JP2000025442A - Blower and air conditioner for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce noise caused by the non-uniformity of wind velocity distribution in a blower having cooling fins for cooling heating elements such as a power transistor in its scroll casing. SOLUTION: Deflection guides 75a, 75b for deflecting the air passed through cooling fins 74 in the specified direction are provided in the air flow-downstream of the cooling fins 74, and the deflecting direction of the deflection guides 75a, 75b are changed in response to the pressure loss in a ventilation system. Thus, since the air deflected by the cooling fins 74 can be deflected in a specified direction, the wind velocity distribution of the air blown-up from a blower 7 can be made nearly uniform independently of the pressure loss in the ventilation system by reducing the wind velocity in a portion which corresponds to the downstream of the cooling fins 74, and thus noise caused by the ununiformity of the wind velocity distribution can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blower using a centrifugal fan, and is effective when applied to a vehicle air conditioner.

[0002]

2. Description of the Related Art Control of electric power supplied to an electric motor of a blower applied to a vehicle air conditioner is performed by a semiconductor such as a power transistor, and the cooling of the power transistor is usually performed in a scroll casing of the blower. This is done with the cooling fins arranged.

[0003]

SUMMARY OF THE INVENTION By the way, the inventor
In order to cope with the amount of heat generated by the power transistor, which increases with the increase in the blowing capacity, the cooling fins are increased and the number of fins is increased.
Low frequency noise below Hz has increased. Therefore,
The inventor has conducted research on the cause of noise generation and found the following.

That is, FIG. 5 (a) is a wind speed distribution diagram on the downstream side of the evaporator when the cooling fins are eliminated, and FIG. 4 (a) is a wind speed distribution on the downstream side of the evaporator when the cooling fins are provided. FIG. Then, as is clear from the two wind speed distribution diagrams, the wind speed of the portion corresponding to the downstream side of the cooling fin is larger than that of the other portions, and the wind speed distribution becomes uneven. The non-uniformity of the wind speed distribution causes turbulence in the air flow on the downstream side of the blower, so that low-frequency noise is generated.

[0005] The reason why the wind speed of the portion corresponding to the downstream side of the cooling fin becomes larger than that of the other portions is that the plate-like cooling fin forcibly removes the air passing through the cooling fin.
This is because the light is turned in a predetermined direction. In view of the above, it is an object of the present invention to reduce noise caused by non-uniform wind speed distribution in a blower having cooling fins for cooling a heating element such as a power transistor in a scroll casing.

[0006]

The present invention uses the following technical means to achieve the above object. Claim 1
According to the third aspect of the present invention, the turning guides (75a, 75b) are disposed downstream of the cooling fins (74) in the air flow direction and turn the air passing through the cooling fins (74) in a predetermined direction.
It is characterized by having.

Thus, the air turned by the cooling fins (74) can be turned in a predetermined direction by the turning guides (75a, 75b). Therefore, the wind speed at the portion corresponding to the downstream side of the cooling fin (74) can be reduced, and the wind speed distribution of the air blown out from the scroll casing (72) can be made uniform. Can be reduced.

According to the second aspect of the present invention, the turning guides (75a, 75b) are connected to the scroll casing (72).
The predetermined direction is changed according to the pressure loss of the ventilation system connected to the downstream side of the air flow. Thus, even if the pressure loss of the ventilation system changes, noise can be reliably reduced, and a reduction in the amount of blown air can be prevented.

Incidentally, the reference numerals in parentheses of the above means are examples showing the correspondence with specific means described in the embodiments described later.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment)
FIG. 1 is a schematic diagram showing a ventilation system of a vehicle air conditioner 1 in which a blower according to the present invention is applied to an air conditioner 1 for a vehicle. Reference numeral 2 denotes an air-conditioning casing 2 which forms a passage for air to be blown into the vehicle interior. At an air upstream side of the air-conditioning casing 2, an internal air intake 3 for inhaling vehicle interior air and an external air intake 4 for inhaling outside air are provided. A suction port switching door 5 that is formed and selectively opens and closes the suction ports 3 and 4 is provided.

A blower 7 according to the present embodiment is provided at a downstream side of the inlet switching door 5, and the air sucked from both the inlets 3 and 4 by the blower 7 is supplied to the blower 7.
The air is blown toward the openings 14, 15, and 17 described below. And, on the downstream side of the air flow of the blower 7, the blower 7
An evaporator (cooling means) 9 for cooling the air blown from is provided, and all the air blown by the blower 7 passes through the evaporator 9. A heater core (heating means) 10 for heating the air is provided downstream of the evaporator 9 in the air flow, and the heater core 10 heats the air using the cooling water of the engine 11 as a heat source. In addition, the drawing of the blower shown in FIG. 1 is a schematic diagram, and details will be described later.

A bypass passage 12 is formed in the air-conditioning casing 2 so as to bypass the heater core 10 and guide air to the downstream side (air mixing chamber) of the heater core 10. An air mix door (air volume ratio adjusting means) 13 for adjusting the air volume ratio between the air volume passing through the heater core 10 and the air volume passing through the bypass passage 12 is provided.

A face opening 1 (not shown) communicating with a face opening (not shown) for blowing out conditioned air to the upper body of the occupant in the passenger compartment is provided at the most downstream side of the air conditioning casing 2.
4, a foot opening 15 communicating with a foot opening (not shown) for blowing air to the feet of the occupant in the passenger compartment, and a defroster outlet (shown in FIG. 4) for blowing air toward the inner surface of the windshield 16. ) Is formed with a defroster opening 17 communicating with the froster.

The air outlet mode switching doors 1 are located at the upstream side of the openings 14, 15 and 17, respectively.
8, 19, and 20 are provided, and by operating these blow-out mode switching doors, the windshield 1 is switched.
6, a defroster mode that blows air-conditioned air toward the upper body of the occupant, a face mode that blows air-conditioned air toward the feet of the occupant, and air conditioning through a face outlet and a defroster outlet. Switch between bi-level mode for blowing air.

In an actual vehicle air conditioner, since the foot opening 15 and the defroster opening 17 are smaller than the face opening 14, the foot mode and the defroster mode have a lower airflow resistance than the face mode. (Pressure loss) has increased. Next, the blower 7 will be described with reference to FIG.

FIG. 2A is a sectional view of the blower 7, and FIG.
Reference numeral 1 denotes a centrifugal multi-blade fan (hereinafter, abbreviated as a fan) that blows out air taken in from a rotation axis direction to a radially outer side. 72 accommodates the fan 71 and
This is a spiral scroll casing that collects the air blown out from the scroll casing. A power transistor (heating element) 73 that controls electric power supplied to an electric motor (not shown) that rotationally drives the fan 71 is provided downstream of the scroll end portion 72 a of the scroll casing 72 in the air flow.
A plurality of plate-shaped cooling fins 74 are provided to cool the fins.

The flat portion of the cooling fin 74 is provided so as to extend in parallel with the tangential direction from the winding end portion 72a of the scroll casing 72. Two turning guides 75a and 75b for turning air passing through the cooling fins 74 in a predetermined direction are disposed downstream of the cooling fins 74 in the scroll casing 72.

The turning guides 75a and 75b change their turning directions in accordance with the pressure loss (ventilation resistance) on the downstream side of the air flow from the blower 7 (scroll casing 72) (from the blower 7 to each outlet). It is configured to be. Specifically, in the present embodiment, in the defroster mode and the foot mode in which the pressure loss is large, the turning guides 75a and 75b are located at positions indicated by solid lines in FIG. ), And in the face mode and the bi-level mode in which the pressure loss is smaller than those in the defroster mode and the foot mode, the position indicated by the two-dot line in FIG.
This position is called position 2. ).

Next, the features of this embodiment will be described. In the present embodiment, since the turning guides 75a and 75b are provided on the downstream side of the cooling fin 74 in the air flow, the cooling fin 7
4, the air diverted in the tangential direction from the winding end portion 72a can be diverted by the diverting guides 75a and 75b in a direction in which the air flows (naturally) when the cooling fin 74 is not provided. .

Therefore, the scroll casing 72
FIG. 3 shows the wind speed distribution of the air blown out from the (blower 7).
As shown in (a), the wind speed of the portion corresponding to the downstream side of the cooling fin 74 is reduced, and the turning guides 75a, 75b
It is possible to make the wind speed distribution more uniform than the wind speed distribution (see FIG. 4A) of a blower that does not have (see FIG. 4A). Therefore, as shown in FIG. 6, noise (low-frequency noise of about 200 Hz or less) caused by uneven wind speed distribution can be reduced.

By the way, in the present embodiment, compared with the prior art,
The noise was reduced by about 4 to 8 dBA, and the air volume was almost unchanged. In the present embodiment, the air passing through the cooling fins 74 is turned in a direction in which the air flows (naturally) when the cooling fins 74 are not provided, so that the wind speed distribution of the air blown out from the scroll casing 72 is changed. This is because the wind speed distribution of the air blown out from the scroll casing 72 (the blower 7) when the cooling fin 74 is not provided is substantially uniform as shown in FIG. is there.

Therefore, if the wind speed distribution of the air blown from the scroll casing 72 when the cooling fins 74 are not provided is not uniform, the turning guide 75
The turning directions of a and 75b are not changed to the direction in which the air flows when the cooling fin 74 is not provided, but the wind speed distribution of the air blown out from the scroll casing 72 (the blower 7) becomes uniform. It is necessary to turn in the direction.

By the way, the wind speed distribution of the air blown out of the scroll casing 72 depends on the pressure loss of the ventilation system connected to the scroll casing 72 on the downstream side of the air flow.
That is, it changes depending on the pressure loss from the evaporator 9 to each outlet. For this reason, in a state where the pressure loss is relatively large, for example, in the defroster mode and the foot mode, the turning guides 75a and 75 are provided so that the wind speed distribution of the air blown out from the scroll casing 72 becomes substantially uniform.
Even if b is set, in a state in which the pressure loss is relatively small, such as in the face mode and the bi-level mode, the turning guides 75a and 75b act as resistances to reduce the amount of blown air and rather increase noise. there is a possibility.

On the other hand, in the present embodiment, the turning guides 75a and 75b respond to the pressure loss (ventilation resistance) downstream of the air flow from the blower 7 (scroll casing 72) (from the blower 7 to each outlet). Therefore, even if the blowing mode is changed and the pressure loss of the ventilation system is changed, the wind speed distribution of the air blown out from the scroll casing 72 can be made uniform. . Therefore, even if the pressure loss of the ventilation system changes, noise can be reliably reduced, and a decrease in the amount of air blow can be prevented.

In the above-described embodiment, the turning guides 75a and 75b are moved in conjunction with the blowing mode, but may be linked with the opening of the air mix door 13.
In this case, the bypass passage 12 (air mix door 13) is fully closed and set to the position 1 during the maximum heating operation in which the pressure loss of the ventilation system becomes large.
It is desirable that the (air mixing door 13) be fully opened and set to position 2 during the maximum cooling operation in which the pressure loss of the ventilation system is reduced.

The turning guides 75a, 75b are linked with both the opening degree of the air mix door 13 and the blowing mode.
May be movable. In this case, it is desirable to set the position to 1 in the foot mode or the defroster mode and the maximum heating operation, and to set the position to 2 in other than the foot mode or the defroster mode and the maximum heating operation.

In the above-described embodiment, the turning guide 7
Although 5a and 75b are moved separately in two positions, the turning guides 75a and 75b may be moved three or more or continuously according to the pressure loss of the ventilation system.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a vehicle air conditioner.

2A is a cross-sectional view of a blower, FIG. 2B is an enlarged view of a turning guide portion, and FIG. 2C is a view of FIG.

FIG. 3A is a wind speed distribution diagram, and FIG. 3B is a schematic diagram of a blower according to the embodiment.

FIG. 4A is a wind speed distribution diagram, and FIG. 4B is a schematic diagram of a blower according to a conventional technique.

5 (a) is a wind speed distribution diagram, and FIG. 5 (b) is a schematic diagram of a blower without cooling fins.

FIG. 6 is a graph showing a noise level for each frequency.

[Explanation of symbols]

7: Centrifugal blower, 71: Centrifugal multi-blade fan, 72: Scroll casing, 73: Power transistor (heating element), 74: Cooling fin, 75a, 75b: Turning guide.

Claims (3)

[Claims] 1. A centrifugal fan (71) for blowing air sucked in from a rotation axis direction to a radially outer side, and a spiral for containing the centrifugal fan (71) and collecting the air blown from the centrifugal fan (71). And a plate-shaped cooling fin (74) disposed in the scroll casing (72) and cooling the heating element (73) by air flowing through the scroll casing (72).
Disposed downstream of the cooling fins (74) in the air flow direction;
A turning guide (75a, 75b) for turning the air passing through the cooling fin (74) in a predetermined direction. 2. The turning guide (75a, 75b)
The blower according to claim 1, wherein the predetermined direction is changed according to a pressure loss of a ventilation system connected to an air flow downstream of the scroll casing (72). 3. The air-conditioning casing (2) forming an air passage for blowing air into a vehicle interior, and the air-conditioning casing (2) is disposed upstream of the air flow and blows air. A blower (7); cooling means (9) disposed in the air-conditioning casing (2) for cooling air blown from the blower (7).
And the cooling means (9) in the air conditioning casing (2).
A heating means (10) disposed further downstream of the air flow for heating the air; and a heating means (10) formed in the air-conditioning casing (2) and bypassing the heating means (10) to heat the air. A) a bypass passage leading to the downstream side of the air flow, and an air flow rate adjusting means for adjusting a ratio of an air flow passing through the bypass passage to an air flow passing through the heating means. A mode provided at the most downstream side of the airflow of the air conditioning casing (2), for blowing air toward the vehicle windshield (16); a mode for blowing air toward the upper body of the occupant; Mode switching means (14, 15, 17-2) for switching between a mode for blowing air and
0).