CASE IH AFX-8010 Service Manual

CASE IH AFX-8010 Service Manual
CASE IH AFX-8010 Repair Manual

How to Use this Manual
This manual is divided into Sections. Each Section is then divided into Chapters. Contents pages are included at the beginning of the manual, then inside every Section and inside every Chapter. An alphabetical Index is included at the end of a Chapter. Page number references are included for every piece of technical information listed in the Chapter Contents or Chapter Index.

Spreader Pump
The spreader pump (2) will pull oil from the hydraulic reservoir (14) and direct it to the spreader valve (4). The spreader valve will direct the full flow of pump on to the rotary air screen valve (5) once the spreader operation is completed. The rotary air screen valve will direct the full flow of pump on to the oil cooler (6) once the air screen operation is completed. In cold whether the cooler may cause excessive restriction so the by-pass valve (7) can direct the oil flow around the cooler the filter housing (9). The filter restriction is monitored by the filter sensor (11) and is protected by the by-pass valve (10). The filter directs the flow to the PFC pump inlet and the reservoir tank.

Fan Pump
The fan pump (3) will pull oil from the hydraulic reservoir (14) and direct it to the fan valve (8). The fan valve will direct the full flow of pump into the flow from the spreader pump headed to the filter base (9). The filter restriction is monitored by the filter sensor (11) and is protected by the by-pass valve (10). The filter directs the flow to the PFC pump inlet and the reservoir tank.

PFC Piston Pump
The PFC pump assembly is mounted to and driven by the PTO gearbox. The PFC pump will only produce the pressure and flow required meeting system demands when they occur. When discussing PFC hydraulics, it is important to realize that with the engine running the hydraulic system will always be in one of three modes:

  1. Low-pressure standby (could be thought of as neutral).
  2. Pressure and flow compensation (when the system is meeting the demand for oil).
  3. High-pressure standby (could be thought of as high-pressure relief).

The pump output is also directed to the parking brake / tow valve where a regulated pressure is created and maintained for the pilot operated valve assembles.

PFC Pump Operation
The PFC pump assembly is located directly in front of the reservoir. The PFC pump is an axial-piston type pump. When the drive shaft of the piston pump is rotated, the piston cylinder block, which is splined to the drive shaft, also turns. The piston block contains nine piston assemblies which have free swiveling slippers attached to the ball-end of the piston assembly. The slippers ride against the machined surface of the swash plate.

When the swash plate is tilted from neutral to its maximum angle by the swash plate control spring, the piston slippers follow the inclined surface of the swash plate and begin moving in and out of the piston block bore. Half of the piston assemblies are being pulled out of the piston block while the remaining half of the pistons are being pushed back into the piston block. As the pistons are pulled from the piston block, they draw oil into the piston block bores. This supply oil comes from the kidney shaped intake port. As the piston crosses over top dead center, the piston push the oil out of the piston block bores into a kidney shaped outlet pressure port. Each of the nine pistons completes this cycle for each revolution of the pump shaft. This causes a continuous even flow of oil from the pump.

The greater the swash plate angle, the greater the piston stroke. This increase in stroke causes more oil to be pulled into the pump and discharged out of the pressure port. When the engine is at high idle and the swash plate is at its maximum angle the pump output is approximately 152 l/m (40 GPM).

Pump Compensator
The pump compensator assembly controls the angle of the swash plate by directing oil to the swash plate control piston. The swash plate control piston will over come the swash plate control spring, placing the swash plate at the proper angle.

The main valve assembly, feeder valve assembly and steering hand pump each contain a signal port. The signal port and associated lines direct a signal pressure to the pump compensator. This signal pressure is equal to the system work pressure. The pump compensator will use this signal to place the piston pump swash plate at the proper angle to meet the system demand. The outlet pressure at the pump will be 27.6 bar (400 psi) higher than the signal line pressure due to the 27.6 bar (400 psi) spring in the compensator. The pump outlet pressure will continue to be 27.6 bar (400 psi) higher than signal line pressure until the high-pressure standby pressure is reached. After high pressure standby is reached, the pump outlet pressure and the signal line pressure will become equal.

Hydraulic Systems Low Pressure Standby
When there is no demand for oil flow, the pump will go into the low-pressure standby mode. Low pressure standby means low pressure and minimal flow in the system. When the engine is not running, no pressure exists in any circuit. In this state, the swash plate control spring is holding the piston pump at full stroke. When the engine is started and the pump begins to rotate, it will momentarily try to pump oil. This creates outlet pressure at the pump. This pressure is directed to the flow compensator spool and the high-pressure spool through passages in the piston pump back plate. The two spools in the pump compensator are both spring biased. The flow compensator spool has a 27.6 bar (400 psi) spring while the high-pressure spool has a 186.3 bar (3050 psi) spring. The pump pressure is directed to the non-spring side of these two spools. As pressure builds, it will cause the flow compensator spool to shift against its 27.6 bar (400 psi) spring. When the spool shifts it allows pump oil to pass to the pump control piston. This piston will extend and cause the swash plate to move against the control spring. The swash plate will move to a nearly zero degree angle, de-stroking the pump. In this condition, the pump will only move enough oil to make up for internal leakage within the system and maintain 31--41.5 bar (450--600 psi). The pump will remain in this position until there is a demand for oil. In low-pressure standby mode the pump produces less heat and uses less horsepower than an open-center system. Low pressure standby also makes starting the engine easier.

Minimum system pressure is 31--41.5 bar (450-600 psi) in the low-pressure standby mode. There is a 0.61 mm (0.024in) dynamic sensor orifice located in the steering priority spool. The dynamic sensor orifice connects the pump outlet port to the signal port of the pump compensator through the orifice check valve. If the oil in the signal line can flow through the steering hand pump too freely a 0.78 mm (0.031′′) orifice in the steering hand pump signal passage provides back pressure in the signal line. This signal pressure of 3.45--10.3 bar (50--150 psi) is sent to the spring-end of the flow compensator spool. The spring pressure of 27.6 bar (400 psi) plus the signal line back pressure puts the pump into low pressure standby mode ranging from 31-41.5 bar (450--600 psi).


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