HYDRAULIC CIRCUIT

Abstract

The invention relates to a hydraulic circuit 1 comprising a high-pressure port 2, a low-pressure port 3, a feed unit 4, and a pump system 5. The low-pressure port 3 is fluidically connected to the high-pressure port 2 by means of a series connection of the feed unit 4 and the pump system 5. The pump system 5 comprises a pump 6 for pumping a fluid, a shaft 7 for driving the pump, and an unlockable check valve system 8. In a first state, the pump pumps the fluid from a first pump port 6a to a second pump port 6b, through the check valve 8, and on to the high-pressure port. In a second state, the pump pumps the fluid from the second pump port 6b to the first pump port 6a and to a control port 8c of the check valve 8.The check valve 8 prevents fluid flow from the high-pressure port to the first pump port 6a and allows fluid flow from the first pump port 6a to the high-pressure port 2. Fluid flow from the high-pressure port 2 to the first pump port 6a can be enabled via the control port 8c. The feed unit 4 is configured to allow fluid flow from the low-pressure port 3 to the respective suction pump ports 6a and 6b and to prevent fluid flow from the respective discharge pump ports 6a and 6b to the low-pressure port 3. When pumping the fluid, the pump 6 exhibits a leakage flow up to the shaft 7. A pressure equalization line 9 connects the shaft 7 to the low-pressure port 3 to discharge the fluid from the shaft 7.