This document is the property of POCLAIN. It is strictly confidential. It may not be used, reproduced, copied, or disclosed to a third party, in full or in part without our prior written consent.This document is the property of POCLAIN
HYDRAULICS.
It is strictly confidential. It may not be used, reproduced, copied, or disclosed
to a third party, in full or in part without our prior written consent.
? Poclain
Hydraulics
Fundamental hydraulics
Fundamental mechanics knowledge,
reminder & validation
― PHTC ― From mechanics to hydraulics
2/55
Speed v
Rotation speed N in rotation per minute (rpm or tr/min )Distance becomes number of wheel rotation, and match to distance via the wheel circumference.
v =
time (s)
distance (m)= m/s
Speed is movement,
more or less fast!
― PHTC ― From mechanics to hydraulics
3/55
Force F
Resistance
R
Pushing force F in Newton (N)
Pushing force
F is force to overcome in order to move the bloc.
Its value is equal to R :addition of all resistances to the bloc movement (mainly frictions with the ground).
1 kg = 10N
― PHTC ― From mechanics to hydraulics
4/55
Torque M
Resisting forces
Tractive effort
Travelling direction
― PHTC ― From mechanics to hydraulics
5/55
Torque M
Laden static radius R ls
Tractive effort TE
Torque M
TE (N)x R ls (m) = M (N.m)
Travelling direction
― PHTC ― From mechanics to hydraulics
6/55
Force or Torque
Power P
Power =
Force x speed
Speed or RPM
x
― PHTC ― From mechanics to hydraulics
7/55
Power P
70 HP (51,5 kW)
300 HP (220 kW)
Power (W)= Force (N)x speed (m/s)
― PHTC ― From mechanics to hydraulics
8/55
Power P
Power (linear movement)
= Force x speed
P (W)= F (N)x v (m/s) P (kW)= F (N)x v (m/s) / 1000
Power (rotary movement)= Torque x rotation speed P (W)= M (N.m)x N (rad/s)P (kW)= M (N.m)x N (rpm) / 9550
― PHTC ― From mechanics to hydraulics
9/55
What about friction and speed?
Friction is a resistance,
an opposed force to the movement.
F r
F = 0 N
v = 0 m/s
P fr = F r x v P fr = 100 x v P fr = 0
P fr = F r x v P fr = 100 x 0P fr = 0
P fr = F r x v P fr = 100 x 10P fr = 1000 W
IMPOSSIBLE !
This document is the property of POCLAIN. It is strictly confidential. It may not be used, reproduced, copied, or disclosed to a third party, in full or in part without our prior written consent.This document is the property of POCLAIN HYDRAULICS. It is strictly confidential. It may not be used, reproduced, copied, or disclosed to a third party, in full or in part without our prior written consent.
? Poclain Hydraulics
Fundamental hydraulics
From mechanics to hydraulics
Transmission:
Transport power
IC engine
Mechanical power (torque x speed)
Wheels
Mechanical power (torque x speed)
T ool(s)
Mechanical power
(torque or force x speed)
― PHTC ― From mechanics to hydraulics
14/55
Transmission definition
On a machine, a transmission is:
Power transportation
Mechanical transmission Electrical transmission
Hydrostatic transmission
Hydrokinetic transmission
How transmit power?
― PHTC ― From mechanics to hydraulics
16/55
Transmission technologies
Mechanics
?
Wheeled vehicle: Europe to India, 3500 BC:?Lever: Ancient Egypt, 3000 BC
―
PHTC ― From mechanics to hydraulics
17/55
Transmission technologies
Hydraulics
?
Pascal principle: France, Pascal 1652
?
Hydraulic press : Joseph Bramah, England, 1795
― PHTC ― From mechanics to hydraulics
18/55
Transmission technologies
Electricity
?
Battery: Alessandro Volta, Italy, 1800
?Dynamo and electric motor: ányos Jedlik, Hungaria, 1828
― PHTC ― From mechanics to hydraulics
19/55
Transmission technologies
Knowledge
Mechanics
Electricity Hydraulics Years of progress
P o t e n t i a l i m p r o v e m e n t
Cost
250
5000
Why hydraulics?
Why hydraulics?
Blaise Pascal (1623-1662)
In 1652, he demonstrated
the hydrostatic laws
–Incompressibility of
liquids
–Pressure is evenly
distributed in a closed
tank
Transport power
hydraulically Transmission hydrostatic:
IC engine Mechanical power (torque x speed)
Wheels Mechanical power (torque x speed)
Hydrostatic
Fluid in static conditions
Static condition means low flowing speed into the pipes. (below 8 m/s)
― PHTC ― From mechanics to hydraulics
25/55
From mechanics to hydraulics
6 key points to memorize!
― PHTC ― From mechanics to hydraulics
26/55
The 6 key points to memorize!
1-Oil is a component to consider as a solid
?
Its behaviors seems as a mechanical steel rod.
2-Oil is lazy, it takes the path of less
?
Work or leave, its choice is done!
3-Motor is a transformer
?
Receptor and actuator in the circuit, it transforms hydraulic energy to mechanical rotary energy.
4-Hydraulic flow becomes mechanical speed
?
Thanks to hydraulic motor and cylinder, the flow becomes mechanical linear or rotary speed.
5-Pressure come from the resistance applied to the actuator
?Linear force on hydraulic cylinder ?
Torque on hydraulic motor
6-Pressure and flow are independent
?Start in a slope (climbing): High pressure and nearly nil flow ?
Going down in a slope: High flow and low pressure
Transport power hydraulically With closed loop circuit
HST : Hydrostatic transmission
Hydraulic power (pressure x flow)
Energy
transformer
Transmission hydrostatic:
IC engine
Mechanical power
(torque x speed)
Wheels
Mechanical power
(torque x speed)
― PHTC ― From mechanics to hydraulics
28/55
Hydraulic values
Flow
Makes it go!
Transmit movement (RPM) from the engine to the wheel via pump, circuit and motor.
Pressure
Come from the resistance.
Transmit resistance (torque) from the wheel to the engine* via motor, circuit and pump.
* (in normal forward motion), second case will be hydrostatic braking.
― PHTC ― From mechanics to hydraulics
29/55
Flow Q
Hydraulic flow becomes mechanical
speed.
Q = 0, v = 0, no movement Q = 1, v = 1, movement
Generator
Actuator
Flow Q in l/min (ou m 3
/s)
― PHTC ― From mechanics to hydraulics
31/55
Have an idea of flow rate…
Up to 100 l/min (for MS02)
Water valve Around 8 l/min
Up to 300 l/min (for VDFH25)
― PHTC ― From mechanics to hydraulics
32/55
Pressure (p)
No load, no pressure
Pressure is proportional to load
Pressure is inversely proportional to the Area of application
F
Pressure gauge
Pressure gauge
― PHTC ― From mechanics to hydraulics
33/55
Pressure p
W
p
Generator
Actuator
Pressure Flow
Pressure
Come from the resistance.
― PHTC ― From mechanics to hydraulics
34/55
Pressure p
Low pressure 1 kg
High pressure
Pressure p =
Aire (m 2)
Force (N)= N/m 2 = Pa (PASCAL)
100000 Pa = 1bar
1 kg
Pressure scale
On snowboard (4000 cm 2)800 N
0.02bar 0.32 bar
3.2 bar
On shoes
(250 cm 2)
On shoe high heels
(2,5 cm 2)Pressure scale
On tires
(500 cm 2)
11 250 N
2.25 bar
450 bar
On high heels
(2,5 cm 2)
11 250 N
Diameter 58 mm
Pressure scale
How many cars a 58 mm diameter
piston reach at 420 bar?
420 bar pressure
58 mm
112 kN
― PHTC ― From mechanics to hydraulics
39/55
Hydraulic power transformation
Hydraulic energy
Mechanical energy
Pressure
T orque Flow Speed X Hydraulic power
X Mechanical power
=
=
Pump does the revers action
― PHTC ― From mechanics to hydraulics
40/55
Power formula
Hydraulic power
P (kW)= p (bar)x Q (l/min) / 600
Mechanic lineaire power
P (kW)= F (N)x v (m/s) / 1000P (kW)= F (daN)x v (m/s) / 100
Mechanic rotative power
P (kW)= M (N.m)x v (tr/min) / 9550P (kW)= M (daN.m)x v (tr/min) / 955