Chapter 3, Intro to drivetrains

How do you find a gear ratio?

# of teeth on driven / # of teeth on drive (driven over drive)

What are the three things a drivetrain must do?

1. Control power 2. Multiply the engine torque 3. Control the engine speed

Gear ratios can be used to increase 1. Horsepower or 2. Torque? 1. Horsepower 2. Torque 3. Both 4. Neither

2. only torque

How much differentials do a AWD vehicle have?

3

The Society of automated engineers created the SAEJ2807, this is a set of _______ tests used to measure the _______ _________ of a vehicle.

3 tests, climbing, accelerating and launching Towing capacity

Drive-tire and wheel diameter will affect? 1. Vehicle speed 2. Tractive force 3. Both 4. Neither

3. Both

At a constant vehicle speed, which gear ratio will result in a higher engine RPM? 1:1 or 3:1

3:1 because it has a bigger gear reduction

Tech A says that bevel gears are used on a diff ring and pinion, Tech B says that hypoid gears are a set of gears that are almost the same as spiral bevel gears because of their perpendicular 90 degree position but are not the same becasue in a spiral bevel gear one gear is below the other gears centerline. Who is correct? 1. A 2. B 3. Both 4. Neither

4. Neither, Bevel gears are used in the carrier for the side gears not for the ring and pinion. Hypoid gears is where one gear is located below the centerline.

Tech A says that Spur gears are slanted and louder, Tech B says Helical gears are straight and quieter who is correct? 1. A 2. B 3. Both 4. Neither

4. Neither, Spur gears are straight and loud, helical gears are slanted and quieter

The transmission is in first gear, which has a 2.5:1 ratio and the rear axle has a ratio of 2:1 the overall gear ratio is?

5:1

A transaxle is a combination of?

A transmission, final drive gear and differential

A gear set that is used to transmit power between two shafts that meet at a right angleis called? A. Hypoid Gear set B. Spiral Bevel Gear set C. Both D. Neither

C. Both

Which car will require the most trasmission gear ratios? A. Light car, small engine B. Light car, big engine C. Heavy car, small engine D. Heavy car big engine

C. Heavy car, small engine because the small engine will have to multiply the output enough to move the heavy car

True or false, 4WD and AWD vehicles use transfer cases.

False, AWD vehicles use an interaxle differential which is not considered a transfer case

In an even set of gears, the directional flow is the same. In an odd set of gear the dirctional flow is the opposite, true or false?

False, Even set is reversed, Odd set is reversed

Spiral Bevel gears may be found in a RWD axle, true or false?

False, Most RWD axles use bevel gears for the side gears. Spiral bevel gears are usually used for the differential carrier ring and driveshaft pinion gear

To find a overall gear ratio, add the first gear to the final drive gear, true or false?

False, Overall gear ratio is determined by multiplying the first gear ratio and the final gear ratio

In order for low/first gear to get the moving going, it must have the smallest gear reduction, true or false?

False, it must have the biggest gear reduction

Low/First gear must provide enough torque to get the vehicle coasting, true or false?

False, must provide enough torque to get the vehicle moving

True or false, the Clutch must engage completely all at once?

False, the clutch must slip a little when engaging.

In a planetary gear set the ring gear is meshed with the sun gear, true or false?

False, the ring gear is meshed with the carrier gears and the carrie gears are meshed with the sun gear.

What kind of gear is this?

Gear rack

What is the gear set called if the drive gear is smaller than the driven gear?

Gear reduction

A driveshaft often used on a vehicle with Independant rear suspension is often called?

Halfshafts

__________gears have their teeth cut at an angle

Helical

__________gears and quiter than ______________ gears

Helical, Spur

What is the equation for horsepower using torque?

Horsepower = Torque x RPM/5252

_______gears are used in most RWD vehicles differentials

Hypoid

When is a transfer case used, where is it usually located and why is it needed?

In 4wd cars. It is needed to split power to front and rear axles.

Where are worm gears usually found?

In speed gears

What shift mode should be used when descending a steep hill?

Low

Can a gear ratio ever be 1:5 or 1:2?

No because in a gear ratio you are seeing how much times the drive gear must rotate in order for the driven gear to make 1 revolution.

What is the gear set called if the drive gear is bigger than the driven gear?

Overdrive gear

The gear ratios in a transmission are used to match _________ and __________ to the requirement of the vehicle.

RPM, Torque

Drive vs Driven what is it?

Set of gears, one gear is the input one gear is the output. Input is considered drive and output is considered driven.

What kind of gear set is this?

Spiral Bevel

________gears have their teeth cut straigh

Spur

What is torque?

Torque is the rotating or twisting force that may or may not result in motion

Gears can be used to modify torque. True or false?

True

The speed of the vehicle is determined by the speed of the engine, overall gear ratio and diameter of the drive tires, true or false?

True

True or False, Highest gear should provide an engine speed sufficient enough for fuel efficient opperation?

True

A differential drives two wheel at different speeds, true or false?

True, it can, but not all the time.

Describe an automated manual tranmission?

Uses two clutches and a manual transmisson type gear. It is shifted hydraulically by computer controlled solenoids. (

What kind of gear set is this?

Worm

What is the purpose of an interaxle on an AWD vehicle?

allows the front-to-rear wheel speed differential

In a planetary gear set the ring gear and carrier gear is condered a?

external and internal gear set

4WD vehicles use a inter-axle differential , true or false?

false, inter- axles are used in AWD

An AWD and 4WD vehicle may contain up to 4 driveshafts, true or false?

false, most AWD vehicles and some 4wd vehicles may contain up to 4 halfshafts or axle shafts

To find overall gear ratio multiply the first drive gear and the final drive driven gear, true or false?

false, to find overall gear ratio you must first find the gear ratio of the first set and the final drive set and multiple the two ratios together

Gear seperation

happens when one gear drives another gear, the force will cause the two gears to want to seperate

What kind of gear set is this?

hypoid

Does an idler gear affect the gear ratio?

no, the gear ratio will still be based off the driven and drive gear.

A turning form of mechanical power that passes through a rotation shaft is called?

torque

A differential is usually composed for 4 or more gears, true or false?

true

Some transfer cases are two- speed and include a set of reduction gears for lower speed, high torque operation. True or false?

true

The pitch diameter of a gear is measured at the middle of the contact area of the tooth, true or false?

true

Gears can be used to increase speed and reverse direction, true or false?

true, it can also be used to increase torque