Shfting Fits And Accesories Flashcards
What are the 5 main types of keys?
Square Pratt/Whitney/boxed/blind Tapered gib key Woodruff Step key
What is the benefit of a spline?
Allows a high torque transfer
What is the rule or thumb for the width of the square key?
1/4 of the diameter of the shaft
Why are woodruff keys used for and what are the numbers on them?
Light applications
The first two digits are width in 32’s and the second two numbers are diameter in in 8’ths
What application are gib head keys used?
What is the typical taper per foot
Used to transmit heavy loads
1/8 in per foot
Or
1in 96
Same thing
Which way do you lock the eccentric lock on a pillow block?
Towards the rotation of the shaft.
When do you use a Quick Detachable (QD) bushing?
Gear reducers, pulleys,
Sprockets
Hubs
Etc
What’s the difference between split taper bushing vs QD bushing?
Split tapers bushings have a split through it and externally and internally keyed
Describe a taper lock bushing?
Usually a series of 3 large set screws. To install bushing and sprocket line up the non threaded holes on the bushing with the threaded holes on the sprocket.
To disassemble move the set screw to the threaded holes on the bushing and tighten
How are tapered sleeve bearing set?
Slide the tapered sleeve on shaft, slide bearing on sleeve, fit lock ring and tighten lock nut.
As you tighten the lock ring it pushes bearing up the sleeve locking it to the shaft and taking up the clearance on the bearing.
What are the different types of locking and positioning devices?
Set screws Tab washers Shear pins Tapered dowel pins Retainer rings Self locking rings Spiral wound rings
What are the two factors that affect shaft selection?
Bending stress
Torsional shear stress
On a 4 inch hollow shaft with a 2” inside bore what is the weight reduction to the Torsional strength reduction?
25percent weight reduction
6.25 percent strength reduction
What is the recommended maximum distance between bearings on a line shaft?
8 ‘
Where is the ideal spot for the bearings on a line shaft?
As close to the gears, pulley’s and sprockets as possible.
What is the purpose of the floating bearings?
To allow for expansion
Where does the fixed bearing go on a line shaft?
As close to the main drive as possible
What bearings are best suited for horizontal line shafts?
Pillow lock
What is added to steel to increase its harden-ability, abrasion resistance, and wear resistance?
Chromium
Describe tolerance?
Tolerance for any dimension is the total variation in size.
Describe fit?
The range of permissible tightness or looseness between mating parts.
What are the three fit types?
Clearance - indicates the shaft is always smaller then the bore
Transition - MMC interference, a minimum bore diameter and maximum shaft diameter.
- LMC clearance fit, maximum bore diameter with minimum shaft diameter
Interference - shaft is always larger than the bore.
What are the 3 main groups for ANSI fits?
Running and sliding fits (RC) Locational fits (LC,LT, and LN) Force fits (FN)
Describe basic size?
The nominal size before tolerances are applied
What is allowance?
The intentional difference between two mating parts at maximum metal condition.
What is Maximum Metal Condition(MMC)?
Largest shaft into smallest hole
What are the three classes of fits?
Class 1 loose fit
Class 2 commercial fit
Class 3 high precision fit
What is the external thread symbol? (Die)
A