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Examples of dynamic synthesis of the throttle brake device of the hydro cylinder As examples of dynamic synthesis of throttle brake devices of hydro cylinders we’ll consider two simplified schemes: braking of the piston at action of impeding force and retraction of a rod (Fig. 2 а ) and at action of passing force at promotion of a rod (Fig. 3 а ). E x a m p l e 1. Let’s consider a variant of the simplified scheme (Fig. 2 а ). Input data for calculation:
D
=140 mm;
d
= 90 mm;
L
=1000 mm;
S o l u t i o n. For given values of parameters we’ll receive: from the formula (6)
Results of dynamic synthesis of the characteristic of the throttle brake device of the hydro cylinder
Fig. 2. The simplified scheme ( a ) and results ( b ) of dynamic synthesis of the throttle brake device
E x a m p l e 2. At synthesis of the characteristic
S o l u t i o n. From the formula (6)
it is found:
Results of dynamic synthesis of the characteristic of the throttle brake device of the hydro cylinder
Fig. 3. The simplified scheme ( a ) and results ( b ) of dynamic synthesis of the throttle brake device
The characteristics of throttle brake devices
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>> Examples of dynamic synthesis
= 90.32 cm²;
=153.94 cm²;
= 12.64 cm²;
=7.7 cm²;
=0.5 m/s;
R
=112.7 kN (impeding load);
= 31.4
= 31.4
= 0.735
= 3.92
= 0;
= 271 l/min;
= 980
=14 mm;
25 cm³;
= – 815.2 cm/s²; from the formula (16)
let’s assume
= 3.3 cm;
= 96.7 cm.
for a considered simplified variant are resulted on Fig. 2
b
. In the same place diagrams of change of pressures
and piston speed
v
are resulted at braking accordingly the planned law of movement.
of hydraulic damper for the second simplified case (Fig. 3
а
) the following input data have been accepted:
=153.94 cm²;
= 90.32 cm²;
= 7.7 cm²;
=12.64 cm²;
= 0 (otherwise in view of differential of areas of the hydro cylinder for maintenance of the piston braking it is necessary to raise much
);
=461.8 l/min; the rest parameters are as in the first simplified case.
= – 462.2 cm/s²; from the formula (16)
let’s assume
= 6 cm;
= 94.0 cm.
for the second simplified variant are resulted on Fig. 3
b
. In the same place diagrams of change of pressure
and piston speed
v
are resulted at braking accordingly the planned law of movement.
received at
certain
parameters of the hydraulic system it is necessary then to survey at change of the reduced masses and loadings in all working range of the projected machine to define a degree of influence of each varied parameter to dynamics and basic parameters of braking process, otherwise, to define "scope" of the synthesized devices at change of external conditions.