DAF LF45, LF55 Series. Manual — part 235

©

200508

2-1

Description of components

PNEUMATIC GEARBOX CONTROL

ΛΦ45/55 series

3

3

2. DESCRIPTION OF COMPONENTS

2.1 FILTER/GOVERNOR

Overview drawing, filter/governor

Filter/governor (1) on gearbox

2

3

4

1

5

V300558-2

6
5
4

3

2

1

10

9

8

V300430

7

1.

Filter/governor

2.

Filter element

3.

Seal

4.

O-ring

5.

Cover

6.

Plug

7.

Output

8.

Selector valve output plug

9.

Attachment bolt

10.

Supply pressure input

PNEUMATIC GEARBOX CONTROL

2-2

©

200508

Description of components

3

ΛΦ45/55 series

3

The full vehicle supply pressure from circuit four

of the brake system must pass through the air

filter.

The supply pressure goes through the bore (1) in

the valve and will force the piston down against

the spring pressure.

The spring cannot be adjusted.

The system pressure (see "Technical data") goes

via connection point (2) to the range group

operating switch and the neutral position valve.

2

1

V302003

©

200508

2-3

Description of components

PNEUMATIC GEARBOX CONTROL

ΛΦ45/55 series

3

3

2.2 GEAR LEVER SELECTOR VALVE

Changing to the low or high speed range is done

with switch (A) on the ball of the gear lever.

When the switch is facing down it means that the

low speed range has been or is being engaged.

When the switch is facing up the high speed

range has been or is being engaged.

Pre-selection is possible. A particular range is

switched only when the gear lever is moved

through the neutral position.

The pressure on connection 1 is the system

pressure. When the switch is operated a

pneumatic command will be sent from connection

21 to the electropneumatic downshift protection

valve.

A

V3 00 562

1

21

V3 00 477

PNEUMATIC GEARBOX CONTROL

2-4

©

200508

Description of components

3

ΛΦ45/55 series

3

2.3 ELECTROPNEUMATIC DOWNSHIFT PROTECTION VALVE

The electropneumatic downshift protection valve

receives a certain frequency value relating to the

vehicle speed from the VIC.

If this value is too high, the connection between

the electropneumatic downshift protection valve

and earth will be broken. Despite the pneumatic

command from the range group operating switch

to connection point (4) on the electropneumatic

downshift valve, it is not now possible to switch to

the low range.

The system pressure to connection point (1) on

the electropneumatic downshift protection valve

is only available when the gear lever, and hence

also the neutral position valve, is in the neutral

position.

1

4

L

H

21

22

V3 00 478