US Patent 8992184 Lubricant pump system

A lubricant pump system may include a lubricant pump controlled by a proportional valve. An actuating unit may be disposed in the lubricant pump and configured to control a delivery output of the lubricant pump. A first pressure chamber and at least one second pressure chamber may be configured to adjust the actuating unit against a spring, wherein the second pressure chamber is smaller than the first pressure chamber. In response to a failure of the proportional valve, the lubricant pump may be exclusively pressurized via the at least one second pressure chamber.