Ch52 Heavy-Duty Drive Axles

3. Technician A says a differential gear set allows for drive axle wheel speed difference in turns. Technician B says a differential gear set can allow a single wheel on a drive axle to spin wildly while the other wheel remains stationary. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B

3.

5. When a vehicle is moving and no differential action is taking place, which fo the following is a correct statement about the spider and side gears? A. They are stationary inside the differential case. B. They are moving opposite to the case direction. C. They are each turning opposite directions. D. They are free-wheeling in the same direction.

5.

Plain bevel gear

A bevel gear set with straight-cut teeth.

Ring gear

A large bevel gear that is driven by a smaller pinion gear in the bevel gear set. Also known as a crown gear.

Planetary two-speed drive axles use

A planetary gear set to produce two ratios through the drive axle.

Pinion gear

A small driving gear

Planetary two-speed drive axle

A two-speed drive axle that uses a planetary gear set of the low range.

Although down-sped axles can help

Achieve greater fuel economy, they increase driveline torque.

Tandem or tridem systems use

Inter-axle differentials to divide the torque between the two or three axles.

Differential case

The housing that holds the differential gears.

Tridem

Three-drive axles connected by power dividers

1. In a single-speed drive axle, the differential case always travels at which of the following speeds? A. 50% of crown gear speed. B. 200% of crown gear speed. C. 0% of crown gear speed. D. 100 of crown gear speed.

1.

1. Technician A says drive axles allow the power from the engine to turn 90 degrees to turn the wheels. Technician B says a drive axle usually provides the last gear reduction in a drivetrain system. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B

1.

2. In a normal or non-locking differential, if one axle is turning at 96% of case speed, at what speed is the other axle turning? A. 96% of case speed. B. 100% of case speed. C. 104% of case speed. D. 92% of case speed.

2.

2. Technician A says a hypoid gear set has the pinion gear mounted above the centerline of the crown wheel. Technician B says a generoid gear set uses a stronger tooth design. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B

2.

3. The inter-axle differential is more susceptible to spinout damage than a main differential for which of the following reasons? A. It is smaller than a main differential B. It turns much faster than a main differential. C. It's differential case is smaller. D. It has to carry four times the torque of a main differential

3.

4. Which of the following describes a planetary double reduction drive axle? A. The axle has two speeds. B. It has a helical gear mounted on either side of the differential case. C. It uses a planetary gear set for high speed. D. It uses a planetary gear set for a compound ratio.

4.

Amboid gear

A bevel gear arrangement with the pinion gear mounted above the centerline of the crown gear.

Spiral bevel gear

A bevel gear set with spirally or helically cut gears.

Spider gear

A beveled gear that is a component of the differential gear set; it is fitted to the four legs of the differential cross and rotates with it. Also known as a differential pinion gear.

Differential pinion gear

A beveled gear that is a component of the differential gear set; it is fitted to the four legs of the differential cross and rotates with it. Also known as a spider gear.

Torsen

A biased torque differential form General Motors

TruTrac

A biased torque differential produced by Dana.

Crank axle

A dead axle in which the main beam is lower than the wheel spindles.

Drop center tubular axle

A dead axle used on river that drops in the middle.

Differential lock

A device that prevents differential action by locking one side gear to the differential case.

Proportional differential

A differential capable of sending more torque to one wheel than the other when a wheel slip condition is encountered. Also known as a biased torque differential.

Biased torque differential

A differential capable of sending more torque to one wheel than the other when a wheel slip condition is encountered. Also known as a proportional differential.

Inter-axle differential

A differential gear set that splits the available torque equally between two drive axles. Also called a power divider.

Power divider

A differential gear set that splits the available torque equally between two drive axles. Also called an inter-axle differential.

Controlled traction differential

A differential that allows the engine to build more torque before the wheels can slip.

Helical double reduction drive axle

A double reduction drive axle that uses a helical gear set for the second gear reduction.

Helical double reduction two-speed drive axle

A double reduction drive axle that uses two selectable sets of helical gears as the second gear reduction.

Integral carrier housing

A drive axle housing that does not have a removable carrier.

Removable carrier type

A drive axle housing with a removable carrier. Also called a banjo.

Banjo

A drive axle housing with a removable carrier. Also called a removable carrier type.

Double reduction drive axle

A drive axle that always uses two gear reductions.

Differential gear

A gear arrangement that splits the available torque equally between two wheels, while allowing them to turn at different speeds, when required.

Power dividers typically have

A gear pump to ensure adequate lubrication of the inter-axle differential gears.

Crown gear

A large bevel gear that is driven by a smaller pinion gear in the bevel gear set. Also known as a ring gear.

Spinout

A low-traction situation where one drive wheel or one drive axle spins wildly while the other remains stationary.

Planetary double reduction drive axle

A planetary drive axle that is permanently fixed in low range.

Tag axle

A rear non-drive axle mounted behind the drive axle.

Pusher axle

A rear, non-drive rear mounted axle, ahead of the drive axle.

Most truck steer axles are

A solid I-beam that is attached to the front suspension and has steering knuckles to allow the vehicle to be turned.

Durapoid gearing

A specially designed spiral bevel gear set designed to provide increased strength and load-carrying capability.

Down-speeding

A strategy that reduces rpm while still achieving desired road speed.

Locking differential

A system that actively prevents differential action from occurring when engaged.

Topoid

A type of amboid gear set with the pinion gear mounted even higher than a normal amboid set.

Hypoid gearing

A type of spiral bevel gear set that mounts the pinion gear below the centerline of the crown gear.

Hypoid gears are

A type of spiral bevel gear that mounts the pinion below the centerline of the crown gear. Hypoid gearing is by far the most popular gear design used in truck drive axles.

Tag and pusher axles typically have

Air suspension systems and can be raised or lowered by the operator, when necessary, to support the vehicle load.

Generoid

An asymmetrical tooth design similar to the durapoid; it gives added strength to the hypoid and amboid gear sets. Also called hypoid generoid.

Semi-floating axle shaft

An axle shaft that carries the entire weight of the vehicle on its outer end.

Full floating axle shaft

An axle that carries none of the vehicle weight.

Dead axle

An axle that supports vehicle weight only.

Self-steering axle

An axle with steering linkage that allows its wheels to automatically follows the curve of a turn.

An inter-axle differential splits the

Available torque between two drive axles, not the wheels.

The differential always splits the

Available torque equally between the two wheels. Spinning wheels in a low-traction condition can cause a lifetime of damage in a very short period of time.

Dead axles merely support the vehicle weight and have numerous subcategories. Tag axles are mounted

Behind the drive axles of the vehicle; pusher axles are mounted n front of the drive axle.

All drive axle gears are

Bevel gears - meaning that they intersect at an angle (90 degrees).

Durapoid gears are spiral

Bevel gears with an asymmetrical tooth design that adds strength.

Most drive axle lubrications is affected

By splash from the rotation of the crown wheel.

The drive axle is

Commonly misnamed the differential because the differential gear set is inside the drive axle. The drive axle and the differential are, however, different.

Differential gear set

Consists of two side gears, four pinion gears, and a cross; allows for speed difference between the two axle shafts of the drive axle when turning.

Differential locks are used

During low traction situations only.

Spinout situations are

Especially damaging for inter-axle differentials because inter-axle differentials turn at driveshaft speed, not at wheel speed.

Heavier vehicles use

Full-floating axle shafts.

Trailer axles come

In many types, depending on the trailer vocation.

The differential gears are contained

In the differential case.

Bevel gears are subdivided

Into several types, including: plain bevel, spiral bevel, durapoid, hypoid, amboid, topoid, and hypoid generoid.

Truck axles can be divided

Into three categories - steer axles, dead axles, and live axles.

LO 52-1 explain fundamentals of axles. LO 52-2 Explain the function and design of differential gear sets. LO 52-3 Describe the various types of differential gear sets. LO 52-4 Explain the design and operation of double reduction and multi-speed drive axles. LO 52-5 Explain the operation of inter-axle differentials (power dividers).

Lo 52-6 explain the role of drive axles and drivelines in greehouse gas reduction strategies.

Bias torque differentials can send

More torque to the wheel with good traction.

Bevel gear sets usually consist

Of a large crown (or ring) gear and a smaller pinion gear.

Worm-and-crown

Older drive axle gear arrangement capable of very high gear reductions in a compact space. Also known as worm wheel.

Worm wheel

Older drive axle gear arrangement capable of very high gear reductions in a compact space. Also known as worm-and-crown.

Side gears

Part of the differential gear set; the side gears are splined to the axles.

Tag and pusher axles can be

Self-steering to prevent tire scrub on turns.

Axle shafts on lighter-duty vehicles are called

Semi-floating

As a vehicle turns a corner, the inner wheel must

Slow down and the outer wheel must speed up. The differential gear set allows this to happen.

Spiral bevel gears are quieter and stronger

Than plain bevel and their pinion gears are mounted at the centerline of the crown gear.

Live axle

The axle that drives the vehicle by turning the power from the driveshaft 90 degrees to deliver it to the wheels and providing the final gear reduction in the drive train. Also known as a drive axle.

Drive axle

The axle that drives the vehicle by turning the power from the driveshaft 90 degrees to deliver it to the wheels and providing the final gear reduction in the drive train. Also known as a live axle.

Carrier

The component that holds the support bearings for the drive axle gearing.

Controlled traction differentials allow

The engine to build more torque before a wheel can spin in low traction situations.

Drive axles usually provide

The final gear reduction in a drive train so they are also known as final drives.

Differential cross

The mechanism that holds the differential pinion or spider gears. Also known as the differential spider.

Through shaft

The output shaft of an inter-axle differential. The rear side gear is part of or splined to the through shaft. Also known as output shaft.

Output shaft

The output shaft of an inter-axle differential. the rear side gear is part of or splined to the output shaft. also known as the through shaft.

The differential gear arrangement allows

The power from the engine to be split equally between two axle shafts., while allowing the axle shafts to turn at different speeds, when required.

Drive axles allow

The power from the engine to turn a 90-degree corner to send that power to the wheels.

Helical drop gear

The set of gears that drive the pinion gear of the front drive axle of a tandem.

Live axles actually drive

The vehicle, so they are also called drive axles.

Plain bevel gears are similar

To spur gears and have the same problems with noise and weakness. Plain bevel gear pinions are mounted at the crown gear's centerline.

Tandem

Two drive axles connected by a power divider.

Double reduction drive axles use

Two gear reductions at all times.

The differential gear set consists of

Two side gears, four pinion or spider gears, and a differential spider or cross.

Amboid gears are a

Type of spiral bevel gearing in which the pinion gear is mounted above the centerline of the crown gear. Amboid gears are typically found only in the rear-rear axle of a tandem drive vehicle.

Generoid or hypoid generoid gears have

asymmetrical tooth flanks for extra strength.