Transmissions Flashcards
What is transmissions achieved by
belts, cables, control chains, chainwheels, pulleys and levers.
Chains.
provide strong, flexible and positive connections and are generally used wherever it becomes necessary to change the direction of control runs in systems where considerable force is exerted.
Control column installation
Where can a change in direction be found
- Control column installations
- Aileron and elevator controls
- Trim control systems
How are chains classified
their pitch, roller diameter and width between plates.
Chain drives
for non-slip power transmission with large spaces between axles when cogwheels are not available to decrease the size of the spaces.
Roller chains and gear chains
Low frictions
Smooth running
Roller chains
Don’t require much maintance
Work with any disturbance
Gear chains
cogged lugs which engage into the gaps between the teeth of the chain wheel. They are virtually silent in operation. The number of teeth of the chain wheels should not be smaller than 17 with regard to wear.
Chain classification
Pitch
Width between inner plates
Diameter of rollers
Change of direction of a chain by 90 degrees is achieved by
Biplaner lock
Trim control
cogged lugs which engage into the gaps between the teeth of the chain wheel. They are virtually silent in operation. The number of teeth of the chain wheels should not be smaller than 17 with regard to wear.
Number of theeth on a roller chain
No less than 12
Number of theeth on a gear chain
No less than 17
Irreversible chain link
To stop chain to be fitted wrong way round
Heart shape
What is a couplings
Couplings are used to connect two shafts with each other. They are classed as:
• Solid couplings
• Movable and disconnectable couplings
• Safety couplings
Solid couplings
Rigid connection
Sleeve ans disk coupling
Sleeve consists of 2 iron cast sleeve fixed into shaft end. If the contact pressure is not high enough to transfer the torque, adjusting springs are added.
Disk coupling two dicks fitted to shaft end, cylindrical insertion or a centre plate to ensure two disks are balanced
Movable couplings
comprise expansion couplings, hinge couplings and elastic couplings. They are used if the shafts are not in alignment or if the position of the shafts change during operation.
Cross links
such as universal joints, are suitable to transfer stronger forces, such as in cars. If the journals of the journal cross assembly run in pin bearings, these links need no maintenance.
Extension coupling
allow a small longitudinal movement of one shaft in relation to the other
Claw coupling
Hinge coupling
comprise cross-links, dry-disc joints and ball- and socket- joints. They are used where the direction of the axes of the shafts linked to the couplings change in a certain, limited angle.