3-2
3
PISTON PUMP
FUNCTION
PISTON PUMP
Operation
This pump is a variable displacement piston pump
with a single cylinder block, which discharges two
equal volumes.
T
en pistons (2) are installed in the cylinder block
(1), and the end surface is in contact with the valve
plate (3). The suction port C and the discharge port A
of the pump P1 and the discharge port B of the pump
P2 are arranged in the valve plate (3). On the other
hand, the swash plate (4) is fastened to the hous-
ing
at a given inclination, and the pistons (2) rotate
along this swash plate (4).
When
the shaft (5) is rotated, the cylinder block (1)
rotates, the pistons (2) in the cylinder block execute
reciprocating movement along the swash plate (4),
and the pump executes suction and discharge. At this
time, the pistons in contact with the discharge port A
of the valve plate (3) operate as the pump P1, while
the pistons in contact with the discharge port B oper-
ate as the pump P2.
In
this way, the ten pistons (2) execute one suction
and discharge stroke with each revolution of the
cylinder block (1), so that suction and discharge are
executed continuously when the shaft (5) is rotated
continuously.
As the piston stroke displacement depends on the
inclination of the swash plate
(4), the discharge flow
quantity can be changed by changing the inclination
of the awash plate (4).
Discharge volume control
The
swash plate (4)
is equipped with the bearings
(6) and is mounted on the housing at an inclination
that can be varied. The swash plate (4) is loaded
with the pistons (9) and the piston (10) in opposi-
tion
to the spring (7). The discharge pressures from
the pumps P1 and P2 work on the pistons (9). The
discharge pressure from the pump P3 works on the
piston (10). When the discharge pressure is below
the value preset for the spring (7), the inclination of
the swash plate (4) is fixed to the maximum value by
the spring (7).
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