MOLDBOARD AS 9D1669 - Caterpillar

Illustration 1 g03785877
Differential lock disengaged
(A) Differential lock actuator
(B) Differential lock solenoid valve
(C) Supply pressure from the implement valve
(D) Pressure reducing valve
Illustration 2 g03785879
Differential lock engaged
(A) Differential lock actuator
(B) Differential lock solenoid valve
(C) Supply pressure from the implement valve
(D) Pressure reducing valve The front axle is equipped with a locking differential. The action of the differential can cause the drive to be lost in adverse ground conditions if the resistance under one wheel is low. In these circumstances, all the drive will be transferred to the wheel with the least resistance.The locking differential enables the axle shafts of the universal joints to be locked together. Both wheels can then rotate at the same speed and torque regardless of different ground resistance between the wheels.
Illustration 3 g02735523
Illustration 4 g03387565The differential lock is controlled by a momentary trigger switch located on the joystick.The differential lock is controlled in the following way:
The differential lock is engaged by oil pressure when the trigger switch is continuously depressed down.
The differential lock is disengaged by spring force when the trigger switch is released.The trigger switch for the differential lock control operates an on/off solenoid valve. When the trigger switch is pulled, a ground is applied to the differential lock circuit in the Electronic Control Module (ECM). The ECM powers on the differential lock solenoid in response to the ground signal from the switch. Supply oil is supplied to the differential lock solenoid from the implement valve. When the trigger switch is released, the ECM will no longer have a ground applied to the differential lock circuit. With no ground on the differential lock circuit, the ECM powers off the differential lock solenoid. With the differential lock solenoid disabled the hydraulic pressure in the differential lock vents to tank and the lock releases.The pressure reducing valve (D) is responsible for controlling differential lock pressure within a tight range, regardless of the implement supply pressure.
Illustration 5 g02735531
(1) Housing
(2) Bevel gears
(3) Differential housing
(4) Piston
(5) Sliding sleeve
(6) Spring
(7) Cover housing
(8) Pressure cap
(9) Pressure ring
(10) Clutch disc In normal operation, the differential is unlocked and the axle shafts are free to rotate at different speeds. The wheel speed is governed by the resistance at the wheel.When the trigger switch is pressed, the solenoid valve (B) activates and sends oil pressure to the differential lock. Oil pressure from the solenoid valve exerts pressure on piston (4). The piston moves the sliding sleeve (5) against pressure cap (8). Pressure cap (8) exerts pressure on to pressure ring (9) forcing the clutch discs together. This action causes the differential to lock. When the trigger switch is released, solenoid valve (B) vents to tank, the oil behind piston (4). Spring (6) forces piston (4) back into the unpressurized position within the housing. This action relieves the force exerted on the clutch discs and unlocks the differential.