JP2004270577A - Centrifugal blower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce blower noise while improving blower efficiency. <P>SOLUTION: This blower is provided with a movable outer circumference side inner wall 73 capable of changing expansion angles of a scroll casing 72 based on parameter in relation to draft resistance such as blower mode and ventilation amount. Consequently, blower noise can be reduced while improving blower efficiency. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a centrifugal blower, and is effective when applied to a blower of a vehicle air conditioner.
[0002]
[Prior art]
As is well known, the scroll casing of the centrifugal blower forms a spiral air flow path on the outer diameter side of the centrifugal multi-blade fan, and a flow path from the winding start portion of the scroll casing, that is, from the nose portion to the winding end portion. The air is blown from the centrifugal multi-blade fan to the downstream side while being efficiently collected by gradually increasing the cross-sectional area.
[0003]
Therefore, as shown in FIG. 7, the optimum shape and size of the scroll casing in terms of the shape and dimensions, that is, the rate of increase in the cross-sectional area such as the divergence angle and the cross-sectional area of the flow path, vary depending on the amount of air flow and the resistance to ventilation.
[0004]
Therefore, conventionally, a spiral air flow path variable blade formed by a scroll casing is provided, and the variable blade is swung in a direction parallel to the rotation axis of the centrifugal multi-blade fan according to the amount of air blown. The cross-sectional area is changed (for example, see Patent Document 1).
[0005]
[Patent Document 1]
JP-A-2002-161896
[Problems to be solved by the invention]
However, the invention described in Patent Literature 1 employs a scroll casing having a constant divergence angle from the beginning to the end of winding of the scroll casing, and the door means is provided at the end of winding of the scroll casing. If the means is rotated, it will greatly deviate from the optimal flow path shape (scroll casing shape).
[0007]
In view of the above points, the present invention firstly provides a new centrifugal blower different from conventional ones, and secondly, aims to reduce blowing noise while improving blowing efficiency.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, the invention has a large number of blades (71a) around a rotation axis, and allows air taken in from an axial direction of the rotation axis to be radially outward. A centrifugal multi-blade fan (71) that blows toward the air, and a spiral air flow path (72a) that houses the centrifugal multi-blade fan (71) and through which air blown from the centrifugal multi-blade fan (71) flows. A scroll casing (72) in which the radius (r) of the outer peripheral side inner wall changes in a logarithmic spiral according to the winding angle (θ), and the scroll casing (72) varies in accordance with the ventilation resistance in the air flow path (72a). The outer peripheral side inner wall (73) of (72) is displaced to change a divergence angle (n) of substantially the entire region from the winding start portion to the winding end portion of the scroll casing (72).
[0009]
This makes it possible to reduce the blowing noise while improving the blowing efficiency.
[0010]
According to the second aspect of the present invention, the outer peripheral side inner wall (73) is a strip spring having one end fixed to the scroll casing (72) and the other end fixed to the winding mechanism (74). In addition, the divergence angle (n) is changed by adjusting the winding amount of the outer peripheral side inner wall (73) by the winding mechanism (74).
[0011]
In the invention according to claim 3, the outer peripheral side inner wall (73) is constituted by a plurality of movable walls (73d) arranged from the winding start side to the winding end side, and furthermore, includes a plurality of movable walls (73d). 73d) The divergence angle (n) is changed by displacing each of them.
[0012]
The invention according to claim 4 is characterized in that at least the outer peripheral side inner wall (73) is provided with a sound absorbing material that attenuates air vibration and reduces noise.
[0013]
According to a fifth aspect of the present invention, there is provided a centrifugal blower (7) according to any one of the first to fourth aspects, and a blow mode switching device (18 to 20) for switching a blow mode of air blown into a room. An air conditioner for a vehicle, comprising: determining a ventilation resistance based on an operation state of a blowing mode switching device (18 to 20).
[0014]
According to a sixth aspect of the present invention, there is provided the centrifugal blower (7) according to any one of the first to fourth aspects, and the ventilation resistance is determined based on the amount of air blown by the centrifugal blower (7). It is characterized by the following.
[0015]
According to a seventh aspect of the present invention, there is provided the centrifugal blower (7) according to any one of the first to fourth aspects, and a blowing mode of air to be blown into a room and a flow rate of the centrifugal blower (7). An air conditioner for an automatic control system that controls at least one of them based on a target temperature (TAO) of air blown into a room, wherein a ventilation resistance is determined based on the target temperature (TAO). Is what you do.
[0016]
Incidentally, reference numerals in parentheses of the above-mentioned units are examples showing the correspondence with specific units described in the embodiments described later.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
(1st Embodiment)
In the present embodiment, the centrifugal blower according to the present invention is applied to an air conditioner for a vehicle, and FIG. 1 is a schematic diagram of an air conditioner 1 for a vehicle according to the present embodiment.
[0018]
At an air upstream side of the air-conditioning casing 2 forming an air flow path, an inside air suction port 3 for sucking vehicle interior air and an outside air suction port 4 for sucking outside air are formed. An inlet switching door 5 for selectively opening and closing the ports 3 and 4 is provided. The inlet switching door 5 is opened and closed by a driving means such as a servomotor or a manual operation.
[0019]
A filter (not shown) for removing dust in the air and a blower 7 according to the present embodiment are disposed downstream of the air flow of the inlet switching door 5. , 4 are blown toward the outlets 14, 15, 17 described later.
[0020]
Further, an evaporator 9 serving as a cooler for cooling the air blown into the room is disposed downstream of the blower 7 in the air. All the air blown by the blower 7 passes through the evaporator 9. The evaporator 9 is a low-pressure side heat exchanger of a vapor compression refrigerator that generates a refrigeration capacity by evaporating a refrigerant.
[0021]
A heater 10 for heating the air blown into the room is provided downstream of the evaporator 9 in the air. The heater 10 heats the air using the cooling water of the engine 11 as a heat source. In addition, the blower apparatus 7 shown in FIG. 1 is a schematic diagram, and details will be described later.
[0022]
In the air-conditioning casing 2, a bypass passage 12 that bypasses the heater core 10 is formed. On the upstream side of the heater core 10, the ratio of the amount of air flowing through the heater core 10 to the amount of air flowing through the bypass passage 12 is adjusted. Accordingly, an air mix door 13 for adjusting the temperature of the air blown into the vehicle compartment is provided.
[0023]
At the most downstream side of the air-conditioning casing 2, a face outlet 14 for blowing out conditioned air to the upper body of the passenger in the passenger compartment, a foot outlet 15 for discharging air to the feet of the passenger in the passenger compartment, and a windshield A defroster outlet 17 for blowing air toward the inner surface of the nozzle 16 is formed.
[0024]
On the air upstream side of each of the air outlets 14, 15, 17 are provided blow-out mode switching doors 18, 19, 20 for controlling the blow-out mode. Incidentally, these blow-out mode switching doors 18, 19, 20 are opened and closed by driving means such as a servomotor or by manual operation.
[0025]
In addition, as the blowing mode, a face mode in which air is mainly blown out from the face outlet 14, a foot mode in which air is mainly blown out from the foot outlet 15, a bi-level mode in which air is blown out from the face outlet 14 and the foot outlet 15, And a defroster mode in which air is mainly blown out from the defroster outlet 17.
[0026]
Incidentally, in general, a vehicle air conditioner requires a large air volume in the face mode in which air is blown out from the face outlet 14, so that the ventilation resistance (pressure loss) in the face mode is different from that in another blow mode (foot mode). And differential mode).
[0027]
Further, as shown in FIG. 2, the electronic control unit (ECU 21) detects an inside air sensor that detects the temperature of the indoor air, an outside air sensor that detects the temperature of the outdoor air, and detects the air temperature immediately after passing through the evaporator 9. A detection signal of the air conditioning sensor 22 such as a post-evaporation sensor and a solar radiation sensor for detecting the amount of solar radiation poured into the room, and a desired room temperature set and input by the occupant, that is, an output of the operation panel 23 and the like are input.
[0028]
Then, the ECU 21 calculates a target temperature of the air to be blown into the room, that is, a target outlet temperature TAO, based on a signal input to the ECU 21 in accordance with a program stored in advance, and based on the target outlet temperature TAO, the inlet switching door. 5. The amount of air blown by the air mix door 13, the blow-out mode switching doors 18, 19, 20 and the blower 7, that is, the voltage applied to the electric motor for rotating the fan 71 or the number of rotations is controlled.
[0029]
Next, the blower 7 will be described in detail.
[0030]
As shown in FIG. 3, the blower 7 has a multi-blade centrifugal fan (hereinafter, referred to as a fan) having a large number of blades 71a around the rotation axis and blowing out air taken in from the rotation axis direction toward the radial outside. 71, an electric fan motor disposed at one end side in the rotation axis direction and serving as driving means for rotating the fan 71, and a spiral air flow path 72a in which the fan 71 is housed and air blown from the fan 71 flows. , And the like.
[0031]
Here, in the scroll casing 72, the flow cross-sectional area gradually increases from the winding start portion, that is, the nose portion 72b to the winding end portion of the scroll casing 72 so that the air blown out from the fan 71 is efficiently collected and flowed to the downstream side. are doing. Specifically, the radius r of the outer peripheral side inner wall of the scroll casing 72 is gradually increased in a logarithmic spiral function with respect to the winding angle θ measured from the nose portion 72b.
[0032]
Here, the logarithmic spiral function is represented by the following equation 1, and θ is an angle measured in a direction of rotation of the fan from a reference line connecting the center of the radius of curvature of the nose portion 72b and the rotation center of the fan 72. (Unit: radian), and ro is the inner radius on the outer peripheral side with respect to the reference line (θ = 0).
[0033]
(Equation 1)
r = ro · e ^{( π / 180) n · θ}
In the present embodiment, the outer peripheral side inner wall 73 of the scroll casing 72 is displaced in accordance with the ventilation resistance in the air flow path 72a, that is, the air pressure in the air flow path 72a, and the scroll casing 72 is wound from the winding start to the winding end. The divergence angle n of substantially the entire area of the part reaching the part is changed in the range of 4 ° to 6 °.
[0034]
Incidentally, the nose portion 72b is, as is well known, a portion where the winding start side and the winding end side of the scroll casing 72 overlap with each other. In the nose portion 72b, a small gap (see FIG. (Not shown)).
[0035]
Further, the outer peripheral side inner wall 73, which is a movable wall, is a band spring having one end fixed to the scroll casing 72 and the other end fixed to the winding mechanism 74. By adjusting the winding amount of the side inner wall 73, the divergence angle n is changed as shown in FIG.
[0036]
Further, as shown in FIG. 5, the outer peripheral side inner wall 73 is formed by embedding a metal wire 73a such as a piano wire for generating a spring characteristic in a flexible resin film member 73b. The right end of the drawing is fixed to the scroll casing 72, and the left end of the drawing is fixed to the winding drum 74 a of the winding mechanism 74 (FIG. 3).
[0037]
Further, as shown in FIG. 3, the winding mechanism 74 engages with the winding drum 74a, the pinion 74b of the winding drum 74a, and moves the rack 74c while rotating the winding drum 74a, and moves the rack 74c in parallel. The ECU 21 controls the actuator, that is, the winding mechanism 74.
[0038]
Incidentally, the stopper guide 73c regulates the amount of displacement so that the displacement of the outer peripheral side inner wall 73 stops at the position where the divergence angle n is the minimum, and the position where the divergence angle n is the maximum is the outer periphery of the scroll casing 72. It is regulated by the side outer wall.
[0039]
Next, the characteristic operation of the centrifugal blower 7 according to the present embodiment and its effects will be described.
[0040]
In the face mode, as described above, the ventilation resistance (pressure loss) becomes smaller and the air volume increases as compared with the other blowing modes (foot mode and differential mode), and the air pressure (static pressure) in the air flow path 72a increases. In order to decrease, the outer peripheral side inner wall 73 is displaced to a position where the divergence angle n becomes maximum.
[0041]
On the other hand, in the foot mode and the differential mode, the ventilation angle (static pressure) increases and the air volume decreases as compared with the face mode, and the air pressure (static pressure) in the air flow path 72a increases. The outer peripheral side inner wall 73 is displaced to a position where.
[0042]
Thereby, the shape and size of the scroll casing 72, that is, the rate of increase of the cross-sectional area such as the divergence angle n and the cross-sectional area of the flow path can be made to be optimal shapes according to the blowing amount and the ventilation resistance. Therefore, it is possible to reduce the blowing noise while improving the blowing efficiency.
[0043]
By the way, in the air conditioner of which the prototype was studied based on the present embodiment, the noise could be reduced by about 3 dB irrespective of the blowing mode as compared with the conventional type.
[0044]
(2nd Embodiment)
In the present embodiment, as shown in FIG. 6, the outer peripheral side inner wall 73 is configured by a plurality of movable walls 73d arranged from the winding start side to the winding end side, and a part of the adjacent movable wall 73d overlaps. In this state, the divergence angle n is changed by displacing each movable wall 73d along the link groove 73e.
[0045]
(Third embodiment)
In the above-described embodiment, the divergence angle is changed in accordance with the blowing mode. However, even if the blowing mode is constant, the ventilation resistance in the air flow path 72a changes when the blowing amount changes, so in the present embodiment, The spread angle n increases as the applied voltage or the rotation speed to the fan motor increases and the air flow increases, and conversely, the spread angle n decreases as the applied voltage or the rotation speed to the fan motor decreases and the air flow decreases. Is reduced (fourth embodiment).
In the vehicle air conditioner of the automatic control method, as described above, since the applied voltage to the fan motor and the blow mode are controlled based on the target blow temperature TAO, in the present embodiment, based on the target blow temperature TAO possible. This is to change the spread angle n.
[0046]
More specifically, when the target outlet temperature TAO decreases, the air conditioner enters the cooling mode to enter the face mode, and when the target outlet temperature TAO increases, the operation enters the heating operation to enter the foot mode. When the value is smaller than the predetermined value, the expansion angle n is maximized. When the target outlet temperature TAO is larger than a second predetermined value that is larger than the first predetermined value, the expansion angle n is minimized. In this case, the divergence angle n is reduced in accordance with the increase in the target outlet temperature TAO.
[0047]
(Other embodiments)
In the above embodiment, the present invention is applied to the vehicle air conditioner, but the present invention is not limited to this.
[0048]
Further, the divergence angle n may be changed by, for example, measuring the air pressure of the ventilation system from the blower 7 to the outlets 14, 15, 17 using a pressure sensor or the like.
[0049]
In addition, if at least the outer peripheral side inner wall 73 is provided with a sound absorbing material that attenuates air vibration to reduce noise, noise can be further reduced.
[0050]
Further, at least two of the first, third, and fourth embodiments may be combined.
[0051]
Further, at least two of the second to fourth embodiments may be combined.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an air conditioner according to an embodiment of the present invention.
FIG. 2 is a schematic diagram showing a control system of the air conditioner according to the embodiment of the present invention.
FIG. 3 is a perspective view of the blower according to the first embodiment of the present invention.
FIG. 4 is an operation explanatory view of the blower according to the first embodiment of the present invention.
FIG. 5 is a perspective view of an outer peripheral side inner wall according to the first embodiment of the present invention.
FIG. 6 is an explanatory diagram of a blower according to a second embodiment of the present invention.
FIG. 7 is a graph showing the relationship between the air volume and noise and pressure.
[Explanation of symbols]
1 ... fan, 72 ... scroll casing,
73 ... outer peripheral side inner wall (movable wall), 74 ... winding mechanism.

Claims (7)

A centrifugal multi-blade fan (71) having a number of blades (71a) around a rotation axis, and blowing out air taken in from the axial direction of the rotation shaft outwardly;
The centrifugal multi-blade fan (71) is housed therein to form a spiral air flow path (72a) through which air blown from the centrifugal multi-blade fan (71) flows. A scroll casing (72) that changes in a logarithmic spiral according to the winding angle (θ),
The outer peripheral side inner wall (73) of the scroll casing (72) is displaced in accordance with the ventilation resistance in the air flow path (72a) so that a portion of the scroll casing (72) from the winding start portion to the winding end portion is displaced. A centrifugal blower characterized by changing a spread angle (n) of substantially the entire area. The outer peripheral side inner wall (73) has a band spring shape in which one end is fixed to the scroll casing (72) and the other end is fixed to a winding mechanism (74).
The centrifugal blower according to claim 1, wherein the divergence angle (n) is changed by adjusting a winding amount of the outer peripheral side inner wall (73) by the winding mechanism (74). The outer peripheral side inner wall (73) is composed of a plurality of movable walls (73d) arranged from the winding start side to the winding end side,
The centrifugal blower according to claim 1, wherein the divergent angle (n) is changed by displacing each of the plurality of movable walls (73d). The centrifugal blower according to any one of claims 1 to 3, wherein at least the outer peripheral side inner wall (73) is provided with a sound absorbing material that attenuates air vibration and reduces noise. An air conditioner for a vehicle, comprising: the centrifugal blower (7) according to any one of claims 1 to 4; and a blowing mode switching device (18 to 20) for switching a blowing mode of air blown into a room,
An air conditioner for a vehicle, wherein the ventilation resistance is determined based on an operation state of the blowout mode switching device (18 to 20). A centrifugal blower (7) according to any one of claims 1 to 4,
An air conditioner for a vehicle, wherein the ventilation resistance is determined based on the amount of air blown by the centrifugal blower (7). The centrifugal blower (7) according to any one of claims 1 to 4, wherein at least one of a blowing mode of air blown into a room and a blowing amount of the centrifugal blower (7) is blown into a room. An air conditioner for a vehicle of an automatic control system for controlling based on a target temperature of air (TAO),
An air conditioner for a vehicle, wherein the ventilation resistance is determined based on the target temperature (TAO).

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