2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 Caterpillar


Installation Notes for Axial Piston Units

Usage:

General

These installation specifications are intended for use with axial piston units from Hydromatik. Adherence to these recommendations has a decisive effect on the service life of the units. These specifications refer to standard units and standards internal elements.

A basic requirement is that the housing of the unit is completely filled with oil on commissioning or re-commissioning and that it remains full when operating.

Commissioning or re-commissioning without filling the housing or with too little fluid in the housing will lead to damage to or immediate and complete destruction of the rotary group. For each type, the ideal filling orientation is specified. Only in this position can complete filling be ensured. On commissioning or re-commissioning, this position should be maintained. In the following text, we will differentiate between installation position (pump/motor to tank) and installation orientation (pump/motor shaft vertical, horizontal etc).

Installation Position

The following installation positions are possible, see figure 1.

(a) Pump/motor above the tank (above the minimum oil level).
(b) Pump/motor alongside or under the tank (below the minimum oil level) or where the upper point on the unit housing is level with the minimum oil level.
(c) Pump/motor in the tank (below the minimum oil level). When installing the unit inside the tank, (a) applies if the unit is above the minimum oil level.


Fig.1:

Installation orientation

The following installation orientations are possible, see figure 2.

(1) horizontal : drive shaft horizontal
(2) vertical: drive shaft up
(3) vertical: drive shaft down
(4) at side: drive shaft horizontal

Intermediate installation orientations require additional measures or are not permitted. Please discuss any other requirements with us at the project stage.


Fig.2:

Piping

The installation position and installation orientation determine the layout of the suction, leakage (case drain) and bleed lines. For all installation positions and installation orientations it should be noted, that the highest "T" port is connected. Furthermore, the end of the drain line may not finish "above immersion depth 'E'" below the minimum oil level in the tank.

Special Points

Suction and drain lines should be as short and straight as possible. When the unit is stopped, vertical lines will empty themselves over a period of time due to gravity.

In this respect, the varying densities of the fluids must be observed, as denser fluids are more difficult to "suck" and fall more quickly. Limiting speeds of units for denser fluids are laid down in RE 90223.

In mobile applications, the arrangement of the tank is particularly important. Centrifugal forces when driving around bends, and inertia effects when accelerating or braking influence the inclination of the surface of the fluid. As the level of fluid in the tank falls, these effects must be taken into consideration. The adverse effects of these forces can be avoided by correct layout of the tank, see RE 90300.

In general, and for all installation positions and installation orientations, a minimum pressure at the suction port "S" is specified:

If the pressure falls below this specified value, damage can occur or the unit destroyed. The maximum suction pressure is determined by the maximum casing pressure.

In variable units, the actual installation position and installation orientation may also have an effect on the control fitted to vary the displacement of the unit. The operating curves can be slightly offset, and variations to control times can occur due to inertia forces and the weight of the internal parts. Please note these points.

During project and design work, the conditions laid down in RE 90220, RE 90221 and RE 90 301.

If further questions arise, please consult us.

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 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. 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.

Plug-in motor, variable displacement A6VE, series 6, Index 1

Caterpillar Information System:

2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 C. Attachment Parts
2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 B. Lube Oils
2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 A. Addresses
2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 10. Spare Parts Ordering
2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 8 Dismantling
2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 7. Maintenance
2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 5. Commissioning
2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 4. Mounting
2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 3. Handling / Storage
2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 2. Product Description
2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 1. Preliminary Notes
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2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 Spare Parts List
2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 Spare Parts List
2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 Spare Parts List
2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 Spare Parts List
2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 Spare Parts List
2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 Spare Parts List
2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 Order No.: 09613836, Denomination: FLUSH & BOOST PRESSURE VALVE W/O ORIF.
2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 Spare Parts List
2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 Spare Parts List
2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 Drawings
2071799 PROPEL DRIVES FOR UNDERCARRIAGE 2040808 E. Parts Lists
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