Air Blowing Unit For Vehicle

Abstract

Provided is an air blowing unit for a vehicle which, even when a backflow prevention means which prevents the flow of air which flows back through a gap formed between a bottom surface of an impeller and an upper surface of a motor flange is adopted, optimally maintains a size of the gap thus suppressing noises and the collection of moisture and, can suitably boost a pressure of air in a scroll case portion.

With respect to a case of an air blowing unit, a projecting portion is formed in a projecting manner on an inner side of a second wall portion on a side opposite to a first wall portion where an air suction port is formed as an air backflow prevention means. The projecting portion is positioned outside an impeller in the radial direction with a predetermined gap between a radial outer end of the impeller and the projecting portion.

Description

TECHNICAL FIELD[0001]The present invention relates to an air blowing unit used for a vehicle such as a vehicle air conditioner or a cooling device of heat source for a vehicle.BACKGROUND ART[0002]An air blowing unit used for a vehicle such as a vehicle air conditioner or a cooling device of heat source for a vehicle is basically constituted of, as disclosed in patent literature 1 and patent literature 2, for example, an impeller which generates an air flow by rotation, a motor which rotatably drives the impeller, a case (particularly, a scroll case portion which houses the impeller and is mainly constituted of a peripheral wall formed around a radial side of the impeller), and a motor flange on which the motor is mounted. As a function of such an air blowing unit, air is sucked into the inside of the scroll case portion through an air suction port formed in the scroll case portion by rotatably driving the impeller by the motor, a pressure of the air is boosted in the scroll case por...

AI Technical Summary

Benefits of technology

[0022]As described above, according to the inventions described in claim 1 to claim 7, even when a gap space having a size of a predetermined reference value is formed between the impeller and the second wall portion such as the motor flange, due to the provision of the air backflow prevention means, the flow of air which intends to flow back to an air suction port from the air blowing passage through the gap space can be dissipated or suppressed. Further, when air moves into the air blowing passage, the generation of a vortex of air can be prevented due to the presence of the air backflow prevention means. Further, even when the air backflow prevention means is provided, the gap space formed between the impeller and the second wall portion such as the motor flange is not defined in a complicated manner and hence, moisture hardly collects in the gap space thus preventing the rotation of the impeller from being locked by the freezing of the moisture.

[0023]Particularly, according to the invention described in claim 2, the projecting portion of the air backflow prevention means is configured to have the inclined surface on a side opposite to the impeller and hence, even when the air backflow prevention means is provided in the inside of the air blowing passage, it is possible to prevent an air flow from the impeller from generating a vortex. Further, by adjusting the inclining direction of the inclined surface of the projecting portion in the same direction as the flow direction of air which flows to the outside of the impeller in the radial direction from the air suction port, the flow of the air which flows to the outside of the impeller in the radial direction and spreads into the air blowing passage using the inclined surface of the projecting portion as a guide is strengthened so that it is possible to suppress the air from flowing into the gap space formed between the bottom surface of the impeller and the upper surface of the second wall portion from a gap between the projecting portion and the radial end portion of the impeller.

[0024]Particularly, according to the invention described in claim 3, it is possible to suppress air in the air blowing passage from flowing back through the gap space formed between the bottom surface of the impeller and the second wall portion. Further, when air which flows to the outside of the impeller in the radial direction from the air suction port is blown to the air blowing passage, the flow of air which flows along the cone portion particularly is not interrupted and hence, it is possible to suppress the lowering of the air blowing efficiency of the air blowing unit.

[0025]Particularly, according to the invention described in claim 4, although there is a possibility that unintended wind noises are generated due to an airflow in the air blowing unit when the crest portion of the projecting portion of the air backflow prevention means is formed with an acute angle, such a drawback can be obviated by forming the crest portion of the projecting portion into a flat surface or a curved surface.

[0026]Particularly, according to the invention described in claim 5, a cross-sectional area of the air blowing passage can be relatively increased and hence, the air flow resistance of the air blowing passage can be decreased whereby it is possible to suppress the drawback that air blowing efficiency of the air blowing unit is lowered.

[0027]Particularly, according to the invention described in claim 6, it is possible to suppress air in the air blowing passage from flowing back through the gap space formed between the bottom surface of the impeller and the second wall portion. Further, the cross-sectional area of the air blowing passage can be relatively decreased and hence, the pressure of air blown to the air blowing passage can be efficiently boosted.

Problems solved by technology

However, when a predetermined size is not ensured with respect to the gap space formed between the bottom surface of the impeller and the upper surface of the motor flange or the gap space formed between the bottom surface of the impeller and the upper surface of the motor flange has a complicated shape, there is a possibility that moisture will collect in the gap space.

In the case where the moisture is frozen, even when the motor is driven, the impeller is locked so that the impeller is not rotated, and there is also a possibility that the motor will catch fire depending on a situation.

On the other hand, in the centrifugal blower disclosed in patent literature 1, the gap space formed between the bottom surface of the impeller and the upper surface of the motor flange has the narrow and complicated structure due to the cylindrical rib formed on the motor flange side and the cylindrical rib formed on the impeller side and hence, risk such as a collision between the impeller and the motor flange due to vibrations or the locking of the rotation of the impeller is increased.

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