STEERINGTechnical Information Steering Unit LAGC

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Contents: Chapter 1 ______________________________________________________________________ 4 Introduction _________________________________________________________________________ 4 Features _____________________________________________________________________________________ 5 Ordering details _______________________________________________________________________________ 5 Function, section ______________________________________________________________________________ 8 Versions _____________________________________________________________________________________ 9 Functions in a steering circuit...

• Ordering details • Function, section • Functions in a steering circuit • Technical data • Pressure fluid technical data • Calculating the steering moment • Defining the steering cylinder and steering pump • Unit dimensions type LAGC/ LAGC LD / LAGC LDA • Ports: Type LAGC/ LAGC LD / LAGC LDA

Features • LAGC steering units are used in hydrostatic steering circuits of vehicles and mobile machines with large axle loads and travel speeds not exceeding 60 kph. • With the aid of a steering unit even heavy vehicles can easily be steered. The absence of a mechanical connection between the steering unit and steering axle allows the designer to realize solutions which would be impossible with conventional steering systems. • The steering unit includes all valves required in the hydraulic steering circuit for the protection of the steering unit and the steering cylinder. This eliminates the...

2 Dynamic load signal for priority valve flanging on 4 To be used for Open Center (OC) versions 5 Only Open Center design (extended flow: see Technical data) 6 The pressure setting of shock valves must be 50 bar higher than the setting of the pressure relief valve, but not exceed 2.2 times the setting of the latter (see §38 StVZO, German Road Traffic Licensing Regulation). Preferably: 150 to 90; 200 to 140; 240 to 175. 7 For thread dimensions see Unit dimensions type LAGC/LAGC LD /LAGC LDA.

Function, section Control spool (1) of the control valve is rotated via the steering column in relation to control sleeve (2). This opens cross-sections between the spool and the sleeve. The pressurized oil acts on the rotor set (3) and sets the latter into motion. The oil is then fed via the rotor set to the steering cylinder. The rotation of the rotor acts on the sleeve, which then follows the rotary movement of the spool. The size of the opened cross-section depends on the turning speed of the steering wheel and on the steering pressure, on Load-Sensing versions it depends exclusively on the...

Versions • Standard version Open Center with Non Reaction = OC / NR Mainly used in steering systems with fixed displacement hydraulic pumps. When no steering movement is performed, the connection between pump port (P) and tank port (T) is open (OC), and the pump flow is directed to the tank almost at zero pressure. Ports L 1 (left) and R1 (right) are blocked in the neutral position (NR). In this way, external forces acting via the steering cylinder are supported without the driver perceiving any resulting reaction forces on the steering wheel (Non Reaction). Contrary to standardization, the actuator...

• Low-noise version Steering units of the LAGC Open Center versions are generally delivered in the low-noise variant “N“. • Load sensing version Steering units with load sensing provide a load signal that can be used to control a priority valve and/or a pump. They are designed as closed center steering systems whereby the connection pump (P) to tank (T) is locked while neutral position. If the steering and implement hydraulics are supplied by a common pump then the use of a priority valve is necessary. The priority valve ensures that the steering unit gets a priority oil supply, whereby the control...

Steering units of type LAGC consist of a manually operated rotary spool valve, one rotor set, which operates according to the gerotor principle, and the required valves for the steering circuit. The nominal size for the power-assisted mode results of the rotor set size. The size of the rotor set is to be selected so that with 3 to 5 turns of the steering wheel it gets possible to steer from lock to lock. During normal operation of the steering unit, when a sufficient amount of oil gets supplied to the steering unit, the torque required on the steering wheel is < 5 Nm. In the event that the oil...

Gi. WHITE During manual steering, the following pressures can be achieved in dependence upon the steering moment:

Gi. WHITE Table 2: Hydraulic 1 Other steering moment variants (e. g. low) on request 2 The cleanliness classes specified for components must be adhered to in hydraulic systems. Effective filtration prevents malfunction and, at the same time, prolongs the service life of components. 3 Related to the steering speed of 100 steering rotations/min.

Pressure fluid technical data Pressure fluids Before carrying out any engineering please refer to the extensive information regarding pressure fluid selection and application conditions in standards or manufacturer instructions. For pressure fluids that require FKM or other seals please contact your sales contact. Operating viscosity We recommend that the operating viscosity (at operating temperature) for efficiency and service life, is selected within the optimum range of vopt = optimum operating viscosity range 16 to 46 mm2/s with reference to the temperature. Limiting viscosity For the limiting...

Pressure fluid filtration The finer the filtration the higher the cleanliness class of the pressure fluid is achieved and so the higher the service life of the entire hydraulic system. Note: To ensure the functionability of the steering pump a minimum pressure fluid cleanliness class of 19 / 16 / 13 to ISO 4406 is necessary (see Technical data). Caution: Operating the unit with contaminated hydraulic fluid may lead to the steering system failing. Figure 6: Selection diagram