Ratgeber zur Wahl des passenden Frontladersteuergerätes

Here you will find a brief guide to choosing your suitable control unit.

Schritt 1: Identify hydraulic system

Possible built-in pump designs:

  • Zahnradpumpe Gear pump
    • Generates a constant current system (oil is continuously pumped)
      • also called open system or open center
    • Common with older tractors, smaller tractors, or tractors with simpler equipment
    • Relatively compact design, chaining multiple pumps is possible
      • Example representation:
    • Caution!
      • It may be that the gear pump is used in conjunction with modern valve blocks (example: Bosch SB23 LS); if existing interfaces are to be used there, m
  • Load-sensing variable displacement pump
    • Generates an LS system (hydraulic power is produced only as needed in pressure and flow rate)
      • short: LS system
    • Common in newer tractors from the mid-power class onwards.
      • Example representation:
  • Radial piston pump
    • Creates a constant pressure system (system is continuously maintained at operating pressure)
      • also called closed center or closed system
    • Comparatively rare, various older John Deere tractors are equipped with it

Schritt 2: Is print forwarding required?

The pressure forwarding ensures that downstream control blocks can be supplied with pressure when the control unit is in the neutral position. In load-sensing systems and constant pressure systems, no pressure forwarding is required; this is only relevant for constant flow systems.

In tractors with a constant flow system, a pressure relay is generally always required. Only if no further valves are installed behind the additionally installed control unit can the pressure relay be omitted.

Note!

In the Bosch SB7 and SB23 OC systems, the control units are only supplied with pressure when the oil returns (the control unit has the lowest priority), so a valve with pressure forwarding must always be used with these control units!

Step 3: What does my front loader need?

There are usually two types of construction here:

  • 2x Double-acting
    • Today’s standard front loader, lowering is done here with pressure, the tractor can usually be lifted via the front loader
    • Device operation (tilt in and out) is performed via a double-acting front loader
  • 1x Single-acting, 1x Double-acting
    • For a long time, this was a common configuration; lowering occurs here only due to the loader's own weight.
    • Device operation (tilt in and out) is performed via a double-acting hydraulic cylinder

For both variants, the lifting/lowering section is usually equipped with a floating position.

Our front loader control units are usually designed for the first-mentioned variant; for the second variant, we offer an additional conversion kit. This also allows for easy retrofitting to the first-mentioned variant at a later time.

Often, the wings are already equipped with hydraulic clutch(es). There are usually three different versions here:

  • BG3 Coupling
    • simple and affordable standard version for many swing arms
  • Flange-sealing couplings
    • höherer Durchfluss
    • geringere leakage when coupling
    • leichter zu reinigen
  • Multiclutch
    • usually designed as a flat-sealing coupling
    • enables simultaneous and non-interchangeable coupling of the front loader connections
    • Also combinable with electrical connections

Die übliche Stoll-Multikupplung ist in der Regel kombinierbar mit unseren Faster-Kupplungen.

Alternatively, the front loader connections can of course also be connected directly to the control unit without couplings.

Schritt 4: Identify installation space and measure Bowden cable length.

Depending on the choice of the front loader control unit, the desired mounting position must now be identified. The installation position of the control unit is basically arbitrary, but mounting on the swing arm has proven to be effective.

The following things should be noted:

  • Routing of the Bowden cables between the control unit and joystick (observe bending radius!)
  • Zuführung supply, return flow and pressure forwarding
  • Connection of the swingarm couplings with the control unit

After the installation position of the joystick in the cabin has been clarified, the appropriate length of the Bowden cables must now be selected.

It is advisable to try laying this path with a rigid cable or something similar as a test.

Step 5: 3rd/4th control circuit or quick drain

Depending on the equipment on the swing arm, the electrical connection for the 3rd/4th control circuit or quick discharge must be provided.

7-pin plug connections, as commonly known from trailers, are usually used as the connection between the front loader and the tractor.

If control is to be done via the joystick, it is important to ensure a sufficient number of buttons (one button for each function).

Step 6: System decision electrically proportional or mechanical?

Advantages of the electrically proportional valve

  • feather-sensitive control
  • geringere Betätigungskräfte
  • höhere Flexibilität beim Einbau (keine starren Bowdenzüge)

Disadvantages of the electrically proportional valve

  • Cost
  • No function during power outage

Advantages of the mechanical system

  • Joystick is more robust
  • lower costs
  • More equipment options
  • Higher reliability

Disadvantages of the mechanical valve

  • Higher operating forces
  • low flexibility during installation

Step 7: Installation of the system

Please refer to the corresponding instruction manual available for download here!

If you have any questions, please feel free to contact us.

Good to know!

  • Check valves on each section are important so that the two sections do not affect each other; these are always installed in our front loader control units, but are often not installed in cheaper alternatives.
  • Jedes Wegeventil dichtet innerlich rein metallisch (der Schieber hat keine Dichtungen), dadurch hat jedes Wegeventil eine gewisse innere Leckage, eine hochwertige Fertigung kann diese allerdings auf ein Minimum reduzieren
  • Front loader control units with higher flow rates are preferred. Higher allowable flow rates reduce the circulation pressure and thus the oil heating and power demand in the system. For example, a 90 l/min control unit can easily be installed on a tractor with a 40 l/min pump. However, the opposite does not apply to constant flow systems!
  • Front loader control units can be selected in the LS system regardless of the size of the LS pump. Thus, a 90 l/min control unit can easily be combined with a 240 l/min load-sensing pump, as the pump provides the flow rate according to demand.
  • We offer end plates for various Bosch valve systems that significantly simplify the connection of external valves, providing the necessary interfaces for supplying the front loader control unit.