Pneumatic And Hydraulic Equipment Page 362

Operating principle Hydraulic motors convert hydraulic energy (pressure, oil flow) into mechanical energy (torque, revolutions). Danfoss hydraulic motors are high torque motors with fixed displacement. For a given oil flow and given pressure the size of the displacement (size of motor) determines the speed and torque. For a given displacement (size of motor) the speed is determined by the size of the oil flow rate and the torque is determined by the pressure differential. Gearwheel set The motor gearwheel set consists of a gear rim with internal teething and a gearwheel. The center of the gearwheel rotates in a circular orbit around the center of the gear rim. There are two forms of gear rim: the OMM - MLHM, DH - HP(Q), DS - HR(Q), and OMP - MLHP have plain teeth, where- as the OMR - MLHR, OMH - MLHH, OMS - MLHS, OMT - MLHT and OMV - MLHV have teeth formed by rollers. Distributor valve The motor cardan shaft ensures that the distributor valve is driven synchronously with the gearwheel set so that the individual chambers of the motor are filled and emptied precisely-without losses. Thereare two forms of distributor valve: Spool valve OMM - MLHM, DH - HP(Q), DS - HR(Q), OMP - MLHP, OMR - MLHR and OMH - MLHH motors have a spool valve: the distributor valve has been integrated with the output shaft. The cardan shaft must therefore rotate the distributor valve as well as transfer mechanical energy from the gearwheel set to the output shaft. Disc valve OMS - MLHS, OMT - MLHT and OMV - MLHV motors have a disc valve: The distributor valve has been separated from the output shaft and it is driven by a short cardan shaft (valve drive). A balance plate counterbalances the hydraulic forces around the distributor valve. Suitable for continuous operation under rough operating conditions: e.g. high pressures, thin oil, or frequent reversals. The tapered roller bearings make the motors suitable for absorbing static and dynamic radial loads. The separately driven and hydraulically balanced disc valve reduces hydraulic and mechanical losses to a minimum. This gives the motors high efficiency, even at high pressures. If the application requires very smooth running at low speeds, the choice of OMS - MLHS, OMT - MLHT or OMV - MLHV is recommended. Features Compact motors with fixed gear rim. These types are suitable for long operating periods at moderate pressures-or short operating periods at high pressures. Main types DH - HP(Q), OMM - MLHM, OMP - MLHP Fixed gear rim Spool valve integrated with output shaft Output shaft supported in slide bearings The rollers in the gear rim and the effective hydrodynamic lubrication of the seats of the rollers reduce friction to a minimum. This gives long operating life and better efficiency even at continuous high pressures. Gearwheel sets with rollers are recommended for operation with thin oil and for applications having continually reversing loads. DS - HR(Q), OMR - MLHR, OMH - MLHH Gear rim with rollers Spool valve integrated with output shaft Output shaft supported in slide bearings OMS - MLHS, OMT - MLHT, OMV - MLHV Gear rim with rollers Disc valve with separate valve drive Output shaft supported in tapered roller bearings HYDRAULIC MOTORS Danfoss / RRUSA (314) 427-0600 800-444-0522 (FAX) 314-427-3502 www. j hf.com JHF Catalog [ Volume 7 ] 362 Prices Subject to Change Without Notice John Henry Foster pneumatic and hydraulic equipment

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