Blower assembly having integral air flow cooling duct

Abstract: A blower assembly (10) includes a motor cover (18) having a body portion (40) defining a motor cavity (19), an air flow guide surface (42) connected to an end (41) of the body portion (40), the guide surface (42) extending radially outwardly from the body portion (40), and a cooling duct (44) integrally formed with the body portion (40) and having an inlet (48) and an outlet (50), the inlet (48) being located at the end (41) of the body portion and the outlet (50) being defined in a sidewall of the body portion (40). The blower assembly (10) further includes a motor (16) positionable in the motor cavity (19) the motor (16) having a motor shaft (20) having a central axis (A1). In addition, the blower assembly (10) includes a fan housing (12) connected to the motor cover (18), wherein the fan housing (12) defines a scroll cut-off line (63), and a plane (P1) passes through the scroll cut-off line (63) and the central axis (A1), and the cooling duct (44) is positioned adjacent to the plane (P1). The blower assembly (10) also includes a fan (14) positioned within the fan housing (12), wherein the fan (14) rotates in a rotational direction (65), and the cooling duct (44) is positioned on the upstream side of the plane (P1) relative to the rotational direction (65) of the fan (14).

Description: Background of the Invention The present invention generally relates to an apparatus for generating a flow of air, and more particularly relates to a blower assembly having an integral air flow cooling duct to provide cooling air for a drive motor. A blower assembly is used in an automobile for generating a flow of air. This flow of air is then advanced to the interior of the automobile. The flow of air may be heated or cooled depending on the ambient weather conditions and the desire of the operator. A blower assembly includes a motor for rotating a fan within a housing. The motor generates heat which may be detrimental to the operation of the motor. For instance, the motor may operate less efficiently or have a reduced operating life at higher temperatures, or alternatively, the internal components of the motor may burn or melt thus resulting in failure of the motor. It is known to provide a flow of cool air to the motor of the blower assembly so as to reduce its temperature. This flow of cool air is usually obtained by channeling some of the air flow generated by the fan and directin the channeled air flow toward the motor. However, some of the designs of mechanisms used to guide air flow from the fan toward the motor are inefficient. Also, some of these designs have many parts and are time consuming and expensive to assemble. Such an arrangement is known from FR-A-2 412 976 or FR-A-2 236 384. Summary of the Invention In accordance with the present invention, there is provided a blower assembly according to claim 1. The blower assembly includes a motor cover having (1) a body portion defining a motor cavity, (2) an air flow guide surface connected to an end of the body portion, the guide surface extending radially outwardly from the body portion, and (3) a cooling duct integrally formed with the body portion and having an inlet and an outlet, the inlet being located at the end of the body portion and the outlet being defined in a sidewall of the body portion. The blower assembly further includes a motor positionable in the motor cavity, the motor having a motor shaft having a central axis. In addition, the blower assembly includes a fan housing connected to the motor cover, wherein (1) the fan housing defines a scroll cut-off line, and (2) a plane passes through the scroll cut-off line and the central axis, and (3) the cooling duct is positioned adjacent to the plane. The blower assembly which includes (1) a motor having a rotatable shaft, (2) a fan attached to the rotatable shaft, (3) a motor cover which receives the motor therein, and (4) a housing which contains the fan therein. The fan includes a first support and a second support. The fan further includes a plurality of blower vanes secured between the first support and the second support. In addition, the fan includes a connection member attached to the second support, the connection member being secured to the rotatable shaft of the motor. The fan also includes a number of secondary vanes attached to the connection member for generating a flow of air toward the motor cover, the secondary vanes being positioned over the motor. The blower assembly which includes a motor having a rotatable shaft. The blower assembly further includes a fan attached to the rotatable shaft, the fan defining a circular rotational path when the motor is operating, and the circular rotational path having a fan radius.Moreover, the blower assembly includes a motor cover which receives the motor therein, the motor cover having (1) a body portion defining a motor cavity, (2) an air flow guide surface connected to an end of the body portion, the guide surface extending radially outwardly from the body portion, (3) a cooling duct integrally formed with the body portion and having an inlet and an outlet, the inlet being located at the end of the body portion and the outlet being defined in a sidewall of the motor cavity, wherein an outer wall of the cooling duct is located a distance away from an axis of the rotatable shaft, and the distance is greater than the fan radius. The above and other objects, features, and advantages of the present invention will become apparent from the following description and attached drawings. Brief Description of the Drawings Fig. 1 is a perspective view of a blower assembly which incorporates the features of the present invention therein; Fig. 2 is a cross-sectional view of the blower assembly of Fig. 1 taken along the line 2-2 of Fig. 1 as viewed in the direction of the arrows; Fig. 3 is a perspective view of the fan of the blower assembly of Fig. 1; Fig. 4 is a first perspective view of the motor cover of the blower assembly of Fig. 1; Fig. 5 is a second perspective view of the motor cover of the blower assembly of Fig. 1; Fig. 6 is a view of a profile of the bottom of the fan and the housing of the blower assembly of Fig. 1, with the cooling duct of the motor cover shown in relation to a plane defined by a cut-off wall of the housing; Detailed Description of the Preferred Embodiment While the invention is susceptible to various modifications and alternative forms, a specific embodiment thereof has been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims. Referring to Figs. 1-2, there is shown a blower assembly 10 which incorporates the features of the present invention therein. The blower assembly 10 includes a housing 12, a fan 14, a motor 16 and a motor cover 18. The motor cover 18 includes a first attachment mechanism 32 while the housing 12 includes a second attachment mechanism 34. The first attachment mechanism 32 cooperates with the second attachment mechanism 34 to secure the motor cover 18 to the housing 12. In particular, the first attachment mechanism 32 includes a plurality of attachment members 36 while the second attachment mechanism includes a plurality of receptacles 38. The plurality of receptacles 38 are configured to receive and engage the plurality of attachment members 36 so as to secure the motor cover 18 to the housing 12. The motor cover 18 defines a motor cavity 19 (see als Figs. 4 and 5) in which the motor 16 is located. The motor 16 includes a rotatable shaft 20. The fan 14 is attached to the rotatable shaft 20. The fan 14 is contained within the housing 12. The motor 16 further includes a housing 17 having a number of inlet ports 77 and outlet ports 78. As shown in Fig. 3, the fan 14 includes an upper support member 22 and a lower support member 24. A plurality of blower vanes 26 are secured between the upper support member 22 and the lower support member 24. The fan 14 further includes a connection member 28 attached between the lower support member 24 and the rotatable shaft 20 of the motor 16 (see also Fig. 2). The fan 14 further includes a number of secondary vanes 30 attached to an underside of the connection member 28 (see Fig. 2). During rotation of the fan 14, the secondary vanes 30 function to assist generation of a flow of air which is pulled through the motor 16 and then directed downwardly toward the motor cover 18. The fan rotates in the direction of arrow 65 as shown in Figs. 1, 4, 5 and 6. As shown in Figs. 4 and 5, the motor cover 18 includes a body portion 40 and an air flow guide surface 42. The guide surface 42 is connected to a first end 41 of the body portion 40. The guide surface 42 extends radially outwardly from the body portion 40. The motor cover 18 additionally includes a cooling duct 44 which is integrally formed with the body portion 40. The cooling duct 44 defines a channel 46 having an inlet 48 and an outlet 50. The inlet 48 is located at the first end 41 of the body portion 40 while the outlet 50 is defined in a sidewall of the body portion 40 at a location between the first end 41 of the body portion 40 and a second end 45 of the body portion 40. Projecting upwardly from the cooling duct 44 at a location adjacent the motor cavity 19 is a pair of fingers 21. The fingers 21 are positioned adjacent to the motor 16 when the motor is located within the body portion 40 of the motor cover 18 as shown in Fig. 2. The channel 46 has a first width R1 at the inlet 48 of the cooling duct 44 (see Fig. 4). The channel's width continuously decreases from the inlet 48 to an intermediate location near the outlet 50 (i.e. a location which is intermediate the inlet 48 and the outlet 50). This is indicated by the width markings R1, R2 and R3, where R1 > R2 > R3. The channel 46 also has depth D1 at the inlet 48 of the cooling duct 44. The channel's depth continuously increases from the inlet 48 to the above intermediate location near the outlet 50. This is indicated by the depth markings D1, D2 and D3, where D1 < D2 < D3. Since the channel depth increases while the channel width decreases, the channel 46 maintains a nearly-constant cross sectional area in the flow direction which provides superior air flow characteristics to the channel 46. The fan 14 defines a circular rotational path which has a radius L1 relative to the axis A1 of the shaft 20 of the motor 16 (see Fig. 2). The channel 46 is configured such that an outer wall 47 of the channel is spaced a distance L2 from the axis A1 of the shaft 20. This feature allows the cooling duct 44 to directly receive some of the air flow being generated by the fan 14 in the radial direction for subsequent advancement into the motor cavity 19. The motor cover 18 also includes a baffle 52 for guiding air flow which is adjacent to the guide surface 42 of the motor cover 18. In particular, the baffle 52 includes a first baffle portion 54 for guiding a flow of cool fan air 58 into the cooling duct 44, and a second baffle portion 56 for guiding a flow of warm exhaust air 60 out of the motor cavity 19. In operation, the baffle 52 keeps the flow of cool fan air 58 separate from the flow of warm exhaust air 60. Referring again to Fig. 1, the housing 12 defines a planar scroll cut-off wall 62. A scroll cut-off line 63 is defined by the vertically-oriented edge of the cut-off wall 62 which is closest to the fan 14 as shown in Fig. 1. A plane P1 passes through the cut-off line 63 and the axis A1 as shown in Fig. 6. The plane P1 is also shown in Fig. 5. The cooling duct 44 is positioned adjacent to the plane P1 on the upstream side of the plane relative to the rotational direction of the fan 14 as shown in Figs. 5 and 6. This feature is beneficial due to the high static pressure created by the fan 14 at the location which is adjacent to the opening of the cooling duct 44. Fig. 6 shows a profile of the bottom of fan 14 and housing 12 which is located adjacent to the guide surface 42 of the motor cover 18. In particular, the static pressure created by the fan 14 at location SP3 (see Fig. 6) is greater than the static pressure at location SP2. Similarly, the static pressure at location SP2 is greater than the static pressure at location SP1. This difference in static pressure is due to the geometry of the housing 12. The optimum location for the opening of the cooling duct 44 is at an area of highest static pressure within the system. This is true because the outlet 50 is located at an area of lower static pressure, and thus a pressure gradient exists that causes the air flow from the bottom of the fan 14 to the motor cavity 19. There is a correspondence between the magnitude of static pressure at the opening of the cooling duct 44 and the magnitude of the flow of air from the bottom of the fan 14 to the motor cavity 19. In particular, the higher the static pressure at the opening of the cooling duct 44, the stronger the flow of air from the bottom of the fan 14 to the motor cavity 19. In operation, the flow of cool fan air 58 is directed into the cooling duct 44 and then is advanced into the inlet ports 77 of the motor 16 (see Fig. 2). Thereafter, the flow of air is advanced through the motor 16 to the outlet ports 78 of the motor 16 (see Fig. 2). During advancement within the motor 16, the flow of cool fan air increases in temperature so as to change to the flow of warm exhaust air 60 which is advanced out of the outlet ports 78. Then, the flow of warm fan air 60 is guided downwardly to the guide surface 42 by pressure differences. Thereafter, the flow of warm fan air 60 is guided away from the motor 16 by the second baffle portion 56 as shown in Fig. 4. It should be noted that the outlet ports 78 are located a distance W1 away from the axis A1 of the motor 16, while the inlet ports 78 are located a distance W2 away from the axis A2 of the motor 16 (see Fig. 2). Further, it should be noted that the secondary vanes 30 are located a distance W3 away from the axis A1 of the motor 16. Beneficial air flow is created by secondary vanes 30 when W1 < W3 < W2.

Claims: A blower assembly comprising a body portion (40) defining a motor cavity (19), an air flow guide surface (42) connected to an end (41) of said body portion (40), said air flow guide surface (42) extending radially outwardly from said body portion (40), and a cooling duct (44) integrally formed with said body portion (40) and having an inlet (48) and an outlet (50), said inlet (48) being located at the end (41) of said body portion (40), and said outlet (50) being defined in a sidewall of said body portion (40), caracterised in that the cooling duct (44) defines a circular rotational channel (46) extending along the air flow guide surface (42) between the inlet (48) and the outlet (50). The blower assembly according to claim 1 characterized in that said circular rotational channel has a first width (R1) at the inlet (48) which is greater than a second width (R2) at an intermediate location in the channel which is between the inlet (48) and the outlet (50). The blower assembly according to claim 2 characterized in that said circular rotational channel's width (R1,R2,R3) continuously decreases from the inlet (48) to the intermediate location. The blower assembly according to one of the preceding claims characterized in that said circular rotational channel (46) has a first depth (D1) at the inlet (48) which is less than a second depth (D2) at the intermediate location. The blower assembly according to claim 4 characterized in that said circular rotational channel's depth (D1,D2,D3) continuously increases from the inlet (48) to the intermediate location. The blower assembly according to claim 1 characterized in that it comprises a motor (16) having a rotatable shaft (20), a fan (14) attached to the rotatable shaft (20), said fan (14) defining a circular rotational path when said motor (16) is operating, said circular rotational channel having a fan radius (L1) and an outer wall (47) of said cooling duct (44) is located a distance (L2) away from an axis (A1) of the rotatable shaft (20) and said distance (L2) is greater than said fan radius (L1). The blower assembly according to claim 6 characterized in that it comprises a fan housing (12) connected to a motor cover (18), the motor (16) being positionable in a motor cavity (19), said motor (16) having a motor shaft (20) having a central axis (A1), said fan housing (12) defining a scroll cut-off line (63) and a plane (P1) passing through the scroll cut-off line (63) and the axis (A1), and the cooling duct (44) is positioned adjacent to said plane (P1). The blower assembly according to claim 7 characterized in that the cooling duct (44) is positioned on the upstream side of said plane (P1) relative to the rotational direction (65) of said fan (14). A blower assembly according to one of the preceding claims 7 or 8 characterized in that a baffle (52) is located on said guide surface (42), said baffle (52) separating a flow of cool fan air (58) which is being advanced into said cooling duct (44) from a flow of warm exhaust air (60) which is being advanced out of the motor cavity (19).

Inventors: GRAHAM MARK A, NEELY MICHAEL J, SAVAGE JOHN R, GRAHAM, MARK A., NEELY, MICHAEL J., SAVAGE, JOHN R.
Applicants: VALEO CLIMATE CONTROL CORP, VALEO CLIMATE CONTROL, CORP.
Application year: 1997
Main classification: F04D25
IPC codes: H02K5, F04D25