pnevmatike in diferencial...
TRANSCRIPT
Prof. dr. Jernej Klemenc
Pnevmatike in diferencial
Tyres and differential gear
Konstrukcija radialne pnevmatike /
Composition of a radial-ply tire
Tekalna plast / Contact surface
Bočnica / support wall
Noga / Tyre foot
Pas / Belt
Karkasa / Carcass plies
Žično jedro /Core steel wire
Platišče /Wheel rim
Tesnilna plast / Sealing layer
2
Označevanje pnevmatik /
Tyre labeling
• 6,40-13/6 PR:
– Diagonalna pnevmatika
– Širina pnevmatike: 6,40”
– Premer platišča: 13”
– Višina pnevmatike: 0,95 (superbalon za D) * 6,40”
– Indeks nosilnosti: PR6
– Simbol hitrosti: -(najvišja hitrost = 150 km/h)
• 6,40-13/6 PR:
– Bias-ply tyre
– Tyre width: 6,40”
– Wheel-rim diameter: 13”
– Tyre-wall height: 0,95
(superballoon for D) *
6,40”
– Loading index: PR6
– Velocity index: no index
(maximum velocity =
150 km/h)
3
Označevanje pnevmatik /
Tyre labeling
• 265/50 R 14 101 V:
– Radialna (R) pnevmatika
– Širina pnevmatike: 265 mm
– Premer platišča: 14”
– Višina pnevmatike: 0,50 * 265 mm
– Indeks nosilnosti: 101
– Simbol hitrosti: V (najvišja hitrost = 240 km/h)
• 265/50 R 14 101 V:
– Radial-ply tyre (R)
– Tyre width: 265 mm
– Wheel-rim diameter :
14”
– Tyre-wall height : 0,50 *
265 mm
– Loading index: 101
– Velocity index: V
(maximum velocity =
240 km/h)
4
Označevanje pnevmatik /
Tyre labeling
• Datum proizvodnje / Production date: DOT xxyy
– xx => teden / week;
– yy => leto / year.
• Indeks nosilnosti pnevmatike / Tyre load index:
5
Označevanje pnevmatik /
Tyre labeling
• Simboli hitrosti za pnevmatike:
– P => 150 km/h
– Q => 160 km/h
– S => 180 km/h
– T => 190 km/h
– H => 210 km/h
– V => 240 km/h
– W => 270 km/h
– Y => 300 km/h
– VR => nad 210 km/h
– ZR=> nad 240 km/h
• Tyre velocity index:
– P => 150 km/h
– Q => 160 km/h
– S => 180 km/h
– T => 190 km/h
– H => 210 km/h
– V => 240 km/h
– W => 270 km/h
– Y => 300 km/h
– VR => above 210 km/h
– ZR=> above 240 km/h
6
Pnevmatika kot torno gonilo – pospeševanje /
Tyre as a friction wheel - acceleration
H
tr,g
tr,m
10 t
konstrZM
v
vv
Z
F
HstH
t
kh
⋅=⋅⋅=
−=
=
µµ
σ
µ
0
0
v
v0
M
rst
Ft
Z
7
Pnevmatika kot torno gonilo – zaviranje /
Tyre as a friction wheel - braking
H
tr,g
tr,m
-10 t
konstrZM
v
vv
Z
K
HstH
t
h
⋅=⋅⋅=
−=
=
µµ
σ
µ
0
8
Sojemalni diagram za radialne in diagonalne pnevmatike /
Traction diagram for radial-ply tires and bias-ply tires
9
H
10 t
Radialna pnevmatika (nova) /Radial-ply tyre (new)
Diagonalna pnevmatika (nova) /Bias-ply tyre (new)
Radialna pnevmatika (stara) /Radial-ply tyre (old)
Sojemalni diagram za pospeševanje in zaviranje /
Traction diagram for accelerating and braking
10
Mikro-kontakt pnevmatike in vozne površine med
pospeševanjem / Micro-contact between tyre and driving
surface during acceleration
11
Mikro-kontakt pnevmatike in vozne površine med
zaviranjem / Micro-contact between tyre and driving surface
during braking
12
Pogon 4x4 / 4x4 wheel drive
• Sredinski razdelilnik pogona brez diferenciala na trdi podlagi:
• Teoretične obodne hitrosti:
• Dejanske obodne hitrosti:
20,20,210,10,1 RrvRrv stst ∝⋅=>∝⋅= ωω
• Central power splitter without
differential gear on a hard
surface:
• Theoretical tangential velocities:
• Actual tangential velocities:
2121 ; MMvv ≠= 13
Pogon 4x4 / 4x4 wheel drive
• Sredinski razdelilnik pogona brez diferenciala na trdi podlagi:
• Central power splitter without
differential gear on a hard
surface:
14
Pogon 4x4 / 4x4 wheel drive
• Sredinski razdelilnik pogona z diferencialom na trdi podlagi:
221
222111
mot
stst
MMM
RrvRrv
==
∝⋅=>∝⋅= ωω
15
• Central power splitter with a
differential gear on a hard
surface:
Pogon 4x4 / 4x4 wheel drive
• Sredinski razdelilnik pogona z diferencialom – trda podlaga zadaj, mehka podlaga spredaj, vožnja naravnost:
16
• Central power splitter with a
differential gear – hard
surface under the rear axle,
soft surface under the front
axle, straight driving:
Pogon 4x4 / 4x4 wheel drive
-M1
+M1
-M2
+M2
M2
v1,0=v2,0
M1
v1=v2
Mmot
17
• Sredinski razdelilnik pogona brez diferenciala – trda podlaga zadaj, mehka podlaga spredaj, vožnja naravnost:
• Central power splitter
without differential gear –
hard surface under the rear
axle, soft surface under the
front axle, straight driving:
TORSEN diferencial /
TORSEN differential gear
18
Mehanski samozaporni diferencial z lamelami /
Mechanical self-locking differential gear with lamellas
19
Avtomatski samozaporni diferencial z lamelami /
Automatic self-locking differential gear - ASD
20
Kotno gonilo /
Angle bevel
gear
Krmilni tlak (desni) / Control pressure
(right)
Krmilni tlak (levi) / Control pressure
(left) Pritrjeno na ohišje kotnega gonila /
Attached to a housing
of a bevel gear
Diferencial z usmerjanjem navora /
Torque vectoring differential
21
Diferencial z usmerjanjem navora /
Torque vectoring differential
Granzow 2013, str. 5. 22
• Učinek na vožnjo v ovinek: • Operation during cornering:
Diferencial z usmerjanjem navora /
Torque vectoring differential
23
• Funkcionalni sestav diferenciala ZF Vector
drive:
• Functional assembly of a ZF
Vector drive differential
gear:
FaFa Fa Fa
Klasični diferencial s kotnim gonilom /
Conventional differential
gear with the angle
bevel gear
Leva enota za vektorsko usmerjanje navora /Left unit for torque-
vectoring
Desna enota za vektorsko usmerjanje navora /Right unit for torque-
vectoring
Večlamelna zavora / Multi-disc brake
Večlamelna zavora / Multi-disc brake
Diferencial z usmerjanjem navora /
Torque vectoring differential
Granzow 2013, str. 8. 24
• Prikaz sestava: • System assembly:
Diferencial z usmerjanjem navora /
Torque vectoring differential
25
• Princip delovanja brez vektorskega usmerjanja navora:
• Principle of operation
without torque-vectoring
function:
Fa=0 Fa=0MKG
M1=MKG /2 M2=MKG /2
Fk,1 Fk,2=Fk,1
Granzow 2013, str. 9.
Diferencial z usmerjanjem navora /
Torque vectoring differential
• Princip delovanja z vektorskim usmerjanjem navora:
Granzow 2013, str. 10.
Fa=0 Fa>0MKG =2000 Nm
M1=480 Nm 420 Nm
Fk,1
Fk,2 >Fk,1
900 Nm
1100 Nm
980 Nm
120 Nm
Σ=1400 Nm
26
• Principle of operation by
applying the torque-
vectoring function:
Diferencial z usmerjanjem navora /
Torque vectoring differential
Granzow 2013, str. 11.
Fa=0 Fa>0MKG =0 Nm
M1=510 Nm 590 Nm
Fk,1
Fk,2
1100 Nm
1100 Nm
980 Nm
120 Nm
Σ=390 Nm
27
• Princip delovanja z vektorskim usmerjanjem navora:
• Principle of operation by
applying the torque-
vectoring function:
Diferencial z usmerjanjem navora /
Torque vectoring differential
Granzow 2013, str. 15. 28
• Prerez sestava: • Assembly cross-section:
Diferencial z usmerjanjem navora /
Torque vectoring differential
Granzow 2013, str. 18. 29
• Aktivacija več-lamelne zavore planetne gredi:
• Activation of a multi-disc
brake of a planetary shaft:
Diferencial z usmerjanjem navora /
Torque vectoring differential
Granzow 2013, str. 19. 30
• Aktivacija več-lamelne zavore planetne gredi:
• Activation of a multi-disc
brake of a planetary shaft:
Diferencial z usmerjanjem navora /
Torque vectoring differential
Granzow 2013, str. 27. 31
• Diferencial z vektorskim usmerjanjem navora je mehatronski sistem:
• The torque-vectoring
differential is a mechatronic
system:
Bočna elastičnost pnevmatike /
Cornering stifness of a tyre
32
=0
Z
S
YPZ
S
x
dZ/dx( =0)
Dotikalna površina pnevmatike /
Contact surface
>0
S
x
dZ/dx( >0)
Y
x x
e
Koeficient sojemanja za prečno silo in kot poševnega
nakotaljevanja /
Lateral traction coefficient and side-slip angle
33
eYM s ⋅=
αs …kot poševnega nakotaljevanja /
Side-slip angle
Z
Ss =µ
µs …bočni koeficient sojemanja /
lateral traction coefficient
s
sss tgc
µ
αβ ==
cs …bočna elastičnost pnevmatike /
cornering stifness of a tyre
Kot zasuka krmilnih koles pri vožnji v ovinek /
Steering angle during cornering
34
λ …krmilni kot / steering angle
)(Rf=λ
Vpliv poševnega nakotaljevanja pri vožnji v ovinek /
Influence of side-slip rolling during cornering
35
Vpliv poševnega nakotaljevanja pri vožnji v ovinek /
Influence of side-slip rolling during cornering
R
v
g
G
R
vmF vc
22
⋅=⋅=
l
lFF
l
lFFRRRRR cccc
';"
0, 212121 ⋅⋅ ≈≈⇒≈≈⇒>>
R
v
gG
Fcs
21⋅==µ
sss
sss
sss
c
c
µα
µα
µµµ
⋅=
⋅=
≈≈
22
11
21
[ ])(
)(21
21
sss
sscc
lRRl
−⋅−=⇒⋅−−=
µλααλ
36
Podkrmarjeno vozilo / Under-steered
vehicle: cs1>cs2
Če se poveča hitrost vožnje v ovinek, je treba
povečati krmilni kot λ.
37
v=20 km/h
v=60 km/h
v=100 km/h
=0 s
t.
=2 s
t.
If a vehicle‘s velocity is
increased during cornering,
the steering angle λ should
be increased.
Prekrmarjeno vozilo / Over-steered
vehicle: cs1<cs2
38
Če se poveča hitrost vožnje v ovinek, je treba zmanjšati krmilni kot λ.
If a vehicle‘s velocity is
increased during cornering,
the steering angle λ should
be reduced.
s
R
v=60 km/h
v=100 km/h
R=v2/( s*g)
R=l/[ s*(cs1-cs2)]
Zvišanje hitrosti vožnje pri R=konst. / Increase of velocity
for constant R.
Vpliv bočnega vetra /
Influence of a side wind
• Podkrmarjeno vozilo / Under-steered vehicle (cs1>cs2):
v
T Fv
v
T Fv
s1
s2
s1
s2
P
Fc
Centrifugalna sila stabilizira silo vetra.
39
The centrifugal force
stabilises the wind force.
Vpliv bočnega vetra /
Influence of a side wind
• Prekrmarjeno vozilo / Over-steered vehicle (cs1<cs2):
40
Centrifugalna sila destabilizira silo vetra.
The centrifugal force de-
stabilises the wind force.
Stabilizacija vozila pri vožnji v ovinek /
Vehicle stabilisation during cornering
• Podkrmarjeno vozilo / Under-steered vehicle:
• Prekrmarjeno vozilo / Over-steered vehicle:
41
v v
Fst
Fst
Dejansko stanje = želja /Actual cornering = wish
Stabilizacija / Stabilisation
Želja / Wish
Dejansko stanje /Actual cornering
Kritična hitrost prekrmarjenega vozila /
Critical velocity of over-steered vehicle
• Kritična hitrost prekrmarjenega vozila je tista hitrost, pri kateri je vozilo ob minimalni bočni motnji (npr. sunek vetra) sposobno voziti v ovinek brez zasuka krmilnih koles:
12 ss cc >
0;0 >= Rλ
s
s
v
gR
R
v
g µµ
22 11⋅=⇒⋅=
)(
1
21
2
ssss
krit
cc
lv
gR
−⋅−=⋅=
µµ
12( ss
kritcc
glv
−
⋅=
42
• A critical velocity of the
under-steered vehicle is the
velocity at which the vehicle
can negotiate curves with a
zero steering angle, if subje-
cted to a lateral disturbance
(e.g. wind blow):
Postavitev vodilnih koles vozila /
Position of steered wheels
• Previs kolesa:
– Izniči zračnost v ležajih.
– Pozitivni previs zmanjšuje stranske vodilne sile pri vožnji v ovinek.
– Negativni previs izboljšuje stransko vodenje pri vožnji v ovinek.
>0 <0=+0,3/+1,5 =-0,5/-2
43
• Camber angle:
– Nullifies bearing clearance.
– Positive camber angle
reduces lateral forces
during cornering.
– Negative camber angle
increased grip during heavy
cornering.
Postavitev vodilnih koles vozila /
Position of steered wheels
• Prečni nagib premnega sornika:
– Povzroči dviganje prednjega dela vozila pri zasuku vodilnih koles.
– Posledica je samodejno vzpostavljanje položaja koles za vožnjo naravnost, če voznik izpusti volan.
=5-10
44
• Lateral slope of a pivot line:
– It causes a raise of the
vehicle‘s front part during a
steering maneuvre.
– A consequence is self-
alignment of the steering
wheels if a driver releases
a steering wheel.
Postavitev vodilnih koles vozila /
Position of steered wheels
• Vzdolžni nagib premnegasornika (kot zaostajanja):
– Kot zaostajanja kolesa usmeri tako, da dosežemo večjo stabilnost zasukanih koles pri višjih hitrostih.
45
• Caster angle:
– Positive caster will make
the vehicle more stable at
high speeds, and will
increase tire lean when
cornering.
Postavitev vodilnih koles vozila /
Position of steered wheels
• Stekanje/raztekanje koles:
– Napenja pnevmatike in drogovje krmilnega mehanizma.
– Zmanjšuje opletanje koles.
46
• Toe angle:
– The angle derived from
pointing the tires inward or
outward from a top view.
– The steering mechanism is
pre-stressed to nullify
clearance.
– Reduces lateral wheel
twisting.
Seznam literature / List of references
• Granzow C.: ZF Vector Drive – better driving dynamics and driving safety through Torque Vectoring. Praktischer Entwurf mechatronischer Systeme, Karlsruhe 13.12.2013.
• Lewis R., Olofsson U. (editors): Wheel-rail interfacehandbook. Boca Raton: Woodhead Publishing in Mechanical Engineering, 2009.
• Wong J.Y.:Theory of Ground Vehicles, 3rd edition. New York: John Willey & Sons, 2001.
• Simić D.: Motorna vozila. Beograd: Naučna knjiga, 1988.
• Janičijević N., Janković D., Todorović J.: Konstrukcija motornih vozila. Beograd: Mašinski fakultet, 1979.
• Goljar M.: Motorna vozila, osnove konstruiranja. Ljubljana: Fakulteta za strojništvo, 1977.
47