DAF LF45, LF55 Series. Manual - part 434

©

 200436

1-1

Brake system and components

TECHNICAL DATA

ΛΦ45/55 series

6

0

1. BRAKE SYSTEM AND COMPONENTS

1.1 GENERAL

Coding of components
All components have been provided with number 

codes.

Structure of the code
First digit

Often used:

Little used:

Where one connection performs several 

functions, additional 1

st

digits will be allocated. 

These are separated by a hyphen.

Second digit
If there are several connections with the same 

function, a 2

nd

 digit will be added immediately 

after the 1

st

 one.

Application example: empty/load relay valve

Meaning:

COMPRESSOR
Knorr model

1

Energy supply (pressure)

2

Energy discharge (outgoing command)

3

Bleed

4

Control connection (incoming command)

0

Suction connection

5

Free

6

Free

7

Anti-freeze connection

8

Lubricating oil connection

9

Coolant connection

1

Air compressor energy supply

2

Energy discharge (command) to the next 

component

41

Control connection (incoming)

42

Second control connection (incoming)

Type: LK3839
Version:

1-cylinder, liquid-cooled

TECHNICAL DATA

1-2

©

 200436

Brake system and components

0

ΛΦ45/55 series

6

AIR SUPPLY UNIT

Front axle, leaf-sprung

24

21

1

F

D

N

J

K

L

M

H

P

3

A

E

C

G

1

12

26

22

21

23

3

23 25

P

U

6.2
6.3
6.4

6.1

6.2

P

U

6.5
6.6
6.7

B

R600702

0

A

Air dryer/pressure regulator (unit)

B

4-circuit protection valve (unit)

C

Filter/drying grid

D

Pressure regulator

E

Blow-off valve

F

Pneumatic time switch for regeneration

G

Heating element

H

Pressure relief valve with bypass, circuit 1

J

Pressure relief valve with bypass, circuit 2

K

Pressure limiting valve, circuit 3

L

Pressure relief valve, circuit 3

M

Flowback valve, circuit 3

N

Pressure relief valve with bypass, circuit 4

P

Pressure sensors

Cut-out pressure of pressure regulator

10.0 

≥ 0.2 bar

Cut-in pressure of pressure regulator

1.2 

≥ 0.2 bar under cut-out pressure

Supply pressure in circuit 1, connection 21

max. 10 bar

Supply pressure in circuit 2, connection 22

max. 10 bar

Supply pressure in circuit 3, connection 23

8.5 - 0.4 bar

Supply pressure in circuit 3, connection 25

8.5 - 0.6 bar

Supply pressure in circuit 4, connection 24

max. 10 bar

Supply pressure in circuit 4, connection 26

max. 10 bar

Opening pressure of circuits 1, 2 and 4

8.5 bar

Opening pressure of circuit 3

7.0 bar

Closing pressure of circuits 1, 2 and 4

7 bar

Closing pressure of circuit 3

5.5 bar

Cut-in temperature of heating element

7

C

Cut-out temperature of heating element

29

C

Circuit 1 activation pressure for flowback function 

of circuit 3

< 4.5 bar

©

 200436

1-3

Brake system and components

TECHNICAL DATA

ΛΦ45/55 series

6

0

Pressure sensor reading, circuits 1 and 2

(connections 6.2 - 6.7 in the diagram above)

FOOT BRAKE VALVE

Pressure reduction in circuits 1 and 2 from 10 to 

8 bar

1V

0V

2V

3V

4V

5V

12

0

2

4

6

8

10

P

21.22

(bar)

U

a

(V)

R600701

4

5

6

7

8

9

10

bar

P21
P22

3
2
1

1 2 3 4 5 6 7 8 9 10 11 12

C

 (cm)

0

P21-P22 = 0,3 

– 0,15

 bar

21

22

R600594

Pressure difference between circuits 1 and 2 (be-

tween 0 and 3 bar)

0.3 

≥ 0.15 bar

Connection 11

circuit 1 supply

Connection 12

circuit 2 supply

Connection 21

circuit 1 braking pressure

Connection 22

circuit 2 braking pressure

TECHNICAL DATA

1-4

©

 200436

Brake system and components

0

ΛΦ45/55 series

6

LOAD-DEPENDENT CONTROL VALVE, 
LEAF SPRING
Characteristic

LOAD-DEPENDENT CONTROL VALVE, 
AIR SUSPENSION
Characteristic

LOW-PRESSURE SWITCH

R600704

1

0

0.6

–0.2

1

2

3

4

5

6

7

8

9

10

2

3

4

5

6

7

8

9

10

R600705

p41
p42

= 4.65 bar

p41
p42

= 3 bar

p41
p42

= 0.3 bar

p4 [bar]

p2 [bar]

1:1

Cut-out pressure:

5.2 

≥ 0.2 bar