摘要 |
A controllable coolant pump for a coolant circuit of an internal combustion engine. The coolant pump has a hollow bearing shaft which is supported in a bearing sleeve, carries a drive wheel at one end, and is permanently connected to an impeller at its opposite end, the impeller having a stop surface at the end face thereof. The space between the stop surface and the impeller forms the pumping cross section for a coolant. A piston that can be axially displaced by an actuation unit is disposed in the hollow bearing shaft and provided at its outer end with a guide plate having a collar facing the impeller for completely or partially closing the pumping cross section in accordance with the position of the piston. The coolant pump has a second actuation unit, and the piston can be displaced by the first or second actuation unit. |