Controllable coolant pump

Abstract

A coolant pump for a coolant circuit of an internal combustion engine, the coolant pump having a pump housing in which is mounted a drivable shaft, to one end of which is attached an impeller-which has vanes extending into a suction chamber and is connected to a cover plate. Fluid can be drawn into the suction chamber through an intake port of the pump housing by joint rotation of the impeller and the cover plate and can be conveyed by the vanes into the pump housing. A guide plate, which is axially displaceable by an actuation unit, is disposed between the impeller and the cover plate. The guide plate has a contour corresponding to the impeller and a collar oriented toward the impeller. The coolant pump is characterized in that the guide plate has at least one opening.

Description

[0001]The present invention relates to a coolant pump for a coolant circuit of an internal combustion engine. The coolant pump has a pump housing in which is mounted a drivable shaft, to one end of which is attached an impeller which has vanes extending into a suction chamber and is connected to a cover plate. As a result of the rotation of the cover plate and the vaned impeller, fluid is drawn into the suction chamber through an intake port of the pump housing and conveyed further into the pump housing by the vanes. A guide plate, which is axially displaceable by an actuation unit, is disposed between the impeller and the cover plate. The guide plate has a contour corresponding to the impeller and a collar oriented toward the impeller.BACKGROUND[0002]In order to achieve rapid heating of the internal combustion engine and to selectively adjust the engine temperature, the coolant pump should be switchable or ideally controllable. This is accomplished selectively by adjusting the flow...

AI Technical Summary

Benefits of technology

[0004]It is an object of the present invention to provide a switchable or controllable coolant pump whose actuator does not require additional cost or space to provide the forces needed to adjust the guide plate.

[0005]The present invention provides that the guide plate has at least one opening. The opening provided reduces the effective pressure difference between the front and rear sides of the guide plate, which in turn reduces the axial force required to displace the guide plate. Fluid communication between the front and rear sides of the guide plate is facilitated. The fluid conveyed radially behind the guide plate has a centrifugal pressure typical of impellers. In conjunction with a certain dynamic pressure component, which is generated when the flow impinges axially on the rear wall of the impeller after entry through the holes, a mean pressure is generated behind the guide plate. Thus, the pressurized fluid has a force component directed in the guide-plate-closing direction. The guide-plate-closing direction refers to the axial displacement of the guide plate toward the cover plate. This leads to a reduction in the resultant force in the guide-plate-opening direction. The guide-plate-opening direction refers to the axial displacement of the guide plate toward the impeller. In this manner, the actuator is relieved of load during the displacement operation in terms of the force to be exerted.

[0006]It has proved advantageous to provide the guide plate with more than one opening. The openings can have different shapes, such as, for example, flow-optimized shapes in order to make use of flow effects, or radial openings extending in the guide plate, or shapes which are optimized for economical manufacture. Regardless of the specific embodiment, the greatest effect is achieved when the openings are located in the region near the axis of rotation of the guide plate.

[0009]In order to be able to use a conventional inexpensive actuator, it has proved advantageous to match the degree of opening of the guide plate to the number in a suitable manner. As a result, a fluid force of 20-50 N develops which acts on the guide plate, forcing it toward the impeller, and thus opening the coolant pump. This is intended to prevent negative fluid forces, which in turn eliminates the need for the use of a fail-safe spring. In a specific embodiment of the present invention, it is therefore proposed that the impeller have an additional closing contour pointing in a direction toward the guide plate, and that the closing contour be engageable into the at least one opening of the guide plate, partially or completely closing the same.

[0012]Another option in accordance with the present invention is to configure at least one closing element in a stepped manner, which allows for partial closure of the opening.

Problems solved by technology

For this reason, the actuators used are mostly expensive and require a large space.

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