793D Off-Highway Truck Power Train: Rear Axle and Final Drive System & Gear Pump (Rear Axle Oil)

1.-Rear Axle and Final Drive System

(1) Priority Valve (2) Outlet to brake cooling motor (3) Oil filter (4) Pressure sensor (5) Auxiliary cooler (6) Rear axle cooling fan motor (7) Outlet to differential lube (8) Bypass valve (9) Final drive bypass manifold (10) Right final drive oil (11) Left final drive oil (12) Rear axle housing sump (13) Rear axle oil pump (14) Pump motor (15) Steering tank (16) Steering accumulator (17) Steering pump(18) Supply valve

The 793D has a continuous lubrication system for the rear axle. This system does not require the truck to be in motion in order to provide oil flow. This hydraulic system lubricates the bearings for the differential and bevel gear group and the bearings for the rear wheels. This hydraulic system also cools the bearings for the differential and bevel gear group and the bearings for the rear wheels. For the correct oil that should be used in the system, refer to the Operation and Maintenance Manual for your machine.

The steering pump (17) supplies oil to the priority valve (1) . The brake ECM controls the supply valve (18) that is based on a temperature sensor that is mounted in the rear axle housing (12) . Oil flow is directed to the pump motor (14) when the supply solenoid valve (18) is OFF. Oil flow is blocked to the pump motor (14) when the supply solenoid valve (18) is ON.

The pump motor (14) drives the rear axle oil pump (13) . The rear axle oil pump (13) sends oil to the rear axle oil filter (3) and to the final drive bypass manifold (9) . If the machine is equipped with an auxiliary cooler (5) , oil will flow through the cooler before the bypass valve. The auxiliary cooler (5) reduces the temperature of the oil.

The bypass solenoid valve (8) sends oil to the final drive and to the differential gear (7) or the bypass solenoid valve (8) will bypass the right final drive (10) and the left final drive (11) . This prevents the final drives from receiving too much oil under certain conditions.

Table 1

Rear Axle Lubrication Strategy
	Supply solenoid valve			Bypass solenoid valve
Rear Axle Oil Temperature	Cold 13° C (55.4° F) or less	Cool 15° to 56° C (59° to 132.8° F)	Hot 58° C (136.4° F) or greater	Cold 13° C (55.4° F) or less	Cool 15° to 56° C (59° to 132.8° F)	Hot 58° C (136.4° F) or greater
Not Moving 0 km/h (0 mph)	OFF ON after 5 min	OFF ON after 5 min	OFF	ON	ON	OFF
Moving 0 to 35 km/h (0 to 22 mph)	ON	OFF	OFF	ON	ON	OFF
Moving Fast > 35 km/h ( > 22 mph)	ON	OFF	OFF	ON	ON	5 min ON 1 min OFF
Gear Limit	3rd	4th	No

Note: When the supply solenoid is OFF, oil flow is directed to the rear axle lubrication pump motor. When the supply solenoid is OFF, the system is ON. When the supply solenoid is ON, oil flow is blocked to the rear axle lubrication pump motor. When the supply solenoid is ON, the system is OFF.

The brake ECM controls the system for the rear axle oil. The temperature sensor is located in the rear axle housing. The temperature sensor is the main control for the supply solenoid valve (18) and the bypass solenoid valve (8) . During start-up, the system is turned ON in order to charge the lube system. The system is turned OFF if the lube oil is cold. If the machine goes faster than 35 km/h (22 mph), the lube system is cycled. When the lube system is cycled, the system turns ON and the system turns OFF. The cycle prevents the final drives from filling with excessive oil. The gear limit is used to prevent the machine from running at high speed until the differential oil has warmed up.

2.-Gear Pump (Rear Axle Oil)

Location of the gear pump for the rear axle (1) Gear pump (2) Motor (3) Suction housing(4) Adapter

Gear pump for the rear axle (3) Suction housing (4) Adapter (5) Coupling(6) Suction screen

Gear pump (1) which provides lubrication oil to the rear axle is driven by hydraulic motor (2). The motor and the pump are connected by coupling (5) that is located in adapter (4). Hydraulic motor (2) is driven by fluid from the steering pump. This means that the rear axle can receive oil if the vehicle is at a stop or if the vehicle is moving. Oil flow is directed to pump motor (1) when the supply solenoid is OFF. Oil flow is blocked to gear pump (1) when the supply solenoid is ON.

Gear pump (1) pulls oil from the bottom of the rear axle housing through suction screen (6). The oil flows through the oil filter for the rear axle. Then, the oil flows through the final drive bypass manifold. The oil is directed to the final drives and the bevel gear. The oil is also distributed to the bearings of the rear wheels.

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793D Off-Highway Truck Power Train: Rear Axle and Final Drive System & Gear Pump (Rear Axle Oil) 2013-01-06T20:01:00-08:00 Rating: 4.5 Diposkan Oleh: Unknown