ILM 190303 A Flashcards Preview

Heavy Equipment Technician 3rd Period- Powertrain > ILM 190303 A > Flashcards

Flashcards in ILM 190303 A Deck (26)
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1
Q

When a Gear Tooth is viewed lengthwise, what are the upper and lower portions named?

A

The upper portion is the face, the lower portion is the flank.

2
Q

What is Gear Tooth Pitch Line?

A

The centreline that seperates the face and the flank.

3
Q

When a gear tooth has a large end and a narrow end, what are they called?

A

The large end is the heel, and the narrow end is the toe.

4
Q

What is the lowest portion of gear teeth, how is it shaped and what is it for?

A

The Root Fillet, this is rounded, and designed for strength.

5
Q

What is the highest portion of each gear tooth called?

A

The tip.

6
Q

When a gear is being driven, or is coasting, what is the shape of each side?

A

The drive side acts upon the convex side, whereas the coast or vehicle weight moving the gear acts on the concave side.

7
Q

What is the gear pitch circle?

A

Pitch Circle is a method for measuring the diameters of a gear.

8
Q

What is the circular gear pitch? How is it measured and what is it for?

A

This is the measurement, in degrees, from pitch circle centreline between two teeth. This is measured from the middle of the pitch circle at centreline. This provides the teeth the greatest amount of useable force.

9
Q

What is Clearance, and what is it for?

A

The space between teeth tip and root fillet, for oil lubrication.

10
Q

What is tooth backlash, and what is it for?

A

Backlash is a measured amount of clearance between gear faces to allow for expansion and lubrication.

11
Q

What is the difference between a Crown gear and a Pinion gear?

A

A pinion gear is typically the smaller, and a crown is larger.

12
Q

What is a Non Hunting Gear Set?

A

A Non Hunting gear set is one where crown and pinion will divide equally. 2:1, 3:1, 4:1. It is always timed.

13
Q

What is a Partial Non Hunting Gear Set?

A

A Partial Non Hunting gear set typically has more teeth on the crown gear, resulting in a 4.25:1, 4.5:1 ratio.

14
Q

What is a Hunting gear set?

A

This gear allows each gear to contact all teeth resulting in a offset gear ratio such as 1.33:1.

15
Q

What is the Formula for finding Gear Ratio

A

Driven/Drive

16
Q

What changes occur in a reduction gearset?

A

Slower speed output, with higher torque.

17
Q

What changes occur in an overdrive gearset?

A

Higher speed output, with lower torque.

18
Q

What is a Spur Gear, and what are some disadvantages and advantages? Where would you see it used?

A

A Spur Gear has straight cut teeth, they are cheaper to manufacture create no end thrust, but are louder. Used on things such as PTO’s

19
Q

What is a Single Helical Gear, some advantages and disadvantages? Where might these be used?

A

These are cut on an angle to increase strength and reduce noise. The angled teeth cause axial thrust requiring thrust bearings.

20
Q

What is a Hypoid angle gear?

A

Beveled helical cut gears, with the centreline of the crown located below the driveline.

21
Q

What is an Amboid gear? What is the importance of these in off road systems?

A

Beveled helical gears that have the centreline of the crown gear above the driveline. This is important because of higher ground clearance.

22
Q

What can cause a Direct Drive in a Planetary?

A

If two members are locked, or driven at the same rotational speed.

23
Q

What can cause a Reverse in a Planetary?

A

The Carrier being the held component, which causes the output to reverse.

24
Q

What can cause a Reduction in a Planetary?

A

When the carrier is the driven component, the result is always a reduction.

25
Q

What can cause an Overdrive in a Planetary?

A

When the Carrier is the drive component, this causes an overdrive.

26
Q

What can cause a Neutral condition in a Planetary?

A

No members held, everything just spins.