LOOP-FLUSHING-SYSTEM FOR HYDROSTATIC APPARATUS

摘要

A hydraulic loop-flushing device (50) for a hydrostatic apparatus (1) comprising a valve housing (8) having a cylindrical valve bore (9) with a high pressure inlet (5 or 6), a low pressure inlet (6 or 5) and a discharge outlet (7). A first flushing valve spool (12) is arranged elastically pre-stressed within the valve bore (9) for enabling a fluid connection between the low pressure inlet (6 or 5) and the discharge outlet (7) by means of a first fluid channel (16). Further, a shuttle valve spool (22) is arranged elastically pre-stressed within the valve bore (9) for further enabling the fluid connection between the low pressure inlet (6 or 5) and the discharge outlet (7) by means of a fluid passageway (29). The first flushing valve spool (12) is moveable into an open position, in which the first fluid channel (16) is open, if the fluid pressure at the low pressure inlet (6 or 5) exceeds a first threshold value, and the shuttle valve spool (22) is moveable into an open position, in which the fluid passageway (29) is open for connecting the low pressure inlet (6 or 5) with the discharge outlet (7), if the pressure difference between the high pressure inlet (5 or 6) and the low pressure inlet (6 or 5) exceeds a second threshold value. For this the first flushing valve spool (12) and the shuttle valve spool (22) are arranged concentrically and moveable relative to each other, and the fluid connection between the low pressure inlet (6 or 5) and the discharge outlet (7) is enabled only, if both the first flushing valve spool (12) and the shuttle valve spool (22) are in the respective open positions.

主权项

1. A hydraulic fluid loop-flushing device for a hydrostatic apparatus comprising:
a valve housing having a cylindrical valve bore with a high pressure inlet, a low pressure inlet and a discharge outlet, a first flushing valve spool being arranged elastically pre-stressed within the valve bore for enabling a fluid connection between the low pressure inlet and the discharge outlet by means of a first fluid channel, a shuttle valve spool being arranged elastically pre-stressed within the valve bore for further enabling the fluid connection between the low pressure inlet and the discharge outlet by means of a fluid passageway, wherein the first flushing valve spool is moveable into an open position, in which the first fluid channel is open, if the fluid pressure at the low pressure inlet exceeds a first threshold value, and wherein the shuttle valve spool is moveable into an open position, in which the fluid passageway is open for connecting the low pressure inlet with the discharge outlet, if the pressure difference between the high pressure inlet and the low pressure inlet exceeds a second threshold value, wherein the first flushing valve spool and the shuttle valve spool are arranged concentrically and moveable relative to each other, and wherein the fluid connection between the low pressure inlet and the discharge outlet is enabled only, if both the first flushing valve spool and the shuttle valve spool are in the respective open positions.