Pumps – Motor driven – Including means utilizing pump fluid for augmenting cooling,...
Reexamination Certificate
2000-03-06
2001-09-04
Freay, Charles G. (Department: 3746)
Pumps
Motor driven
Including means utilizing pump fluid for augmenting cooling,...
C417S368000, C417S370000, C415S058400
Reexamination Certificate
active
06283726
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a radial blower, particularly for heating and air-conditioning systems in automobiles. Such blowers have a spirally shaped blower housing with air inlets in one housing sidewall and a blower motor mounted to the blower housing, so that a fan wheel driven by the motor faces the air inlets.
BACKGROUND INFORMATION
The space available in an automobile for installing a heating, venting and air cooling system is generally rather limited. Often, a centrifugal blower is used for circulating air, particularly to achieve a desired quiet operation. A space-saving construction of such a blower is achieved if the air is drawn directly into the blower at an intake positioned in a blower housing wall opposite the wall to or on which an electric blower motor is mounted. However, in such a construction it is difficult to adequately cool the blower motor itself.
German Patent Publication DE 195 47 674 A1 discloses a radial blower, particularly for heating and air-conditioning systems for automobiles. In the known blower, a fan wheel driven by an electric blower motor is encased in a spiral housing section. The housing has a suction air inlet opening into a suction chamber and an air outlet leading to the outside. A closed portion of the housing opposite the air inlets has a shell-shaped recess in which at least a portion of the electric blower motor is arranged. The other portion of the electric blower motor is arranged within a shell-shaped and vaulted carrier or fan disk that connects a hub of a fan wheel with its fan ring. The fan ring supported by the carrier or fan disk has first fixed blades (
31
) arranged at the radial outer run of the carrier or fan disk and extending axially and radially outwardly of the electric blower motor. Second fixed blades (
41
) are positioned on a smoothly formed, closed inner surface facing the motor for diverting a cooling air flow from a main air flow, into the spiral housing for cooling the electric blower motor. The known radial blower brought some improvement in the cooling of the blower motor, relative to the then known art. However, especially during extended operation, the components become too hot, which has a negative effect on the service life of the blower motor.
U.S. Pat. No. 4,470,753 (Witzel—September /1984), corresponding to German Patent Publication DE 2,939,385 discloses an improved cooling of the electric motor by a radial blower in a housing having an air intake opening on its front side and a drive motor for a fan wheel on its rear side. The fan wheel has a fan ring with fan blades on a hub. A shell-shaped curved fan disk connects the fan ring to the hub. The fan disk is provided with openings through which motor-cooling air is drawn into the intake side of the fan wheel, thereby achieving good cooling of the electric motor. However, there is room for improvement.
German Patent Publication DE 34 27 565 C2 also discloses a radial blower with a radial fan driven by an electric motor. A fan disk is provided with axially outwardly extending fan blades arranged on the radial outer area of the disk. The fan disk has openings through which the cooling air which has been warmed by the electric motor, is drawn to the intake or suction side of the fan wheel, mixed with the inflow air, and diverted into the spiral delivery chamber. This fan wheel, however, is less suitable for applications that require quiet operation because the openings in the fan disk allow “short-circuit” flow between the pressure side and the suction side and, thus, the blower tends to be noisy.
OF THE INVENTION
In view of the foregoing, it is the aim of the invention to achieve the following objects singly or in combination:
to provide a radial blower, particularly for use in heating and air-conditioning systems in automobiles, that will adequately cool the electric blower motor, yet will run quietly;
to avoid or overcome the disadvantages of the prior art, particularly to increase the operational life of vehicle heating and cooling systems, especially of the motor of such system;
to improve the cooling air flow through the blower motor generally at all blower motor r.p.m.s, and particularly in a normal r.p.m. range where the fan does not run at high speed, to keep particularly the motor at a non-critical temperature range.
SUMMARY OF THE INVENTION
According to the invention there is provided a radial blower comprising a spiral housing, an air inlet in the spiral housing, a fan wheel in said spiral housing, a blower drive motor mounted for driving said fan wheel in said spiral housing. The fan wheel comprises a hub, fan blades forming a fan ring and a shell-shaped, vaulted fan disk connecting the fan ring to the hub. The fan disk comprises at least one fan disk opening. A hood is arranged on a fan disk surface facing away from said blower drive motor. The hood is so shaped and positioned that it covers at least a forward or leading portion of the fan disk opening relative to a direction of rotation of the fan wheel for generating a negative pressure on the fan disk surface facing away the blower motor when the fan wheel rotates, whereby airflow through the at least one fan disk opening and thus also through the blower motor is increased by suction caused by the negative pressure.
Preferably, the fan disk according to the invention has a plurality of partially-hooded openings which are so constructed that a forward or leading end of an opening relative to the direction of rotation of the fan wheel, is partly covered by the respective raised hood that is open at a trailing or rear end facing opposite to the direction of rotation of the fan wheel. As the fan wheel rotates, a negative pressure is generated by the plurality of hoods each covering at least partly a respective opening. The negative pressure occurs just behind the hood above the opening on the side of the fan disk facing away from the drive motor. This negative pressure or suction increases the airflow through the blower drive motor, thereby providing effective cooling of the motor and its components. The cooling air passing through the blower drive motor is pulled through the partially-hooded openings in the fan disk into the intake or suction chamber in the spiral housing of the blower wheel, mixed with the main airflow volume, and transported to the blower air discharge opening or openings. Increasing airflow through the motor reduces the temperature of the motor components to an uncritical temperature range whereby the service life of the drive motor and thus of the system is increased. The shape of the hoods also contributes to a quieter blower operation. Furthermore, because of its compact construction, the radial blower can be used advantageously in automobiles that have very little available space.
It is advantageous to construct the fan wheel or impeller with its hub, its fan ring with the fan blades, and the fan disk with its openings and hoods as a single component, preferably as an injection-molded part, preferably made of a plastic material.
REFERENCES:
patent: 3081975 (1963-03-01), Sproule et al.
patent: 3280750 (1966-10-01), White
patent: 4470753 (1984-09-01), Witzel
patent: 5743721 (1998-04-01), Graham et al.
patent: 2939385 (1981-04-01), None
patent: 3427565 (1986-02-01), None
patent: 19547674 (1997-06-01), None
Fackelmann Walter
Hillrichs Heinrich
Fasse W. F.
Fasse W. G.
Freay Charles G.
TEMIC Automotive Electric Motors GmbH
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