated hole  43  for inserting the elbow tube  23  therethrough. The left cover  40  can be moved in the right and left direction without being hindered by the elbow tube  23 .  
      The moving section  42  consists of a cam  44 , a motor (not shown), and a spring  45 . The egg-shaped cam  44  is disposed between the left cover  40  and the right cover  41 , and is always in contact with the covers  40  and  41 . A rotating shaft  46  of the cam  44  is rotatably supported on the upper case  2   a , and is rotated by the motor. When the cam  44  is rotated, the covers  40  and  41  move in the same direction in association with each other according to the shape of the cam  44 . The motor is controlled by the control section  12 . When the cleaner body  1  approaches the side of wall or furniture, the control section  12  moves the covers  40  and  41  in the direction such that the covers  40  and  41  are brought close to the side of wall etc.  
      Between the covers  40  and  41 , a pair of right and left springs  45  are provided. One end of each of the springs  45  is attached to the cover  40  or  41 , and the other end thereof is attached to a pillar  47  erected on the upper case  2   a . The covers  40  and  41  are urged by the springs  45  so as to come to the center. The rotating shaft  46  and the pillars  47  are located on the centerline CL perpendicular to the right and left direction. This center line CL is in variable with respect to the cleaner body  1  and the suction port body  2 .  
      Also, a suction port variable means is provided to displace the main suction port  20  in the right and left direction in association with the expansion of the suction port body  2 . As shown in  FIGS. 6 and 8 , a pair of right and left shutters  50  and  51  are provided in the main suction port  20  of the suction port body  2 . Each of the shutters  50  and  51  is movably supported on the inside of the lower case  2   b , and is moved in the same direction by a motor or a solenoid. These elements constitute the suction port variable means. The clearance between the shutters  50  and  51  is set so as to be always constant. Even if the shutters So and  51  move, the opening area of the main suction port  20  is unchanged; however, the position of the main suction port  20  shifts to the right or the left.  
      The driving of the shutters  50  and  51  is controlled by the control section  12  so that the shutters  50  and  51  move in the same direction in association with the covers  40  and  41 . The covers  40  and  41  and the shutters  50  and  51  move in either of the right direction and the left direction with the centerline CL being the reference.  
      In the case where the side of wall or the side of furniture is cleaned using the above-described vacuum cleaner, when the cleaner body  1  runs, for example, along the side of wall etc. on the right hand side and approaches the wall etc., the wall etc. are detected by the obstacle detecting sensor  13  at the side. Then, the control section  12  moves the covers  40  and  41  and the shutters  50  and  51  in the right direction. As shown in FIGS.  6 (B) and  7 (B), the cam  44  rotates, and the right cover  41  is moved in the right direction by being pushed by the cam  44 . The left cover  40  is moved in the right direction by being pulled by the springs  45 . At the same time, the shutters  50  and  51  move in the right direction.  
      The right cover  41  is located on the outside of the bumper  3 , and projects from the cleaner body  1 . In other words, a part of the suction port main body expands to the side. If the right cover  41  shifts in the right direction with respect to the suction port body  2  in this manner, the right cover  41  is located closer to the wall etc. than the cleaner body  1 . An expansion space A covered by the right cover  41  is formed on the right-hand side of the suction port main body, and therefore the region capable of being cleaned is expanded to the side. Dust and dirt on the floor surface facing to this expansion space A is sucked from the main suction port  20  together with air. Since the main suction port  20  is displaced in the right direction and approaches the expansion space A, even if a part of the suction port body  2  is expanded, a sufficient suction force can be obtained. Therefore, the side of wall etc. can be cleaned automatically without bringing the cleaner body  1  close to the side of wall etc.  
      Inversely, when the cleaner body  1  approaches the side of wall etc. on the left-hand side, as shown in FIGS.  6 (C) and  7 (C), the left cover  40  is moved in the left direction by being pushed by the cam  44  in the same way. The right cover  41  is moved in the left direction by being pulled by the springs  45 . At the same time, the shutters  50  and  51  move in the left direction. An expansion space A covered by the left cover  40  is formed on the left-hand side of the suction port main body, and the main suction port  20  is also displaced in the left direction. Thereby, dust and dirt on the floor surface facing to this expansion space A is sucked, so that the side of wall etc. can be cleaned.  
      If a part of the suction port body  2  is expanded in either of the right direction and the left direction, the region capable of being cleaned while the cleaner body  1  advances can be shifted in the right or left direction, so that the side of wall etc. can be cleaned easily.  
      When the cleaner body  1  approaches the side of wall etc., the wall etc. are detected by the obstacle detecting sensor  13 . The distance from the cleaner body  1  to the wall at the time of detection is set so as to be larger than the length of projection of the cover  40 ,  41  from the bumper  3 , so that the cover  40 ,  41  can be prevented from colliding with the wall at the time of projection. Also, if the obstacle detecting sensor  13  is used as a distance measuring sensor, the distance to the wall can be found. Therefore, the control section  12  controls the rotation of the cam  44  according to the distance to the wall, thus controlling the moving distances of the covers  40  and  41  and the shutters  50  and  51 . When the cleaner body  1  approaches the wall, the moving distances of the covers  40  and  41  are decreased. By doing this, too, the covers  40  and  41  can be prevented from colliding with the wall.  
      When the vacuum cleaner advances, the front suction port  22  is closed by the opening/closing body  27 . At this time, the dust and dirt struck by the rotating brush  19  float, being sucked through the main suction port  20  together with air, and are introduced into the dust collector  4 . The dust and dirt are collected in the dust collection chamber  4   a.    
      When the bumper  3  collides with a wall etc., the bumper  3  retracts and comes into contact with the protrusion  30  of the opening/closing body  27 , by which the opening/closing body  27  is turned upward around the horizontal shaft  28 . Then, the auxiliary wheel  29  that has closed the front suction port  22  is turned upward to open the front suction port  22 .  
      If the blower  9  and the rotating brush  19  are driven in this state, the dust and dirt are introduced to the central portion by a swirl flow generated by the rotating brush  19 , and are sucked through the main suction port  20 . The dust and dirt at the side of wall are also sucked through the front suction port  22 .  
      When the vacuum cleaner goes away from the side of wall, the external force is removed from the bumper  3 . Therefore, the bumper  3  is restored to the original front position by a spring, not shown, and accordingly, the opening/closing body  27  is also turned in the closed direction by the gravity or a spring, not shown. The auxiliary wheel  29  closes the front suction port  22 .  
      Since dust and dirt can be sucked together with air through the front suction port  22  located at the front of the main suction port  20 , even in the case where the cleaner body  1  collides with a wall etc. and cannot advance further, the dust and dirt at the side of wall can be sucked easily through the front suction port  22 , so that the cleaning efficiency can be enhanced. Also, since the front suction port  22  is provided with the opening/closing body  27 , when the central portion of the room is cleaned, the front suction port  22  is closed, by which the suction capability of the main suction port  20  can be enhanced.  
      When the vacuum cleaner approaches a wall or furniture while advancing along the side of wall etc., the obstacle detecting sensor  13  on the front surface detects the wall etc. During this advance, either one of the covers  40  and  41  is in a projecting state. The cleaning body  1  has a possibility of turning when approaching the wall etc. at the front. Therefore, the control section  12  carries out control so that when the obstacle detecting sensors  13  on the front surface and the side surface detect a wall etc., the projecting cover  40 ,  41  is retracted. The shutters  50  and  51  return to the original positions in association with the retraction of the cover  40 ,  41 . Therefore, when the cleaner body  1  turns, the covers  40  and  41  are in a state of being housed in the cleaner body  1 , and hence do not hinder the turning motion.  
      Also, when the vacuum cleaner advances along the side of wall and approaches a wall etc. at the front, the cleaning of the side of wall etc. finishes. When the vacuum cleaner retreats without turning, if the front obstacle detecting sensor  13  detects that the cleaner body  1  is moving away from the front wall, the control section  12  carries out control so that the cover  40 ,  41  and the shutter  50 ,  51  are returned to the original position even if the side obstacle detecting sensor  13  detects a side wall etc. Therefore, when the cleaner body  1  retreats, the cover  40 ,  41  does not project, and hence does not hinder the travel of the cleaner body  1 .  
      By projecting and retracting a part of the suction port body  2  from the cleaner body  1  as described above, the mechanism of the moving section  42  can be simplified, and also a large space is not needed. Thereby, the construction can be made such that the rectangular suction port body  2  is provided on the front side of the cleaner body  1  formed into a square shape. Usually, the suction port body  2  lies in the cleaner body  1  and does not project to the outside, and hence does not become a hindrance when the cleaner body  1  runs.  
      As shown in  FIGS. 3 and 4 , the configuration may be such that side suction ports  34  are provided on both sides, right and left, of the suction port main body, and each of the side suction ports  34  is formed by an L-shaped nozzle made of rubber etc. to suck dust and dirt at the side. Even if the side suction ports  34  are provided, the cover can be provided so as to cover the side suction port  34 .  
      Also, the rotating brush may be made movable in the right and left direction by a motor or a solenoid, or may be made capable of being expanded or contracted in the right and left direction. Also, the suction capability at the side of wall etc. can be enhanced by moving or expanding the rotating brush in either direction of right and left in association with the cover and the shutter.  
      Also, the covers may be moved independently instead of being moved in association with each other. A driving section such as a motor is provided for each of the covers so that only the cover on the wall side is projected when the cleaner body approaches the side of wall etc. Also, the cover is not divided into two, and one cover for covering the whole of the suction port body may be provided. One cover is moved in the right and left direction. Alternatively, the lower case that forms the dust collection chamber may be made capable of being expanded or contracted, and a cover movable in the right and left direction is attached to the lower case. This cover is projected to the outside of the bumper to expand the dust collection chamber.  
      As the driving section of the cover, a link mechanism or a rack-and-pinion mechanism may be used in place of the cam. In this case, the moving distance of the cover is controlled according to the distance to the wall etc. to prevent the cover from colliding with the wall etc.  
     Second Embodiment  
      FIGS.  9  to  11  show a second embodiment of the present invention. In this embodiment, as the expanding means, the side suction ports  34  extending from the suction port main body toward the side are provided to expand the region capable of being cleaned by the suction port  34  to the side of wall.  
      The suction port body  2  is provided with the side suction ports  34  on both sides, right and left, of the dust suction chamber  18 . Each of the side suction ports  34  is made of a flexible material such as rubber, and is formed by an L-shaped tubular nozzle whose lower surface is open. A proximal end portion  34   a  of the side suction port  34  is formed into a bellows shape so as to be deformed and absorb a shock even when the cleaner body  1  collides with a wall surface at the time of cleaning. The side suction ports  34  are communicatingly connected to both end portions at the right and left of the dust suction chamber  18 , and a suction path through which dust and dirt flow into the suction flow path l 7  after passing through the main suction port  20  in the center of the dust suction chamber  18  is formed.  
      The both end portions at the right and left of the dust suction chamber  18  are bearing portions of the rotating brush  19 . The bearing portion is covered by a dust-proof cover  39  to prevent the dust and dirt having been sucked through the side suction port  34  from intruding into the bearing portion. The dust-proof cover  39 , which is also used as a bearing, has a tubular construction whose outer end side is closed, and the shaft  19   a  of the rotating brush  19  is supported in the dust-proof cover  39  so as to be fitted therein.  
      Communicating portions at both ends, right and left, of the side suction port  34  and the dust suction chamber  18  are provided so that the opening area is smaller than that of other portions and hence so that the flow rate is high because the bearing portion of the rotating brush  19  is present. Therefore, the dust and dirt having been sucked through the side suction port  34  pass through the dust suction chamber  18  and are sucked to a suction path  25  through the main suction port  20  efficiently.  
      Also, the side suction port  34  is projected to the side from the side surface of the cleaner body  1 , and is projected to the side to the same degree as the transverse width of the bumper  3  or slightly to easily remove dust and dirt at the side of wall etc. Since the side suction port  34  is formed of a flexible material such as rubber, even if the side suction port  34  is projected to the side from the bumper  3 , the vacuum cleaner can run while the side suction port  34  is deflected.  
      Thus, the suction path  25  for separating and collecting the dust and dirt having been sucked through the main suction port  20  together with air follows the above-described path. Also, for the suction flow path  17  of the suction port body  2 , the front suction port  22  forms a path  17   c  having an arcuate shape, in the side view, toward the rear, and a rear flow path  17   d  is formed so as to be open to the main suction port  20  in an intermediate portion and widen in the right and left direction on the rear end side. The flexible elbow tube  23  is connected to the end portion of the rear flow path  17   d . The elbow tube  23  forming a part of the suction path  17  is formed of a flexible rubber elastic material, and apart thereof is formed into a bellows shape, so that even when the suction port body  2  turns around the vertical shaft  15 , the path of the suction path  17  can be secured.  
      The running means for running the cleaner body  1  includes the driving wheels  11  and the auxiliary wheel  29 . The driving wheels  11  rotate independently, and are configured so as to make straight running and turning possible by controlling each of the driving wheels  11 . Therefore, the driving wheels  11  and the control section  12  for controlling the driving wheels  11  constitute the steering means for controlling the running direction.  
      According to the above-described configuration, when the vacuum cleaner runs along the side of wall, dust and dirt at the side of wall can be sucked for cleaning by the side suction port  34 . At this time, since the side suction ports  34  are communicatingly formed in the right and left end portions of the dust suction chamber  18 , a suction system for sucking dust and dirt from the main suction port  20  and a suction system for sucking dust and dirt from the side suction ports  34  join to each other. Since the suction system is simplified, a suction system that is compact as a whole can be formed.  
      Also, the side suction port  34  can be projected to the side from the overall width of the cleaner body  1 . If the side suction port  34  is projected to the side from the cleaner body  1 , dust and dirt at the side of wall can easily be sucked for cleaning when the vacuum cleaner runs along the side of wall. At this time, in the case where the side suction port  34  collides with a wall, the wall surface is not damaged because the side suction port  34  is made of a flexible material.  
      The dust and dirt having been sucked through the side suction port  34  are sucked to the dust suction chamber  18  side. At this time, since the rotating brush  19  is provided with the dust-proof cover  39 , even if fine dust and dirt are going to intrude into the bearing portion of the rotating brush  19  through the side suction port  34 , the intrusion of fine dust and dirt can be prevented by the dust-proof cover  39 .  
       FIG. 12  shows a modification of the second embodiment. In this modification, the side suction port  34  is disposed on the same surface as the side surface of the bumper  3 , and is connected by an interlock mechanism  60  so as to move in association with the movement in the right and left direction of the bumper  3 .  
      The bumper  3  is attached to the cleaner body  1  so as to be movable in the front and rear direction and the right and left direction, and is urged to the outside by a spring  61 . The interlock mechanism  60  has a connecting body  62  for connecting the bumper  3  to the side suction port  34 . The side suction port  34  can be formed of a flexible material as in the case of the above-described embodiments. However, in the case where the bumper  3  and the side suction port  34  are connected to each other by the connecting body  62 , the flexibility is unnecessary.  
      In the above-described configuration, since the side suction port  34  disposed on the same surface as the side surface of the bumper  3  moves in association with the movement in the right and left direction of the bumper  3 , even if the bumper  3  collides with a wall surface and moves to the inside in the right and left direction, the side suction port  34  follows in association with the movement of the bumper  3  by means of the connecting body  62 . Therefore, the side suction port  34  is prevented from being left alone and damaging the wall surface.  
      In the above-described embodiments, an example in which the main suction port, the front suction port, and the side suction ports are provided in the suction port body has been explained. However, the suction port body may be configured so that the front suction port is not formed. Also, in the above-described embodiments, explanation has been given by taking a self-propelled vacuum cleaner as an example. However, the present invention can be applied to a manually-operated vacuum cleaner.