Shift device adapted for transmission

A shift device adapted for a transmission comprising:

• a shaft for transmitting drive power;
• a hub having a boss portion splined with the shaft, a ring portion located outwardly away from the boss portion and formed on an outer peripheral surface thereof with splines, and a flange portion connecting the boss portion and the ring portion, the ring portion and the flange portion being formed with a plurality of cut-off portions;
• a sleeve slidably supported on the hub, the sleeve being provided on an inner peripheral surface thereof with splines which engage with the splines of the ring portion of the hub, the splines of the sleeve being formed with a groove on an inner circumferential surface of the sleeve, a first inner diameter portion and a second inner portion each formed on the inner circumferential surface of the sleeve, a high-speed-stage slanting surface provided between a bottom of the groove and the first inner diameter portion, and a turn-off slanting surface provided between the bottom of the groove and the second inner diameter portion;
• a speed gear having splines engageable with the splines of the sleeve and a cone surface at a hub side;
• a synchronizer ring having a friction surface pressable on the cone surface of the speed gear on an inner surface of the synchronizer ring, splines having chamfer surfaces on an outer circumference of the synchronizer ring, and first projecting portions extending in an axial direction at the hub side;
• and
• a plurality of lever members arranged among the sleeve, the hub and the synchronizer ring, the lever members being capable of transmitting pushing force generated due to an axial movement of the sleeve to the synchronizer ring, wherein
• the frictional surface of the synchronizer ring is pushed against the cone surface of the speed gear to generate frictional torque, the synchronizer ring being pushed by the lever members pressed by the high-speed-stage slanting surface of the sleeve so that the synchronizer ring is synchronized with the speed gear with pushing force generated due to a movement of the sleeve through the splines of the synchronizer ring, wherein
• the lever members turn over and transmit pushing force applied from the turn-over slanting surface of the sleeve to the synchronizer ring to press the friction surface of the synchronizer ring against the cone surface of the speed gear to synchronize the synchronizer ring and the speed gear when the sleeve moves in a direction opposite to a speed gear side, and wherein
• a diameter of the first inner diameter portion is set to be larger than a diameter of the second inner diameter portion.