JPH07208396A - Centrifugal blower - Google Patents

Abstract

PURPOSE:To provide a centrifugal blower which smoothens air flow blown from a centrifugal fan in the centrifugal direction, and reduces pressure loss in a discharge flow passage and noise. CONSTITUTION:This centrifugal blower is provided with a centrifugal fan 2 blowing off air in the centrifugal direction, a scroll case part 51 receiving the centrifugal fan 2, and an enlarged extended case part 52 connected to the outlet side of the scroll case part 51. The enlarged extended case part 52 is constituted of an enlarged extended upper wall case 62, an enlarged extended lower wall case 63, and side wall cases. The enlarged extended case part 52 is provided with a discharge passage 70 enlarging the flow passage opening area as going to the discharge side. The upper wall case 62 is enlarged upward as going in the discharge flow direction, and the lower wall case 63 is enlarged downward. When the upward enlarging quantity of the upper wall case 62 is set HUP, and the downward spreading quantity of the lower wall case 63 is set HLR, a scroll enlarging ratio HUP/HLR is set 0.4-1.1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal blower, and more particularly to a centrifugal blower for generating an air flow for supplying air to a passenger compartment via a cooling unit for cooling or a heater unit for heating. Type blower.

[0002]

2. Description of the Related Art As a conventional centrifugal blower, an actual Kaihei 1
As disclosed in Japanese Patent Laid-Open No. 108398, there is known a case in which a motor-side wall surface of a case accommodating a fan is formed in a curved shape along a blowing direction of air blown from the fan. In this article, no specific configuration is disclosed regarding how the wall surface on the motor side is formed in a curved shape along the air blowing direction.

On the other hand, conventionally, as shown in FIG. 13 (a), a vehicle air conditioner for air conditioning the interior of a vehicle is located below a switching box (not shown) that switches the intake ratio between the air inside the vehicle and the air outside the vehicle. Is connected to an air intake 101 of a scroll casing SC that surrounds the centrifugal fan 100 of the centrifugal blower B1, and a duct 103 whose flow passage area rapidly expands to a spiral discharge flow passage 102 formed in the scroll casing SC.
Is connected, and the cooling unit C is connected to this duct 103.
Are connected. An evaporator E is housed inside the cooling unit C.

The scroll casing SC has an upper wall 104 forming the air intake 101, and the upper wall 104.
And a side wall 106 that connects the outer peripheral end of the upper wall 104 and the outer peripheral end of the lower wall 105. The rapid expansion of the flow passage area at the outlet of the discharge flow passage 102 formed in the centrifugal blower B1 causes problems such as an increase in pressure loss and noise, and an uneven wind velocity distribution of air passing through the evaporator E. Occurs.

Therefore, as shown in FIG. 13B, the scroll casing SC is gradually expanded in the vertical direction toward the outlet of the discharge passage 102 to cool the passage area near the outlet of the discharge passage 102. A vehicle air conditioner equipped with a centrifugal blower B2, which is enlarged according to the entrance of the unit C, is also in practical use.

[0006]

However, in the conventional centrifugal blower B2 described above, the scroll casing S
C is simply expanded in the vertical direction toward the outlet of the discharge passage 102, and the discharge passage 1 in the scroll casing SC is
The swirling flow (secondary flow) around the axis 02 does not flow smoothly to the outlet side of the discharge flow passage 102 due to collision with the lower wall 105 of the scroll casing SC, and the noise level of the centrifugal blower B2 itself is the above-mentioned centrifugal type. There is a problem in that it is increased by about 4 dB when the air volume is large compared to the blower B1.

As a conventional example in which the noise of the centrifugal blower is reduced by avoiding the collision of the flow with the lower wall 105 of the scroll casing SC, the above-mentioned actual Kaihei 1-108398.
As shown in the publication, there is a scroll casing having a lower wall formed in a curved shape along the blowing direction of air blown from a centrifugal fan. However, in this centrifugal blower, the air blown from the centrifugal fan toward the fan radial direction at a predetermined blowing angle is sent upward along the outer peripheral edge from the outer peripheral end of the curved lower wall.
The centrifugal blower B1 is caused by the interference of the upward air along the outer peripheral wall with the air blown outward in the radial direction of the centrifugal fan or the generation of a vortex near the upper wall of the scroll casing. In comparison with B2 and B2, pressure loss and noise cannot be significantly reduced.

An object of the present invention is to provide a centrifugal blower that smoothes the flow of air blown radially outward from a centrifugal fan to reduce pressure loss and noise in the discharge passage.

[0009]

SUMMARY OF THE INVENTION A centrifugal blower according to the present invention comprises a number of circumferentially arranged blades, an annular holding ring formed at the air suction side ends of the plurality of blades, and A centrifugal fan having a bottom plate formed at an end portion of a large number of blades on the side opposite to the air intake, an upper plate forming an air intake port on one end side in the axial direction of the centrifugal fan, and the upper plate. A scroll case part which is formed of a lower plate facing each other and an outer peripheral wall connecting the outer peripheral end part of the upper plate and the outer peripheral end part of the lower plate, and which forms a discharge flow path in a spiral shape; An extended lower wall case, and an enlarged extension case portion which is formed of a side wall case and communicates with the discharge passage, and which forms a discharge passage whose flow passage opening area increases toward the discharge side. Enlarged extension Upper wall case up The larger extension lower wall casing expanding downward expansion amount H _UP upward the enlarged extension upper wall case, when the enlargement amount H _LR downward of the enlarged extension lower wall case while expanding to scroll Expansion ratio H _UP / H
_It has a configuration characterized in that _LR is set to 0.4 to 1.1.

The centrifugal blower of the present invention having the above structure is
Preferably, the scroll enlargement ratio H _UP/ H_LR0.5 to
Set to 1.0. Further, the centrifugal type of the present invention having the above configuration
The blower is preferably the expansion extension upper wall case and the front.
Enlarging extension Scroll enlarging angle of lower wall case θ_UPAnd θ_LR
Is set to 7 to 45 °. This skull
Magnification angle θ_UPAnd θ_LRAt least one of the
Specifically, it is set to 10 to 35 °.

The centrifugal blower of the present invention having the above structure is
More preferably, the scroll enlargement ratio H _UP / H _{LR is set} to 0.
5 to 1.0, and the scroll expansion angles θ _UP and θ of the expansion extension upper wall case and the expansion extension lower wall case.
_At least one of _LR is set to 10 to 35 °.

[0012]

According to the centrifugal blower of the present invention, the flow passage area of the discharge flow passage is gradually expanded toward the discharge port side of the scroll casing. The expansion of the discharge flow passage area is configured by providing the suction side scroll expansion angle θ _UP and the motor side scroll expansion angle θ _LR .

By selecting the values of the suction side scroll enlargement angles θ _UP and θ _LR , the pressure loss of the discharge flow path formed by the scroll casing is reduced, or the collision flow to the wall which obstructs the air flow is reduced. Therefore, the air flow to the discharge side of the scroll casing is made smooth and noise is reduced.

[0014]

Embodiments of the present invention will be described with reference to the drawings.
1 to 6 show a first embodiment in which the present invention is applied to a centrifugal blower that takes in air to a vehicle air conditioner. In FIG. 5, a vehicle air conditioner 20 includes an inside / outside air switching box A that switches an intake ratio between air inside the vehicle and air outside the vehicle, a centrifugal blower B that generates an air flow toward the vehicle interior, and an evaporator E.
The cooling unit C includes a cooling unit C, a heater core H, and a heater unit D that accommodates a plurality of dampers (not shown) and the like. In this example, these are sequentially connected from the upstream side to the downstream side in the air flow direction. Has been done.

Next, the centrifugal blower B will be described in detail with reference to FIGS. The centrifugal blower B has a motor 1
And a scroll casing 4 that surrounds the periphery of the centrifugal fan 2 and forms a spiral discharge passage 3 through which air toward the vehicle interior flows. The motor 1 is fixed to the scroll casing 4 so as to penetrate the lower wall of the scroll casing 4, and the rotation shaft of the motor 1 is located inside the scroll casing 4, and the centrifugal fan 2 is attached to this rotation shaft. It is connected.

The centrifugal fan 2 is made of resin and has a large number of blades 6 arranged in the circumferential direction, and an annular holding ring 2 formed at the ends of the plurality of blades 6 on the air intake side.
6 and a bottom plate 5 formed at the ends of the plurality of blades 6 on the side opposite to the air intake side. This centrifugal fan 2
Is housed in the central portion of the scroll casing 4, and a large number of blades 6 having a substantially arcuate cross section are integrally formed on the upper portion of the bottom plate 5 near the outer peripheral edge thereof at equal intervals.
Further, when the centrifugal fan 2 is rotationally driven by the motor 1 arranged below the bottom plate 5, the air sucked from the air intake 36 is blown outward in the radial direction and is pressure-fed to the discharge passage 3. A retaining ring 26 for reinforcement is provided on the outer peripheral portion of the upper end of the blade 6 of the centrifugal fan 2.

The discharge passage 3 is formed between the outer peripheral surface of the centrifugal fan 2 and the inner peripheral surface of the scroll casing 4, and sends air blown radially outward from the centrifugal fan 2 to the discharge port 11. It is a ventilation path for. The scroll casing 4 is mainly made of resin and, as shown in FIG. 3, includes a scroll case portion 51 and an enlarged extension case portion 52 forming an outlet portion of the discharge passage 3 formed by the scroll case portion 51. . The (1) scroll case portion 51 and the (2) enlarged extension case portion 52 will be described in detail below.

(1) The scroll case portion 51 has a bellmouth-shaped air inlet 3 at the upper end side in the axial direction of the centrifugal fan 2.
6, an upper plate 8 on which the motor 6 is formed, a lower plate 9 arranged on the motor 1 side so as to face the upper plate 8, an outer peripheral edge of the upper plate 8 and the lower plate 9
The side plate 10 connects the outer peripheral edge of the. The distance from the fan center to the outer peripheral edge of the upper plate 8 is gradually increased so as to expand the flow passage area of the discharge flow passage 3 toward the discharge side.

The lower plate 9 is the bottom plate 5 of the centrifugal fan 2.
The annular portion 13 located on the side, the spiral inclined flat plate portion 14 provided on the most side plate 10 side substantially orthogonal to the side plate 10, and inclined downward with respect to the radial direction of the centrifugal fan 2. It has a spiral-shaped inclined connection portion 15 provided. A circular mounting hole 16 for mounting the motor 1 is formed in the center of the annular portion 13, and the annular portion 13 is formed in an annular plate shape so as to have an outer diameter substantially the same as the outer diameter of the centrifugal fan 2. . Here, the annular portion 13 is constituted by a mounting flange integrally attached to the motor 1 in this example.

As shown in FIG. 4, the inclined flat plate portion 14 begins to incline downward from a fulcrum M whose outside along the side plate 10 is angularly displaced about 60 ° downstream from the nose position N of the scroll casing 4 to the downstream side. The bulge height and width gradually increase toward the discharge port 11 along the longitudinal direction of the discharge flow channel 3, and the flow channel area of the discharge flow channel 3 gradually increases. The fulcrum M may coincide with the nose position N, and may be on the upstream side of 60 ° from the nose position N or on the further downstream side.

The inclined connecting portion 15 linearly connects the outer peripheral end of the annular portion 13 and the inner peripheral end of the inclined flat plate portion 14. In this example, the tilted connecting portion 15 is a weight surface below the radial direction of the centrifugal fan 2, that is, in the figure, the tilt angle θ is 30 ° to 60 ° with respect to the axial direction of the centrifugal fan 2. The inclination angle θ can be appropriately selected within the range of 0 <θ <90 ° depending on the specifications of the centrifugal fan 2, the ventilation resistance of the ventilation system, and the like.

(2) As shown in FIGS. 1 and 3, the expansion extension case portion 52 is composed of an expansion extension upper wall case 62, an expansion extension lower wall case 63, and side wall cases 64 and 65. A discharge passage 70 is formed that is in communication with the discharge passage 70 and has a flow passage opening area that increases toward the discharge side. In the expansion extension case portion 52, the expansion extension upper wall case 62 of the scroll casing 4 expands from the line AA shown in FIG. 2 toward the discharge port at the suction side scroll expansion angle θ _UP . This A
The line A is a position near the nose N after the end of scroll winding. The range of this suction side scroll expansion angle θ _UP is 10
° <θ _UP <40 °, preferably 15 ° <θ _UP <3
It is 0 °.

The enlarged extension case portion 52 is shown by B- in FIG.
The expansion extension lower wall case 63 of the scroll casing 4 expands from the line B to the discharge port side at an angle of the suction side scroll expansion angle θ _LR . The line B-B passes near the center of the fan and is located on the upstream side of the air flow with respect to the line A-A. The range of the motor side scroll expansion angle θ _LR is 10 ° <θ
_LR <30 °, preferably 15 ° <θ _LR <20 °.

The suction side scroll expansion amount H _UP, when the motor-side scroll expansion amount H _LR, H _UP, either H _LR is at 10mm or more, the suction-side scroll expansion amount H _UP and the motor-side scroll expansion amount H _LR Scroll enlargement ratio H _UP
/ H _LR is 0.4 to 1.1, preferably 0.5 to 1.0
Is. Here, the scroll enlargement ratio H _UP / H _LR is set to a value within the above range because the secondary flow 77 shown in FIG. 1 due to the sudden enlargement can be minimized in one of the scrolls, and the other side of the scroll in FIG. This is because the source of the collision flow 88 shown can be minimized and the noise reduction effect is great. This secondary flow 77 and collision flow 8
8 can be greatly reduced by setting the scroll enlargement ratio H _UP / H _LR within the above range.

Next, experimental data will be shown. Regarding the test conditions, the fan diameter of the test fan Φ: 120 mm, 150 m
m, fan height H: 65 mm, 85 mm, blower motor voltage: 12 V (constant), gap δ between holding ring and scroll casing / fan outer diameter: 0.02, scroll casing scroll side expansion angle θ _UP and motor The side scroll enlargement angle θ _LR has the above-mentioned specifications. As a result, the relationship between the scroll enlargement ratio H _UP / H _LR and the minimum specific noise was as shown in FIG. From this result, it was found that the minimum specific noise was small when the scroll enlargement ratio H _UP / H _LR was in the above range.

Next, modified examples of the layout of the centrifugal blower fan are shown in FIGS. 7, 8 and 9. (Modification 1) The blower 18 shown in FIG.
It is composed of a centrifugal multi-blade fan 220 and a case 222. Here, the case 222 is a resin-molded upper case 222a.
The lower case 222b and the lower case 222b are integrally assembled with each other by clamps, screws, etc., and are formed in a well-known scroll shape like the scroll casing 4 shown in FIG. 3. The air outlet portion extending in the radially outward direction is an evaporator. It is connected to the air inlet side of E.

A fan driving motor (not shown) is supported and fixed to the lower case 222b of the case 222. The centrifugal multi-blade fan 220 includes a bottom plate 224, a large number of blades 225, and a shroud 226 that is annularly formed on the top of the blades 225 and also functions as a reinforcing ring. Here, the shroud 226 corresponds to the retaining ring of the present invention. The bottom plate 224 has a boss portion 228 to which the driving force from the fan driving motor is transmitted. The top surface 224a of the bottom plate 224 is formed into a curved surface that smoothly curves from the central portion toward the outer circumference. The blades 225 are formed so as to rise from the vicinity of the outer peripheral end 224b of the bottom plate 224, and are arranged in the vicinity of the outer peripheral end 224b of the bottom plate 224 along the circumferential direction at predetermined arc intervals. . Shroud 22
6 is joined to the top of the blade 225, and the line connecting the shroud inner peripheral end 226a and the bottom plate outer peripheral end 224b coincides with the mold dividing line 230. An annular protrusion 226b is formed upward from the shroud inner peripheral end 226a.

The case 222 for accommodating the centrifugal multi-blade fan 220 has a bell mouth 23 formed in a semi-arcuate shape so as to surround the projection 226b of the shroud 226.
1 is formed, and the bell mouth inner wall 231a and the protrusion 22 are formed.
There is a minute fixed interval δ ₁ between 6b, for example, about 3 mm. The case inner wall 222c near the base of the bell mouth 231 is formed with a substantially constant minute interval δ _1, for example, about 3 mm from the top surface 226c of the shroud 226. Such a substantially constant minute interval δ ₁ is formed from the outer peripheral wall of the projection 226b of the shroud 226 to the radially outer end 226d of the top surface 226c that is smoothly curved radially outward.

According to the first modification, the air intake port 236.
The shroud 226 is formed in a substantially arcuate cross-sectional shape so as to redirect the air flow taken in from the fan axial direction to the fan radial outward direction, and the clearance between the bell mouth inner wall 231a and the case inner wall 222c and the shroud 226 is minute. Since it is formed by δ ₁ narrowly and over a long distance from the inner diameter side to the outer diameter side, the amount of air flowing back from the outlet of the blade 225 to the inner diameter side through this gap is reduced. Therefore, it is possible to improve fan efficiency and reduce noise. (Modification 2) The blower 306 shown in FIG.
Consists of a centrifugal multi-blade fan 320 and a case 321.
Here, the case 321 is a resin-molded upper case 32.
2 and the lower case 323 are integrally assembled by a clamp, a screw, or the like, and are formed in a well-known scroll shape, and an air outlet portion extending radially outward is connected to an air inlet side of the evaporator E. There is.

The upper case 322 is a flat ceiling 322.
a is located near the height of the top of the centrifugal multi-blade fan 320, and a bell mouth 340 is formed at the inner diameter end. Bellmouth 34
At 0, an annular rising portion 322b that rises vertically upward from the ceiling portion 322a is formed.
A hanging portion 322c having a quarter arc section is formed so as to curve in a circular arc shape and hang downward from the upper portion of 2b. The lower end 322d of the hanging part 322c hangs down to near the top surface of the centrifugal multiblade fan 320. The clearance δ ₂ between the bottom lower surface 322e of the root of the rising portion 322b and the fan top surface 320a is set to a minute distance, and the clearance δ ₃ between the inner diameter end 322f of the ceiling portion 322a and the fan outer surface 320b is also a minute distance. Is set to.

A fan driving motor (not shown) is supported and fixed to the lower case 323. Centrifugal multi-blade fan 320
Is composed of a bottom plate 324, a number of blades 325, and a retaining ring 326 which is annularly formed on the top of the blades 325 and also serves as a reinforcing ring. The bottom plate 324 has a boss portion 328 to which the driving force from the fan driving motor is transmitted. Blade 325
The bottom plate 324 is formed so as to rise from the vicinity of the outer peripheral end 324b of the bottom plate 324, and is arranged in the vicinity of the outer peripheral end 324b of the bottom plate 324 along the circumferential direction at predetermined arc intervals.

Retaining ring 326 is joined to the top of blade 325. A line connecting the inner peripheral edge 326a of the retaining ring and the outer peripheral edge 324b of the bottom plate coincides with the mold dividing line 330. According to the second modification, the blade 325
Retaining ring 326 and bell mouth 34 formed on the top of the
The clearance between the lower end 322e of the rising portion 322b of 0 and the height position of the ceiling portion 322a is lowered, and the extra space above the scroll is reduced. Therefore, the backflow from the outlet of the blade 325 to the inner diameter side is generated. Prevent
In addition, since the generation of swirl in the space above the scroll is prevented, noise performance and fan efficiency can be improved. (Modification 3) The blower 406 shown in FIG. 9 according to Modification 3.
Comprises a centrifugal multi-blade fan 420 and a case 422.
Here, the case 422 is a resin-molded upper case 42.
2a and the lower case 422b are integrally assembled by a clamp, a screw, or the like, and are formed in a well-known scroll shape. An air outlet portion extending radially outward is connected to an air inlet side of the evaporator E. There is.

A fan drive motor is supported and fixed to the lower case 422b of the case 422. The centrifugal multi-blade fan 420 includes a bottom plate 424 and a number of blades 425.
And a holding ring 426 which is annularly formed on the top of the blade 425 and also serves as a reinforcing ring, and is made of a resin integrally molded product. The bottom plate 424 has a boss portion 428 to which the driving force from the fan driving motor is transmitted. The top surface 424a of the bottom plate 424 is formed into a curved surface that smoothly curves from the central portion toward the outer peripheral direction. The blades 425 are formed so as to rise from the vicinity of the outer peripheral end 424b of the bottom plate 424, and are arranged in the vicinity of the outer peripheral end 424b of the bottom plate 424 along the circumferential direction at predetermined arc intervals. .
The retaining ring 426 is annular and is joined to the top of each blade 425. The tip 431a of the bell mouth 431 and the top surface 426 of the retaining ring 426 have a substantially constant minute distance δ.
₄ For example, it is formed with a gap of about 3 mm.

The inclination angle α of the side surface of the case 422 is
Is a reference line X which is a line connecting the center point O ₁ of the fan 420 and the center point O ₂ of the curved surface of the scroll-shaped nose portion N of the case 422. When the winding angle θ of the scroll is taken from this reference line X, Is in the range of 0 ≦ θ ≦ 45 °, the inclination angle α = 0, and in the range of 45 ° <θ ≦ 270 °, the inclination angle α of the side surface of the case is set to gradually increase as the winding angle θ increases. . In this example, the winding angle θ is 270 ° and the inclination angle α is 8 °.

This is from the air intake 36 to the blade 42.
The shape of the side surface of the case is taken into consideration so as to secure the volume proportional to the air flow rate in correspondence with the velocity distribution of the air that has passed through the space 5 in the radial direction. As shown in the speed distribution at each position of the scroll winding angle θ = 0 °, 45 °, 90 °, 180 °, 270 °, the inclination angle α of the side surface of the case is set to an angle corresponding thereto. As a result, the air flow that escapes from between the blades 425 hits the bottom surface 422c of the case and is formed,
It is possible to prevent an ascending flow due to the pressure difference between the upper and lower sides of the outlet of 25, and also to prevent a circulating flow that is likely to occur in the vicinity of the air intake port 36 in the case. By eliminating them, air turbulence is reduced, noise is reduced, and fan efficiency is improved.

Next, modified examples 4, 5, and 6 of the layout of the air conditioner using the centrifugal fan of the present invention are shown in FIGS.
1 and FIG. (Modification 4) A modification 4 shown in FIG.
7 is an example in which the centrifugal fan 2 of the present invention is provided between the heater core 48 and the heater core 48. As described above, the scroll casing 4 of the centrifugal fan 2 is formed to be inclined with the suction side scroll enlargement angle θ _UP and the motor side scroll enlargement angle θ _LR . An outlet 49 is formed on the downstream side of the heater core 48. (Modification 5) A modification 5 shown in FIG.
This is an example in which the centrifugal fan 2 is provided on the inlet side of 7. The scroll and the inlet of the evaporator 47 are connected to the portion connected from the centrifugal fan 2 to the evaporator 47 with the enlargement angles θ _UP and θ _LR of the scroll casing, which is a characteristic part of the present invention. (Modification 6) A modification 6 shown in FIG.
Two are provided, and the inlet side of the centrifugal fan 2 is provided at two locations on the opposite side of the drive motor of the centrifugal fan 2, and the air taken in from this air intake is used for the centrifugal fan. 2 through the outlet through the evaporator 47, the heater core 48 and the outlet 50 into the passenger compartment.

The centrifugal blower according to the present invention can be applied to the air conditioners having the respective layouts shown in FIGS. 10, 11 and 12. In this case, vortex flow, backflow, etc. generated inside the centrifugal fan are prevented and air is smoothly blown out from the discharge port, so that noise leaking from the air conditioner into the vehicle compartment is reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a centrifugal fan according to a first embodiment of the present invention.

FIG. 2 is a schematic plan view showing an enlarged portion of the scroll casing of the centrifugal fan according to the first embodiment of the present invention.

FIG. 3 is a perspective view showing a centrifugal fan according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view of the centrifugal fan according to the first embodiment of the present invention.

FIG. 5 is a perspective view of an air conditioner to which the centrifugal fan according to the first embodiment of the present invention is applied.

FIG. 6 is an experimental data diagram showing a relationship between a scroll enlargement ratio of a suction side scroll enlargement amount and a motor side scroll enlargement amount and a minimum specific noise.

FIG. 7 is a modification 1 of a blower layout to which the present invention is applied.
FIG.

FIG. 8 is a modification 2 of a blower layout to which the present invention is applied.
FIG.

FIG. 9 is a modified example 3 of a blower layout to which the present invention is applied.
FIG.

FIG. 10 is a schematic diagram showing a layout modification 4 of an air conditioner to which the centrifugal blower of the present invention is applied.

FIG. 11 is a schematic view showing a layout modification example 5 of an air conditioner to which the centrifugal fan of the present invention is applied.

FIG. 12 is a schematic diagram showing a layout modification example 6 of an air conditioner to which the centrifugal fan of the present invention is applied.

FIG. 13 is a cross-sectional view showing a main part of a vehicle air conditioner incorporating a conventional centrifugal blower.

[Explanation of symbols]

 B Centrifugal blower 2 Centrifugal fan 3 Discharge flow path 4 Scroll casing 8 Top plate 9 Bottom plate 10 Side plate 36 Air intake 51 Scroll case part 52 Expansion extension case part 62 Expansion extension upper wall case 63 Expansion extension lower wall case 64 Side wall Case 65 Side wall case 70 Discharge passage

Claims (4)

[Claims] 1. A number of blades arranged in a circumferential direction,
A centrifugal fan having an annular holding ring formed at the air suction side ends of the plurality of blades, and a bottom plate formed at the counter air suction side ends of the plurality of blades, and a shaft of the centrifugal fan. An upper plate forming an air intake on one end side in the direction, a lower plate facing the upper plate, and an outer peripheral wall connecting an outer peripheral end of the upper plate and an outer peripheral end of the lower plate. It is composed of a scroll case part that forms the discharge flow path in a spiral shape, an expansion extension upper wall case, an expansion extension bottom wall case, and a side wall case, and is connected to the discharge passage, and the flow path opening area is enlarged toward the discharge side. And an enlarged extension case portion that forms a discharge passage, the enlarged extension upper wall case is enlarged upward and the enlarged extension lower wall case is enlarged downward in the discharge flow direction. Above Larger amount H _UP to, when the enlargement amount H _LR downward of the enlarged extension lower wall casing, centrifugal, characterized in that setting the scroll expansion ratio H _UP / H _LR to 0.4 to 1.1 Blower. 2. A number of blades arranged in a circumferential direction,
A centrifugal fan having an annular holding ring formed at the air suction side ends of the plurality of blades, and a bottom plate formed at the counter air suction side ends of the plurality of blades, and a shaft of the centrifugal fan. An upper plate forming an air intake on one end side in the direction, a lower plate facing the upper plate, and an outer peripheral wall connecting an outer peripheral end of the upper plate and an outer peripheral end of the lower plate. It is composed of a scroll case part that forms the discharge flow path in a spiral shape, an expansion extension upper wall case, an expansion extension bottom wall case, and a side wall case, and is connected to the discharge passage, and the flow path opening area is enlarged toward the discharge side. And an enlarged extension case portion that forms a discharge passage, the enlarged extension upper wall case is enlarged upward and the enlarged extension lower wall case is enlarged downward in the discharge flow direction. Above Larger amount H _UP to, when the enlargement amount H _LR downward of the enlarged extension lower wall casing, centrifugal, characterized in that setting the scroll expansion ratio H _UP / H _LR to 0.5-1.0 Blower. 3. The expansion extension upper wall case and the expansion extension lower wall case have at least one of scroll expansion angles θ _UP and θ _LR of 7 to 45 °.
The described centrifugal blower. 4. The centrifuge according to claim 1, wherein at least one of scroll enlargement angles θ _UP and θ _LR of the enlarged extended upper wall case and the enlarged extended lower wall case is 10 to 35 °. Blower.