Patent ID: 7533592

Claim:
A sleeve spline structure of a synchronizer, provided in a hub sleeve of the synchronizer in which a synchronizer ring is interposed between the hub sleeve and a gear piece, comprising: a first tooth portion for synchronization in shifting up, said first tooth portion includes a first long inclined surface that comes in surface contact with a first facet of a tooth portion of said synchronizer ring when said synchronizer ring rotates in a first direction with respect to said hub sleeve, and a first short inclined surface having a length along a circumferential direction shorter than said first long inclined surface; a second tooth portion for synchronization in shifting down, said second tooth portion includes a second long inclined surface that comes in surface contact with a second facet of the tooth portion of said synchronizer ring when said synchronizer ring rotates in a second direction with respect to said hub sleeve, and a second short inclined surface having a length along a circumferential direction shorter than said second long inclined surface; and a third tooth portion in a shape readily inserted between tooth portions of the gear piece, said third tooth portion has a tip end that has an angle smaller than that of a tip end of each of said first and second tooth portions and is located closer to the gear piece than the tip end of each of said first and second tooth portions.