Mower deck with tilted idle pulleys

1. A mower unit receiving power transmitted from a drive source, comprising:

a mower deck liftable up/down by a lift mechanism;

a plurality of blade rotational shafts extending through a top plate of the mower deck perpendicularly;

a plurality of blade pulleys mounted on the respective blade rotational shafts;

an idle pulley unit comprising plural tilted pulleys with non-parallel tilt axes; and

a single belt routed around an output pulley of the drive source, the idle pulley unit, and the blade pulleys;

wherein a pulley height of the idle pulley unit is set higher than a pulley height of the blade pulleys; and

a belt portion of the belt running between the output pulley and the idle pulley unit extends to pass over and above the other belt portion.

2. The mower unit according to claim 1 , wherein:

the plural tilted pulleys are a tilted tension idle pulley and a tilted normal idle pulley.

3. The mower unit according to claim 2 , wherein the tension idle pulley is disposed at a position more distant from the output pulley than the blade pulleys.

4. The mower unit according to claim 2 , wherein the tension idle pulley and the normal idle pulley are disposed at positions more distant from the output pulley than the blade pulleys.

5. The mower unit according to claim 2 , further comprising a movement mechanism configured to move the tension idle pulley toward an outer side of the mower deck so as to increase a running length of the belt.

6. A mower machine having a mower unit configured to rotate a blade by a rotational power from an engine, the mower unit comprising:

a mower deck liftable up/down by a lift mechanism;

a plurality of blade rotational shafts extending through a top plate of the mower deck perpendicularly;

a plurality of blade pulleys mounted on the respective blade rotational shafts;

an idle pulley unit comprising plural tilted pulleys with tilt axes that tilt away from each other relative to a vertical axis of an output pulley of the engine; and

a single belt routed around the output pulley of the engine, the idle pulley unit, and the blade pulleys;

wherein a pulley height of the idle pulley unit is set higher than a pulley height of the blade pulleys; and

a belt portion of the belt running between the output pulley and the idle pulley unit extends to pass over and above the other belt portion.

7. The mower machine according to claim 6 , wherein:

the plural tilted pulleys include a tilted tension idle pulley and a tilted normal idle pulley; and

a pulley support shaft for the tension idle pulley and a pulley support shaft for the normal idle pulley have axes tilted relative to vertical axes of the blade pulleys.

8. The mower machine according to claim 7 , wherein the tension idle pulley is disposed at a position more distant from the output pulley than the blade pulleys.

9. The mower machine according to claim 7 , wherein the tension idle pulley and the normal idle pulley are disposed at positions more distant from the output pulley than the blade pulleys.

10. The mower machine according to claim 7 , further comprising a movement mechanism configured to move the tension idle pulley toward an outer side of the mower deck so as to increase a running length of the belt.

11. A mower unit, comprising:

a height adjustable mower deck;

a plurality of blade rotational shafts extending through a top plate of the mower deck;

a plurality of blade pulleys mounted on the respective blade rotational shafts;

a first pulley that rotates about a first axis that is tilted relative to axes of the blade rotational shafts;

a second pulley that rotates about a second axis that is tilted relative to axes of the blade rotational shafts;

the first and second axes being non-parallel to one another and tilting away from each other;

a single belt having:

a first belt portion configured to pass around an output pulley of a drive source and pass around the first and second pulleys; and

a second belt portion that passes around each of the blade pulleys;

a pulley height of the first and second pulleys being higher than a pulley height of the blade pulleys; and

a portion of the first belt portion running between the output pulley and the first and second pulleys passes over and above a portion of the second belt portion.

12. The mower unit according to claim 11 , wherein:

the first pulley is a tension or spring biased idle pulley; and

the second pulley is a fixed axis idle pulley.

13. The mower unit according to claim 11 , wherein the first pulley is disposed at a position more distant from the output pulley than the blade pulleys.

14. The mower unit according to claim 11 , wherein the first and second pulleys are disposed at positions more distant from the output pulley than the blade pulleys.

15. The mower unit according to claim 11 , wherein the first and second axes are spaced from an axis of the output pulley by different amounts.

16. The mower unit according to claim 11 , further comprising a movement mechanism movably mounted to the mower deck and configured to move the first pulley away from the output pulley.

17. The mower unit according to claim 11 , wherein

the second pulley is coupled to a mount that is fixed to the mower deck; and

the first pulley is coupled to a pivotally mounted tension mechanism.

18. The mower unit according to claim 11 , wherein

the second pulley is coupled to a mount that is fixed to the mower deck; and

the first pulley is coupled to a pivotally mounted mechanism that adjusts a position of the second pulley relative to the mower deck.

19. The mower unit according to claim 11 , wherein

the plurality of blade rotational shafts comprises three blade rotation shafts;

the plurality of blade pulleys comprises three blade pulleys;

the second pulley is coupled to a mount that is fixed to the mower deck;

the first pulley is coupled to a pivotally mounted tension mechanism that adjusts a position of the second pulley relative to the mower deck.

20. The mower unit according to claim 11 , wherein the single drive belt:

passes around more than half of the drive pulley;

passes around more than half of the first pulley; and

passes around more than half of each of the blade pulleys.