1528713 PROPEL DRIVES FOR UNDERCARRIAGES 9Q5872 9Q5982 Caterpillar

Installation Notes for a Axial Piston Units

Usage:

Filling the unit

Separate suction and drain chambers

All installation orientations (and also for intermediate orientations not shown) are to be arrived at after the optimum filling orientation. The housing is to be filled from the highest drain port. At this point in time, all other ports must be plugged. Ports which will be required later must be closed by means of pipe bends or non return valves. This prevents air entering the unit when turning it into its installation orientation. When installing the unit inside the tank (below the minimum oil tank), it should be noted, that the ports are then only opened after the tank has been filled and when the unit is below oil level. The sequence of operations is shown in figure 3.

Fig 3:

Suction and drain chambers connected internally

Filling of the housing in these units is not possible. The unit is filled when the tank is filled as the oil flows in via the "S" port. The units are bled via the highest "T" port in the housing.

Installation

Installation position (a)

Pump/motor above the tank (above the minimum oil level).

In this position, the highest drain port "T" must be connected to tank via a non return valve. The height difference between the unit and the tank can be negated in this way and the weight of the oil column in the drain line causing a negative pressure at the case drain port does then not need to be considered (a height of 1 metre above oil level causes = 0,1 bar negative pressure). When selecting the cracking pressure of the valve, the maximum housing pressure must be observed. See the relevant data sheet.

The higher the cracking pressure the higher the resulting casing pressure. This leads to a reduction in the shaft seal life (see shaft seal diagrams in the individual data sheets).

With long stationary periods, the fact that the unit may slowly empty itself due to internal leakage through the service line must also be taken into account.

Fitting leak free valves in the service lines can overcome this problem.

These measures do not mean that the regular checking of the oil level inside the housing can be overlooked. This check can be made at the highest drain port or bleed port.

If the oil level has fallen, the unit should be re-commissioned if required.

The notes on page 12 should also be noted for variable pumps A7VO and fixed pumps A7FO.

Installation position (b)

Pump/motor alongside or below the tank (below the minimum oil level).

The maximum height difference between the tank and the unit is dependent upon the maximum casing pressure (a height of 1 metre below oil level = 0,1 bar pressure).

With units which the suction and drain chambers are connected internally, complete bleeding of the unit must be carried out, as it is not possible to fill the housing. Bleeding must take place via the highest bleed or drain port.

Installation position (c)

Pump/motor inside the tank (below the minimum oil level).

With units in which the suction and drain chambers are connected internally, complete bleeding of the unit must be carried out, as it is not possible to fill the housing. In units with separate suction and drain chambers, the unit must be filled before installation. The connections may then only be opened when they are below oil level in order to avoid the entry of air and loss of fluid.

Suction

Minimum immersion level (E)

For installation positions (a) and (b), the prescribed minimum immersion level (E) must be maintained. This dimension applies to suction, drain and bleed lines, see figure 4.

Minimum distances (TU) and (SU)

Dimension (TU) for the highest drain port (T), and dimension (SU) for suction port (S) must be maintained. The bleed port (U) is not used in this case. In mobile installations, the tank layout must be carefully designed in order to prevent air being sucked in, see figure 5.

NOTE:

The "optimum filling positions" and the permissible "installation positions" and "installation orientations" for our pumps and motors are shown on the following pages.

These pages are subdivided into three columns:

Installation positions (a), (b) and (c)and also into five horizontal blocks:

1.) installation orientation (1)

2.) installation orientation (1) (turned 180° about its longer axis)

3.) installation orientation (2)

4.) installation orientation (3)

5.) installation orientation (4)

This sequence applies to each of the relevant pages. If a column or row is blank, this installation position or installation orientation is not permitted by Hydromatik, or requires further steps to be taken to ensure correct installation. Please enquire for further information.