Dual drive axles, often found in heavy-duty vehicles like trucks, utilize a system where power is delivered to two rear axles instead of just one. This setup, commonly known as a tandem drive, significantly enhances traction and load-carrying capacity.
At the heart of a tandem drive system with a power divider is the mechanism that manages the distribution of power between the two axles.
The Role of the Power Divider
In a typical tandem drive setup, the power from the transmission goes to a component called a power divider. The power divider's primary function is to split the engine's torque between the front and rear axles of the tandem set.
According to the reference, the power divider works like a differential lock between the two axles. This is a crucial function because it ensures that both axles will run at the same speed, even during loss of traction.
- Enhanced Traction: If one axle loses traction (e.g., on slippery surfaces), the power divider prevents all the power from going to the slipping axle. By locking the speed between the two axles, it forces the axle with traction to continue receiving power, allowing the vehicle to maintain movement.
- Load Distribution: Distributing the driving force across two axles helps manage heavier loads more effectively.
Individual Axle Differentials
While the power divider manages the speed between the two axles, each individual axle still contains its own standard differential. The reference states that each axle's differential means that the wheels on either end can run at different speeds to help with cornering.
- Cornering Ability: When a vehicle turns, the wheels on the outer side of the turn travel a greater distance than the wheels on the inner side. The differential in each axle allows the left and right wheels on that specific axle to rotate at different speeds, preventing tire scrub and strain on the drivetrain during turns.
- Combination: The system combines the power divider (locking speed between axles) with individual axle differentials (allowing speed difference between wheels on the same axle) to provide both enhanced straight-line traction and the ability to corner smoothly.
System Components
A dual drive axle system typically includes:
- Transmission: Provides the initial power and gear reduction.
- Drive Shaft: Connects the transmission to the power divider.
- Power Divider: Splits power between the two axles and can lock their speeds together.
- Inter-Axle Drive Shaft: Connects the power divider to the second axle.
- Rear Drive Axles (2): Each contains a differential and final drive gears to transmit power to the wheels.
In summary, dual drive axles, particularly tandem drives with a power divider, work by delivering power to two axles. The power divider ensures these two axles rotate at the same speed for maximum traction, acting like a differential lock between them. Simultaneously, the differential within each axle allows the wheels on opposite sides of that axle to turn at different speeds, which is essential for smooth cornering.
