Case 1650K Crawler Dozer Service Manual

Table of Contents

1. General
2. Engines
3. Fuel System
4. Electrical System
5. Track System
6. Power Train
7. Brakes
8. Dozer Hydraulic System
9. Mounted Equipment

Manual Extract

The 1650K is equipped with a steering differential letting a dozer to transmit constantly power while steering to both track chains, changing the speed without never blocking the track. The speed of one track chain increases or decreases in the same entity with respect to the other, without any loss of power while pushing. It is particularly advantageous also for finishing jobs, especially in particularly closed spaces. When pilot valve (Ms) is actuated, oil is forwarded to steering piloting block (Vp), thus piloting directly steering spool on control valve (D).

Piston pump (P) driven by the torque converter powers both the steering circuit and the equipment circuit through the control valve. The regulation of the flow distribution system operates under priority logic for the steering, through the Load Sensing between control valve and pump.

When high performance is required by the steering, when operating the steering and equipment at the same time, it would occur that at a high pressure of 190 bar, the flow to the equipment is zeroed, since it is fully absorbed by the hydraulic motor.
Thus, the advancing speed remains unchanged, since the power subtracted from one track chain is added in the same entity to the other, providing a constant steering without locking the track chain and with a precise control on the trajectory.
When the travel is straight without operating the equipment, the power flows fully to the bevel gear set and thus the track chains that being linked to move at the same speed, since the hydraulic motor is, in this case, inoperative.
In the vent the pilot valve is actuated in neutral, the pump delivery flows entirely toward the hydraulic motor without actuating the equipment.

This makes provides the two track chains to be moving in opposite directions (counter rotation) at a speed of 0 through 2 km/h. Thus the machine is capable of turning on itself providing a rightward counter rotation when the right pilot valve is actuated and leftward when the left pilot lever is actuated.