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Transmission Design and Function
The Komatsu TORQFLOW transmission is a robust power-shift system commonly equipped on Komatsu dozers and heavy equipment models such as the D155A-8 and D475A-8. It combines a water-cooled, three-element, single-stage torque converter with lock-up clutch and a planetary gear train featuring multiple-disc clutches. This design ensures smooth power delivery, efficient gear shifting, and reliable traction under heavy loads.
Key Features
Users of TORQFLOW transmissions appreciate the blend of power, fuel efficiency, and durability. The automatic lockup feature notably reduces fuel consumption during steady-state operations, a critical factor in heavy equipment lifecycle cost control. The design also yields smooth operator experience with reliable gear shifting even under heavy loads.
Conclusion
The Komatsu TORQFLOW transmission represents advanced powertrain engineering tailored for heavy equipment requiring efficient power delivery, reliable shifting, and robust cooling. Its combination of torque converter technology, planetary gear sets, hydraulic actuation, and modern electronic control makes it well-suited for diverse heavy machinery applications from dozing to hauling under demanding field conditions. Proper maintenance of hydraulic and lubrication systems ensures long-term performance and equipment uptime.
The Komatsu TORQFLOW transmission is a robust power-shift system commonly equipped on Komatsu dozers and heavy equipment models such as the D155A-8 and D475A-8. It combines a water-cooled, three-element, single-stage torque converter with lock-up clutch and a planetary gear train featuring multiple-disc clutches. This design ensures smooth power delivery, efficient gear shifting, and reliable traction under heavy loads.
Key Features
- Torque Converter: The 3-element, 1-stage, water-cooled torque converter with lock-up clutch improves torque multiplication during initial movement and enhances fuel efficiency by locking up at higher speeds.
- Planetary Gear System: Offers multiple-disc clutch operation with hydraulic actuation allowing quick and smooth gear changes.
- Hydraulic Actuation: Clutch packs and gear shifts are controlled hydraulically for precise and consistent operation.
- Force Lubrication: The transmission uses a gear pump to provide force lubrication, ensuring proper cooling and reduced wear among clutch discs.
- Gearshift Safety: Equipped with gearshift lock levers and neutral safety switches to prevent accidental starts or shifts.
- Gear Options: Typically includes three forward speeds and three reverse speeds, sometimes with multiple low or high ranges depending on model.
- Speeds: Forward travel speeds range generally from about 3.4 km/h (2.1 mph) in 1st gear to 14.3 km/h (8.9 mph) in 3rd gear.
- Reverse Speeds: Reverse speeds are slightly higher at each gear to support maneuvering, from 4.4 km/h (2.7 mph) 1st gear reverse up to 14.3 km/h (8.9 mph) 3rd gear reverse.
- Heat Dissipation: Water cooling and forced lubrication help maintain optimal operating temperatures, supporting durability in tough field conditions.
- The hydraulic control unit uses a closed-center load sensing system (CLSS) for precise control of transmission and other hydraulic functions.
- External spool control valves simplify maintenance access.
- Oil filters are full-flow to ensure clean lubrication.
- Operators can switch between manual and automatic gearshift modes to suit different operating conditions—automatic mode optimizes fuel efficiency by managing shifts according to load, whereas manual mode provides rigid control, useful in precise earthmoving or ripping tasks.
- Gearshift lock and neutral safety features help protect both operator and equipment during operation.
- Torque Converter: A device transferring rotating power from engine to transmission while amplifying torque at lower speeds.
- Lock-up Clutch: A clutch within the torque converter that locks the input and output to eliminate slippage at higher speeds.
- Planetary Gear Train: Gear set providing multiple gear ratios compactly.
- Power Shift Transmission: Transmission that allows gear changes under load without clutching.
- Closed-Center Load Sensing (CLSS): Hydraulic system that maintains optimal flow and pressure to components based on demand.
Users of TORQFLOW transmissions appreciate the blend of power, fuel efficiency, and durability. The automatic lockup feature notably reduces fuel consumption during steady-state operations, a critical factor in heavy equipment lifecycle cost control. The design also yields smooth operator experience with reliable gear shifting even under heavy loads.
Conclusion
The Komatsu TORQFLOW transmission represents advanced powertrain engineering tailored for heavy equipment requiring efficient power delivery, reliable shifting, and robust cooling. Its combination of torque converter technology, planetary gear sets, hydraulic actuation, and modern electronic control makes it well-suited for diverse heavy machinery applications from dozing to hauling under demanding field conditions. Proper maintenance of hydraulic and lubrication systems ensures long-term performance and equipment uptime.
