KIT-CROSS & BEARING 1405883 - Caterpillar

Hydraulic Schematic (Pilot Circuit)
(7) Stick 1 control valve. (9) Parallel feeder passage. (13) Boom 1 control valve. (16) Logic valve. (21) Parallel feeder passage. (24) Selector valve. (27) Pilot line. (28) Solenoid valve II. (29) Pilot line. (30) Port. (32) Pilot line. (37) Port. (39) Drain port. (42) Pilot passage.When work mode switch (1) is set to position (3) for a side wall crowding operation, solenoid valve II (28) is energized. Spool (38) moves down. Passages (36) and (40) open, and passage (41) is closed. This allows no oil flow through pilot lines (27), (29) and (32). As a result, logic valve (16) is closed which in turn allows no oil flow from parallel feeder passage (9) to stick 1 control valve (7).Also, selector valve (24) remains open because the pilot pressure in pilot line (32) is equal to that in pilot passage (42).Straight Travel Control
Introduction
Control Valve Compartment
(1) Right travel. (2) Straight travel valve. (3) Left travel.
Hydraulic Schematic (Partial) (Only Right and Left Travel Activated)
(1) Right travel control valve. (2) Straight travel valve. (3) Left travel control valve. (4) Main control valves. (5) Line (from front pump outlet). (6) Line (from rear pump outlet). (7) Front pump. (8) Rear pump. (9) Pilot pump.If the upper structure or implements are operated while the machine is traveling, straight travel valve (2) makes sure that the machine travels straight. It also allows better control for operations such as pipe laying or placement of timbers.When the machine travels with no swing or implement operation, oil from front pump (7) drives the left travel motor and oil from rear pump (8) drives the right travel motor. Since both these circuits are separated, the machine continues to travel straight, unless a difference in travel resistance occurs between the right and left tracks.However, if a swing or implement operation was used during travel without the straight travel system, the amount of oil supplied from front pump (7) and rear pump (8) would differ. This would affect the oil supplied to the right and left travel motors and cause the machine not to travel in a straight line.The straight travel system makes sure that the machine travels straight when circuits other than the travel circuits are simultaneously operated while the machine is traveling. When straight travel valve (2) is actuated by pilot pressure, the following occurs.1. Front pump (7) supplies oil not only to the right travel circuit but also to the left travel circuit to drive both motors in parallel.2. The swing and implement circuits get their supply of pressure oil from rear pump (8). However, when the machine is traveling, the swing and implement circuits do not require a large amount of flow. They are operated at speeds low enough to keep the machine stable. Therefore, the remainder of the pressure oil is divided between the right and left travel circuits.Implement And Travel Operation
Hydraulic Schematic (Partial) (Bucket and Travel Activated)
(1) Return line. (2) Parallel feeder passage. (3) Main control valves. (4) Stick 1 control