Patent ID: 8545199

Claim:
Vane pump, in particular a regulatable oil pump for a lubricating system, with a pump housing with at least one housing tank and with a vane rotor disposed in the at least one housing tank mounted so as to be rotatable about a drive shaft in the pump housing constituting an axis of rotation, the vane rotor providing a mount for vanes in approximately radially extending fitting slots, and with an adjusting ring circumferentially bounding pump cells surrounding the vane rotor, wherein the adjusting ring can be displaced via a cylindrical internal wall surface between a concentric position with respect to the vane rotor and an eccentric position with respect to the vane rotor, and with a mutually separate, pressure-tight suction and pressure region, and with a positioning mechanism for regulating a pressure level in a delivery flow, and with a working surface of a cavity disposed circumferentially on the adjusting ring, said cavity being between the adjusting ring and the pump housing, the cavity forming a pressure chamber with a flow connection to a pressure region, wherein the cavity is disposed between a sealing web extending out from an external circumferential surface of the adjusting ring and a pressure-tight pivot bearing arrangement of the adjusting ring constituting a pivot axis, and the sealing web has a sealing surface curving in an arc about the pivot axis, the sealing surface, in conjunction with an oppositely lying sealing surface of a wall part of the pump housing, constituting the second seal arrangement wherein the working surface of the pressure chamber for applying pressure to the external circumference of the adjusting ring constitutes between 5% and 45% of the external circumferential surface of the adjusting ring.