The Sauer MF axial piston variable displacement motors, Series 20, are of swash plate construction with variable flow capability suitable for hydrostatic transmissions with closed circuit. The flow rate is proportional to the motors driven speed displacement, which, in turn, is determined by the swash plate angle. The latter is infinitely adjustable between zero and maximum displacement. Flow direction is reserved by titling the swash plate to the opposite side of the neutral or zero displacement position. These units and parts are fit, form and function replacements for Sauer-Sundstrand series 20 components.The full-length shaft with a high efficient tapered roller bearing arrangement offers a high loading capacity for external radial forces. Additional motors can be built on. The hydro-mechanical servo displacement control maintains the selected swash plate position and hence motor displacement.
Upon release of the control handle, the swash plate automatically returns to the null position and the flow become zero.
High case pressures can be archived without leakage even at the lowest temperature by using suitable shaft seals. The servo valve arrangement offers the facility to incorporate function regulators and remote control system. Axial piston units are designed for easy servicing, complete dismantling and reassembly can be carried out standard hand tools, and all components or sub-assemblies are replaceable.
Table of values (theoretical values, without efficiency and tolerances; values rounded)
Size | Dimension | Sauer-Sundstrand MF motor | |||||||
MF20 | MF21 | MF22 | MF23 | MF24 | MF25 | MF26 | MF27 | ||
Max. displacement | cm3 | 33,3 | 51,6 | 69,8 | 89,0 | 118,7 | 165,8 | 227,3 | 333,7 |
Max. flow | dm3min-1 | 119,5 | 159,9 | 196,1 | 230,5 | 278,9 | 348,1 | 429,59 | 557,2 |
4 | 6 | 4 | 1 | 4 | 8 | 8 | |||
Charge motor | cm3 | 12,3 | 12,3 | 18,03 | 18,03 | 18,8 | 32,8 | 32,8 | 65,5 |
Max. pressure | MPa | 35 | |||||||
Nominal pressure | MPa | 21 | |||||||
Max. pressure of control | MPa | 3,5 | |||||||
Charge pressure | MPa | 0,8 - 2,0 | |||||||
Max. pressure in case | MPa | 0,25 continuous 0,5 intermittent | |||||||
Maximum speed + | min-1 | 3590 | 3100 | 2810 | 2590 | 2350 | 2100 | 1890 | 1670 |
Minimum speed | min-1 | 500 | |||||||
Nominal speed | min-1 | 1500 | |||||||
Kinematic viscosity range of working fluid
- starting - operating - optimum |
mm2s-1 |
1000 12 - 600 25 - 35 |
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Kind of working fluid | mineral oil | ||||||||
Operating temperature | oC | - 40 to + 50 | |||||||
Max. temperature of working fluid in tank | oC | 80 | |||||||
Purity of working fluid | µm | 10 | |||||||
Maximum swash plate angle | o | ± 18 o | |||||||
Weight | kg | 30 | 35 | 40 | 47 | 70 | 124 | 152 | 197 |