SPECIFIC ADVANTAGES OF HYDROMATIK TRANSMISSION UNITS
In addition to the traditional features of hydrostatic transmission systems (freedom of transmission installation, minimum space requirement, instant drive reversal, no clutches, dynamic braking), HYDROMATIK transmission units have the following advantages : 1) 2) 3) 4) 5) 6)
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Specific output of A 4 VG pumps is the highest on the market. High speed A 4 VG pumps and A 6 VM motors. Bent axis design of A 6 VM motors, the pistons have no shoes, this allows 90% of the rated load torque to be transmitted on start-up and produces a wide control range. Continuous automatic variation of transmission ratio, controlled by the operator (accelerator pedal) or according to the load, and consequently a better use of the installed capacity. Conventional drive with accelerator pedal and brake and inching pedal. The DA control acts as a “maximum load power control”. Pumps with DA control are used universally on diesel engines and do not require any power calibration, thus making the corresponding settings easier. The DA control allows peak pressure and maximum displacement to be reached well before the maximum diesel engine speed (1600 - 2000 rpm), and therefore maximum machine power or 75% of the travel speed are achieved within a favourable fuel consumption range and a restricted noise level range. When used on loaders, a high average travel speed and maximum propulsive force for a favourable diesel engine speed is possible. The efficiency of the machine (hourly capacity : hourly consumption) is also very high. The TH 7 valve coupled up to the brake pedal clearance stroke allows the driver to reduce the machine travel speed whilst increasing the IC engine speed, and, consequently, the delivery of the pump supplying the various hydraulic movements. It is therefore possible to achieve maximum lifting speed at low travel speed, hence more efficient handling. Thanks to the TH 7 (inching) valve, when the driver brakes, firstly hydrostatic braking of the machine occurs, then the brakes are activated, giving economy and long life to the braking system. Limited negative impact on diesel engine speed at full load. No diesel engine overload. When immobilized, diesel power is not transformed into heat ; the HP relief valves are not activated due to the combined restoring force-DR valve system. Displacement of the A 6 VM variable motor controlled by the same pilot pressure as the pump (still the only system of this type on the market). The installation of the DA controlled variable motor allows the pump module to be better adapted to the power of the IC engine (and not to the apparent power of the machine). Thus, the constant power delivery range of the pump is maximized and is still satisfactory with the transfer of power to the working hydraulics. HP locking system on the A 6 VM motor permitting detection of the torque direction in relation to the direction of travel, thus avoiding untimely braking in stoppage. The A 6 VM motor is equipped with an exchange system allowing a certain quantity of oil to be drawn from the low pressure circuit. This oil is directed to the reservoir via the cooler. The booster flow therefore compensates for this exchange.
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