HYDRAULIC SYSTEM Ch 5 page 6 Hydraulic System Components The hydraulic system consists of the following components: 1. Variable displacement piston pump; Maximum displacement 140cc.The pump has maximum pressure and load sensing delta-P controller. The maximum pressure is factory set at 280bar. LS delta-P is set at 20bar at engine idle speed and no flow output (i.e. standby setting) 2. Main control manifold assembly; It has included a control section with electrohydraulic pilot controlled three position spool operated bin lift function and lift cylinder pressure protection.
The manifold also incorporates functions for steering priority, steering maximum pressure limitation, brake charging, brake- and parking brake pressure control, fan activation and speed control, pilot pressure supply, bin float function, pump de-stroking damping, pump pressure spike protection and suspension leveling. The manifold also acts as a junction block for connection and distribution of various supply- and tank lines. It also offers gauge ports for various important control pressures. Many of those control pressures are routed to an external test block, [Item 8], for easy access. 3.
Brake Pressure Accumulators; The 2,15 Liter parking brake accumulator is placed on the right side of the front frame, along with the 3,3 Liter front service brake accumulator, and the 3,3 Liter rear service brake accumulators. The accumulators are from Doosan Infracore Norway AS factory loaded with Nitrogen (N 2 ). 4. Return Filter The filter is mounted in the tank and flow passes through it via a pipe connection from below. The optimal flow conditions created by flow from beneath guarantee optimum air separation, high pulsation stability and very long filter service lives. They consist of a housing tube, filter head and filter cover.
The element is top-removable, and is equipped with a bypass valve and a non-return valve. 5. Orbitrol Displacement: HA30 - 160 cmі (9.76 inі / rev) HA45 - 250 cmі (15.25 inі / rev) Rated oil flow: 25 L/min (6.60 U.S. gal / min) 6. Steering Valve When the orbitrol is activated, a controlled oil flow is directed to the steering valve. This oil flow is amplified in the steering valve and the total oil flow is directed to the steering cylinders. The orbitrol has a displacement of 160cm3/rev (HA30) and 250cm3/rev (HA45) and the amplification factor is 8. This means that total displacement is 160 cm3 x 8 = 1280 cm3(HA30) and 250 cm3 x 8 = 2000(HA45) per steering wheel revolution.
The principle applied to the controlled operation of the flow amplifier, called “load sensing”. As name suggest , it is a system in which the load is used in this system, to control the priority valve in the flow amplifier, so that oil flow and pressure precisely matches momentary demands. 7. Steering Cylinders The Steering Cylinders are located on each side of the articulation hinge and are responsible for the front frame turning. Their specifications are: HA30 HA45 Double acting; Cylinder Diameter 100mm 115mm Piston rod 63mm 70mm Stroke 515mm 550mm End cushion. SHOP MANUAL