Centrifugal clutch fitting structure in vehicle

1. A centrifugal clutch fitting structure for mounting a hub of a centrifugal clutch to a rotary shaft of an engine, wherein

the hub includes: a hub boss at a center of the hub; a hub flange contiguous to an outer periphery of the hub boss; and a clutch element held to the hub flange, and

the hub boss is fastened to one end portion of the rotary shaft with a plurality of fastening members extending parallel to the rotary shaft;

wherein the hub boss has an oil hole formed therein, the oil hole communicating with an oil passage formed in the rotary shaft, the oil hole being configured to supply oil into the centrifugal clutch.

2. The centrifugal clutch fitting structure as claimed in claim 1 , wherein four of the fastening members are disposed equally spaced in a circumferential direction about an axis of the hub boss.

3. The centrifugal clutch fitting structure as claimed in claim 2 , wherein each of the fastening members comprises a bolt having a cylindrical head portion with a tool insertion hole.

4. The centrifugal clutch fitting structure as claimed in claim 1 , wherein a knock pin for circumferential positioning is disposed between the one end portion of the rotary shaft and one end portion of the hub boss that is brought into abutment therewith.

5. The centrifugal clutch fitting structure as claimed in claim 1 , wherein the one end portion of the rotary shaft and one end portion of the hub boss that is brought into abutment therewith define a spigot and socket structure.

6. The centrifugal clutch fitting structure as claimed in claim 1 , further comprising: a clutch housing couplable with the hub via the clutch element; and a one-way clutch interposed between the clutch housing and the hub boss.

7. The centrifugal clutch fitting structure as claimed in claim 1 , wherein the hub boss and the hub flange are of one-piece construction.