Mechanical Power Train
The Cat mechanical drive power train and power shift transmission provides unmatched operating efficiency and control on steep grades, in poor underfoot conditions, and on haul roads with high rolling resistance.
Transmission
Pairing the Caterpillar seven-speed planetary power shift transmission with the C15 diesel engine with ACERT Technology delivers constant power over a wide range of operating speeds.
• Transmission Chassis Control (TCC)
Transmission shifting is based on Transmission Output Speed for optimum performance efficiency and clutch life. The TCC provides integrated functionality to controlled throttle shifting, directional shift management, neutral coast inhibitor, body-up shift limiter and body-up reverse neutralizer.
Throttle Lock
The operator can now electronically lock the throttle pedal at full throttle, to reduce fatigue on long uphill hauls. The throttle can be locked on by momentarily depressing the throttle lock switch located on the operator console, while depressing the pedal fully. The throttle is released whenever braking is applied or the throttle is again depressed.
Lock-Up Torque Converter
Combines maximum rimpull and cushioned shifting of torque converter drive with the efficiency and performance of direct drive. The torque converter includes: an additional clutch plate to maintain power train capability for higher horsepower and top speed, a new torque converter adapter that provides extra length to house the additional clutch plate and enables the converter components to be changed without having to change the housing, and a new sump oil level switch that serves as an emergency warning if oil is lost. The lock-up torque converter engages at approximately 8 km/h (5 mph), delivering more power to the wheels.
Lock-Up Clutch
Quickly releases and re-engages to reduce power train torque loads for smoother shifting, long life and a more comfortable ride.
New Differential and Proven Final Drives
The new Cat differential works with the proven final drives as a system to deliver maximum power to the ground. For improved serviceability, the pinion gear is cantilever mounted, which allows inspection of the differential without pulling the rear-end. Visual inspection of the pinion gear and bearings can be performed in 1-2 hours versus 8 hours on the previous models. In addition, the differential bevel pinion gear set is designed for improved adjustability, which results in improved contact patterns and life. The differential gear set also provides enhanced bending life for steeper grade applications.
New Differential Center Housing
A new, ductile iron center housing improves quality and reliability. The improved stiffness allows for better main support bearing life. The new housing also uses bolts, reducing maintenance time. This change also improves wheel station bolted-joint life.
New A-Frame
The new A-frame mounts directly to the spindles. The new A-frame eliminates the “king” bolt and includes a pin and bushing style mounting, consistent with the 777 and 793. This new design is simpler to maintain and service.
New Ductile Iron Spindles
A stress-optimized, ductile iron spindle is splined to the rear brakes, reducing brake pack rebuild time by up to two hours. In addition, the spindles are longer and wider with fewer seals for increased strength and durability.
Brake Packs
A single-piece brake anchor eliminates more than 200 fasteners and a row of bolted joints. Rebuild time is reduced by up to two hours. In addition, the brake pack is removable without taking the spindle off the truck. The 770 features 24 brake discs. The brake discs have increased in diameter from 19 to 21 in (482.6 to 533.4 mm). By increasing the diameter, Caterpillar has improved the overall reliability and durability of the brake packs and has also designed the brake packs to improve the OD/ID ratio. The new 770 brake pack design, moves the braking forces to the outer edge of the disc, thereby using greater surface area for improved braking forces and longer life, improving reliability and lowering maintenance cost.
Wheel Stations
The wheel stations now integrate both the wheel and the hub. The single-piece design reduces removal and installation time, and the risk of brake cooling oil leakage. The inner Duo-cone™ seal has been changed from a formed type to a cast design. Brake cooling flow and the Duo-cone seal has also been reversed for better sealing performance and improved seal life. Wheel stations are now interchangeable, reducing the number of replacement parts: left and right wheel stations are symmetric and can be interchanged. In addition, the new design eliminates one o-ring seal, which improves reliability and simplifies the system and the wheel bearings have been enhanced for longer bearing life.
Tires
The 770 uses 18.00R33 tires as the standard tire configuration.
• Steering System
Hydraulic steering control system is designed for exceptional smoothness and precise control. A separate circuit prevents cross contamination for long life.
• Battery Powered Supplemental Steering
A battery powered supplemental steering system uses pressure accumulators and allows up to three 90 degree turns in case of engine failure.
• Wheels and Rims
Cast rear wheels and Cat center-mount rims are mounted using studs and nuts to minimize maintenance and maximize durability.
Mechanical Power Train
The Cat mechanical drive power train and power shift transmission provides unmatched operating efficiency and control on steep grades, in poor underfoot conditions, and on haul roads with high rolling resistance.
Transmission
Pairing the Caterpillar seven-speed planetary power shift transmission with the C15 diesel engine with ACERT Technology delivers constant power over a wide range of operating speeds.
• Transmission Chassis Control (TCC)
Transmission shifting is based on Transmission Output Speed for optimum performance efficiency and clutch life. The TCC provides integrated functionality to controlled throttle shifting, directional shift management, neutral coast inhibitor, body-up shift limiter and body-up reverse neutralizer.
Throttle Lock
The operator can now electronically lock the throttle pedal at full throttle, to reduce fatigue on long uphill hauls. The throttle can be locked on by momentarily depressing the throttle lock switch located on the operator console, while depressing the pedal fully. The throttle is released whenever braking is applied or the throttle is again depressed.
Lock-Up Torque Converter
Combines maximum rimpull and cushioned shifting of torque converter drive with the efficiency and performance of direct drive. The torque converter includes: an additional clutch plate to maintain power train capability for higher horsepower and top speed, a new torque converter adapter that provides extra length to house the additional clutch plate and enables the converter components to be changed without having to change the housing, and a new sump oil level switch that serves as an emergency warning if oil is lost. The lock-up torque converter engages at approximately 8 km/h (5 mph), delivering more power to the wheels.
Lock-Up Clutch
Quickly releases and re-engages to reduce power train torque loads for smoother shifting, long life and a more comfortable ride.
New Differential and Proven Final Drives
The new Cat differential works with the proven final drives as a system to deliver maximum power to the ground. For improved serviceability, the pinion gear is cantilever mounted, which allows inspection of the differential without pulling the rear-end. Visual inspection of the pinion gear and bearings can be performed in 1-2 hours versus 8 hours on the previous models. In addition, the differential bevel pinion gear set is designed for improved adjustability, which results in improved contact patterns and life. The differential gear set also provides enhanced bending life for steeper grade applications.
New Differential Center Housing
A new, ductile iron center housing improves quality and reliability. The improved stiffness allows for better main support bearing life. The new housing also uses bolts, reducing maintenance time. This change also improves wheel station bolted-joint life.
New A-Frame
The new A-frame mounts directly to the spindles. The new A-frame eliminates the “king” bolt and includes a pin and bushing style mounting, consistent with the 777 and 793. This new design is simpler to maintain and service.
New Ductile Iron Spindles
A stress-optimized, ductile iron spindle is splined to the rear brakes, reducing brake pack rebuild time by up to two hours. In addition, the spindles are longer and wider with fewer seals for increased strength and durability.
Brake Packs
A single-piece brake anchor eliminates more than 200 fasteners and a row of bolted joints. Rebuild time is reduced by up to two hours. In addition, the brake pack is removable without taking the spindle off the truck. The 770 features 24 brake discs. The brake discs have increased in diameter from 19 to 21 in (482.6 to 533.4 mm). By increasing the diameter, Caterpillar has improved the overall reliability and durability of the brake packs and has also designed the brake packs to improve the OD/ID ratio. The new 770 brake pack design, moves the braking forces to the outer edge of the disc, thereby using greater surface area for improved braking forces and longer life, improving reliability and lowering maintenance cost.
Wheel Stations
The wheel stations now integrate both the wheel and the hub. The single-piece design reduces removal and installation time, and the risk of brake cooling oil leakage. The inner Duo-cone™ seal has been changed from a formed type to a cast design. Brake cooling flow and the Duo-cone seal has also been reversed for better sealing performance and improved seal life. Wheel stations are now interchangeable, reducing the number of replacement parts: left and right wheel stations are symmetric and can be interchanged. In addition, the new design eliminates one o-ring seal, which improves reliability and simplifies the system and the wheel bearings have been enhanced for longer bearing life.
Tires
The 770 uses 18.00R33 tires as the standard tire configuration.
• Steering System
Hydraulic steering control system is designed for exceptional smoothness and precise control. A separate circuit prevents cross contamination for long life.
• Battery Powered Supplemental Steering
A battery powered supplemental steering system uses pressure accumulators and allows up to three 90 degree turns in case of engine failure.
• Wheels and Rims
Cast rear wheels and Cat center-mount rims are mounted using studs and nuts to minimize maintenance and maximize durability.
Box-Section Design
The 770 frame uses a box-section design, incorporating two forgings and 13 castings in high-stress areas with deep penetrating and continuous wrap-around welds to resist damage from twisting loads without adding extra weight.
• Steel Structures
Mild steel used throughout the frame provides flexibility, durability and resistance to impact loads, even in cold climates and allows for easy field repairs.
• Castings
Castings have large radii with internal reinforcing ribs to dissipate stress in areas of high stress concentration. Castings move welds to lower stress areas for greater frame life.
Integral Four-Post ROPS Cab
Resiliently mounted to the main frame with all-new cab mounts that reduce vibration and sound, the integral ROPS is designed as an extension of the truck frame. The ROPS/FOPS structure provides “five-sided protection” for the operator.
Forgings and Castings
- The 770 features a drop tube/casting design and two forged steel mountings for hoist cylinders, similar to the design as found on the 773.
- A volcano casting that holds the center tube is enhanced with thicker wall dimensions for increased durability.
- New strut-mount castings have been moved 10 in (254 mm) forward and 1 in (25.4 mm) outward on each side. These thicker strut-mount castings and their location improve ride characteristics as well as durability.
- New steering casting (same as 773) accommodates larger steering cylinders and ball studs.
- New tail casting accommodates new angled rail design.
Superior Weld Quality
Structural frame welds are J-groove type, ensuring full weld penetration for strength and longevity. During fabrication, weld integrity is further enhanced by rotating the frames 360 degrees to provide optimal, flat welding surfaces.
Technology Enhanced
Caterpillar structures are tested using System Structural Analysis (SSA) to dynamically simulate operations in field environments and identify potential structural improvements in high stress areas. With analysis of machine structures and variables, such as haul road and payload, structural improvements were made to the frame to accommodate the new cab, platform, engine and radiator.
Quality Control
A Coordinate Measuring Machine (CMM) is used to inspect truck frames for consistency in the manufacturing process. In addition, all critical welds receive testing to verify weld penetration, which results in frame durability.
Structural frame welds are J-groove type, ensuring full weld penetration for strength and longevity. During fabrication, weld integrity is further enhanced by rotating the frames 360 degrees to provide optimal, flat welding surfaces.
Caterpillar structures are tested using System Structural Analysis (SSA) to dynamically simulate operations in field environments and identify potential structural improvements in high stress areas. With analysis of machine structures and variables, such as haul road and payload, structural improvements were made to the frame to accommodate the new cab, platform, engine and radiator.
A Coordinate Measuring Machine (CMM) is used to inspect truck frames for consistency in the manufacturing process. In addition, all critical welds receive testing to verify weld penetration, which results in frame durability.
