Functional Description - Bosch rexroth 11 Series Instruction Manual

20/64 About this product
Pump function
Control
Charge pump (optional)
Bosch Rexroth AG, A15V(L)O Series 11, RE 92511-01-B/2019-10-09

5.2.2 Functional description

Torque and rotational speed are applied to the drive shaft (1) by a drive motor.
The drive shaft is connected to the cylinder (9) by splines, causing the cylinder to
rotate. With every revolution, the pistons (10) perform a stroke in the cylinder bores,
the size of which depends on the pitch of the cradle (12). The slipper pads (11) are
held on with the pistons and guided along the glide surface of the cradle by the
retaining plate (2). The pitch of the swashplate during a revolution causes each
piston to move over the bottom and top dead centers and back to its initial position.
Hydraulic fluid is fed into and out through two control slots in the control plate (7)
according to displacement. Hydraulic fluid flows into the piston chamber as the
piston recedes on the suction side (8). At the same time, the hydraulic fluid is
pushed out of the cylinder chamber into the hydraulic system by the pistons on the
high-pressure side (3).
The swivel angle of the cradle (12) is infinitely variable. Adjusting the swivel angle
changes the piston stroke and, with it, the displacement. The swivel angle is
controlled hydraulically by means of the stroking piston. The cradle is mounted in
swivel bearings for smooth operation, and it is kept in balance by the opposed
piston (not illustrated). Increasing the swivel angle increases the displacement;
reducing the angle reduces displacement accordingly.
Various control devices are available depending on requirements.
Information about this can be found in data sheet 92511.
The axial piston unit A15VLO is equipped with a charge pump (4). The charge pump
(impeller) is a centrifugal pump with which the pump is filled and can be operated at
higher rotational speeds. This also facilitates cold starting at low temperatures and
high viscosity of the hydraulic fluid. Externally increasing the inlet pressure is
therefore unnecessary in most cases. Charging the reservoir with compressed air is
not permissible.
M
A
Fig. 3: Circuit diagram A15VLO with charge pump
A P
4
S M T T T
1 2 3