Honda TRX680FA Service Manual page 52

TECHNICAL FEATURES
TORQUE CONVERTER
STRUCTURE
• Pump
The pump, directly connected to the crankshaft, converts engine output (torque) into oil flow.
• Turbine
Receiving the oil from the pump, the turbine transmits the torque to the transmission by way of the primary drive gear.
• Stator
The stator changes the direction of the oil flow drained from the turbine. It drains the oil toward the pump.
• Stator Shaft
It transmits the stator rotation to the one-way clutch.
• Stator One-way Clutch
The stator one-way clutch locks the stator at stalling and it releases (rotates) the stator at coupling (page 2-8).
• Inner Collar
The inner collar, prevented from turning by the stopper pin fixed on the crankcase, stops the rotation force at stalling,
which is transmitted from the stator by way of the one-way clutch.
• Engine Brake One-way Clutch
When the engine braking is applied, the engine brake one-way clutch directly transmits the input torque from the pri-
mary drive gear to the crankshaft. This allows the machine to slow down by engine braking.
• Seal Ring and Seal Collar
The seal ring and seal collar are provided to prevent oil leakage.
TURBINE BLADES
PUMP BLADES
STATOR BLADES
ENGINE BRAKE ONE-WAY CLUTCH
SEAL RINGS
STATOR ONE-WAY CLUTCH
Hydraulic Oil
SEAL COLLAR
INNER COLLAR
PRIMARY DRIVE GEAR
STOPPER PIN
OPERATION PRINCIPLE
1. Oil Flow:
The oil in the torque converter flows in this order; from the pump, to the turbine, and to the stator. The oil is supplied
from the inside of the pump, and the excess oil is drained from the turbine. The torque converter is cooled down by
draining (exchanging) the excess oil.
2. Stall Range:
When the difference of rotation speed between the pump and turbine is large, the stator turns in the reverse direction
from that of the turbine by receiving the reaction force from the turbine. As this motion is locked by the one-way clutch,
the counter torque is applied to the stator. To balance the rotation direction, the turbine torque (output torque) becomes
the sum of the pump torque and counter torque of the stator. Therefore, the output torque is amplified by the amount of
counter torque of the stator.
3. Coupling Range:
When the difference of rotation speed between the pump and turbine is small (0.8 or more), the reaction force applied
from the turbine to the stator is small and the stator turns in the same direction as that of the turbine. As the torque is
not amplified this time, the torque ratio is about 1.0 and the torque transfer efficiency to speed ratio changes in the ratio
of 1:1.
4. Engine Braking:
The input force from the primary drive gear is directly transmitted to the crankshaft by the one-way clutch, which pro-
duces the engine braking (Same as the conventional ATV).
2-8