摘要 |
A lubricant pump for pumping a pressurized lubricant to an engine includes a shiftable control ring, a pump rotor, a pump outlet port, a pressure control system and a preload control arrangement. The pressure control system comprises a first pressure control chamber, a first pressure conduit connecting the pump outlet port with the first pressure control chamber, and a pressure control valve. The pressure control valve comprises an outlet port, a control valve cylinder wall comprising a control port connected with the outlet port, a control plunger which opens and closes the control port, an input pressure plunger connected with the control plunger, and a control spring preloading the control plunger into a closed position. The preload control arrangement comprises a preload cylinder, a preload plunger in the preload cylinder supporting a basis of the control spring, a preload cylinder inlet, and a preload control valve controlling a lubricant pressure. |