Mobile Pumps and Motors
Selected by machine duty as well as by displacement: gear pumps for service and implement circuits, open-circuit piston pumps where flow has to follow lever demand, and matched closed-circuit pump and motor sets for travel and drum drives.
Features
- Closed-circuit pump and motor pairs for travel and drum drives come as a matched set with charge pressure and flushing flow specified together.
- Tandem and multi-section gear pumps drive several services from one drive point, which is why a single failed section can affect two circuits.
- Load-sensing control keeps flow proportional to lever demand and is the reason a replacement pump with fixed displacement feels wrong to the operator.
- Drive couplings, splined adaptors and pump drive gearboxes are ordered with the pump, since the old drive is frequently worn as well.
- Cold-start behaviour is a real specification on machines working below freezing; a pump that starts against thick oil needs an unloaded start path.
Specifications
| Figure | Typical range | Unit | Why it matters |
|---|---|---|---|
| Circuit type | closed circuit, servo controlled | closed and open circuit pumps cannot substitute for each other | |
| Displacement | 0 - 71 variable | cm3/rev | range, not a single figure, on variable units |
| Charge pressure | 20 - 30 | bar | low charge pressure is the usual cause of closed-circuit cavitation |
| Case drain flow | 1 - 8 | l/min | the line must be sized for it and returned to tank unrestricted |
| Control | electric proportional, 24 V | must match the machine's existing control signal |