Bosch A4VG A4VG 32 Series Instruction Manual page 43

notes on routing lines
Risk of confusion with
threaded connections
Observe the following notes when routing the suction, pressure, and drain lines.
• Lines and hoses must be installed without pretension, so that no further
mechanical forces are applied during operation that will reduce the service life of
the axial piston unit and, if applicable, the entire machine/system.
• Use suitable seals as sealing material.
• Suction line (pipe or hose)
– The suction line should be as short and straight as possible.
– Measure the line cross section of the suction line so that the pressure at the
suction port does not drop below the minimum permissible pressure. Make sure
that the maximum suction pressure is not exceeded (e.g. when pre-filling).
– Make sure the connections and connecting elements are airtight.
– The hose must be pressure-resistant, also for external air pressure.
• Pressure line
– For the pressure lines, use only pipes, hoses and connecting elements rated for
the working pressure range specified in data sheet 92003 (see Table 10).
• Drain line
– Always route the drain lines so that the housing is constantly filled with hydraulic
fluid and to ensure that no air gets through the shaft seal even during extended
standstill periods.
– Under no operating circumstances may the case pressure exceed the maximum
limit values specified for the axial piston unit in the data sheet.
– The drain line joint in the reservoir must always be below the minimum fluid level
(see Chapter 7.3 "Installation position" on page 34).
• If the axial piston unit is equipped with installed screw fittings, these must not be
unscrewed. Screw the stud end of the fitting directly into the installed screw fitting.
Axial piston units are employed in application areas that use the metric measuring
system as well as the Anglo-American (imperial) and the Japanese measuring system
(JIS – Japan Industrial Standard). Moreover, various kinds of seal are used.
The system of units, the kind of seal and the size of female thread and stud ends
(e.g., threaded plug) must all match.
The limited ways of telling them apart visually poses a risk of confusing them.
wARnInG. Leaky or bursting stud ends.
For fittings, if a stud end which is of a different measurement system, kind of seal and
size with respect to the female thread is pressurized, the stud end may loosen itself
or even be ejected from the hole in a projectile-like manner. This can result in serious
injury and property damage. Hydraulic fluid can escape from this leakage point.
▶ Use the drawings (installation drawing) to determine the required stud end for
each fitting.
▶ Make sure the right fittings, mounting bolts and threaded plugs are installed.
▶ For all female threads, use a stud end from the same system of units and of the
correct size.
RE 92003-01-B/12.2015, A4VG Series 32, Bosch Rexroth AG
Installation 43/68