gears fundamental Flashcards
Gears are positive power transmission device that are used where there can be no slippage? True or false
True
The pinion gear is usually the smaller gear true or false?
True
Most gears are made to the standards set by the AGMA true or false?
True
A drive using helical gears can have the gears set up so they are over hung true or false?
True
In a compound gear system, there can be six gears and four shafts true or false?
True
The flank of the gear tooth is located in the addendum true or false?
False. The tooth flank is the contact part of the tooth below the pitch circle (dedendum) including the fillet
A gear set that has a 20° pressure angle is stronger than a great set with a 14 1/2° pressure angle true or false?
True
It is best to measure the backlash of a great set at the pitch circle. True or false?
True
A gear with a diameter pitch of 4 has very small teeth true or false?
False. Gear that has a diameter pitch of 4 has larger teeth
A gear train that has 15 gears meshing together with the input gear rotation in the clock wise direction.The output gear should turn in the counter clockwise direction. True or false?
False. Odd number of teeth turn in the same direction.
If there are several gear reductions in a gearbox, with ratios of 4:1,5:1 and 2.5:1, the final reduction of the gearbox is 45:1 true or false?
False, the final reduction of the gearbox is 50:1
A gearbox has a 10:1 reduction driven by a 1hp electric motor at 1750rpm .The output from the gearbox is 10hp at a speed of about 175rpm true or false?
False, hp cannot be increased in a great set.
Helical gears with parallel shafts must use gears of the opposite hand true or false?
True
Double helical gears are good for high speed and heavy loads true or false?
True
A spur gear set that intersects at 90° must be if the same hand, true or false?
False, spur gears are straight cut and do not intersect
Herringbone gears are for light duty drivers. True or false?
False, they are used for heavy duty drivers
Spiral bevel gears look very similar to hypoid gears, true or false?
True
Hypoid gears have high sliding action and req an EP additives in the oil, true or false?
True
The heel of a Hypoid or spiral bevel gear is near the inner circle true or false?
False. The heel of a Hypoid or spiral bevel gear is near the outer circle.
Worm gears have a lot of sliding action true or false?
True
Worm gears are less efficient than most other types of gears true or false?
True
A double-throated worm and worm wheel gear set have maximum gear tooth contact true or false?
True
Where is the addendum?
It is the top half of the tooth.
Where is the dedendum?
Is at the bottom half of the tooth including the clearance.
What is working depth
Is the depth that the gear tooth extends toward the root of the mating tooth when both are in full mesh.This equal the addendum plus the dedendum minus the clearance.
What is clearance?
It is the space between the bottom land of one gear and the top land of the meshing gear. Clearance allows room for lubricant, thermal expansion of the gear and gear run out
Circular pitch ?
Also called gear pitch, is the distance from the center of one tooth to the centre of the next tooth at the pitch circle
Pitch circle?
The diameter at the pitch circle, also called the pitch diameter, approximately in the middle of the gear tooth
Diameter pitch?
This indicates tooth size, is the number of teeth on the gear divided by the pitch diameter.
Meshing mean?
Sliding to rolling action and back to sliding.
Idler gears do what?
They change the direction of rotation or keep it the same.They can connect two gears with a centre to centre distance that I’d greater than the diameters of the gears.They can function as movable gears this allows you to set the backlash and mesh pattern
Fixed speed gearbox drives.What are some types?
Parallel drives, angle drive, compound drives, planetary gear system
Simple planetary gear set consist of three parts what are they?
Sun gear,a carrier with planets gears mounted to it,a ring gear.
What are the two gear system’s?
Fixed speed gearbox drives, and planetary gear drives.
Are worm gear and wheel of the same hand true or false?
True which gives a very quiet, smooth and steady speed output.
If a worm gear has only a few starts it tends to be self locking?
Only true if it is new
The installation and gear set up for Hypoid gears is more critical than for spiral bevel gears true or false?
True and if set up incorrectly they whine or howl
Hypoid gears are used for and how are they set up?
Hypoid gear is a bevel gear that forms a drive between two shafts that cross over acc are at 90°.and they used for 90° mechanical drivesin many industrial applications and automotive and heavy truck differentials.
What is pressure angle?
I’d the angle between the line of action the points of contact as the gear turns and a line tangent to the pitch circle.
What is binding and how to check binding?
Check binding by rotating the gears without a load.and binding is where tight spots are felt.
Mitre gears have a ratio of what?
1:1
Where is most common angle bevel gears intersect at ?
90° but Zune intersect at other angles.
Are spiral bevel gears stronger than straight bevel gears?
Yes and give a smoother transfer of power because they have more teeth in contact at the same time.
What type of lube or additive is used in helical gear arrangements?
EP
The worm is always the____member?
Input
Pitchx#of starts=____?
Lead
What is one of the main disadvantage of a worm and worm wheel set?
Excessive sliding action on the teeth.
What worm and wheel arrangement gives the maximum tooth friction?
A double throated gear set.
What effect on the gear ratio does the idler gear have?
They have no effect.
