Patent Publication Number: US-2022220700-A1

Title: Work vehicle

Description:
TECHNICAL FIELD 
     The present disclosure relates to a work vehicle. 
     BACKGROUND ART 
     For example, Japanese Patent Laying-Open No. 2010-95999 (PTL 1) discloses a hydraulic excavator including a revolving frame and a cab provided on the revolving frame and delimiting an operator&#39;s cab. 
     CITATION LIST 
     Patent Literature 
     PTL 1: Japanese Patent Laying-Open No. 2010-95999 
     SUMMARY OF INVENTION 
     Technical Problem 
     Since the hydraulic excavator disclosed in PTL 1 above may in some cases perform operations on a rough terrain or an inclined terrain, it is expected that the hydraulic excavator may fall down in such an area due to erroneous operation by an operator. When the hydraulic excavator falls down and excessive external force is applied to the cab, the cab may become deformed, which may cause restrictions on a living space for the operator. 
     Accordingly, an object of the present disclosure is to provide a work vehicle in which a cab is not excessively deformed when excessive external force is applied to the cab. 
     Solution to Problem 
     A work vehicle according to the present disclosure includes: a revolving frame; and a cab. The cab is provided on the revolving frame. The cab includes: a floor member; a support base; a first pillar member; and a reinforcing member. The floor member faces the revolving frame in an up-down direction, with a gap therebetween. 
     The support base is provided on the floor member. The support base supports an operator&#39;s seat. The first pillar member extends in the up-down direction. The first pillar member is connected to one end of the floor member in a left-right direction. The reinforcing member is provided on the floor member. The reinforcing member is connected to the first pillar member and the support base. The work vehicle further includes a restriction member. The restriction member is provided in the gap. The restriction member protrudes from one of the revolving frame and the floor member toward the other of the revolving frame and the floor member. The restriction member has a protrusion length shorter than a length of the gap in the up-down direction. The restriction member is provided below the support base or the reinforcing member. 
     Advantageous Effects of Invention 
     According to the present disclosure, there can be provided a work vehicle in which a cab is not excessively deformed when excessive external force is applied to the cab. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view showing a hydraulic excavator according to the present embodiment. 
         FIG. 2  is a perspective view showing a cab and a revolving frame. 
         FIG. 3  is a perspective view showing the revolving frame. 
         FIG. 4  is a perspective view showing the cab. 
         FIG. 5  is another perspective view showing the cab. 
         FIG. 6  is a cross-sectional view partially showing the hydraulic excavator when seen in a direction indicated by an arrow line VI-VI in  FIG. 2 . 
         FIG. 7  is a perspective view partially showing the interior of the cab in  FIG. 4 . 
         FIG. 8  is another perspective view partially showing the interior of the cab in  FIG. 4 . 
         FIG. 9  is a perspective view showing a support base in  FIGS. 7 and 8 . 
         FIG. 10  is another perspective view showing the support base in  FIGS. 7 and 8 . 
         FIG. 11  is a perspective view showing a reinforcing member in  FIGS. 7 and 8 . 
         FIG. 12  is another perspective view showing the reinforcing member in  FIGS. 7 and 8 . 
         FIG. 13  is a cross-sectional view showing deformation of the cab when the hydraulic excavator falls down. 
         FIG. 14  is a cross-sectional view showing a range surrounded by a two-dot chain line XIV in  FIG. 13  in an enlarged manner. 
         FIG. 15  is a cross-sectional view showing a state in which the cab is further deformed when the hydraulic excavator falls down. 
         FIG. 16  is a top view showing the interior of the cab. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     An embodiment of the present disclosure will be described with reference to the drawings. In the drawings referenced below, the same or corresponding components are denoted by the same reference numerals. 
       FIG. 1  is a perspective view showing a hydraulic excavator according to the present embodiment. First, an overall structure of the hydraulic excavator will be described. 
     As shown in  FIG. 1 , a hydraulic excavator  100  includes a vehicular body  11  and a work implement  12 . Vehicular body  11  includes a revolving unit  13  and a traveling unit  15 . 
     Traveling unit  15  includes a pair of crawler belts  15 Cr and a travel motor  15 M. Hydraulic excavator  100  can travel by rotation of crawler belts  15 Cr. Travel motor  15 M is provided as a drive source of traveling unit  15 . Traveling unit  15  may include a wheel (tire). 
     Revolving unit  13  is provided on traveling unit  15 . Revolving unit  13  can swing about the center of swing  26  with respect to traveling unit  15 . The center of swing  26  corresponds to an axis extending in the up-down direction. Revolving unit  13  includes a cab (operator&#39;s cab)  30 . A living space  120  for an operator is formed in cab  30 . An operator&#39;s seat  31  is provided in living space  120  for the operator. The operator rides in living space  120  and is seated on operator&#39;s seat  31  to operate hydraulic excavator  100 . 
     Revolving unit  13  includes an engine compartment  19  and a counter weight that is provided in a rear portion of revolving unit  13 . Engine compartment  19  accommodates an engine, a hydraulic oil tank, an air cleaner, a hydraulic pump, and the like. 
     Work implement  12  is attached to vehicular body  11 . Work implement  12  is attached to revolving unit  13 . Work implement  12  performs operations such as excavation of soil. Work implement  12  includes a boom  16 , an arm  17 , and a bucket  18 . 
     Boom  16  is pivotably coupled to vehicular body  11  (revolving unit  13 ) through a boom pin  23 . Arm  17  is pivotably coupled to boom  16  through an arm pin  24 . Bucket  18  is pivotably coupled to arm  17  through a bucket pin  25 . 
     Work implement  12  further includes boom cylinders  20 A and  20 B, an arm cylinder  21 , and a bucket cylinder  22 . 
     Boom cylinders  20 A and  20 B, arm cylinder  21 , and bucket cylinder  22  each are a hydraulic cylinder driven by hydraulic oil. Boom cylinders  20 A and  20 B, which are provided as one pair, each are provided on a corresponding one of both sides of boom  16 , and operate boom  16  to pivot. Arm cylinder  21  operates arm  17  to pivot. Bucket cylinder  22  operates bucket  18  to pivot. 
     Herein, the front-rear direction refers to a front direction and a rear direction of the operator seated on operator&#39;s seat  31 . The direction facing the operator seated on operator&#39;s seat  31  is defined as the front direction, and the direction backward the operator seated on operator&#39;s seat  31  is defined as the rear direction. The left-right (lateral) direction refers to a left direction and a right direction of the operator seated on operator&#39;s seat  31 . When the operator seated on operator&#39;s seat  31  faces the front, the right side of the operator is defined as the right direction. When the operator seated on operator&#39;s seat  31  faces the front, the left side of the operator is defined as the left direction. The up-down direction refers to a direction orthogonal to a plane including the front-rear direction and the left-right direction. The side downward the ground is defined as a lower side, and the side upward the sky is defined as an upper side. 
       FIG. 2  is a perspective view showing the cab and a revolving frame.  FIG. 3  is a perspective view showing the revolving frame. 
     As shown in  FIGS. 1 to 3 , revolving unit  13  further includes a revolving frame  14 . Revolving frame  14  is a frame unit that forms a base of revolving unit  13 , and is provided directly on traveling unit  15 . Cab  30 , engine compartment  19  and the like are mounted on revolving frame  14 . Work implement  12  is attached to revolving frame  14 . 
     As shown in  FIG. 3 , revolving frame  14  includes a bottom plate  95 , a pair of left and right vertical plates  93  ( 93 L and  94 R), and a plurality of rib portions  91  ( 91 A,  91 B and  91 C). 
     Bottom plate  95  is formed of a plate member extending in a horizontal direction. Vertical plates  93  are erected on bottom plate  95 . Each of vertical plates  93  is formed of a plate member that is orthogonal to the left-right direction. Vertical plate  93 L and vertical plate  93 R are spaced apart from each other and face each other in the left-right direction. Boom  16  in  FIG. 1  is arranged between vertical plate  93 L and vertical plate  93 R. Each of vertical plates  93  is provided with a pin hole  94  into which boom pin  23  in  FIG. 1  is inserted. 
     Rib portions  91  are provided on bottom plate  95 . Rib portions  91  extend in the left-right direction. Each of rib portions  91  has a rib shape in which the front-rear direction corresponds to a width direction, the left-right direction corresponds to a longitudinal direction, and the up-down direction corresponds to a height direction. The plurality of rib portions  91  are provided on the left side of vertical plate  93 L. Rib portion  91 A, rib portion  91 B and rib portion  91 C are aligned from the front side to the rear side in the listed order. Rib portion  91 A and rib portion  91 C are provided with damper attachment holes  92  to which front dampers  96  ( 96 L and  96 R) and rear dampers  97  ( 97 L and  97 R) described below are attached, respectively. 
     As shown in  FIGS. 2 and 3 , cab  30  is provided on the left side of vertical plate  93 L. Cab  30  is provided above the plurality of rib portions  91 . 
       FIGS. 4 and 5  are perspective views showing the cab. As shown in  FIGS. 4 and 5 , cab  30  is formed of a box having a rectangular parallelepiped shape and including a front surface  30 A, a rear surface  30 B, a right surface  30 C, a left surface  30 D, a top surface  30 E, and a bottom surface  30 F. 
     Front surface  30 A is provided to face the front side. Rear surface  30 B is provided to face the rear side. Right surface  30 C is provided to face the right side. Right surface  30 C faces work implement  12  shown in  FIG. 1  in the left-right direction. Left surface  30 D is provided to face the left side. Top surface  30 E is provided to face the upper side. Bottom surface  30 F is provided to face the lower side. Bottom surface  30 F faces revolving frame  14  in  FIG. 2  in the up-down direction. 
     Cab  30  includes a floor member  40 , a pair of left and right pillar members  42  ( 42 L and  42 R), a pair of left and right pillar members  43  ( 43 L and  43 R), a pair of left and right pillar members  44  ( 44 L and  44 R), beam members  51 ,  52  and  53 , a pair of left and right girder members  54  ( 54 L and  54 R), and a pair of left and right girder members  55  ( 55 L and  55 R). 
     Floor member  40 , pillar members  42 , pillar members  43 , pillar members  44 , beam members  51 ,  52  and  53 , girder members  54 , and girder members  55  are integrally formed with each other by welding, to thereby form a cab frame. 
     Floor member  40  is provided on bottom surface  30 F. Floor member  40  is formed of a plate member (e.g., a steel plate). 
     Each of pillar members  42 , pillar members  43 , pillar members  44 , beam members  51 ,  52  and  53 , girder members  54 , and girder members  55  is formed of a frame member extending in one direction in an elongated manner. Pillar members  42 , pillar members  43 , pillar members  44 , beam members  51 ,  52  and  53 , girder members  54 , and girder members  55  are provided around living space  120  for the operator. Living space  120  for the operator is provided at a position surrounded by pillar members  42 , pillar members  43 , pillar members  44 , beam members  51 ,  52  and  53 , girder members  54 , and girder members  55 . 
     Pillar members  42 , pillar members  43  and pillar members  44  are erected on floor member  40 . Pillar members  42 , pillar members  43  and pillar members  44  are connected to floor member  40 . Pillar members  42 , pillar members  43  and pillar members  44  extend in the up-down direction between top surface  30 E and bottom surface  30 F. 
     Pillar member  42 L and pillar member  42 R are arranged to be spaced apart from each other in the left-right direction. Pillar member  42 L and pillar member  42 R are located to face each other in the left-right direction. Pillar member  42 L is provided at a corner portion where front surface  30 A and left surface  30 D intersect with each other. Pillar member  42 L is provided at a front end of left surface  30 D. Pillar member  42 R is provided at a front end of right surface  30 C. Pillar member  42 L and pillar member  42 R are provided on the front side of operator&#39;s seat  31  shown in  FIG. 1 . 
     Pillar member  43 L and pillar member  43 R are arranged to be spaced apart from each other in the left-right direction. Pillar member  43 L and pillar member  43 R are located to face each other in the left-right direction. Pillar member  43 L and pillar member  43 R are provided on the lateral sides of operator&#39;s seat  31  shown in  FIG. 1 . Pillar member  43 L is provided on left surface  30 D. Pillar member  43 R is provided on right surface  30 C. Pillar member  43 L and pillar member  43 R are provided on the rear side of pillar member  42 L and pillar member  42 R. 
     Pillar member  44 L and pillar member  44 R are arranged to be spaced apart from each other in the left-right direction. Pillar member  44 L and pillar member  44 R are located to face each other in the left-right direction. Pillar member  44 L is provided at a corner portion where left surface  30 D and rear surface  30 B intersect with each other. Pillar member  44 L is provided at a rear end of left surface  30 D. Pillar member  44 R is provided at a corner portion where right surface  30 C and rear surface  30 B intersect with each other. Pillar member  44 R is provided at a rear end of right surface  30 C. Pillar member  44 L and pillar member  44 R are provided on the rear side of pillar member  43 L and pillar member  43 R. Pillar member  44 L and pillar member  44 R are provided on the rear side of operator&#39;s seat  31  shown in  FIG. 1 . 
     Beam members  51 ,  52  and  53 , girder members  54  and girder members  55  are provided on top surface  30 E. Beam member  51 , beam member  52  and beam member  53  extend in the left-right direction. Girder members  54  and girder members  55  extend in the front-rear direction. 
     Beam member  51  is provided at a corner portion where front surface  30 A and top surface  30 E intersect with each other. A left end of beam member  51  is connected to a connection portion that connects pillar member  42 L and below-described girder member  54 L. A right end of beam member  51  is connected to a connection portion that connects pillar member  42 R and below-described girder member  54 R. 
     Beam member  52  is provided on the rear side of beam member  51 . A right end of beam member  52  is connected to an upper end of pillar member  43 R. A left end of beam member  52  is connected to an upper end of pillar member  43 L. 
     Beam member  53  is provided at a corner portion where top surface  30 E and rear surface  30 B intersect with each other. Beam member  53  is provided on the rear side of beam member  52 . A right end of beam member  53  is connected to an upper end of pillar member  44 R. A left end of beam member  53  is connected to an upper end of pillar member  44 L. 
     Girder member  54 L and girder member  54 R are arranged to be spaced apart from each other in the left-right direction. Girder member  54 L and girder member  54 R are located to face each other in the left-right direction. 
     Girder member  54 L is provided at a corner portion where left surface  30 D and top surface  30 E intersect with each other. A front end of girder member  54 L is connected to an upper end of pillar member  42 L. Girder member  54 L and pillar member  42 L are formed of an integrated frame member. A rear end of girder member  54 L is connected to an upper end of pillar member  43 L. Girder member  54 R is provided at a corner portion where right surface  30 C and top surface  30 E intersect with each other. A front end of girder member  54 R is connected to an upper end of pillar member  42 R. Girder member  54 R and pillar member  42 R are formed of an integrated frame member. A rear end of girder member  54 R is connected to an upper end of pillar member  43 R. 
     Girder member  55 L and girder member  55 R are arranged to be spaced apart from each other in the left-right direction. Girder member  55 L and girder member  55 R are located to face each other in the left-right direction. 
     Girder member  55 L is provided at a corner portion where left surface  30 D and top surface  30 E intersect with each other. A front end of girder member  55 L is connected to an upper end of pillar member  43 L. A rear end of girder member  55 L is connected to an upper end of pillar member  44 L. Girder member  55 R is provided at a corner portion where right surface  30 C and top surface  30 E intersect with each other. A front end of girder member  55 R is connected to an upper end of pillar member  43 R. A rear end of girder member  55 L is connected to an upper end of pillar member  44 R. 
     As shown in  FIGS. 1 and 4 , cab  30  further includes a ceiling member  45  and a door member  32 . Ceiling member  45  is provided on top surface  30 E. Ceiling member  45  is formed of a plate member (e.g., a steel plate). Ceiling member  45  is provided on beam members  51 ,  52  and  53 , girder members  54 , and girder members  55 . 
     Door member  32  is provided on left surface  30 D so as to be openable and closable. Door member  32  is opened and closed when the operator enters and leaves living space  120 . 
     As shown in  FIG. 4 , cab  30  further includes a front transparent member  46 , a lower transparent member  47  and a lateral transparent member  48 . Each of front transparent member  46 , lower transparent member  47  and lateral transparent member  48  is formed of a transparent member that allows light to transmit therethrough. Each of front transparent member  46 , lower transparent member  47  and lateral transparent member  48  is formed of, for example, glass or acryl. 
     Front transparent member  46  and lower transparent member  47  are provided on front surface  30 A. Front transparent member  46  and lower transparent member  47  are provided between pillar member  42 L and pillar member  42 R in the left-right direction. Front transparent member  46  and lower transparent member  47  are provided on the front side of pillar members  43 . Front transparent member  46  and lower transparent member  47  are provided on the front side of operator&#39;s seat  31 . Front transparent member  46  is provided on the upper side of lower transparent member  47 . 
     Lateral transparent member  48  is provided on right surface  30 C. Lateral transparent member  48  is provided across pillar member  42 R, pillar member  43 R and pillar member  44 R in the front-rear direction. Lateral transparent member  48  may be provided only across pillar member  42 R and pillar member  43 R in the front-rear direction. 
     Lower transparent member  47  and lateral transparent member  48  are of fixed type, whereas front transparent member  46  is of movable type that allows front transparent member  46  to be opened and closed. Front transparent member  46  is opened and closed between a position where front surface  30 A enters an open state and a position where front surface  30 A enters a closed state. When front transparent member  46  is operated to the position where front surface  30 A enters the open state, front transparent member  46  moves to top surface  30 E. 
       FIG. 6  is a cross-sectional view partially showing the hydraulic excavator when seen in a direction indicated by an arrow line VI-VI in  FIG. 2 .  FIG. 6  shows a center position  101  of operator&#39;s seat  31  in the left-right direction, and a center position  102  of cab  30  in the left-right direction. 
     As shown in  FIGS. 2 to 6 , hydraulic excavator  100  further includes a pair of left and right front dampers  96  ( 96 L and  96 R) and a pair of left and right rear dampers  97  ( 97 L and  97 R). Front dampers  96  and rear dampers  97  are interposed between cab  30  (floor member  40 ) and revolving frame  14  (rib portion  91 A and rib portion  91 C) in the up-down direction. Front dampers  96  and rear dampers  97  elastically support cab  30 . 
     Front dampers  96  are provided at a front end of cab  30 . Front damper  96 L and front damper  96 R are arranged to be spaced apart from each other in the left-right direction. Rear dampers  97  are provided at a rear end of cab  30 . Rear damper  97 L and rear damper  97 R are arranged to be spaced apart from each other in the left-right direction. In a top view, front damper  96 L, front damper  96 R, rear damper  97 L, and rear damper  97 R are provided at four corners of cab  30 . 
     Front dampers  96  are attached to floor member  40  and rib portion  91 A. Rear dampers  97  are attached to floor member  40  and rib portion  91 C. Rib portion  91 B is provided between front dampers  96  and rear dampers  97  in the front-rear direction. 
     Floor member  40  faces revolving frame  14  in the up-down direction, with a gap  210  therebetween. Floor member  40  faces rib portions  91  ( 91 A,  91 B and  91 C) in the up-down direction, with gap  210  therebetween. 
       FIGS. 7 and 8  are perspective views partially showing the interior of the cab in  FIG. 4 . As shown in  FIGS. 6 to 8 , pillar member  43 L is connected to a left end  220  of floor member  40 . Pillar member  43 R is connected to a right end  230  of floor member  40 . 
     Cab  30  further includes a support base  61  and a reinforcing member  71 . Support base  61  and reinforcing member  71  are provided in living space  120  for the operator. Support base  61  and reinforcing member  71  are provided on floor member  40 . 
     Support base  61  is provided at a position distant from left end  220  of floor member  40  in the left-right direction. Support base  61  is provided at a position distant from right end  230  of floor member  40  in the left-right direction. Support base  61  is provided on both of the left side and the right side, with center position  101  of operator&#39;s seat  31  interposed therebetween. Support base  61  is provided on both of the left side and the right side, with center position  102  of cab  30  interposed therebetween. 
     Support base  61  is connected to floor member  40 . Support base  61  is fastened to floor member  40  by a bolt. Operator&#39;s seat  31  is provided at a position distant from and above floor member  40 . Operator&#39;s seat  31  is supported by support base  61 . Operator&#39;s seat  31  is provided on support base  61 . 
     Reinforcing member  71  is provided between pillar member  43 L and support base  61  in the left-right direction. Reinforcing member  71  is provided at a position close to left end  220  of floor member  40  relative to center position  101  of operator&#39;s seat  31  in the left-right direction. Reinforcing member  71  is provided at a position close to left end  220  of floor member  40  relative to center position  102  of cab  30  in the left-right direction. 
     Reinforcing member  71  is connected to pillar member  43 L and support base  61 . Reinforcing member  71  is fastened to pillar member  43 L and support base  61  by a bolt. Reinforcing member  71  is connected to floor member  40 . Reinforcing member  71  is fastened to floor member  40  by a bolt. 
       FIGS. 9 and 10  are perspective views showing the support base in  FIGS. 7 and 8 . As shown in  FIGS. 7 to 10 , support base  61  is formed of metal (e.g., a steel material). Support base  61  includes a pair of left and right leg portions  63  ( 63 L and  63 R), a horizontal plate portion  62 , a rear plate portion  64 , a flange portion  66 , and a first connection portion  67 . 
     Leg portions  63  are provided to rise upward from floor member  40 . Leg portion  63 L and leg portion  63 R are arranged to be spaced apart from each other in the left-right direction. Lower ends of leg portions  63  are fastened to floor member  40 . The lower end of leg portion  63 L is fastened to floor member  40  at a position close to left end  220  of floor member  40  relative to center position  101  of operator&#39;s seat  31  (center position  102  of cab  30 ) in the left-right direction. The lower end of leg portion  63 R is fastened to floor member  40  at a position close to right end  230  of floor member  40  relative to center position  101  of operator&#39;s seat  31  (center position  102  of cab  30 ) in the left-right direction. 
     Horizontal plate portion  62  has a plate shape that is parallel to the horizontal direction. Horizontal plate portion  62  is provided at a position distant from and above floor member  40 . Horizontal plate portion  62  connects an upper end of leg portion  63 L and an upper end of leg portion  63 R. Together with leg portion  63 L and leg portion  63 R, horizontal plate portion  62  forms a tunnel shape extending in the front-rear direction. 
     Rear plate portion  64  has a plate shape that is orthogonal to the front-rear direction. Rear plate portion  64  is provided at a rear end of support base  61 . Rear plate portion  64  extends from leg portion  63 R toward leg portion  63 L in the left-right direction, and further extends to a position where rear plate portion  64  protrudes leftward from leg portion  63 L. Rear plate portion  64  includes a second connection portion  65 . Second connection portion  65  is provided at a left end of rear plate portion  64 . Second connection portion  65  is provided at a position where rear plate portion  64  protrudes leftward from leg portion  63 L. 
     Flange portion  66  extends rearward from a lower end of rear plate portion  64 . When seen in the left-right direction, flange portion  66  has an L shape, together with rear plate portion  64 . Flange portion  66  has a plate shape that is parallel to the horizontal direction, and is overlapped with floor member  40 . Flange portion  66  is fastened to floor member  40 . 
     First connection portion  67  has a plate shape that is parallel to the horizontal direction. First connection portion  67  faces flange portion  66  in the up-down direction. First connection portion  67  extends rearward from an upper end of rear plate portion  64  at a position where rear plate portion  64  protrudes leftward from leg portion  63 L. First connection portion  67  is located to face pillar member  43 L in the left-right direction. 
       FIGS. 11 and 12  are perspective views showing the reinforcing member in  FIGS. 7 and 8 . As shown in  FIGS. 7, 8, 11, and 12 , reinforcing member  71  is formed of metal (e.g., a steel material). Reinforcing member  71  includes a base plate portion  72 , an angle portion  74 , a third connection portion  73 , and a fourth connection portion  75 . 
     Base plate portion  72  has a plate shape that is orthogonal to the left-right direction. Base plate portion  72  is overlapped with pillar member  43 L in the left-right direction. Base plate portion  72  is fastened to pillar member  43 L. 
     Angle portion  74  protrudes rightward from base plate portion  72 . Angle portion  74  is provided to rise upward from floor member  40 . A lower end of angle portion  74  is fastened to floor member  40 . 
     Third connection portion  73  protrudes rightward from base plate portion  72 . Third connection portion  73  has a plate shape that is orthogonal to the front-rear direction. Third connection portion  73  is provided at a position distant from and on the front side of angle portion  74 . Third connection portion  73  is overlapped with second connection portion  65  of support base  61  in the front-rear direction. Third connection portion  73  is arranged on the rear side of second connection portion  65  of support base  61 . Third connection portion  73  is fastened to second connection portion  65  of support base  61 . 
     Fourth connection portion  75  protrudes rightward from base plate portion  72 . Fourth connection portion  75  connects third connection portion  73  and angle portion  74  in the front-rear direction. Fourth connection portion  75  is provided at a position distant from and above floor member  40 . Fourth connection portion  75  is arranged above first connection portion  67  of support base  61 . First connection portion  67  of support base  61  is arranged on the front side of angle portion  74 . Fourth connection portion  75  is fastened to first connection portion  67  of support base  61 . 
     The shapes of support base  61  and reinforcing member  71  described above are provided as one example and are not particularly limited. A connection structure that connects reinforcing member  71  to support base  61  and pillar member  43 L is not limited to fastening by a bolt, and may be welding, for example. 
     As shown in  FIG. 6 , floor member  40  includes a high rigidity portion  260  and a low rigidity portion  270 . High rigidity portion  260  and low rigidity portion  270  are aligned in the left-right direction. High rigidity portion  260  has rigidity higher than that of low rigidity portion  270 . 
     High rigidity portion  260  extends from left end  220  of floor member  40  and over a range in which reinforcing member  71  and support base  61  are provided in the left-right direction. Low rigidity portion  270  extends from right end  230  of floor member  40  and over a range in which reinforcing member  71  and support base  61  are not provided in the left-right direction. Low rigidity portion  270  extends from right end  230  of floor member  40  to a right end  69  of support base  61  in the left-right direction. Low rigidity portion  270  is exposed from reinforcing member  71  and support base  61 . 
     As shown in  FIGS. 5 and 6 , hydraulic excavator  100  further includes a restriction member  81 . Restriction member  81  is provided in gap  210  between floor member  40  and revolving frame  14  (rib portion  91 B). Restriction member  81  protrudes from one of revolving frame  14  and floor member  40  toward the other of revolving frame  14  and floor member  40 . Restriction member  81  is provided on floor member  40 . 
     Restriction member  81  protrudes from floor member  40  toward revolving frame  14 . 
     Restriction member  81  has a pin shape that protrudes downward from floor member  40 . A protrusion length H 2  of restriction member  81  from floor member  40  is shorter than a length H 1  of gap  210  in the up-down direction (H2&lt;H 1 ). Protrusion length H 2  of restriction member  81  corresponds to a length in the up-down direction between floor member  40  and a protruding end of restriction member  81 . Length H 1  of gap  210  corresponds to a length in the up-down direction between floor member  40  and a top surface  91   a  of rib portion  91 B. Restriction member  81  faces revolving frame  14  (rib portion  91 B) in the up-down direction, with a gap therebetween. 
     The protrusion length of restriction member  81  from floor member  40  is shorter than a length of the gap between the protruding end of restriction member  81  and revolving frame  14  (H 2 &lt;H 1 −H 2 ). The protrusion length of restriction member  81  from floor member  40  may be equal to or longer than the length of the gap between the protruding end of restriction member  81  and revolving frame  14  (H 2 ≥H 1 −H 2 ). 
     Restriction member  81  is provided below support base  61  or reinforcing member  71 . Restriction member  81  is provided below support base  61 . Restriction member  81  is provided in high rigidity portion  260  of floor member  40 . 
     Restriction member  81  has a rectangular parallelepiped shape. The shape of restriction member  81  is not particularly limited, and may be a cylindrical shape in which the up-down direction corresponds to an axial direction, for example. 
       FIG. 13  is a cross-sectional view showing deformation of the cab when the hydraulic excavator falls down.  FIG. 14  is a cross-sectional view showing a range surrounded by a two-dot chain line XIV in  FIG. 13  in an enlarged manner. 
     As shown in  FIGS. 13 and 14 , when hydraulic excavator  100  falls down, external force in the horizontal direction (force indicated by an arrow F in  FIG. 13 ) is applied to left surface  30 D of cab  30 . In such a case, even when cab  30  becomes deformed, it is required to prevent excessive deformation of cab  30  and secure a sufficient distance between left surface  30 D and the operator in cab  30 . 
     In hydraulic excavator  100 , reinforcing member  71  connected to pillar member  43 R and support base  61  is provided on floor member  40 . With such a configuration, pillar member  43 R, and reinforcing member  71  and support base  61  on floor member  40  together receive the external force in the horizontal direction applied to left surface  30 D, and thus, bending of pillar member  43 R at the connection portion at left end  220  of floor member  40  can be suppressed. Therefore, it is possible to suppress such deformation that left surface  30 D falls down toward the operator seated on operator&#39;s seat  31 . 
     In addition, floor member  40  includes high rigidity portion  260  having higher rigidity, which extends from left end  220  of floor member  40  and over the range in the left-right direction in which reinforcing member  71  and support base  61  are provided. In such a configuration, when the external force in the horizontal direction is applied to left surface  30 D, floor member  40  becomes deformed such that high rigidity portion  260  is lifted to a higher level with decreasing distance from left end  220  of floor member  40  in the left-right direction. More specifically, floor member  40  becomes deformed such that floor member  40  bends downward near a boundary between high rigidity portion  260  and low rigidity portion  270 , and high rigidity portion  260  is lifted to a higher level with decreasing distance from left end  220  of floor member  40  in the left-right direction. As a result, the operator seated on operator&#39;s seat  31  assumes a posture with the lowered right shoulder, which makes it possible to secure a sufficient distance between left surface  30 D and the operator. 
       FIG. 15  is a cross-sectional view showing a state in which the cab is further deformed when the hydraulic excavator falls down. 
     As shown in  FIG. 15 , when floor member  40  is further deformed, a downward component of the external force applied to left surface  30 D increases, which may cause a phenomenon in which high rigidity portion  260  as a whole sinks downward. 
     In order to deal with this, in hydraulic excavator  100 , restriction member  81  protruding from floor member  40  toward revolving frame  14  is provided in gap  210  between floor member  40  and revolving frame  14 . Since the protrusion length of restriction member  81  from floor member  40  is shorter than the length of gap  210  in the up-down direction, restriction member  81  abuts against revolving frame  14  as the deformation of floor member  40  progresses. Since restriction member  81  is provided below support base  61  that forms high rigidity portion  260 , restriction member  81  can suppress the phenomenon in which high rigidity portion  260  sinks downward, when restriction member  81  abuts against revolving frame  14 . As a result, the operator&#39;s posture with the lowered right shoulder is maintained, which makes it possible to continue to secure a sufficient distance between left surface  30 D and the operator. 
     For the above-described reason, it is possible to prevent excessive deformation of cab  30  and secure a sufficient distance between cab  30  and the operator when hydraulic excavator  100  falls down. 
     As shown in  FIG. 13 , in hydraulic excavator  100 , a highly rigid rollover protective structure (ROPS) is implemented by pillar members  43  ( 43 L and  43 R) and beam member  52  that form a gate shape around living space  120  for the operator. This makes it possible to more effectively suppress such deformation that left surface  30 D falls down toward the operator seated on operator&#39;s seat  31  when hydraulic excavator  100  falls down. 
       FIG. 16  is a top view showing the interior of the cab. As shown in  FIG. 16 , operator&#39;s seat  31  can slide in the front-rear direction between a front position indicated by an operator&#39;s seat  31 A and a rear position indicated by an operator&#39;s seat  31 B. 
     Pillar members  43  ( 43 L and  43 R) are located on the lateral sides of operator&#39;s seat  31  in an entire range in the front-rear direction in which operator&#39;s seat  31  slides. However, the present disclosure is not limited thereto, and pillar members  43  ( 43 L and  43 R) may be located on the lateral sides of operator&#39;s seat  31  in a part of the range in the front-rear direction in which operator&#39;s seat  31  slides. 
     As shown in  FIGS. 6, 15 and 16 , restriction member  81  is provided between center position  101  of operator&#39;s seat  31  and left end  220  of floor member  40  in the left-right direction. 
     According to such a configuration, restriction member  81  abuts against revolving frame  14  at a position close to left end  220  of floor member  40  relative to center position  101  of operator&#39;s seat  31  in the left-right direction. In this case, when restriction member  81  abuts against revolving frame  14 , the phenomenon in which high rigidity portion  260  sinks downward is suppressed under the left half body (under the left foot) of the operator, and thus, the operator&#39;s posture with the lowered right shoulder is easily maintained. This makes it possible to further secure a sufficient distance between left surface  30 D and the operator when hydraulic excavator  100  falls down. 
     As shown in  FIG. 16 , restriction member  81  is provided between center position  102  of cab  30  and left end  220  of floor member  40  in the left-right direction. 
     Front damper  96 L and rear damper  97 L are provided in high rigidity portion  260  in the left-right direction. Front damper  96 R and rear damper  97 R are provided in low rigidity portion  270  in the left-right direction. Restriction member  81  is provided between front damper  96 L and front damper  96 R in the left-right direction. Restriction member  81  is provided between rear damper  97 L and rear damper  97 R in the left-right direction. Restriction member  81  is provided between front and rear dampers  96 L and  97 L and center position  101  of operator&#39;s seat  31  (center position  102  of cab  30 ) in the left-right direction. 
     Restriction member  81  is provided on the front side of pillar members  43  ( 43 L and  43 R). Restriction member  81  may be provided at a position aligned with pillar members  43  ( 43 L and  43 R) in the front-rear direction, or may be provided on the rear side of pillar members  43  ( 43 L and  43 R) in the front-rear direction. Restriction member  81  is provided on the front side of reinforcing member  71 . Restriction member  81  may be provided at a position aligned with reinforcing member  71  in the front-rear direction, or may be provided on the rear side of reinforcing member  71 . 
     Restriction member  81  is provided between front dampers  96  ( 96 L and  96 R) and rear dampers  97  ( 97 L and  97 R) in the front-rear direction. 
     In a top view, at least a part of restriction member  81  overlaps with support base  61 . A part of restriction member  81  overlaps with support base  61 . 
     According to such a configuration, the rigidity of floor member  40  is increased by support base  61  at the position where restriction member  81  is provided. Thus, deformation of floor member  40  caused by an impact when restriction member  81  abuts against revolving frame  14  can be suppressed. As a result, the phenomenon in which high rigidity portion  260  sinks downward can be suppressed more effectively. 
     In a top view, at least a part of restriction member  81  overlaps with rib portion  91 B. The whole of restriction member  81  overlaps with rib portion  91 B. 
     According to such a configuration, rib portion  91 B having high rigidity is provided at the position where restriction member  81  abuts against revolving frame  14 . Thus, deformation of revolving frame  14  caused by an impact when restriction member  81  abuts against revolving frame  14  can be suppressed. As a result, the phenomenon in which high rigidity portion  260  sinks downward can be suppressed more effectively. 
     In a top view, restriction member  81  overlaps with operator&#39;s seat  31  in a part of the range in the front-rear direction in which operator&#39;s seat  31  slides. Restriction member  81  may overlap with operator&#39;s seat  31  in the entire range in the front-rear direction in which operator&#39;s seat  31  slides. 
     The configuration and effect of hydraulic excavator  100  according to the present embodiment described above will be summarized. 
     Hydraulic excavator  100  as a work vehicle according to the present disclosure includes: revolving frame  104 ; and cab  30 . Cab  30  is provided on revolving frame  14 . Cab  30  includes: floor member  40 ; support base  61 ; pillar member  43 L as a first pillar member; and reinforcing member  71 . Floor member  40  faces revolving frame  14  in an up-down direction, with gap  210  therebetween. Support base  61  is provided on floor member  40 . Support base  61  supports operator&#39;s seat  31 . Pillar member  43 L extends in the up-down direction. Pillar member  43 L is connected to left end  220  as one end of floor member  40  in a left-right direction. Reinforcing member  71  is provided on floor member  40 . Reinforcing member  71  is connected to pillar member  43 L and support base  61 . Hydraulic excavator  100  further includes restriction member  81 . Restriction member  81  is provided in gap  210 . Restriction member  81  protrudes from one (floor member  40 ) of revolving frame  14  and floor member  40  toward the other (revolving frame  14 ) of revolving frame  14  and floor member  40 . Restriction member  81  has a protrusion length shorter than a length of gap  210  in the up-down direction. Restriction member  81  is provided below support base  61  or reinforcing member  71  (support base  61 ). 
     According to such a configuration, reinforcing member  71  connected to pillar member  43 R and support base  61  is provided on floor member  40 , and thus, the connection strength of pillar member  43 R at left end  220  of floor member  40  can be increased. This makes it possible to suppress such deformation that cab  30  falls down toward the operator seated on operator&#39;s seat  31  when excessive external force in the horizontal direction is applied to pillar member  43 R. 
     When excessive external force in the horizontal direction is applied to pillar member  43 R, floor member  40  becomes deformed such that high rigidity portion  260  is lifted to a higher level with decreasing distance from left end  220  of floor member  40  in the left-right direction, high rigidity portion  260  being a portion extending from left end  220  of floor member  40  and over the range in the left-right direction in which reinforcing member  71  and support base  61  are provided. As a result, the operator seated on operator&#39;s seat  31  assumes the posture with the lowered right shoulder, and thus, the operator can be kept away from cab  30  that deforms to fall down toward the operator. 
     When the deformation of floor member  40  progresses, the phenomenon in which high rigidity portion  260  as a whole sinks downward may occur. In order to deal with this, restriction member  81  provided below support base  61  or reinforcing member  71  abuts against revolving frame  14 , thereby suppressing the phenomenon in which high rigidity portion  260  sinks downward. As a result, the operator&#39;s posture with the lowered right shoulder is maintained. For the above-described reason, it is possible to prevent excessive deformation of cab  30  and secure a sufficient distance between cab  30  and the operator. 
     Restriction member  81  is provided between center position  101  of operator&#39;s seat  31  and left end  220  of floor member  40  in the left-right direction. 
     According to such a configuration, restriction member  81  abuts against revolving frame  14  at the position close to left end  220  of floor member  40  relative to center position  101  of operator&#39;s seat  31  in the left-right direction. In this case, when restriction member  81  abuts against revolving frame  14 , the phenomenon in which high rigidity portion  260  sinks downward is suppressed under the left half body of the operator, and thus, the operator&#39;s posture with the lowered right shoulder is easily maintained. 
     In a top view, at least a part of restriction member  81  overlaps with support base  61 . 
     According to such a configuration, the rigidity of floor member  40  is increased by support base  61  at the position where restriction member  81  is provided. Therefore, when restriction member  81  abuts against revolving frame  14 , the phenomenon in which high rigidity portion  260  sinks downward can be suppressed more effectively. 
     Revolving frame  14  includes bottom plate  95 , and rib portion  91 B. Rib portion  91 B is erected on bottom plate  95 . Rib portion  91 B extends in the left-right direction. In a top view, at least a part of restriction member  81  overlaps with rib portion  91 B. 
     According to such a configuration, reinforcing rib portion  91 B erected on bottom plate  95  is provided at the position where restriction member  81  abuts against revolving frame  14 . Therefore, when restriction member  81  abuts against revolving frame  14  (rib portion  91 B), the phenomenon in which high rigidity portion  260  sinks downward can be suppressed more effectively. 
     Cab  30  further includes: pillar member  43 R as a second pillar member; and beam member  52 . Pillar member  43 R extends in the up-down direction. Pillar member  43 R is connected to right end  230  as the other end of floor member  40  in the left-right direction. Beam member  52  extends in the left-right direction. Beam member  52  is connected to an upper end of pillar member  43 L and an upper end of pillar member  43 R. 
     According to such a configuration, pillar member  43 L, beam member  52  and pillar member  43 R form a gate shape around living space  120  for the operator. This makes it possible to more effectively suppress such deformation that cab  30  falls down toward the operator when excessive external force is applied to cab  30 . 
     Although the configuration in which restriction member  81  is provided on floor member  40  has been described in the present embodiment, the present disclosure is not limited thereto. Restriction member  81  may be provided on revolving frame  14  (rib portion  91 B). 
     In addition, the cab in the present disclosure is applicable not only to the hydraulic excavator but also to various work vehicles such as a crane. 
     It should be understood that the embodiment disclosed herein is illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims. 
     REFERENCE SIGNS LIST 
       11  vehicular body;  12  work implement;  13  revolving unit;  14  revolving frame;  15  traveling unit;  15 Cr crawler belt;  15 M traveling motor;  16  boom;  17  arm;  18  bucket;  19  engine compartment;  20 A,  20 B boom cylinder;  21  arm cylinder;  22  bucket cylinder;  23  boom pin;  24  arm pin;  25  bucket pin;  26  center of swing;  30  cab;  30 A front surface;  30 B rear surface;  30 C right surface;  30 D left surface;  30 E top surface;  30 F bottom surface;  31 ,  31 A,  31 B operator&#39;s seat;  32  door member;  40  floor member;  42 ,  42 L,  42 R,  43 ,  43 L,  43 R,  44 ,  44 L,  44 R pillar member;  45  ceiling member;  46  front transparent member;  47  lower transparent member;  48  lateral transparent member;  51 ,  52 ,  53  beam member;  54 ,  54 L,  54 R,  55 ,  55 L,  55 R girder member;  61  support base;  62  horizontal plate portion;  63 ,  63 L,  63 R leg portion;  64  rear plate portion;  65  second connection portion;  66  flange portion;  67  first connection portion;  69  right end;  71  reinforcing member;  72  base plate portion;  73  third connection portion;  74  angle portion;  75  fourth connection portion;  81  restriction member;  91 ,  91 A,  91 B,  91 C rib portion;  91   a  top surface;  92  damper attachment hole;  93 ,  93 L,  93 R vertical plate;  94  pin hole;  95  bottom plate;  96 ,  96 L,  96 R front damper;  97 ,  97 L,  97 R rear damper;  100  hydraulic excavator;  101 ,  102  center position;  120  living space;  210  gap;  220  left end;  230  right end;  260  high rigidity portion;  270  low rigidity portion.