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About this product | A4... with HS5E(V)(L) control system Series 1x and 30
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5.2.2 Functional description HS5E(L)
An electrically actuated proportional valve with OBE (1) controls the swivel angle
and pressure of the A4V... variable pump and limits its torque. By means of the
pump's stroking piston (2), this valve determines the position of the swashplate (3).
With a non-rotating pump and depressurized actuating system, the system uses
spring centering to retain the swashplate in swivel angle position "zero" or at swivel
angle value "zero" (when properly calibrated, "retention" is by spring force only).
The control electronics consists of one swivel angle controller, one pressure
controller, and one valve controller as well as one torque limiter. A swivel angle
sensor (4) determines the position of the swashplate, with a pressure measuring
sensor acquiring the actual pressure value. Both of the actual values are fed to the
control electronics and linked with one another via the software. The torque actual
value is formed from the product of the actual pressure value, the actual swivel angle
value, and the displacement. By means of a minimum value former, the controller
software ensures that the controller that corresponds to the operating point is
always active.
In the static state, i.e. the swivel angle command value is equal to the actual swivel
angle value; the torque command value is equal to the torque actual value; or the
pressure command value is equal to the actual pressure value, the valve's control
spool is in the central position.
If the higher-level controllers request an increase in the swivel angle, for example
(which corresponds to an increase in the flow), the system must keep deflecting
the valve spool from the central position until the swivel angle has reached the
required value.
The sectional view (see Fig. 2, position 5) shows the A4VSO variable pump with
HS5E control; the on-board control electronics actuates the proportional valve (1).
Notice on HS5E control:
With a de-energized proportional valve and a clockwise-turning pump, as well as
control pressure present, the pump swivels in the following cases:
– Standard version A4VSO and A4VBO to swivel angle α = 0% (V
)
g min
– Standard version A4VSG and A4CSG to swivel angle α = –100%.
With the HS5E, the necessary control pressure supply must be provided externally.
On the other hand, the HS5EL obtains the control pressure supply internally from
the boost pressure or from the high-pressure lines A or B (depending on which
pressure is highest).
Notice on HS5EL control:
With a de-energized proportional valve and a clockwise-turning pump, as well as
control pressure present (>20 bar), the pump swivels in the following cases:
– Standard version A4CSG to swivel angle α = -100%
5.2.3 Functional description HS5EV
An electrically actuated proportional valve with OBE (1) controls the swivel angle
and pressure of the A4V... variable pump and limits its torque. By means of the
pump's stroking piston (2), this valve determines the position of the swashplate (3).
RE 92076-01-B/2021-04-22, Bosch Rexroth AG
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