Hydraulically Connecting The Axial Piston Unit - Bosch REXROTH A4 Series Instruction Manual

notices on routing lines

7.4.8 Hydraulically connecting the axial piston unit

Insufficient suction pressure!
Generally, a minimum permissible suction pressure at port "S" is specified for axial
piston pumps in all installation positions. If the pressure at port S drops below the
specified values, damage may occur which may lead to the axial piston pump being
damaged beyond repair!
▶ Make sure that the necessary suction pressure is not undercut. This is
influenced by:
– the piping (e.g. suction cross-section, pipe diameter, length of suction line)
– The position of the reservoir
– The viscosity of the hydraulic fluid
– A filter element or check valve in the suction line, if fitted, (check the filter
element's level of contamination on a regular basis)
The machine/system manufacturer is responsible for dimensioning the lines. The
axial piston unit must be connected to the rest of the hydraulic system in accordance
with the hydraulic circuit diagram of the machine/system manufacturer.
The ports and fastening threads are designed for the maximum permissible
pressures p , see Table 12 "A4V ports Series 3x" on page 51. The machine/
max
system manufacturer must ensure that the connecting elements and lines
correspond to the specified application conditions (pressure, flow, hydraulic fluid,
temperature) with the necessary safety factors.
Connect only hydraulic lines that are appropriate for the axial piston unit port
(pressure level, size, system of units).
Observe the following notes when routing the suction, pressure, and drain lines
• Lines and hoses must be installed without pre-charge pressure, 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 regarding 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 92050 (see Table 12).
RE 92076-01-B/10.2017, A4... with HS5E pilot control valve/Series 3x, Bosch Rexroth AG
NOTICE
Installation 49/104