JP3391361B2 - Multi-wing blower - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal multiblade blower, and more particularly to a centrifugal multiblade blower suitable for use in an air conditioner mounted on a vehicle.

[0002]

2. Description of the Related Art Conventionally, a multi-blade blower in which a fan having a large number of blades is housed in a case having a bell mouth is known. In such a multi-blade blower, there is a problem that a back flow occurs near the air suction port formed by the bell mouth. For example, in the one disclosed in Japanese Patent Publication No. 1-44919, a part of the air discharged from the fan is returned to the suction port from the inside of the fan case and is boosted again without losing the energy. The total pressure of the air discharged from the discharge port is increased.

[0003]

However, in such a conventional multi-blade blower, according to the experiments and studies by the present inventor, for example, as shown in FIG. 18, an air intake port 36 formed by a bell mouth 6 is formed. After the air is sucked into the case 7 from the above, the vortex 101
It has been found that the backflow 102 occurs between the retaining ring 24 and the case 7 as well. The generation of the vortex 101 or the backflow 102 is irrelevant to the air volume of the blower, which wastefully consumes the work of the multiblade fan, and has a large effect on disturbing the suction flow and the discharge flow, resulting in the efficiency of the blower. Lower the noise and increase the noise of the blower.

Therefore, as a result of various experiments, the present inventor attempts to reduce the backflow 102 by reducing the gap between the lower surface of the case 7 and the retaining ring 24 in the multiblade blower shown in FIG. , This time the retaining ring 2
It has been found that a backflow 103 occurs in the upper part between the adjacent plates 1 and 1 below 4. This backflow 10
3 is an air intake 3 in a scroll-shaped case 7.
When the pressure difference between the blade 6 and the space 7a of the case 7 outside the blade 1 becomes larger than the work of the blade, it occurs at a part or almost the entire circumference in the circumferential direction.

Further, during the experiment, such a backflow 103
It was found that the notion does not occur uniformly over the entire circumference of the scroll-shaped case 7, but remarkably occurs in a certain angle range with the scroll nose portion as a starting point with respect to the rotation direction of the fan. Backflow like this 1
Although the occurrence status of No. 03 varies depending on the number of revolutions of the blower, the specifications of the blower, etc., as an example of the occurrence of the backflow, as shown in FIG. 3, the range of the partial angle β from the scroll nose portion 21 to the fan rotation direction is shown. It turned out that it is likely to occur inside.

Further, when this type of centrifugal multiblade blower is applied as a blower fan for a rear cooler mounted on a passenger car, when a rear cooler unit is mounted between a rear panel below a rear window and a trunk below it, Since it is necessary to mount the blower fan in a limited space volume in the vertical height range, it is required to make the length of the blower fan in the fan axial direction as small as possible.

The present invention has been made in order to solve such a problem, and a part of the air intake is blocked to suppress a backflow which is likely to occur in an upper space in the case, thereby improving fan efficiency. It is also an object of the present invention to provide a multi-blade blower capable of reducing noise. Further, the present invention is
An object of the present invention is to provide a multi-blade blower which is designed to reduce pressure loss and noise when a fan shaft for a rear cooler of a passenger car is mounted in a substantially vertical direction below a rear panel.

[0008]

In order to achieve the above object, a multi-blade blower according to the present invention according to claim 1 is provided with a case having a bell mouth forming an air intake, and is housed in the case. Centrifugal multiple having a plurality of blades arranged in the circumferential direction, an annular shroud formed at the air suction side end of the plurality of blades, and a bottom plate formed at the anti-air suction side end of the plurality of blades. In a multi-blade fan including a blade fan, the shroud has a substantially arc-shaped cross-sectional shape along the air flow that flows from the air intake port between the blades while changing the direction from the fan axial direction to the fan radial outward direction. The inner wall cross-sectional shape of the case near the bell mouth is formed along the cross-sectional shape of the shroud with a minute gap between the inner wall and the shroud. A backflow suppressing means for suppressing the flow rate of the backflow flowing from the blade side to the air intake side along the shroud lower surface is provided in a part of the upper part of the mouse in the circumferential direction, and the radially inward end portion of the backflow suppressing means is provided. A drive motor for transmitting a rotational drive force is attached to the bottom plate, and the case is fixed to a radially outer end portion of the backflow suppressing means.

The multiblade blower of the present invention according to claim 2 is
A case having a bell mouth forming an air intake, a large number of blades housed in the case and arranged in the circumferential direction, an annular holding ring provided at the air suction side end of the large number of blades, and In a multi-blade blower comprising a centrifugal multi-blade fan having a bottom plate formed at the end on the side opposite to the air suction side of the plurality of blades, in the lower part of the retaining ring at a part of the upper part of the bell mouth in the circumferential direction. A backflow suppressing means for suppressing the flow rate of the backflow flowing from the blade side to the air intake side is provided along with a drive motor for transmitting the rotational driving force to the bottom plate at the radially inner end of the backflow suppressing means. The case is fixed to the radially outer end of the backflow suppressing means.

The multiblade blower of the present invention according to claim 3 is
A case, a motor stay having a bell mouth forming an air intake port, a number of blades housed in the case and arranged in the circumferential direction, and an annular shape formed at the air suction side end of the number of blades. A multi-blade blower having a shroud and a centrifugal multi-blade fan having a bottom plate formed at the end of the plurality of blades on the side opposite to the air intake side,
The shroud is formed in a substantially arcuate cross-sectional shape along the air flow that flows in while changing the direction from the fan axial direction to the fan radial direction from the air intake port to the blade, and the inner wall cross section near the bell mouth. The shape is formed so as to follow the cross-sectional shape of the shroud with a minute gap between the shroud, and the air intake from the blade side along the lower surface of the shroud in a part of the bell mouth in the circumferential direction. A backflow suppressing means for suppressing the flow rate of the backflow flowing to the side, a drive motor transmitting a rotational driving force to the bottom plate is attached to the radially inner end of the motor stay, and a radially outer end of the motor stay is attached to the motor stay. The case is fixed.

The multiblade blower of the present invention according to claim 4 is
A case, a motor stay having a bell mouth forming an air intake, a number of blades housed in the case and arranged in a circumferential direction, and an annular shape provided at an end on the air suction side of the number of blades. A multi-blade blower having a retaining ring and a centrifugal multi-blade fan having a bottom plate formed at the anti-air suction side ends of the plurality of blades,
Backflow suppression means for suppressing the flow rate of the backflow flowing from the blade side to the air intake side along the lower surface of the retaining ring is provided in a part of the bell mouth in the circumferential direction, and the radially inner end of the motor stay is provided. A drive motor for transmitting a rotational drive force is attached to the bottom plate, and the case is fixed to a radially outer end of the motor stay.

The multi-blade blower of the present invention according to claim 5 is
The structure according to claim 3 or 4, wherein the backflow suppressing means has a substantially flat plate shape. According to a sixth aspect of the present invention, in the multi-blade blower of the present invention, in the configuration according to the third or fourth aspect, the tip of the backflow suppressing means is formed into a second bell mouth shape having a hollow arc shape.

[0013]

According to the multi-blade blower of the present invention, the shroud is held or held below the shroud in a certain angle range from the reference line connecting the center of the fan to the tip of the nose part with the nose part of the case as the reference line. Focusing on the fact that a backflow is likely to occur in the upper part between adjacent blades below the ring, and in the range where this backflow is likely to occur, a backflow suppressing means is provided at the upper part of the bell mouth, so that a backflow is likely to occur near the bell mouth. Effectively suppresses backflow.

According to the multi-blade blower of the third, fourth, fifth or sixth aspect, when the air is taken into the centrifugal multi-blade fan, the air is taken from the bell mouth formed in the motor stay.
Then, the flat plate portion or the bell mouth portion formed on a part of the motor stay suppresses the backflow that tends to flow from the blade side to the air intake side. Therefore, backflow of the air flow is prevented, pressure loss is reduced, and fan efficiency is improved and noise is reduced.

Further, according to the multi-blade blower of the present invention, since the drive motor fixed to the motor stay constituting the backflow suppressing means is provided on the air intake side, the fan drive motor is sucked. By mounting from the side, the axial length of the fan and the motor (thickness of the blower) can be reduced.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIGS. 1 to 6 show a first embodiment in which the present invention is applied to a blower for taking in air of a vehicle air conditioner.

As shown in FIG. 5, the ventilation system uses the outside air intake 42 for taking in the air outside the passenger compartment or the air taken in from the inside air intake 43 for taking in the air inside the passenger compartment from the air intake 36 of the blower 46. It is taken into the case 7 and guided to the evaporator 47 by the centrifugal multi-blade fan 20. The outside air intake 42 and the inside air intake 43 are opened and closed by a rotatable inside / outside air switching damper 45. Evaporator 47
An air mix damper 48 is provided on the outlet side of the first flow path 1 partitioned by the air mix damper 48.
The heater core 17 is attached to the second flow passage 19 on one side of the second flow passage 19 and the second flow passage 19. Air mix damper 4
The air mix chamber 49 formed on the outlet side of the heater core 17 and the heater core 17 is directed toward the upper air outlet 13 that blows upward in the vehicle compartment, the upper air outlet 12 that blows toward the upper portion of the vehicle occupant, and the feet of the vehicle occupant. It communicates with the foot outlet 10 that blows out. A damper 1 for adjusting the opening of each outlet is provided on the inlet side of each outlet 10, 12, 13.
4, 15 and 16 are rotatably attached.

The blower 46 is shown in FIG. 1, FIG. 2, FIG. 3 and FIG.
A perspective view of is shown in FIG. The blower 46 includes the centrifugal multi-blade fan 20 and the case 7. The case 7 is formed by integrally assembling a resin-molded upper case 7b and lower case 7c with clamps, screws, etc., and is formed in a known scroll shape, and extends in the radially outward direction.
2 has an air outlet portion 37, which is connected to the air inlet side of an evaporator 47. A fan drive motor 33 that rotationally drives the centrifugal multi-blade fan 20 is supported and fixed to the case 7.

The centrifugal multi-blade fan 20 includes a bottom plate 2 and
It is composed of a plurality of blades 1 and a shroud 4 formed in an annular shape on the top of the blades 1 and also serving as a retaining ring. The bottom plate 2 has a boss portion 3 to which the driving force from the fan driving motor 33 shown in FIG. 5 is transmitted.
The blade 1 is formed so as to rise from the vicinity of the outer peripheral end 2b of the bottom plate 2, and a plurality of blades are arranged in the vicinity of the outer peripheral end 2b of the bottom plate 2 along the circumferential direction at predetermined arc intervals. .

The shroud 4 is joined to the air suction side end of the blade 1 and has a substantially arcuate cross-sectional shape so as to redirect the air flow taken in from the air intake 36 from the fan axial direction to the fan radial outward direction. It is formed. An annular protrusion 4b protruding upward is formed on the shroud inner peripheral end 4a. Further, as shown in FIGS. 1 and 2, the upper case 7b has a bell mouth 6 which forms an air intake 36 in the axial direction.
The bell mouth 6 is formed in a substantially semicircular arc shape so as to wrap around the projection 4b of the shroud 4. There is a small fixed interval δ between the bellmouth inner wall 6a and the protrusion 4b, for example, about 3 mm.

As shown in FIGS. 1, 2 and 6, three stays 51, 52 and 5 are provided on the upper part of the upper case 7b.
3 are provided at intervals of 120 ° above the center of the fan shaft. (1) The first stays 51 and 52 are the end portions 5 in the outer diameter direction of the case.
1a and 52a are fixed to the upper part of the upper case 7b, and the radially inner ends 51b and 52b support the drive motor 33.

(2) The second stay 53 is in the shape of a flat fan, and the radially outer end portion 53a is fixed near the nose portion 21 above the fan case, and the radially inner end portion 53b is driven. It supports the motor 33. This second stay 53
Are provided on the upper part of the blade 1 along the lower surface of the shroud 4 at a position where the backflow 103 is likely to occur. Stay 5
If the fan rotation direction is positive from the reference line m connecting the fan center and the nose portion 21 as shown in FIG. 3, the fan-shaped angular range in which the 3 is provided is, for example, 7 in the negative direction from the reference line m.
The angle range β of 0 ° and 80 ° in the positive direction is made a part or the whole.

In this way, as shown in FIG. 3, since the stay 53 is provided in the range where the backflow is likely to occur, the backflow which is likely to occur in a part of the entire peripheral portion immediately below the shroud 4 is effectively prevented and noise is reduced. There is an effect that it can be reduced. According to the first embodiment,
For example, as shown in FIG. 3, since the stay 53 is provided in the range of the angle β at which the backflow 103 is likely to occur from the radially outer side to the radially inner side of the blade 1 passing through the upper portion between the blades 1, as shown in FIG. Since the above-described backflow 103 is reduced, the generation of noise due to this backflow is reduced.

(Second Embodiment) In the second embodiment shown in FIG. 7, the radially outer end of the stay 253 for fixing the motor 33 is fixed to the case 7, and a step 253c is formed in the middle of the stay. This is an example in which the drive motor 33 is supported by the radially inner end 253b of the step 253c. In this case, the axially intermediate outer peripheral portion of the drive motor 33 is connected to the stay radial inner end 253b.
Since it is fixed by the above, the support rigidity is enhanced, and the extra space 254 around the motor 33 is formed, so that the extra space around the fan case can be effectively used.

(Third Embodiment) A third embodiment shown in FIG.
This is an example in which the present invention is applied to an example in which the upper part of the blade 1 is held by a holding ring 70 instead of the shroud in the shape of the fan. That is, the bell mouth 6 of the fan case 71 is dripped above the blade 1 so as to draw an arc inside the arc. The stay 53 for fixing the motor 33 is similar to that of the first embodiment.

(Fourth Embodiment) The fourth embodiment shown in FIG.
This is an example in which the present invention is applied to a fan 201 that fixes a plurality of blades with a retaining ring 70 as in the third embodiment shown in FIG. A stay 253 that supports the drive motor 33
Has a step 253c in the middle thereof, and the radially outer end 2
53a is fixed to the upper part of the fan case 71, and the radially inner end 253b supports the drive motor 33.

Also in the fourth embodiment, similarly to the second embodiment shown in FIG. 7, the rigidity for supporting the drive motor 33 is increased and the spare space 254 above the drive motor 33 can be effectively used. effective. Also in the above embodiment, the backflow suppressing means is provided so as to block the backflow of a part of the circumferential portion in which the backflow that tends to escape from the air intake tends to occur in the lower part of the shroud or the retaining ring. Since it is provided, backflow can be effectively prevented and noise can be effectively reduced.

Further, in these embodiments, in order to suppress the backflow that is likely to occur in the space above the blade, a part of the air intake is closed, and the thickness of the blower fan in the axial direction of the fan is reduced without using a separate component. Can be thin. (Fifth Embodiment) A fifth embodiment of the present invention is shown in FIGS.

As shown in FIGS. 10 and 11, in the fifth embodiment, the shape or structure of the motor stay 60 is modified to reduce the axial length of the blower. The motor stay 60 includes legs 61, 62, 63 and a bell mouth 6.
4, cover portion 65, mounting portion 66 and flat plate portions 67, 68
Consists of. The legs 61, 62, 63 extend radially at intervals of 120 °, and one ends 61a, 62a, 63a thereof are connected to a fixing portion 69 for fixing the drive motor 33. The other ends 61b, 62b, 63 of the legs 61, 62, 63
Reference numeral b denotes a member that extends radially outward from the one end 61a, 62a, 63a and is connected to the bell mouth 64.

The bell mouth 64 is formed in an annular shape so as to form an air intake therein. Legs 61, 62,
Reference numeral 63 is formed in a semi-circular cross section so as to be convex upward so as to reduce air resistance. The outer peripheral portion of the bell mouth 64 is connected to the annular cover portion 65. Cover 65
Has a lower surface extending radially outward so as to form a minute gap with the shroud 4 in a direction along the shape of the shroud 4, and is formed in an annular shape similar to the shroud 4. The radially outer side of the cover portion 65 has legs 61, 62,
It is connected to a mounting portion 66 formed on the radially outward extension of 63.

The mounting portions 66 are provided at three places in this embodiment, and are fitted to the upper end of the case 7, and the mounting portions 66 and the case 7 are fastened and fixed by bolts 75 from the upper portion of the mounting portion. ing. Further, flat plate portions 67 and 68 are formed at predetermined locations near the case nose portion 21 of the bell mouth 64. The flat plate portions 67 and 68 are
It has a function of suppressing leakage of the air flow, which is about to flow backward from the blade 1 side to the bell mouth 64 side, to the outside. The flat plate portions 67 and 68 are located inside the bell mouth 64 in the vicinity of the nose portion 21, and are formed in a wing shape so as to overhang the leg portions 63 in a direction perpendicular to the extending direction. The flat plate portions 67 and 68 are shaped like the leg portion 63.
Is formed symmetrically on both sides. As a result, the flat plate portions 67 and 68 are formed in a wing shape, unlike the fan shape in the first embodiment.

Legs 61, 6 constituting the motor stay 60
2, 63, bell mouth 64, cover portion 65, mounting portion 66
The flat plate portions 67 and 68 are integrally formed of resin. Therefore, each of these component parts is integrally resin-molded in advance, so that there is an effect that the assembling work can be easily performed. In the fifth embodiment, by effectively utilizing the extra space in the fan axis direction, it becomes effective in a layout such as a rear cooler in which there is no extra space in the fan axial direction, and the size in the fan axial direction is reduced. By doing so, the blower can be downsized. Therefore, it can be attached to a small space portion in the axial direction of the fan such as a rear cooler.

Further, in the fifth embodiment, the bell mouth portion is formed not on the case 7 but on a part of the motor stay 60. Therefore, since the case shape can be simplified by simplifying the case shape part of the space part of the fan upper part, there is an effect that the complicated shape of the case is avoided and resin molding is facilitated. Further, although the flat plate portions 67 and 68 correspond to the backflow suppressing means described in the claims, an experiment was conducted to find out what kind of noise reduction effect the flat plate portions 67 and 68 have the backflow suppressing effect. The results of this experiment are shown in FIG.

The experimental conditions are those corresponding to the shape of the fifth embodiment, and the flat plate portions 67 and 68 are not formed (comparative example).
And the frequency characteristics of the noise level of the shape of the fifth embodiment were compared. Frequency ranges from 40Hz to 1
The noise level was measured in the range up to 0 kHz. The experimental results are as shown in FIG. As shown in FIG. 12, it can be understood that the noise level of the fifth example is lower than that of the comparative example in any frequency range. In particular, at a frequency of 1 kHz, the fifth embodiment is 3 compared to the comparative example.
There is a noise reduction effect of dB and the overall value is 2
It was found that there is a noise reduction effect of dB.

Next, FIG. 13 shows an example in which the fifth embodiment is applied to a blower fan for a rear cooler of a passenger car. It is a layout example of a rear cooler mounted between a tray behind a rear seat of a passenger car and an upper surface of a fuel tank below the tray. Figure 1
As can be seen by comparing FIG. 3 with FIG. 5, both are schematic diagrams, but it can be understood that the layout for the rear cooler shown in FIG. 13 is generally thin. In FIG. 13, an air intake port 78 communicating with the vehicle interior is formed in a portion connected to the rear tray part on one end side of the case 77, and a filter 79 is attached below the air intake port 78. A centrifugal multiblade blower is attached to the downstream side of the filter 79. A scroll-shaped case 80 is formed on the air outlet side of the blower, and an evaporator 47 is formed on the outlet side of the scroll-shaped case 80. An air duct 81 is provided on the outlet side of the evaporator 47.
And 82. The air ducts 81 and 82 are
It is a duct that branches so that the air is blown to the rear seats through air outlets located above the rear side doors of the vehicle compartment.

The air in the vehicle compartment is taken into the case 77 from the air intake 78, passes through the filter 79, and is blown to the rear evaporator 47 by the blower fan. The wind cooled by the evaporator 47 is the air duct 81 or 82.
Is blown into the passenger compartment. (Sixth Embodiment) A sixth embodiment of the present invention is shown in FIG.

The sixth embodiment shown in FIG. 14 is an example in which the fan shape of the fifth embodiment shown in FIG. 11 is replaced by a shroud and the upper portion of the blade 1 is held by a holding ring 70. That is, the bell mouth 85 of the motor stay 60 is dripped above the blade 1 in a substantially arcuate shape on the inner diameter side. Since the motor stay 60 for fixing the motor 33 is the same as that of the fifth embodiment, the substantially same components are designated by the same reference numerals, and the description thereof will be omitted.

By applying the present invention to the fan of the example in which the blade 1 is held by the holding ring 70 shown in the sixth embodiment, the fan axial direction can be reduced and the case 7 and the motor stay 60 can be easily attached. There is an effect that. (Seventh Embodiment) A seventh embodiment of the present invention is shown in FIGS.
6 shows.

The seventh embodiment shown in FIGS. 15 and 16 is
This is an example in which the flat plate portions 67 and 68 shown in the fifth and sixth embodiments are replaced with second bell mouths 83 and 84. In the seventh embodiment, in order to improve the reduction of the noise reduction effect due to the new disturbance of the flow of the suction air at the tips of the flat plate portions 67 and 68 shown in the fifth and sixth embodiments, the flat plate The purpose is to reduce the noise by forming the tip portion into a bell mouth shape so as to suppress the turbulence of the wind generated at the tip.

The second bell mouths 83 and 84 are shown in FIG.
As shown in FIG. 3, the legs 63 extend on both sides, and each portion is formed in a bell mouth shape. The portion opposite to the bell mouth is connected to the first bell mouth 64, and is continuously connected in the vicinity of the leg portion 63. The second bell mouths 83 and 84 are also formed integrally with the leg portion 63, the bell mouth 64, the cover portion 65, the mounting portion 66, and the like by resin as the motor stay 60.

According to the seventh embodiment, not only the size in the axial direction of the fan can be reduced but also the backflow preventing effect and the noise reducing effect at the air intake portion can be achieved at the same time. (Eighth Embodiment) An eighth embodiment of the present invention is shown in FIG.

The eighth embodiment shown in FIG. 17 is an example in which the present invention is applied to an example in which the upper portion of the blade 1 is held by a holding ring 70 instead of the shroud of the seventh embodiment shown in FIG. That is, the bell mouth 64 (not shown) of the motor stay 60 is formed on the upper part of the blade 1 so as to droop in a substantially circular arc on the radially inner side. The motor stay 60 for fixing the motor 33 has second bell mouths 83 and 84, and the substantially same parts as those in the seventh embodiment are designated by the same reference numerals and the description thereof will be omitted.

The second bell mouths 83 and 84 are also formed integrally with the leg portion 63, the bell mouth 64, the cover portion 65, the mounting portion 66 and the like by resin as the motor stay 60. Also in the eighth embodiment, there is an effect that the reduction in the fan axis direction and the noise reduction effect are great.

[Brief description of drawings]

FIG. 1 is a plan view of a multi-blade fan according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the multi-blade blower according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram illustrating a range in which the backflow suppressing unit of the multiblade blower of the present invention is mounted.

FIG. 4 is a perspective view showing a centrifugal multi-blade fan according to a first embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view showing an air conditioner to which the centrifugal multiblade blower of the present invention is applied.

FIG. 6 is a cross-sectional view showing the right half of the multiblade blower according to the first embodiment of the present invention.

FIG. 7 is a cross-sectional view showing the right half of a multiblade fan according to a second embodiment of the present invention.

FIG. 8 is a sectional view showing the right half of a multiblade fan according to a third embodiment of the present invention.

FIG. 9 is a sectional view showing the right half of a multiblade fan according to a fourth embodiment of the present invention.

FIG. 10 is a plan view of a multiblade fan according to a fifth embodiment of the present invention.

FIG. 11 is a sectional view showing the right half of a multiblade fan according to a fifth embodiment of the present invention.

FIG. 12 is an experimental data diagram of the fifth example of the present invention.

FIG. 13 is a schematic diagram showing a layout example of an air conditioner in which the multi-blade fan of the fifth embodiment of the present invention is attached to a rear cooler fan of a passenger vehicle.

FIG. 14 is a sectional view showing the right half of a multiblade fan according to a sixth embodiment of the present invention.

FIG. 15 is a plan view of a multiblade fan according to a seventh embodiment of the present invention.

FIG. 16 is a sectional view showing the right half of a multiblade fan according to a seventh embodiment of the present invention.

FIG. 17 is a sectional view showing the right half of a multiblade fan according to an eighth embodiment of the present invention.

FIG. 18 is a cross-sectional view showing the right half of a conventional multiblade blower.

[Explanation of symbols]

1 blade 2 bottom plate 4 shrouds 6 Bellmouth 7 cases 20 centrifugal multi-blade fan 33 Drive motor 36 Air intake 37 Air outlet 51 First Stay 52 First Stay 53 Second stay (backflow suppressing means) 60 motor stay 61, 62, 63 legs 64 bellmouth 65 Cover 66 Mounting part 67, 68 Flat plate portion (backflow suppressing means) 70 retaining ring 83, 84 Second bell mouth (backflow suppressing means) 253 Second stay (backflow suppressing means)

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Taiji Kondo, 1-1, Showa-cho, Kariya city, Aichi prefecture, Nippon Denso Co., Ltd. (72) Hideo Asano, 1-1, Showa-cho, Kariya city, Aichi prefecture, Nippon Denso Co., Ltd. (72) Inventor Koji Ito 1-1, Showa-cho, Kariya city, Aichi Japan Denso Co., Ltd. (72) Inventor Teruhiko Kameoka 1-1, Showa-cho, Kariya city, Aichi prefecture (72) Inventor, Japan Akiaki Watanabe 1-chome, Showa-cho, Kariya city, Aichi, Japan (56) References JP-A-4-356631 (JP, A) JP-A-4-350399 (JP, A) Actual development Shou 50-147205 (JP, U) Actual opening 55-60497 (JP, U) Actual opening Sho 62-36296 (JP, U) Actual opening Sho 62-192 (JP, U) Actual opening Sho 61-202698 (JP, U) Special Kohei 1-44 919 (JP, B2) (58) Fields surveyed (Int.Cl. ⁷ , DB name) F04D 17/16 F04D 29/44 F04D 29/28 F04D 29/42 F04D 17/04

Claims (6)

(57) [Claims] 1. A case having a bell mouth forming an air intake, a plurality of blades housed in the case and arranged in a circumferential direction, and formed at an end of the plurality of blades on an air suction side. In a multi-blade blower having an annular shroud and a centrifugal multi-blade fan having a bottom plate formed at the anti-air suction side ends of the plurality of blades, the shroud comprises a fan between the air intake and the blades. It is formed in a substantially arcuate cross-sectional shape along the air flow that flows in while changing the direction from the axial direction to the fan radial direction, and the inner wall cross-sectional shape near the bell mouth of the case forms a minute gap between the shroud. Is formed along the cross-sectional shape of the shroud through, from the blade side along the shroud lower surface in a part of the circumferential direction of the upper part of the bell mouth The backflow suppressing means for suppressing the flow rate of the backflow flowing to the air intake side is provided, and a drive motor for transmitting a rotational driving force is attached to the bottom plate at the radially inner end of the backflow suppressing means. A multi-blade blower in which the case is fixed to an end portion in the radial direction. 2. A case having a bell mouth forming an air intake, a plurality of blades housed in the case and arranged in a circumferential direction, and provided at an end of the plurality of blades on an air suction side. In a multi-blade blower having an annular retaining ring and a centrifugal multi-blade fan having a bottom plate formed at the anti-air suction side ends of the plurality of blades, in a part of the upper part of the bell mouth in the circumferential direction. Backflow suppressing means for suppressing the flow rate of the backflow flowing from the blade side to the air intake side along the lower surface of the retaining ring is provided, and the rotational driving force is transmitted to the bottom plate at the radially inner end of the backflow suppressing means. A multi-blade blower, characterized in that a drive motor is attached, and the case is fixed to the radially outer end of the backflow suppressing means. 3. A case, a motor stay having a bell mouth forming an air inlet, a large number of blades housed in the case and arranged in a circumferential direction, and air suction side end portions of the large number of blades. In a multi-blade blower having an annular shroud formed in and a centrifugal multi-blade fan having a bottom plate formed at the anti-air suction side ends of the plurality of blades, the shroud is provided from the air inlet. It is formed in a substantially arcuate cross-sectional shape along the air flow flowing in while changing the direction from the fan axial direction to the fan radial direction between the blades, and the inner wall cross-sectional shape near the bell mouth is a minute gap between the shroud. Is formed along the cross-sectional shape of the shroud through, in the circumferential direction part of the bell mouth along the shroud lower surface from the blade side to the front. Backflow suppressing means for suppressing the flow rate of the backflow flowing toward the air intake side is provided, and a drive motor for transmitting a rotational driving force to the bottom plate is attached to an end portion of the motor stay in the radial direction, and a radial direction of the motor stay is set in the radial direction. A multi-blade blower in which the case is fixed to an end portion. 4. A case, a motor stay having a bell mouth forming an air intake, a plurality of blades housed in the case and arranged in a circumferential direction, and air suction side end portions of the plurality of blades. In a multi-blade fan having an annular retaining ring provided in and a centrifugal multi-blade fan having a bottom plate formed at the end opposite to the air suction side of the plurality of blades, wherein a part of the bell mouth in the circumferential direction is provided. A backflow suppressing unit that suppresses the flow rate of the backflow that flows from the blade side to the air intake side along the lower surface of the holding ring is provided, and a rotational driving force is applied to the bottom plate at the radially inner end of the motor stay. A multi-blade blower in which a drive motor for transmission is attached, and the case is fixed to a radially outer end of the motor stay. 5. The multiblade blower according to claim 3 or 4, wherein the backflow suppressing means has a substantially flat plate shape. 6. The backflow suppressing means has a tip end shaped like a second bell mouth in the shape of a hollow arc.
Or the multi-blade blower described in 4.