JP2006298180A - Blower motor cooling structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blower motor cooling structure capable of attaining excellent cooling efficiency, and suppressing the occurrence of any defective operation of a blower motor while increasing the degree of versatility of a layout. <P>SOLUTION: A cooling duct 15 which is communicated with an inlet 14d formed on the side face 14c of a motor storage recess 14b to introduce air in a fan room 2 to the lower end side of a blower motor 5 downwardly in the diagonal direction is integrated with the bottom face 14a of a lower casing 14 of a case 12. In the cooling duct part 15, a longitudinal sectional shape of a curved wall 15a is an arc shape which is also used for a guide to guide the introduced cooling air in a smoothly curved manner to allow the air to be directly introduced from the front side to the inlet 14d opened in the side face 14c and lower vent holes 5b, 5b opened in a side face in the vicinity of the lower end of the blower motor 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a blower motor cooling structure that is used in a vehicle air conditioner and has a blower fan that blows air to a temperature control device, a ventilator, and the like, and more particularly, a blower motor cooling that can efficiently cool a blower motor that rotates the blower fan. Concerning structure.

  In the conventional blower motor cooling structure, the case 1a of the blower device 1 has an upper housing 3 constituting a substantially cylindrical fan chamber 2 and a lower housing 4 having a flange-shaped bottom surface portion 4a. It is configured.

  Among these, the upper housing 3 is formed with an air introduction opening 3b in the upper surface portion 3a.

  In addition, a blower outlet 2b is formed in the side surface 2a of the fan chamber 2 of the upper housing 3.

  Further, the bottom surface portion 4a of the lower housing 4 facing the top surface portion 3a is formed with a motor housing recess 4b that bulges outward in a substantially cylindrical shape.

  And the lower end side of the blower motor 5 provided in this fan chamber 2 is fitted and fixed to this motor accommodation recessed part 4b.

  Further, a sirocco fan 6 as a fan member is pivotally supported on a rotation drive shaft 5a provided so as to be rotationally driven in the blower motor 5, and the rotation drive shaft 5a is rotationally driven, whereby the air The air introduced from the introduction opening 3b is configured to be sent to a temperature control device or a ventilator (not shown) through the blower outlet 2b.

  Further, the blower motor 5 has lower ventilation holes 5b and 5b formed in the side surface near the lower end, and upper ventilation holes 5c and 5c are formed in the upper end surface portion around the rotary drive shaft 5a. Yes.

  And the air introduction duct 7 connected to the exterior is connected to the lower end side surface part 4c of the said motor accommodation recessed part 4b (for example, refer patent document 1, 2).

  Next, the operation of this conventional blower motor cooling structure will be described.

  In the conventional blower motor cooling structure configured as described above, when the rotational drive shaft 5a of the blower motor 5 is rotationally driven, the sirocco fan 6 is operated to enter the fan chamber 2 from the air introduction opening 3b into the vehicle compartment. Outside air is introduced, and air is sent to a temperature control device or a ventilator (not shown) through the blower outlet 2b.

At this time, since the inside of the sirocco fan 6 in the air chamber 2 in the radial direction is a negative pressure region, the air in the vehicle compartment introduced from the air introduction duct 7 is fitted into the motor housing recess 4b. The inside of the blower motor 5 is cooled from the lower ventilation holes 5b and 5b of the blower motor 5, and is discharged from the upper ventilation holes 5c and 5c, so-called self-contained cooling is performed.
Japanese Patent Laid-Open No. 9-240249 (FIG. 1, paragraphs 0009 to 0016) Japanese Utility Model Publication No. 4-121498 (FIG. 1)

  However, in such a conventional blower motor cooling structure, when the air introduction duct 7 introduces air from the vehicle interior into the motor housing recess 4b, foreign matter such as dust is sucked into the bottom of the motor housing recess 4b. There is also a risk of causing malfunction of the blower motor 5 by being deposited or being wound inside the blower motor 5.

  The air introduction duct 7 is formed of a separate part and is connected to the lower end side surface 4c of the motor housing recess 4b. For this reason, since the space in the direction in which the air introduction duct 7 is connected is used, it is difficult to improve the layout with good space efficiency.

  The present invention has been made in view of the above circumstances, and provides a blower motor cooling structure that can improve the cooling efficiency and increase the degree of freedom of layout while suppressing the occurrence of malfunction of the blower motor. The task is to do.

  In order to achieve the above object, according to the first aspect of the present invention, an air introduction opening is formed in a part of a substantially cylindrical fan chamber, and an air discharge port is formed in a side surface of the fan chamber. A motor housing recess that bulges outwardly on the bottom surface facing the top surface, and at least a part of the lower end side is fitted into the motor housing recess in the case. A blower motor cooling structure for sending air introduced from the air introduction opening to the blower outlet by rotating a fan member pivotally supported on a rotation drive shaft of the blower motor, A blower motor cooling structure in which a cooling duct portion that communicates with the side surface portion of the motor housing recess and introduces air in the fan chamber to the lower end side of the blower motor toward the lower side is integrally formed on the bottom surface portion. It is a symptom.

  Further, in the present invention, the cooling duct portion is in a region having a pressure gradient formed from a high pressure region of the blower outlet to a low pressure region located in a circumferential direction. The blower motor cooling structure according to claim 1 is provided.

  Here, the region having a pressure gradient formed across the low pressure region located in the circumferential direction away from the high pressure region of the blower outlet is the cooling duct portion from the circumferential direction position of the nose portion, It is within the range of 0 to 160 degrees.

  According to a third aspect of the present invention, the cooling duct portion is formed on the downstream side in the wind flow direction while being spaced apart in the circumferential direction from the circumferential position of the nose portion formed at the blower outlet. The blower motor cooling structure according to claim 1, wherein the blower motor cooling structure is set in the vicinity of a position reaching a pressure increasing region beyond a low pressure region.

  Furthermore, what is described in Claim 4 is characterized by the blower motor cooling structure as described in any one of Claims 1 thru | or 3 which makes the wall part of the said cooling duct part the curved wall part of cross-sectional arc shape.

  In the first aspect of the present invention configured as described above, the cooling duct introduces the air in the fan chamber obliquely downward to the lower end side of the blower motor.

  The air in the fan room is less contaminated with foreign matter such as dust than the outside air or the air in the passenger compartment.

  For this reason, compared with the case where air is introduced from the vehicle interior space, it is possible to reduce the possibility that the blower motor will cause malfunction due to sucking in foreign matters such as dust.

  Further, in the present invention, the cooling duct portion is provided in a region having a pressure gradient formed from a high pressure region of the blower discharge port to a low pressure region located in a circumferential direction. ing.

  For this reason, the air in the fan chamber is introduced with a good wind flow generated by the pressure gradient, the temperature rise is suppressed, and the cooling efficiency can be improved.

  According to a third aspect of the present invention, the cooling duct portion is formed so as to be spaced apart in the circumferential direction from a circumferential position of a nose portion formed at the blower outlet.

  For this reason, since it is spaced apart from the ventilation outlet, noise generated by the ventilation resistance is hardly heard to the outside, and the silent performance is good.

  In addition, the cooling duct portion is set in the vicinity of a position that reaches the pressure increasing region beyond the low pressure region formed on the downstream side in the wind flow direction.

  For this reason, air can be easily introduced into the cooling duct from the fan chamber, and the amount of air passing through the motor housing recess or the blower motor can be increased.

  Therefore, the cooling efficiency is good.

  Further, in the present invention, the wall portion of the cooling duct portion is a curved wall portion having a circular arc cross section, so that air that is inserted obliquely downward is smoothly put into the motor housing recess. Guided airflow resistance is reduced.

  For this reason, the cooling efficiency can be further improved.

  The best mode for carrying out the invention will be described below based on the examples shown in FIGS.

  In addition, the same code | symbol is attached | subjected and demonstrated about the same thru | or equivalent part as before.

  In the blower device 11 of this embodiment, the case 12 mainly includes an upper housing 3 constituting a substantially cylindrical fan chamber 2 and a lower housing 14 having a flange-like bottom surface portion 14a. Has been.

  Among these, the upper housing 3 is formed with an air introduction opening 3b in a part of the upper surface portion 3a.

  In addition, a blower outlet 2b is formed in the side surface 2a of the fan chamber 2 of the upper housing 3. As shown in FIG. 2, a nose portion 2 c is formed on one side edge of the opening in the blower outlet 2 b.

  A high pressure region 2d and a low pressure region 2e are formed in the space in the fan chamber 2 with the nose portion 2c as a boundary by rotation of a sirocco fan 6 to be described later in the direction of an outlined arrow R. Yes.

  Further, a motor housing recess 14b that bulges outward in a substantially cylindrical shape is formed on the bottom surface 14a of the lower housing 14 that faces the top surface 3a.

  The fan chamber 2 houses a blower motor 5 having a rotation drive shaft 5a that is inserted in a substantially vertical direction through shaft holes formed in the upper and lower end surfaces of the motor case and rotatably supported. Yes.

  The blower motor 5 has lower ventilation holes 5b, 5b formed in the side surfaces near the lower end, and upper ventilation holes 5c, 5c are formed in the upper end surface portion around the rotary drive shaft 5a. Yes.

  And the lower end side of this blower motor 5 is fitted and fixed to the said motor accommodation recessed part 14b.

  Further, the blower motor 5 has a sirocco fan 6 as a fan member pivotally attached to a rotational drive shaft 5a provided so as to be rotationally driven. By rotating the rotational drive shaft 5a, the air The air introduced from the introduction opening 3b is configured to be sent to a temperature control device or a ventilator (not shown) through the blower outlet 2b.

  1 to 8 show a blower motor cooling structure according to a first embodiment of the best mode of the present invention.

  First, from the configuration of the first embodiment, the bottom surface portion 14a of the lower housing 14 shown in FIGS. 3 and 4 constituting the case 12 is formed on the side surface portion 14c of the motor housing recess 14b. A cooling duct portion 15 that communicates with the introduction port 14d and that introduces the air in the fan chamber 2 to the lower end side of the blower motor 5 is formed integrally with the inlet port 14d obliquely downward.

  In the cooling duct portion 15 of the first embodiment, as shown in FIG. 1, the curved wall portion 15a as the wall portion has a longitudinal cross-sectional shape, and the cooling air to be introduced is formed in the side surface portion 14c. The inlet 14d and the blower motor 5 are configured to have a circular arc shape that also serves as a guide that is smoothly bent and guided so as to be directly inserted into the lower ventilation holes 5b and 5b formed in the side surface near the lower end of the blower motor 5 from the front.

  Further, the opening area of the upper surface of the bottom surface portion 14a is expanded so that the inlet side opening 15b of the cooling duct portion 15 is located inside the outermost diameter of the sirocco fan 6 and close to the outer peripheral surface of the blower motor 5. As shown in the figure, it is set to a substantially rectangular shape in top view along the longitudinal direction in the radial direction.

  As shown in FIG. 2, the cooling duct portion 15 according to the first embodiment is circumferentially moved from the circumferential position of the nose portion 2 c formed in the blower outlet 2 b in the direction of the white arrow R that is the rotational direction of the sirocco fan 6. The direction is separated by about 100 degrees or more.

  In the first embodiment, as shown in the upper graph of FIG. 5, it is separated from the circumferential position where the air blowing outlet 2 b is formed, and on the opposite side (about 150 to 180 degrees) in the circumferential direction. When the cooling duct portion 15 is formed, the noise volume generated by the ventilation resistance that can be heard outside is reduced. In the graph shown in FIG. 5, as shown in FIG. 2, the position of the nose portion 2c of the blower outlet 2b is set to 0 degree around the rotational drive shaft 5a of the blower motor 5, and the sirocco The angle is measured in the direction of the white arrow R, which is the rotation direction of the fan 6.

  In the first embodiment, the pressure increasing region (about approximately) extends from the circumferential position of the nose portion 2c beyond the low pressure region 2e formed on the downstream side of the wind flow direction (the white arrow in FIG. 2) that is the rotational direction of the sirocco fan 6. The position where the cooling duct portion 15 is formed is set in the vicinity of the position immediately before reaching 150 degrees to about 220 degrees).

  Further, in the first embodiment, in FIG. 2, the cooling duct portion 15 has a pressure gradient formed from the high pressure region 2d of the blower discharge port 2b to the low pressure region 2e located in the circumferential direction. It is provided in the area to have.

  For this reason, the air in the fan chamber 2 is introduced into the cooling duct portion 15 with a good wind flow generated by the pressure gradient, the temperature rise is suppressed, and the cooling efficiency can be improved.

  That is, in Example 1, the wind flow is good from the high pressure region 2d to the low pressure region 2e with the nose portion 2c as a boundary (from 0 degrees to about 160 degrees). As shown in the graph, the range E in which the wind flow is the best and the cooling efficiency is good is the highest in the cooling efficiency due to the pressure difference from 0 degrees to about 150 degrees.

  For this reason, in the first embodiment, the cooling duct portion is located at a position of about 150 degrees where the noise is sufficiently reduced and the condition of the region E with good cooling efficiency is satisfied immediately before the region F where boosting is started. 15 forming position is set.

  Next, the operation of the blower motor cooling structure of the first embodiment will be described.

  When the rotational drive shaft 5a of the blower motor 5 is rotationally driven, the sirocco fan 6 is operated to introduce air outside the vehicle interior into the fan chamber 2 from the air introduction opening 3b and to the air discharge port 2b. Via this, air is sent to a temperature control device or a ventilator (not shown).

  At this time, the inlet side opening 15b of the cooling duct 15 portion has a good wind flow in the inner area of the sirocco fan 6, and the air in the fan chamber 2 immediately before the area F where the pressure increase is started. It introduce | transduces diagonally below and guides toward the lower end side of the said blower motor 5 (refer the dashed-two dotted line in FIG. 1).

  The air in the fan chamber 2 is less contaminated with foreign matter such as dust than the outside air or the air in the passenger compartment.

  For this reason, compared with the case where air is introduced from the interior space of the vehicle, there is almost no possibility of sucking in foreign matters such as dust, and the possibility that the blower motor 5 will malfunction is reduced.

  Then, the cooling air directly entering the inlet 14d formed in the side surface 14c of the motor housing recess 14b and the lower ventilation holes 5b, 5b formed in the side surface in the vicinity of the lower end of the blower motor 5 passes through the blower motor 5. While ascending, each part in the blower motor 5 is cooled and returned to the fan chamber 2 from the upper vents 5c and 5c, and discharged from the blower outlet 2b.

  Moreover, in this Example 1, as shown in FIG. 2, the said cooling duct part 15 is spaced apart about 150 degree | times to the circumferential direction from the circumferential direction position of the nose part 2c formed in the said ventilation discharge port 2b, It is formed on the bottom surface portion 14a.

  As described above, since the air blowing outlet 12a is separated to the vicinity of the substantially opposite side, the noise generated by the ventilation resistance is difficult to hear to the outside through the air blowing outlet 12a and the noise performance is good. .

  Further, as shown in FIG. 2, the cooling duct portion 15 is set in the vicinity immediately before the position reaching the pressure increasing region 2f beyond the low pressure region 2e formed on the downstream side in the wind flow direction.

  For this reason, air that has lost its escape due to pressure increase is easily introduced into the fan chamber 2 from the inlet side opening 15b opened in the bottom surface portion 14a into the cooling duct portion 15, and the motor housing recess 14b or The amount of air passing through the blower motor 5 can be increased.

  Therefore, the ventilation flow rate can be further increased to improve the cooling efficiency.

  Further, in the first embodiment, since the curved wall portion 15a of the cooling duct portion 15 has an arcuate cross section, the air inserted obliquely downward is smoothly guided into the motor housing recess 14b. Therefore, the draft resistance is reduced.

  For this reason, the cooling efficiency can be further improved.

  Further, in the first embodiment, the cooling duct portion 15 has a curved wall portion 15a having a substantially circular arc section from the bottom surface portion 14a of the lower housing 14 to the side surface portion 14c of the motor housing recess 14b. Are integrally molded.

  Therefore, for example, like the conventional blower motor cooling structure shown in FIG. 12, the straight air introduction duct 7 is formed as a separate part and is connected to the lower end side surface 4c of the motor housing recess 14b. The number of parts can be reduced as compared with the configuration having the above structure, and the outer side in the radial direction from the curved wall portion 15a can be used as an arrangement space for another part, so that the space efficiency can be improved. Can be improved.

  Next, an example that the blower motor cooling structure according to the first embodiment has a good cooling efficiency will be described with reference to FIGS.

  6 to 8 show the temperature distribution in a state where a certain time has elapsed after the start of cooling when the blower device 11 is viewed from above. The hatched portion indicates the high temperature region, and the portion surrounded by the alternate long and short dash line indicates the medium temperature. It is a schematic diagram which shows an area.

  Here, FIG. 6 shows the temperature distribution at 0 seconds after the start of cooling from a constant high temperature state, and FIG. 7 shows the temperature distribution at 120 seconds after the start of cooling. It can be seen that the middle temperature range of the water suddenly decreases with time.

  In the temperature distribution at 300 seconds from the start of cooling shown in FIG. 8, it can be seen that the high temperature region in the shaded area and the middle temperature region surrounded by the alternate long and short dash line are almost lost.

  FIG. 9 shows a blower motor cooling structure of Example 2 of the embodiment of the present invention.

  In addition, the same code | symbol is attached | subjected and demonstrated about the same thru | or equivalent part as the blower motor cooling structure of the said embodiment and Example 1. FIG.

  In the blower motor cooling structure of the second embodiment, the cooling duct portion 25 is a slant having a straight vertical cross-sectional shape so that the air in the fan chamber 2 is introduced obliquely downward to the lower end side of the blower motor 5. It has a wall portion 25a.

  Next, the operation of the blower motor cooling structure of the second embodiment will be described focusing on the differences from the first embodiment.

  In the blower motor cooling structure of the second embodiment, the air in the fan chamber 2 is introduced into the lower end side of the blower motor 5 in a straight line obliquely downward by the inclined wall portion 25 a of the cooling duct portion 25. For this reason, the cooling efficiency is good.

  Other configurations and operational effects are the same as or equivalent to those of the above-described embodiment and Example 1, and thus description thereof is omitted.

  FIG. 10 shows a blower motor cooling structure of Example 3 of the embodiment of the present invention.

  In addition, the same code | symbol is attached | subjected and demonstrated about the same thru | or equivalent part as the blower motor cooling structure of the said embodiment and Example 1, 2. FIG.

  In the blower motor cooling structure of the third embodiment, a vertical curved wall having a straight vertical cross-sectional shape so that the cooling duct portion 35 introduces air in the fan chamber to the lower end side of the blower motor 5 obliquely downward. It has the part 35a.

  In the blower motor cooling structure of the second embodiment, the longitudinal curved wall portion as the wall portion of the cooling duct portion 35 has the radial dimension of the inlet side opening 35b, and the radial dimension a of the inlet side opening 15b of the first and second embodiments. It is set to be smaller than the dimension b.

  Next, the operation of the blower motor cooling structure of the third embodiment will be described focusing on the differences from the first and second embodiments.

  In the blower motor cooling structure of the third embodiment, the radial dimension of the inlet-side opening 35b is set to be smaller than the radial dimension a of the inlet-side opening 15b of the first and second embodiments.

  For this reason, the arrangement space of another part radially outside the longitudinally curved wall 35a can be further expanded to improve the layout.

  Other configurations and operational effects are the same as or equivalent to those of the above-described embodiment and Examples 1 and 2. Therefore, the description thereof is omitted.

  FIG. 11 shows a blower motor cooling structure of Example 4 of the embodiment of the present invention.

  In addition, the same code | symbol is attached | subjected and demonstrated about the same or equivalent part as the blower motor cooling structure of the said embodiment and Examples 1-3.

  In the blower motor cooling structure according to the fourth embodiment, the cooling duct portion 45 includes a vertically formed vertical wall portion 45a, a horizontally formed bottom wall portion 45b, and these vertical wall portions 45a and bottom wall portions 45b. Are formed so that the air in the fan chamber 2 is introduced obliquely downward to the lower end side of the blower motor 5.

  Next, the operation of the blower motor cooling structure of the fourth embodiment will be described focusing on the differences from the first to third embodiments.

  In the blower motor cooling structure of the fourth embodiment, the cooling duct portion 45 is formed by having the vertical wall portion 45a formed vertically and the bottom wall portion 45b formed horizontally. It is easy to create and can suppress an increase in manufacturing cost.

  Further, the upper surface portion of the bottom wall portion 45b formed horizontally can be used as a dust or rainwater collecting portion, and furthermore, the possibility of dust or the like entering the blower motor 5 can be reduced.

  Other configurations and functions and effects are the same as or equivalent to those of the above-described embodiment and Examples 1 to 3, and thus description thereof is omitted.

  As described above, the embodiment and Examples 1 to 4 of the present invention have been described in detail with reference to the drawings, but the specific configuration is not limited to this embodiment and Examples 1 to 4, and the present invention is not limited thereto. Design changes that do not depart from the gist are included in the present invention.

  That is, in the first to fourth embodiments, the position of the cooling duct portion 15 or the like is located at about 150 degrees from the circumferential position of the nose portion 2c toward the downstream side in the wind flow direction that is the rotational direction of the sirocco fan 6. However, it is sufficient that the wind flow is the best and the cooling efficiency is good, such as any part in the range of 0 to 160 degrees from the nose part 2c. The angle, the shape, quantity and material of the cooling duct portion are not particularly limited.

  Further, in the first to third embodiments, the air guided into the motor housing recess 14b by the cooling duct portion 15 is introduced into the blower motor 5 from the lower ventilation holes 5b and 5b formed in the side surface near the lower end of the blower motor 5. However, for example, it may be configured to be introduced into the blower motor 5 from an opening formed on the lower surface side of the blower motor 5, or an opening through which the blower motor 5 and air are inserted. There are no particular restrictions on the shape, quantity, or the like.

FIG. 5 is a cross-sectional view at a position along the line AA in FIG. 4 in the blower motor cooling structure according to the first embodiment of the present invention. It is a blower motor cooling structure concerning Example 1 of the present invention, and is a mimetic diagram showing a high and low pressure field which looked at a blower device from the upper part. It is the blower motor cooling structure which concerns on Example 1 of this invention, and is the perspective view which looked at the lower housing | casing which comprises a case from diagonally downward. It is the blower motor cooling structure which concerns on Example 1 of this invention, and is the perspective view which looked at the lower housing | casing which comprises a case from diagonally upward. In the blower motor cooling structure according to the first embodiment of the present invention, the relationship between the position where the cooling duct portion is provided and the cooling efficiency will be described, and the circumferential separation angle from the nose portion of the cooling duct portion will be taken as the horizontal axis. It is the graph which took the temperature rise after progress for a fixed time from the vertical axis | shaft. In the blower motor cooling structure according to the first embodiment of the present invention, after starting cooling when the blower device is viewed from above, the temperature distribution at 0 seconds is shown, the hatched portion is the high temperature region, and the portion surrounded by the one-dot chain line is It is a schematic diagram which shows a middle temperature range. In the blower motor cooling structure according to the first embodiment of the present invention, after starting cooling when the blower device is viewed from above, the temperature distribution at 120 seconds is shown, the hatched portion indicates the high temperature region, and the portion surrounded by the one-dot chain line indicates It is a schematic diagram which shows an intermediate temperature range. In the blower motor cooling structure according to the first embodiment of the present invention, after starting cooling when the blower device is viewed from above, the temperature distribution at 300 seconds is shown, the hatched portion indicates the high temperature region, and the portion surrounded by the one-dot chain line indicates It is a schematic diagram which shows an intermediate temperature range. It is a longitudinal cross-sectional view of the principal part which shows the cross-sectional shape of a cooling duct part with the blower motor cooling structure of Example 2 of this invention. It is a longitudinal cross-sectional view of the principal part which shows the cross-sectional shape of a cooling duct part with the blower motor cooling structure of Example 3 of this invention. It is a longitudinal cross-sectional view of the principal part which shows the cross-sectional shape of a cooling duct part by the blower motor cooling structure of Example 4 of this invention. It is a blower motor cooling structure of a prior art example, and is a longitudinal cross-sectional view of the blower apparatus in the position equivalent to FIG.

Explanation of symbols

2 Fan chamber 2b Air outlet 2c Nose part 3 Upper housing 3b Air introduction opening
DESCRIPTION OF SYMBOLS 5 Blower motor 11 Blower apparatus 12 Case 14 Lower housing | casing 14a Bottom part 14b Motor accommodation recessed part 14c Side part 14d Inlet port 15,25,35,45 Cooling duct 15a Curved wall part

Claims (4)

An air introduction opening is formed in a part of the substantially cylindrical fan chamber, and a ventilation discharge port is formed in a side surface portion of the fan chamber, and is swelled outward in a bottom surface portion facing the top surface portion. A fan having a case in which a motor housing recess is formed, and a blower motor that fits at least a part on the lower end side into the motor housing recess is provided in the case, and a fan that is pivotally supported by a rotation drive shaft of the blower motor A blower motor cooling structure for sending air introduced from the air introduction opening to the blower outlet by rotating a member,
The blower motor is characterized in that a cooling duct portion that communicates with a side surface portion of the motor housing recess and introduces air in the fan chamber to the lower end side of the blower motor in an obliquely downward direction is integrally formed on the bottom surface portion. Cooling structure.   The said cooling duct part is provided in the area | region which has a pressure gradient formed over the low pressure area | region located in the circumferential direction away from the high pressure area | region of the said ventilation outlet. The blower motor cooling structure described.   The cooling duct portion is spaced apart from the circumferential position of the nose portion formed at the blower discharge port in the circumferential direction and reaches the pressure increasing region beyond the low pressure region formed on the downstream side in the wind flow direction. The blower motor cooling structure according to claim 1, wherein the blower motor cooling structure is set in the vicinity of the position. The blower motor cooling structure according to any one of claims 1 to 3, wherein the wall portion of the cooling duct portion is a curved wall portion having a circular arc shape in cross section.

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