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TRANSMISSION - Coggle Diagram

- - - - Input shaft (from clutch)
      - Countershaft (layshaft)
      - Output shaft
      - Constant mesh gears
      - Synchronizer assemblies
      - Shift fork & shift lever
      - Single clutch (between engine and gearbox)
    - - Engine torque → clutch → input shaft.
      - All gears are constantly meshed.
      - Driver selects gear using shift lever.
      - Synchronizer locks selected gear to output shaft.
      - Power path: Input shaft → countershaft → selected gear → output shaft.
      - Different gear ratios provide torque multiplication or speed increase.
      - Reverse gear uses an idler gear to reverse rotation.
  - - - Main transmission (like 1-stage manual)
      - Additional range gearbox or splitter
      - Extra gear set for high/low range
      - Two shifting mechanisms
      - Single clutch
    - - First stage: main gearbox selects gear (1,2,3,4…).
      - Second stage: range or splitter changes gear ratio again (High/Low).
      - Power flow:
        Engine → clutch → main gearbox → auxiliary gearbox → output shaft.
      - Provides more gear ratios without increasing gear pairs in main box.
  - - - Torque converter (instead of clutch)
      - One or more planetary gear sets
        
        Sun gear
        
        Planet gears
        
        Ring gear
        
        Planet carrier
      - Multi-plate clutches
      - Brake bands
      - Hydraulic control system (valve body)
      - ATF (automatic transmission fluid)
    - - Torque converter transmits and multiplies torque hydraulically.
      - Gear ratios achieved by
        
        Locking one planetary member
        
        Driving another
        
        Taking output from the third
      - Different combinations produce
        
        Reduction
        
        Direct drive
        
        Overdrive
        
        Reverse
      - Gear shifting is automatic via hydraulic or electronic control.
  - - - Two variable-diameter pulleys (drive & driven)
      - Steel belt or chain
      - Hydraulic or electronic actuator
      - Torque converter or start clutch
      - Control unit
    - - Each pulley consists of two movable cones.
      - Changing distance between cones changes effective diameter.
      - As drive pulley diameter increases → driven pulley decreases.
      - This creates infinite gear ratios within range.
      - No fixed gear steps.
  - - - Two clutches
        
        Clutch A (odd gears: 1,3,5…)
        
        Clutch B (even gears: 2,4,6…)
      - Two input shafts (one inside another)
      - Gear sets similar to manual transmission
      - Mechatronic control unit
    - - One gear engaged while next gear is pre-selected.
      - Example
        
        Gear 1 active (Clutch A)
        
        Gear 2 already engaged on other shaft
      - During shifting
        
        Clutch A disengages
        
        Clutch B engages simultaneously
      - Very fast and smooth shifting.
      - No torque converter.