JP2010019078A - Blower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To compatibly materialize improvement of maintainability and prevention of air leak. <P>SOLUTION: A blower includes first and second blast fans 12, 13, first and second casings 15, 16, and a drive source 11. The second blast fan 13 and the second casing 16 are disposed at positions farther from a drive source 11 than positions of the first blast fan 12 and the first casing 15. A detachment and attachment hole 16b for detaching and attaching the second blast fan in a direction in parallel with a rotary shaft 11a of the drive source 11 is formed at the second casing 16. An annular gap 17 is formed between an opening edge part of the detachment and attachment hole 16b and an outer circumference part of the second blast fan 13. An annular blocking plate 18 blocking the gap 17 from an outer side of the second casing 16 is fixed on the rotary shaft 11a. A section 19 near an opening edge of the detaching and attaching hole 16b of the blocking plate 18 constructs a labyrinth seal structure sealing the gap 17. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a blower including two blower fans, and is suitable for use in a blower of a vehicle air conditioner.

  2. Description of the Related Art Conventionally, as a blower that blows air into a vehicle interior in a vehicle air conditioner, a blower that rotates two blower fans housed in different scroll casings with a common electric motor is known.

  For example, Patent Document 1 discloses a blower that includes a so-called double-axis motor in which both end portions of a rotating shaft protrude from a motor main body, and a blower fan is connected to each end portion of the rotating shaft of the both-axis motor. Has been.

  The blower disclosed in Patent Document 1 employs a double-shaft motor, so that the manufacturing cost is likely to increase due to the complexity of the bearing structure. Moreover, it is difficult to apply the double-axis motor to a blower provided with one blower fan. Therefore, if a double-axis motor is employed, it is difficult to share the components of the blower.

  On the other hand, Patent Document 2 discloses a blower that includes a so-called single-axis motor in which only one end side of the rotary shaft protrudes from the motor body, and a blower fan is connected to the rotary shaft of the single-axis motor. Has been.

Since the blower disclosed in Patent Document 2 employs a single-axis motor, the manufacturing cost of the electric motor itself can be reduced as compared with the double-axis motor employed by the blower disclosed in Patent Document 1. Furthermore, since the single-axis motor can be applied to a blower including one blower fan, it is possible to reduce the manufacturing cost of the blower by using a common electric motor.
JP 2006-7946 A JP 2000-136996 A

  The present inventor made a trial study on the blower shown in FIG. 4 for the purpose of improving the maintainability of the blower of Patent Document 2. In the prototype examination product, a demounting hole 16b for detaching the second blower fan 13 is formed on the wall surface on the electric motor 11 side of the second casing 16 in which the second blower fan 13 is accommodated. According to this, since the second centrifugal multiblade fan 13 can be attached to and detached from the second casing 16 through the attachment / detachment hole 16b, the maintainability can be improved.

  However, in this prototype product, an annular gap 17 is formed between the opening edge of the attachment / detachment hole 16b and the outer peripheral part of the second blower fan 13, so that the air from the gap 17 as indicated by the arrow in FIG. Leaks. Therefore, there exists a problem that the ventilation performance of an air blower will fall.

  In addition, when the prototype product is applied to a blower in which one of the first and second blower fans 12 and 13 blows the inside air and the other fan blows the outside air, air leaks from the gap 17. As a result, there is a problem in that the inside air on one fan side and the outside air on the other fan side are mixed.

  In view of the above points, an object of the present invention is to achieve both improvement in maintainability and prevention of air leakage.

In order to achieve the above object, according to the first aspect of the present invention, a first blower fan (12) and a second blower fan (13) that are given a rotational driving force to blow air,
A first casing (15) in which the first blower fan (12) is accommodated;
A second casing (16) in which the second blower fan (13) is accommodated;
A rotation source (11a) protruding in one direction, and a drive source (11) for applying a rotation driving force to the first and second blower fans (12, 13) by the rotation axis (11a),
The second blower fan (13) and the second casing (16) are disposed at positions farther from the drive source (11) than the first blower fan (12) and the first casing (15),
The second casing (16) is formed with a demounting hole (16b) for demounting the second blower fan (13) in a direction parallel to the rotating shaft (11a).
An annular gap (17) is formed between the opening edge of the desorption hole (16b) and the outer periphery of the second blower fan (13),
An annular shielding plate (18) that shields the gap (17) from the outer side of the second casing (16) is fixed to the rotating shaft (11a),
A portion (19) in the vicinity of the opening edge of the desorption hole (16b) in the shielding plate (18) constitutes a labyrinth seal structure that seals the gap (17).

  According to this, since the labyrinth seal structure constituted by the shielding plate (18) seals the gap (17), it is possible to prevent air from leaking from the gap (17).

  In addition, since the shielding plate (18) is fixed to the rotating shaft (11a) so as to block the gap (17) from the outer side of the second casing (16), the second air blow to the second casing (16). When the fan (13) is attached / detached through the attachment / detachment hole (16b), the shielding plate (18) can be prevented from obstructing the attachment / detachment of the second blower fan (13) (see FIG. 1 described later).

  For this reason, maintainability can be improved similarly to the prototype examination product shown in FIG. From the above, it is possible to achieve both improvement in maintainability and prevention of air leakage.

In invention of Claim 2, in the air blower of Claim 1, the 1st ventilation fan (12) has the 1st boss | hub part (12d) in which a rotating shaft (11a) is inserted,
The second blower fan (13) has a second boss part (13d) into which the rotating shaft (11a) is fitted,
A cap (14) that is fitted on the outside of the first and second boss portions (12d, 13d) and prevents the first and second blower fans (12, 13) from being detached from the rotating shaft (11a);
The shielding plate (18) is fixed to the rotating shaft (11a) through the cap (14).

  According to this, since the shield (18) can be fixed to the rotating shaft (11a) using the cap (14), the shield (18) is independent of the cap (14) and the rotating shaft (11a). The configuration can be simplified as compared with the case of fixing to the frame.

  According to a third aspect of the present invention, in the blower according to the second aspect, the shielding plate (18) is integrally formed with the cap (14). Thereby, the number of parts can be reduced and the manufacturing cost can be reduced.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described. In this embodiment, the air blower of this invention is applied to the electric blower 10 which comprises the air blower unit of the indoor unit in a vehicle air conditioner. The indoor unit in the vehicle air conditioner is disposed in a space between a dash panel that partitions the engine room and the vehicle interior and an instrument panel (instrument panel) in the foremost part of the vehicle interior.

  The indoor unit is roughly classified into a blower unit that blows air blown into the vehicle interior and an air conditioning unit that adjusts the temperature of the blown air from the blower unit. The air conditioning unit is disposed at a substantially central portion in the vehicle width direction, and the blower unit is disposed offset from the central portion toward the passenger seat.

  Inside the air conditioning unit, an air passage is formed through which the air blown into the passenger compartment blown from the blower unit flows. In this air passage, a cooling heat exchanger that cools the air blown into the passenger compartment, a heating heat exchanger that reheats the cold air cooled by the cooling heat exchanger, and a heating heat exchanger that reheats the air. An air mix door for adjusting the amount of cold air is arranged.

  The cooling heat exchanger is an evaporator of a vapor compression refrigeration cycle, and is disposed on the upstream side of the air flow in the air passage of the air conditioning unit. The heat exchanger for heating is a heater core that heats the air blown into the passenger compartment by using engine coolant as a heat source, and is disposed on the downstream side of the air flow of the evaporator.

  The air mix door continuously changes the air flow ratio of the air volume that passes through the heater core and the air volume that bypasses the heater core among the cold air cooled by the evaporator by continuously changing the opening degree. The temperature adjusting means adjusts the temperature of the air blown into the passenger compartment, and is disposed between the evaporator and the heater core.

  The vehicle interior blown air whose temperature is adjusted by the air mix door is blown into the vehicle interior from an outlet provided in the vehicle interior via an opening and a duct formed in the most downstream portion of the air flow of the air conditioning unit. Specifically, the air is blown from the face outlet to the occupant's face, from the foot outlet to the lower part of the occupant, and from the defroster outlet to the vehicle front window glass.

  Next, the blower unit is configured such that the inside / outside air introduction box disposed at the upper part thereof and the electric blower 10 disposed on the lower side of the inside / outside air introduction box are integrally configured. The inside / outside air introduction box has a case forming its outer shell.

  The case is formed with an outside air inlet for introducing outside air (inside air) into the case and an inside air inlet for introducing inside air (inside air) into the case. The outside air introduction port communicates with an opening hole for introducing outside air formed in a dash panel (not shown), and introduces outside air flowing in through the opening hole.

  Inside the case, an air passage that guides the outside air introduced from the outside air introduction port and the inside air introduced from the inside air introduction port to the electric blower 10 is formed.

  Fig.1 (a) is sectional drawing of the electric blower 10, FIG.1 (b) is the A section enlarged view of Fig.1 (a). In addition, the up, down, left, and right arrows in FIG. 1 indicate directions in the vehicle mounted state of the blower unit. Accordingly, the rear side of the sheet of FIG. 1 is the front side of the vehicle, and the front side of the sheet is the rear side of the vehicle.

  The electric blower 10 is a centrifugal type in which two first and second centrifugal multiblade fans (hereinafter referred to as first and second blower fans) 12 and 13 are rotationally driven by a common electric motor 11. It is a blower. The electric motor 11 is a so-called single-axis motor that is provided so that the rotating shaft 11a protrudes in only one direction from the motor body 11b.

  As the electric motor 11, either a direct current motor or an alternating current motor may be employed. The operation of the electric motor 11 is controlled by a control signal (such as a control voltage or a control half frequency signal) output from the air conditioning control device.

  The first blower fan 12 includes a plurality of first blades 12a and a plurality of first blades 12a that are annularly arranged around the rotating shaft 11a of the electric motor 11 from one end side (the lower end side in FIG. 1). A first boss plate 12b that holds and transmits the rotational driving force generated by the electric motor 11 to the first blade 12a, and a circle that holds the plurality of first blades 12a from the other end side (the upper end side in FIG. 1). An annular first ring 12c is provided.

  In this example, the first blade 12a, the first boss plate 12b, and the first ring 12c are integrally formed of resin (for example, polypropylene resin). Of course, these may be configured separately and integrally configured by a bonding means such as adhesion or welding.

  A first boss portion 12d is formed at the rotation center of the first boss plate 12b. The first boss portion 12d is formed with an insertion hole into which the rotation shaft 11a of the electric motor 11 is inserted. By inserting the rotation shaft 11 a into the first boss portion 12 d, the rotation center axis of the first boss plate 12 b is arranged coaxially with the rotation shaft 11 a of the electric motor 11.

  The rotating shaft 11a and the first boss portion 12d of the electric motor 11 are fixed by fixing means such as press fitting, and are prevented from rotating by fitting a D hole. Therefore, when the rotating shaft 11a of the electric motor 11 rotates, the first boss plate 12b (first blowing fan 12) rotates in conjunction with the rotating shaft 11a.

  The basic configuration of the second blower fan 13 is the same as that of the first blower fan 12. Accordingly, the second blower fan 13 includes a plurality of second blades 13a, a second boss plate 13b, and a second ring 13c similar to the first blower fan 12, and the second boss plate 13b includes a rotating shaft 11a. A second boss portion 13d is provided in which is inserted and fixed.

  Here, the difference between the first blower fan 12 and the second blower fan 13 will be described. First, the second blower fan 13 is disposed at a position farther from the electric motor 11 than the first blower fan 12.

  Next, the second boss plate 13b is formed in a cup shape whose central portion is recessed in the direction opposite to the protruding direction of the rotating shaft 11a (downward in FIG. 1), but the first boss plate 12b is The center portion is formed in a cup shape that is recessed in the same direction as the protruding direction of the rotating shaft 11a (upward in FIG. 1).

  And the part by the side of the rotating shaft 11a (upper side in FIG. 1) among the motor main-body parts 11b is accommodated in the inside of the 1st boss | hub plate 12b. In this example, the outer diameter of the first blower fan 12 is set larger than the outer diameter of the second blower fan 13.

  A cap 14 is fitted on the outer peripheral side of the first boss portion 12d and the second boss portion 13d. The cap 14 serves to prevent the first and second blower fans 12 and 13 from being detached from the rotating shaft 11 a of the electric motor 11.

  The cap 14 is made of a resin harder than the first and second blower fans 12 and 13, and more specifically, is made of a resin having a high tensile strength such as a glass reinforcing agent of polyamide. The cap 14 includes an annular cap boss portion 14a into which the rotating shaft 11a of the motor main body portion 11b is press-fitted, and legs extending from the outer peripheral portion of the cap boss portion 14a toward the first and second boss portions 12d and 13d. Parts 14b and 14c.

  The first and second blower fans 12 and 13 are rotatably accommodated in separate first and second casings 15 and 16, respectively. The first and second casings 15 and 16 are formed of a resin (for example, polypropylene) having a certain degree of elasticity and excellent in strength.

  In this example, each of the first and second casings 15 and 16 is divided into two upper and lower divided cases 151, 152, 161 and 162, and then the upper and lower divided cases are fixed to metal springs, clips and screws. It is fastened integrally by fastening means such as. Further, in this example, although not shown, the first casing 15 and the second casing 16 are integrally coupled by appropriate means.

  The first casing 15 is a scroll casing that forms an air passage through which air blown from the first blower fan 12 passes. More specifically, when the outer wall surface of the first casing 15 is viewed from a direction perpendicular to the rotation shaft 11 a, the distance (scroll radius) from the rotation shaft 11 a gradually increases toward the rotation direction of the first blower fan 12. It has a shape that expands. Therefore, the air passage is formed in a spiral shape that gradually expands in the rotation direction.

  A first wall of the first casing 15 that is perpendicular to the rotating shaft 11 a and that is away from the electric motor 11 has a circular first suction that sucks air into the inner peripheral side of the first blower fan 12. A mouth 15a is formed.

  Although not shown, the first suction port 15a communicates with the inside air introduction port of the inside / outside air introduction box. Therefore, the first suction port 15 a sucks the inside air introduced from the inside air introduction port into the inner peripheral side of the first blower fan 12.

  The opening edge portion of the first suction port 15a is formed in a bell mouth shape. In this example, the opening diameter of the first suction port 15 a is set larger than the outer diameter of the second blower fan 13. A first air outlet (not shown) for blowing out air is formed on the winding end side of the air passage in the first casing 15.

  On the other hand, the electric motor 11 is fixed to a wall surface of the first casing 15 that is perpendicular to the rotating shaft 11a and that faces the wall surface provided with the first suction port 15a.

  The second casing 16 is a scroll casing that forms an air passage through which the air blown from the second blower fan 13 passes. The basic configuration of the second casing 16 is the same as that of the first casing 15. Accordingly, the second casing 16 is also provided with a second suction port 16a and a second air outlet (not shown) similar to those of the first casing 15.

  Although not shown, the second suction port 16a communicates with the outside air introduction port of the inside / outside air introduction box. Therefore, the second suction port 16 a allows the outside air introduced from the outside air introduction port to the inner periphery side of the second blower fan 13 to be sucked into the inner periphery side of the second blower fan 13.

  As shown in FIG. 1B, the wall surface of the second casing 16 that is perpendicular to the rotation shaft 11a and that faces the wall surface provided with the second suction port 16a, that is, the wall surface on the electric motor 11 side. In this case, a demounting hole 16b for demounting the second blower fan 13 in a direction (vertical direction in FIG. 1) parallel to the rotation shaft 11a is formed in a circular shape.

  That is, since the opening diameter of the attachment / detachment hole 16b is set larger than the outer diameter of the second blower fan 13, the attachment / detachment of the second blower fan 13 with respect to the second casing 16 can be performed through the attachment / detachment hole 16b.

  Along with the formation of such a desorption hole 16 b, an annular gap 17 is formed between the opening edge of the desorption hole 16 b and the outer peripheral portion of the second blower fan 13. The gap 17 is blocked from the outer side of the second casing 16 by an annular shielding plate 18. A portion 19 in the vicinity of the opening edge of the attachment / detachment hole 16 b of the shielding plate 18 constitutes a labyrinth seal structure that seals the gap 17 so as to prevent air leakage from the gap 17.

  More specifically, an annular groove-shaped portion that opens toward the opening edge side of the desorption hole 16b is formed in a portion 19 in the vicinity of the opening edge of the desorption hole 16b in the shielding plate 18, and the opening of the desorption hole 16b is formed. The labyrinth seal structure is configured by forming an annular projecting portion 20 projecting toward the inside of the groove-shaped portion 19 of the shielding plate 18 at the edge portion. In this example, the protrusion 20 is integrally formed on the opening edge of the detachment hole 16b.

  The shield 18 is fixed to the rotating shaft 11a and rotates integrally with the rotating shaft 11a. In this example, since the end portion on the radially inner side of the shielding plate 18 is coupled to the tip of the leg portion 14c extending toward the second boss portion 13d side of the cap 14, the shielding plate 18 is interposed via the cap 14. Thus, the rotary shaft 11a is fixed.

  Further, in this example, the shielding plate 18 is integrally formed with the cap 14. In this example, the opening diameter of the attachment / detachment hole 16b and the outer diameter of the shielding plate 18 are set smaller than the opening diameter of the first suction port 15a.

  Next, the operation of this embodiment in the above configuration will be described. When the vehicle air conditioner is activated, the air conditioning controller outputs a control signal to the electric motor 11 to rotate the electric motor 11. The first and second blower fans 12 and 13 are rotated by the rotational driving force from the electric motor 11 to blow the air blown into the vehicle interior.

  Specifically, in the 1st ventilation fan 12, the inside air suck | inhaled from the 1st inlet 15a to the rotating shaft 11a direction is blown out to radial direction outer side, and it goes to an air-conditioning unit via a 1st blower outlet (not shown). Blow. On the other hand, in the 2nd ventilation fan 13, the external air suck | inhaled from the 2nd inlet 16a to the rotating shaft 11a direction is blown out to radial direction outer side, and it ventilates to an air-conditioning unit via a 2nd blower outlet (not shown).

  In this embodiment, since the single-axis motor is adopted as the electric motor 11, even if it is an electric blower provided with the two 1st, 2nd ventilation fans 12 and 13, the manufacturing cost of electric motor 11 itself can be reduced. . Furthermore, since the single-axis motor can be applied to an electric blower including one blower fan, it is possible to reduce the manufacturing cost of the electric blower by sharing the electric motor.

  Moreover, since the 1st, 2nd ventilation fans 12 and 13 and the 1st, 2nd casings 15 and 16 are collectively arrange | positioned to the one side (upper side of FIG. 1) of the electric motor 11, 1st, 2nd The electric motor 11 can be maintained without removing the blower fans 12 and 13 and the first and second casings 15 and 16.

  Furthermore, since the detaching hole 16b for detaching the second blower fan 13 is formed in the second casing 16, the second casing 16 is fastened integrally without being disassembled into two upper and lower divided cases 161, 162, The second blower fan 13 can be attached to and detached from the second casing 16. For this reason, the maintainability of the 2nd ventilation fan 13 can be improved.

  Moreover, since the outer diameter of the second blower fan 13, the opening diameter of the first suction port 15a, and the outer diameter of the shielding plate 18 are set as described above, the first and second blower fans 12 and 13 are electrically driven. It can be detached from the first and second casings 15 and 16 while being fixed to the motor 11.

  In this example, the first and second blower fans 12 and 13 are detached from the first and second casings 15 and 16 by detaching the upper and lower divided cases 151 and 152 of the first casing 15. Can do. Therefore, the maintainability of the electric motor 11 and the first and second blower fans 12 and 13 can be improved.

  Further, since the gap 17 between the opening edge of the attachment / detachment hole 16b and the outer peripheral part of the second blower fan 13 is sealed by the labyrinth seal structures 19 and 20, it is possible to prevent air from leaking from the gap 17.

  For this reason, while being able to prevent the ventilation performance fall of the electric blower 10, it can prevent that the internal air by the side of the 1st ventilation fan 12 and the external air by the side of the 2nd ventilation fan 13 are mixed. From the above, it is possible to achieve both improvement in maintainability and prevention of air leakage.

  Furthermore, in this embodiment, the shielding plate 18 constituting the labyrinth seal structure is formed integrally with the cap 14, and the shielding plate 18 is fixed to the rotating shaft 11 a via the cap 14. The configuration can be simplified and the number of parts can be reduced as compared with the case where the shield plate 18 is formed separately and fixed to the rotating shaft 11a independently of the cap 14. Therefore, the manufacturing cost can be further reduced.

(Second Embodiment)
In the first embodiment, the labyrinth seal structure is configured by the groove-shaped portion 19 of the shielding plate 18 and the protruding portion 20 at the opening edge of the attachment / detachment hole 16b. In the second embodiment, as shown in FIG. In addition, an annular projecting portion 21 is formed in a portion of the second casing 16 radially outside the groove-shaped portion 19, and the groove-shaped portion 19 and both projecting portions 20, 21 constitute a labyrinth seal structure. .

  Thereby, it is possible to further prevent the blown air from leaking from the gap 17 between the opening edge portion of the desorption hole 16 b and the outer peripheral portion of the second blower fan 13. In this example, the protruding portion 21 is integrally formed with the second casing 16.

(Third embodiment)
In the first embodiment, of the groove-shaped portion 19 and the protrusion 20 constituting the labyrinth seal structure, the groove-shaped portion 19 is formed on the shielding plate 18 and the protrusion 20 is formed on the opening edge of the attachment / detachment hole 16b. However, in the third embodiment, as shown in FIG. 3, the groove-shaped portion 19 is formed on the opening edge portion of the attachment / detachment hole 16 b, and the protruding portion 20 is formed on the shielding plate 18. Thereby, the effect similar to the said 1st Embodiment can be acquired.

(Other embodiments)
(1) In the above-described embodiment, an example in which a centrifugal multiblade fan is employed as the first and second blower fans 12 and 13 has been described. However, the first and second blower fans are not limited to this. For example, a cross flow fan that sucks in from one radial direction of the impeller and blows air from the opposite radial direction may be employed.

  (2) In the above-described embodiment, the shielding plate 18 is formed integrally with the cap 14. However, the shielding plate 18 may be formed separately from the cap 14. In the above-described embodiment, the shielding plate 18 is fixed to the rotating shaft 11a via the cap 14, but the shielding plate 18 may be fixed to the rotating shaft 11a independently of the cap 14.

  (3) In the above-described embodiment, the first and second blower fans 12 and 13 and the electric motor 11 are simultaneously detached by detaching the upper and lower divided cases 151 and 152 of the first casing 15. However, the first casing 15 has a wall surface perpendicular to the rotating shaft 11a and opposed to the wall surface provided with the first suction port 15a, that is, on the wall surface on the electric motor 11 side. If the detaching holes for detaching the two blower fans 12, 13 are formed, the first and second blower fans 12, through the detaching hole of the first casing 15 (without detaching the upper and lower divided cases 151, 152). 13 and the electric motor 11 can be detached.

  In addition, if the electric motor 11 is fixed via the attachment / detachment hole peripheral part of the first casing 15 and a bracket and the gap between the electric motor 11 and the attachment / detachment hole of the first casing 15 is closed by the bracket, the gap Leakage of the blast air from can be prevented.

  (4) In the above-mentioned embodiment, although the example which applied this invention to the electric blower 10 which comprises the air blower unit of a vehicle air conditioner was shown, it is not limited to this, For the electric blower of various uses Of course, the present invention is applicable.

  (5) In the above-described embodiment, the example in which the present invention is applied to the electric blower using the electric motor 11 as the drive source of the first and second blower fans 12 and 13 has been described. However, the present invention is not limited to this. Of course, the present invention can be applied to a blower using various drive sources other than the electric motor.

(A) is sectional drawing of the air blower in 1st Embodiment of this invention, (b) is the A section enlarged view of (a). It is principal part sectional drawing of the air blower in 2nd Embodiment of this invention. It is principal part sectional drawing of the air blower in 3rd Embodiment of this invention. It is sectional drawing of the air blower in a prior art.

Explanation of symbols

11 Electric motor (drive source)
11a Rotating shaft 12 First blower fan 13 Second blower fan 14 Cap 15 First casing 16 Second casing 16b Detachment hole 17 Clearance 18 Barrier plate 19 Groove shape part (labyrinth seal structure)

Claims (3)

A first blower fan (12) and a second blower fan (13) which are given rotational driving force to blow air;
A first casing (15) in which the first blower fan (12) is accommodated;
A second casing (16) in which the second blower fan (13) is accommodated;
A rotation source (11a) protruding in one direction, and a drive source (11) for applying the rotation driving force to the first and second blower fans (12, 13) by the rotation axis (11a),
The second blower fan (13) and the second casing (16) are disposed at positions farther from the drive source (11) than the first blower fan (12) and the first casing (15),
The second casing (16) is formed with a demounting hole (16b) for demounting the second blower fan (13) in a direction parallel to the rotating shaft (11a),
An annular gap (17) is formed between the opening edge of the desorption hole (16b) and the outer periphery of the second blower fan (13),
An annular shielding plate (18) that shields the gap (17) from the outer side of the second casing (16) is fixed to the rotating shaft (11a),
The blower characterized in that a portion (19) in the vicinity of the opening edge of the shielding plate (18) constitutes a labyrinth seal structure for sealing the gap (17). The first blower fan (12) has a first boss part (12d) into which the rotating shaft (11a) is fitted,
The second blower fan (13) has a second boss part (13d) into which the rotating shaft (11a) is fitted.
Caps (14) that are fitted on the outer sides of the first and second boss portions (12d, 13d) and prevent the first and second blower fans (12, 13) from being detached from the rotating shaft (11a). Prepared,
The blower according to claim 1, wherein the shielding plate (18) is fixed to the rotating shaft (11a) via the cap (14).   The blower according to claim 2, wherein the shielding plate (18) is integrally formed with the cap (14).

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