Raising trailing axle function

W35.50-1022-09

1 Hydraulic cylinder

2 Trailing axle

3 Lift solenoid valve

4 Lowering solenoid valve

5 Motor

6 Hydraulic pump relay

7 Pressure limiting switch

K18 Check indicator relay

K19 Lowering end shutoff relay

K20 Lowering relay

K21 Lifting end shutoff relay

S94 Lift axle switch

S95 Lower axle ON switch

8 Nummek axle control module

9 Trailing axle display field

A39 Nummek axle

K14 Starting-off aid time relay

K15 Reclosing lock time relay (France)

K16 Lower time relay

K17 Drop-off delay time relay

The lowered trailing axle can be raised by switching on the lower axle ON switch (S95) and actuating the lift axle switch (S94).

Function sequence

Function prerequisites:

 Ignition: ON

 Trailing axle lowered

 Drive axle load below 13 t (vehicle empty or only partially loaded)

When the ignition is turned on the input S and input terminal 15 of the drop-off delay time relay (K17) are supplied with power. The relay picks up and power is supplied from terminal 30 at the lower axle ON switch (S95).

 The drop-off delay time relay (K17) has a time delay of 5 seconds.

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This allows the driver to switch on terminal 15 again up to 5 seconds after switching off the engine in order to prevent the trailing axle from dropping (rail gate circuit).

If the lower axle ON switch (S95) is pressed up, the lower axle ON switch (S95) closes. The input S of the lower time relay (K16) is supplied with power.

 If the drop-off delay time relay (K17) fails (5 seconds after switching off terminal 15), the lowering time relay (K16) ensures power is supplied for 60 seconds to lower the trailing axle.

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France

At the same time, power is supplied at the lift axle switch (S94) via the NC contact of the reclosing lock time relay (K15) and at the starting-off aid time relay (K14), input terminal 15.

Foreign (EC)

At the same time, power is supplied at the lift axle switch (S94) and at the starting-off aid time relay (K14), input terminal 15.

If the lift axle switch (S94) is pressed, input S of the starting-off aid time relay (K14) is supplied with power. The relay picks up and switches via the overload switch (S96) to self-hold.

The lift solenoid valve (3) is supplied with power via the NC contact of the lifting end shutoff relay (K21). The hydraulic pump relay (6) is supplied with power via the NC contact of the lowering relay (K20).

The hydraulic pump relay (6) picks up and switches B+ to the motor (5). The motor is switched on and drives the pump component of the hydraulic pump in the hydraulics box. The trailing axle is raised.

The check indicator relay (K18) is supplied with power simultaneously. The relay picks up and the indicator lamp lights up.

At a pressure of 140 bar (France ) or 128 bar (foreign EC) the pressure limiting switch (7) closes. The lifting end shutoff relay (K21) is supplied with power via the diode box V1 and the relay switches to self-hold.

As a result, the power supply is interrupted to lowering relay (K20) and the lift solenoid valve (3) and the hydraulic pump relay (6) drop out. The motor (5) of the hydraulic pump is switched off.

 If the overload switch is switched due to uneven road surfaces when the vehicle is moving, it is buffered by the OFF delay of the starting-off aid time relay (K14).