ENGINE AR 7E5565 - Caterpillar

Signal Resolver Network
Resolver Network Line Schematic
(1) Primary resolver. (2) Secondary resolver.Each control valve section in the implement hydraulic system has two resolvers, a primary resolver and a secondary resolver. Each resolver compares two pressure signals. The higher of the two signals goes to the next resolver.
Typical Control Valve
(1) Primary resolver. (2) Secondary resolver.The primary resolver is installed parallel to the control spool. The ball check is built into the resolver. The secondary resolver is installed perpendicular to the primary resolver. The ball check is not contained in a housing. A plug holds the ball check in the valve body.
Check Valve
(3) Signal line from cylinder head end. (4) Outlet line. (5) Ball check. (6) Signal line from the rod end.
Partial Resolver Network Section Schematic
(1) Primary resolver. (2) Secondary resolver.The primary resolver compares the pressure between the two work ports in each control valve section. In other words, it compares the head end pressure of the cylinder to the rod end pressure of the same cylinder.In the previous illustration, the head end pressure in line (3) is greater than the rod end pressure in line (6). The head end pressure forces ball check (5) left. This blocks line (6). The pressure in line (3) is now the highest resolved pressure in this resolver. This pressure can now go through outlet line (4) to the next resolver.The secondary resolver in each valve section works similarly. It compares the pressure signals between two valve sections. In other words, the secondary resolver compares the highest primary pressure signal in its control valve to the highest resolved signal from the previous control valve.The signal network is arranged in series. It starts at the backhoe section. The secondary resolver in the last backhoe control valve section is connected to the first secondary resolver of the loader control valve section. The highest resolved signal pressure from the backhoe section goes to the loader section. The highest resolved signal from the loader section goes to the steering sections secondary resolver. The highest resolved signal from the steering section (HMU) goes to the compensator valve on the pump. This signal now instructs the pump to vary its output to meet the highest resolved load requirements. The compensator valve adds margin pressure to the load requirements. Note that the resolver network does not add the various loads together. Instead, the single highest resolved load plus margin governs pump output. Therefore, the entire system is supplied with 1380-1700 kPa (200-245 psi) more pressure than necessary to handle the single largest load. The pump will not change its output until the resolver network identifies a different highest resolved signal.Hydraulic Cylinders
Cylinder Identification Right Side Of MachineThe backhoe and loader cylinders are the threaded gland design. The rod end assembly is called the gland. It houses the wear band, buffer seal, U-cup seal and wiper. The gland is threaded into the expanded rod end of the cylinder. This keeps the gland threads bathed in oil to prevent them from corroding.
Basic Hydraulic CylinderThe piston