Major Components of the Auxiliary System
The AP-655C Asphalt Paver is equipped with an auxiliary hydraulic system that provides the additional auxiliary pressure that is needed in order to operate most of the functions of the asphalt paver. The auxiliary system on the AP-655C Asphalt Paver is similar to previous models.
Location of Auxiliary Components
(1) Auxiliary pump
(2) Auxiliary bank valve
(3) Pressure manifold
(4) Return manifold
(5) Hydraulic tank
(6) Hydraulic return filter
(7) Hydraulic suction strainers
(8) Cooler bypass valve
(9) Engine oil cooler
(10) Screed counterbalance (On/Off) valve
(11) Screed counterbalance valve
(12) Cylinders for screed hoist (both sides)
(13) Manual brake release pump
(14) Cylinders for hopper hoist (both sides)
(15) Cylinders for auger hoist (both sides)
(16) Ventilation motor and blower wheel
(17) Track tension cylinders (both sides)
(18) Charge valve for track tension (both sides)
(19) Accumulator (both sides)
(20) Counterbalance valve for tow point (both sides)
(21) Tow point cylinders (both sides)
(22) Valve for truck hitch (option)
(23) Cylinders for truck hitch (option) (both sides)
The auxiliary hydraulic system utilizes the following main components with other systems:
- Hydraulic tank
- Hydraulic return filter
- Hydraulic suction strainers
- Cooler bypass valve
- Oil cooler
The auxiliary hydraulic system has the following main components:
- Auxiliary pump
- Auxiliary bank valve
- Pressure manifold
- Return manifold
The auxiliary hydraulic system controls the following functions:
- Screed Counterbalance System
- Screed Hoist
- Manual brake release pump
- Planetary shift
- Planetary brake
- Hopper Hoist
- Auger Hoist
- Ventilation System
- Screed Extension
- Track takeup and tension
- Tow point control
- Truck hitch (option)
A common hydraulic tank provides hydraulic oil to all of the hydraulic systems on the machine. The hydraulic tank has a capacity of 151 L (40 US gal). The hydraulic tank has an internal hydraulic return filter and eight internal suction strainers.
Hydraulic Return Filter
The hydraulic return filter protects the hydraulic auxiliary system and all other hydraulic systems from damaging and unwanted contamination. The hydraulic return filter will filter contaminants in the return oil that are larger than 10 microns. The return filter should be replaced regularly. Refer to the Operation and Maintenance Manual, "Hydraulic System Oil and Filters - Change" for the correct maintenance interval.
Hydraulic Suction Strainer
Hydraulic oil in the tank flows through the suction strainers before flowing to the auxiliary system and other hydraulic systems. The suction strainers are located inside the hydraulic tank. The suction strainers are constructed with a 100/mesh screen in order to help protect against preliminary contamination. The suction strainers will sustain a hydraulic flow rate of125 L/min (33 US gpm) maximum.
Cooler Bypass Valve
The cooler bypass valve opens when the pressure in the return manifold reaches 105 kPa (15 psi). The cooler bypass valve is used in order to bypass the oil cooler when the hydraulic oil is cold. This valve will bypass oil until the pressure in the return hydraulic circuit is below 105 kPa (15 psi). The return bypass valve will also aid in heating the hydraulic oil in cold weather conditions.
Oil flows to the oil cooler when the pressure in the return hydraulic circuit is below 105 kPa (15 psi). The oil cooler will cool the hydraulic oil as air from the cooling fan is pulled across the oil cooler. As the temperature of the hydraulic tank oil increases, the speed of the cooling fan will increase.
The auxiliary pump is an axial piston pump with a variable displacement. The auxiliary pump is capable of delivering a flow rate of 138 L/min (36.4 US gpm). The auxiliary pump has a pressure compensator control and displacement limiters. The auxiliary pump output will only take place when there is a demand. The auxiliary pump will compensate for low demand and destroke according to demand. This helps to conserve power. In addition, this will also reduce the wear on the components.
Auxiliary Bank Valve
The auxiliary bank valve is a solenoid operated control valve. The auxiliary bank valve contains most of the solenoid operated valves for the auxiliary system. In addition, the auxiliary bank valve contains flow regulators, control valves, and pressure reducing valves for some of the different auxiliary systems. The flow rate of the auxiliary bank valve is rated to 38 L/min (10 US gpm). The maximum pressure for the auxiliary bank valve is 15170 kPa (2200 psi).
The pressure manifold for the auxiliary system will act as a flow divider. The auxiliary pump will distribute the hydraulic flow to the pressure manifold. The pressure manifold will then route hydraulic oil to the auxiliary bank valve and some of the other auxiliary functions. The hydraulic oil will not return through this manifold. The rate and pressure will not change as a result of this pressure manifold.
The return manifold for the auxiliary system will act as a flow divider. In addition, the return will route the hydraulic oil back through the return filter. Any contaminants in the system that are larger than 10 microns will be trapped. The oil is then routed to the tank. The hydraulic oil is distributed again into the system. The rate and pressure will not change as a result of this return manifold.