Utility vehicle

1. A utility vehicle comprising: a vehicle body frame; a pair of right and left front wheels disposed at a front end of the vehicle body frame; a pair of right and left rear wheels disposed at a rear end of the vehicle body frame; and a seat disposed in a riding space located between the pair of right and left front wheels and the pair of right and left rear wheels, wherein:

the vehicle body frame has, at a bottom thereof,

a bottom main frame extending in an anteroposterior direction at a center of the vehicle in a vehicle width direction,

a pair of right and left bottom side frames extending in the anteroposterior direction between the front wheels and the rear wheels at outer ends of the vehicle in the vehicle width direction, and

a bottom panel extending in a downwardly slanting direction from one of the bottom side frames toward a center in the vehicle width direction and being connected directly or indirectly to an outer end in the vehicle width direction of the bottom main frame, and covering from below between the one bottom side frame and the bottom main frame;

the front wheels and the rear wheels are swingably supported vertically relative to the vehicle body frame;

the bottom main frame has a portion that is located higher than a line anteroposteriorly connecting a lower end of a bottom main frame front portion and a lower end of a bottom main frame rear portion; and

a whole of the bottom side frames are located above the bottom main frame and outside with respect to inner ends of the rear wheels in the vehicle width direction and each of the bottom side frames extends at the same height as a lower end of the seat in the anteroposterior direction.

2. The utility vehicle according to claim 1 , wherein the bottom side frames are located higher than rotation axes of the front wheels and the rear wheels and lower than upper ends of the front wheels and the rear wheels, when these wheels are not swinging vertically.

3. The utility vehicle according to claim 2 ,

wherein the bottom side frames are not lower than a vertically center position between the rotation axes of the front and the rear wheels and a line connecting both of the upper ends of the front and the rear wheels when these wheels are not swinging vertically.

4. The utility vehicle according to claim 2 ,

wherein the bottom side frames are not lower than a vertically center position between the bottom main frame and a line connecting both of the upper ends of the front and the rear wheels when these wheels are not swinging vertically.

5. The utility vehicle according to claim 1 , further comprising a pair of right and left coupling frames coupling the bottom main frame to the pair of right and left bottom side frames,

wherein the bottom panel includes a slanted face extending between the bottom side frame and the coupling frame and attached to lower ends thereof, and

the slanted face has an inner end in the vehicle width direction located inside the front wheel and the rear wheel.

6. The utility vehicle according to claim 5 , wherein the slanted face extends straight.

7. The utility vehicle according to claim 1 , further comprising a pair of right and left coupling frames coupling the bottom main frame to the pair of right and left bottom side frames,

wherein the bottom panel includes a bottom face extending from the coupling frame to the outer ends in the vehicle width direction of the bottom main frame and attached to lower ends thereof, and

the bottom face extends substantially horizontally at a higher level than the bottom main frame.

8. A utility vehicle comprising: a vehicle body frame; a pair of right and left front wheels disposed at a front end of the vehicle body frame; a pair of right and left rear wheels disposed at a rear end of the vehicle body frame; and a seat disposed in a riding space located between the pair of right and left front wheels and the pair of right and left rear wheels, wherein:

the vehicle body frame has, at a bottom thereof,

a bottom main frame extending in an anteroposterior direction just under the seat at a center of the vehicle in a vehicle width direction,

a pair of right and left bottom side frames extending in the anteroposterior direction between the front wheels and the rear wheels at outer ends of the vehicle in the vehicle width direction, and

a pair of right and left coupling frames coupling the bottom main frame to the pair of right and left bottom side frames;

the front wheels and the rear wheels are swingably supported vertically relative to the vehicle body frame;

the bottom main frame has a portion that is located higher than a line anteroposteriorly connecting a lower end of a bottom main frame front portion and a lower end of a bottom main frame rear portion;

a whole of the bottom side frames are located above the bottom main frame and outside with respect to inner ends of the rear wheels in the vehicle width direction and each of the bottom side frames extends at the same height as a lower end of the seat in the anteroposterior direction; and

the coupling frame is, in a bottom view, at least partially overlapped with the seat in the vehicle width direction.

9. The utility vehicle according to claim 8 , wherein the bottom side frames are located higher than rotation axes of the front wheels and the rear wheels and lower than upper ends of the front wheels and the rear wheels, when these wheels are not swinging vertically.

10. The utility vehicle according to claim 9 , wherein the bottom side frames are not lower than a vertically center position between the rotation axes of the front and the rear wheels and a line connecting both of the upper ends of the front and the rear wheels when these wheels are not swinging vertically.

11. The utility vehicle according to claim 9 , wherein the bottom side frames are not lower than a vertically center position between the bottom main frame and a line connecting both of the upper ends of the front wheels and the rear wheels when these wheels are not swinging vertically.

12. The utility vehicle according to claim 8 , further comprising a slanted face extending in a downwardly slanting direction from one of the bottom side frames toward a center in the vehicle width direction and connected directly or indirectly to an outer end in the vehicle width direction of the bottom main frame.

13. The utility vehicle according to claim 12 , wherein the slanted face has an inner end in the vehicle width direction located inside the front wheel and the rear wheel.

14. The utility vehicle according to claim 12 , wherein the slanted face extends straight.

15. The utility vehicle according to claim 8 , further comprising a bottom panel extending in a downwardly slanting direction from one of the bottom side frames toward a center in the vehicle width direction and being connected directly or indirectly to an outer end in the vehicle width direction of the bottom main frame, and covering from below between the one bottom side frame and the bottom main frame,

wherein the bottom panel includes a bottom face extending from the coupling frame to the outer ends in the vehicle width direction of the bottom main frame and attached to lower ends thereof, and

the bottom face extends substantially horizontally at a higher level than the bottom main frame.

16. The utility vehicle according to claim 8 , wherein the bottom main frame has an intermediate portion including a cross member extending in the vehicle width direction and located at an intermediate position between the front wheels and the rear wheels in the anteroposterior direction,

wherein the cross member is located at a higher level above the ground than the bottom main frame front and rear portions.

17. The utility vehicle according to claim 16 , wherein the intermediate portion increases in height, relative to the ground, from the bottom main frame rear portion and the bottom main frame front portion to the cross member.

18. A utility vehicle comprising: a vehicle body frame; a pair of right and left front wheels disposed at a front end of the vehicle body frame; a pair of right and left rear wheels disposed at a rear end of the vehicle body frame; and

a seat disposed in a riding space located between the pair of right and left front wheels and the pair of right and left rear wheels, wherein:

the vehicle body frame has, at a bottom thereof,

a bottom main frame extending in an anteroposterior direction at a center of the vehicle in a vehicle width direction,

a pair of right and left bottom side frames extending in the anteroposterior direction between the front wheels and the rear wheels at outer ends of the vehicle in the vehicle width direction, and

a bottom panel extending in a downwardly slanting direction from one of the bottom side frames toward a center in the vehicle width direction and being connected directly or indirectly to an outer end in the vehicle width direction of the bottom main frame, and covering from below between the one bottom side frame and the bottom main frame;

the front wheels and the rear wheels are swingably supported vertically relative to the vehicle body frame; and

a whole of the bottom side frames are located above the bottom main frame and outside with respect to inner ends of the rear wheels in the vehicle width direction and each of the bottom side frames extends at the same height as a lower end of the seat in the anteroposterior direction.