JP2005163651A - Centrifugal blower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a centrifugal blower capable of reducing noise during rotary drive as much as possible and to improve blowing efficiency. <P>SOLUTION: A blade 58 constructing a blower fan 30 comprises an outside blade 60 having a draft angle set in the direction of an arrow B, and an inside blade 62 having a draft angle set in the direction of an arrow A. By setting the position of the primary surface without a step between the outside blade 60 and the inside blade 62 toward a plate 56, blown air passes through a part with the smallest step, and occurrence of noise can be suppressed and blowing efficiency can be improved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a centrifugal blower, and more particularly, a plurality of blades in a circumferential direction for rotationally driving by a rotational drive source to forcibly send fluid from one fluid inlet to another fluid outlet. The present invention relates to a centrifugal blower that is integrally molded.

  Centrifugal blowers in which a boss portion is formed on a rotational drive shaft of a rotational drive source and a large number of blades are integrally formed with a plate extending from the boss portion are widely used. Preferably, it has been used in a large number of air conditioners for automobiles. As described above, this type of centrifugal blower forms a blower fan by integrally forming a plurality of blades at predetermined intervals on the outer peripheral end of the plate. In this case, a set of molds is used to form the blower fan constituting the blower with a synthetic resin. Since the blade has a complicated shape, when the blower fan including the blade is taken out from the mold with respect to the set of molds, naturally, the direction of the mold and the parting line are problematic.

  Generally, the inside and outside of the blower fan, that is, the mold for forming the blade outer peripheral portion and the mold for forming the blade inner peripheral portion are opposite to each other. Eventually, because the two molds are used together, a level difference due to a different draft occurs at the position of the parting line on the blade surface. Due to the presence of this level difference, the blower assembled as a product is in rotation. It will generate noise.

  In order to avoid the generation of such noise as much as possible, the invention “multiblade fan” has already been proposed as Patent Document 1. In this prior art, a plurality of blades are provided on the outer peripheral side of the boss portion connected to the rotary drive shaft, and a mold dividing surface is provided in a boundary region that divides the radially inner portion and the radially outer portion of each blade. The draft angle in the vicinity of the parting plane is set to be smaller than the draft angle of other parts. This ensures ease of die removal after molding the blade, and forms a step-free shape at the part corresponding to the parting surface of the blade mold, greatly reducing noise during rotation. It is said that there is an effect that can be achieved.

  The prior art is shown in FIG. According to FIG. 4, a boss portion 6 is fixed to a shaft 4 extending from a motor 2 that is a rotational drive source, and a predetermined interval in the circumferential direction is provided on a bottom portion 10 of a plate 8 extending from the boss portion 6 in the outer peripheral direction. A plurality of blades 12 are integrally formed so as to be spaced apart from each other, and a holding ring 14 is fixed to the outer periphery of the top of the blade 12 to increase the strength of the blade 12.

  The blade 12 includes a radially outer side 12a and a radially inner side 12b. Between the radially outer side 12a and the radially inner side 12b, a mold dividing surface 16 formed between an outer mold (not shown) and an inner mold is formed. Have. This prior art attempts to avoid the generation of noise during driving by reducing the level difference of the mold dividing surface 16 as much as possible.

JP-A-5-231384

  However, according to this prior art, the mold split surface 16 is formed in the intermediate portion from the radially inner side 12b to the radially outer side 12a of the blade 12 as described above, and the inner mold removal direction A and the outer mold are formed. Since the die draft is reversed in the direction B of the die, it is inevitable that the blade 12 has a step at the portion corresponding to the die splitting surface 16, and the vicinity of the upper end portion of the blade 12 and the lower end of the blade 12 are inevitable. The same level of step must be generated near the site. For this reason, the flow of the fluid passing through the blade 12, for example, the air flow is disturbed due to the step generated in the blade 12 at the portion corresponding to the mold dividing surface 16. There is a disadvantage that noise during blowing increases and the blowing efficiency also decreases.

  An object of the present invention is to overcome the above-mentioned drawbacks and to provide a centrifugal blower capable of reducing the noise during rotational driving as much as possible and further improving the blowing efficiency.

In order to achieve the above object, the present invention provides:
A rotational drive source;
A blower fan having a plurality of blades fixed in a rotational drive shaft extending from the rotational drive source and held by a plate in a circumferential direction;
A fluid inlet for introducing fluid into the blower fan that rotates under the driving action of the rotational drive source;
A fluid outlet for guiding the introduced fluid in a predetermined direction;
The fluid introduction port disposed on one side of the rotational drive shaft and the fluid outlet port disposed on the other side of the rotational drive shaft and on the outer side of the blade are formed. A casing that surrounds the fan,
With
Each blade of the blower fan has a first half portion with a draft angle set toward one side of the rotary drive shaft, and a second half with a draft angle set toward the other side of the rotary drive shaft. And a position where the step between the first half and the second half is zero is set closer to the plate in the direction of the rotation drive shaft.

  The present invention focuses on the fact that the fluid flowing from the fluid inlet to the fluid outlet formed in the casing is sent closer to the plate, and the first half and the first half of the blade formed by die cutting in different directions. The position where the step between the two halves becomes zero is set so as to be closer to the plate. As a result, the central portion of the fluid flow is located at a position corresponding to the zero step portion, so that the noise generated by the urging of the rotational drive source is remarkably reduced and the air blowing efficiency is increased.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In this embodiment, an air conditioning system incorporated in an automobile will be described as an example.

  The air conditioning system 20 shown in FIG. 1 has an outside air inlet 22 for taking in air outside the passenger compartment, and the air taken in by the blower 24 arranged in the vicinity of the outside air inlet 22 is sent to the evaporator 26. The Note that a damper 28 for switching the air blowing path is disposed at the outside air inlet 22.

  A damper 36 is provided on the downstream side of the evaporator 26. The damper 36 sends air to the heater core 38 on one side and feeds air without passing through the heater core 38 on the other side. The air supplied via the heater core 38 or the fluid flow path formed by the damper 36 is supplied to the defroster outlet 40, the chest outlet 42, or the foot outlet 46. . The defroster outlet 40, the chest outlet 42, and the foot outlet 46 are provided with dampers 44 and 48 for selecting the outlet.

  Next, the blower 24 will be described in detail.

  In FIG. 2, the blower 24 includes a motor 29 as a rotational drive source, and a blower fan 30 is fixed to the rotational drive shaft 50 of the motor 29. The blower fan 30 is surrounded by a casing 32. The casing 32 has an air inlet 33 for introducing air from the outside air inlet 22 and an air outlet 34 for leading the introduced air to the evaporator 26.

  The blower fan 30 includes a boss portion 54, and the boss portion 54 is screwed to the rotation drive shaft 50. As can be easily understood from FIG. 2, the blower fan 30 includes a plate 56 whose section is curved and bulges at a central portion, and lower end portions of a plurality of blades 58 at a portion descending from the middle of the plate 56. Will stand up together. A holding portion 70 is formed at the upper end portion of each blade 58.

  The blade 58 includes an outer blade 60 (first half) and an inner blade 62 (second half), and the outer blade 60 is formed by an outer mold (not shown). , Formed by an inner mold (not shown). In this case, the inner blade 62 is punched in the direction of arrow A, and the outer blade 60 is punched in the direction of arrow B.

  In this blade 58, the draft of the outer blade 60 and the inner blade 62 is shown in FIG. Note that the configuration of the blade 58 shown in FIG. 3 is merely for easy understanding, and needless to say, it is different from the actual shape.

  2 and 3, the outer blade 60 is formed such that its thickness is smaller on the plate 56 side (see the width D4) than on the air inlet 33 side (see the width D3). Further, the inner blade 62 is formed so as to increase in thickness from the width D1 to the width D2 from the air inlet 33 side to the plate 56 side. In FIG. 3, reference numeral D <b> 0 indicates a reference plane in which the thicknesses of the outer blade 60 and the inner blade 62 are substantially the same.

  The intersecting lines D0 ′ and D0 ″ between the reference plane D0 and the surface of the blade 58 do not need to be straight lines and need not be parallel to each other. That is, the intersecting lines D0 ′ and D0 ″ are outside. It is only necessary that the connection portion between the blade 60 and the inner blade 62 be continuous smoothly, and therefore, the intersecting lines D0 ′ and D0 ″ may be curved. Similarly, the die cutting slope surfaces of the outer blade 60 and the inner blade 62 may be configured to bend in the vertical direction instead of in a plane.

  The position of the reference plane D0 is set closer to the plate 56 with respect to the length H from the air inlet 33 side to the plate 56 side. That is, in FIG. 3, h1> h2. In this case, the length H is, for example, 70 mm, h1 is 40 mm, and h2 is 30 mm.

  The blower 24 of the present embodiment is basically configured as described above, and the operation thereof will be described next.

  By driving the motor 29, the rotational drive shaft 50 is rotationally driven, and the blower fan 30 is rotated with this. The air sent from the outside air inlet 22 forcibly moves from the air inlet 33 formed in the casing 32 to the blade 58 side of the blower fan 30.

  As shown in FIG. 2, the air in this case is forcibly led down along the surface of the plate 56 as indicated by a thick arrow. The descending air flows centering on a reference plane D0 (see FIG. 3) without a step of the blade 58 set in a portion near the plate 56. Therefore, since the step between the outer blade 60 and the inner blade 62 is zero at the reference plane D0, the strong air flow does not cause any noise here, and is close to the reference plane D0 ( In FIG. 3, the step between the outer blade 60 and the inner blade 62 is extremely small on the upper and lower sides of the reference plane D0, so that no problematic noise is generated.

  As a result, the air supplied to the blower 24 is led out to the air outlet 34 in a very calm state. In addition, since the resistance due to the step between the outer blade 60 and the inner blade 62 is small, an effect of improving the blowing efficiency can be obtained.

It is a block diagram of the air conditioning system of the motor vehicle incorporating the air blower of this embodiment. It is a schematic longitudinal cross-sectional explanatory drawing of the air blower of this embodiment. FIG. 3 is a perspective explanatory view simply showing a draft angle of the blade shown in FIG. 2. It is a partial cross section side view of the multiblade ventilation fan which concerns on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 ... Air conditioning system 24 ... Blower 29 ... Motor 30 ... Blower fan 33 ... Air inlet 34 ... Air outlet 56 ... Plate 58 ... Blade 60 ... Outer blade 62 ... Inner blade

Claims (1)

A rotational drive source;
A blower fan having a plurality of blades fixed in a rotational drive shaft extending from the rotational drive source and held by a plate in a circumferential direction;
A fluid inlet for introducing fluid into the blower fan that rotates under the driving action of the rotational drive source;
A fluid outlet for guiding the introduced fluid in a predetermined direction;
The fluid introduction port disposed on one side of the rotational drive shaft and the fluid outlet port disposed on the other side of the rotational drive shaft and on the outer side of the blade are formed. A casing that surrounds the fan,
With
Each blade of the blower fan has a first half portion with a draft angle set toward one side of the rotary drive shaft, and a second half with a draft angle set toward the other side of the rotary drive shaft. A centrifugal blower comprising: a half portion, wherein a position where a step between the first half portion and the second half portion is zero is set closer to the plate in the direction of the rotation drive shaft.

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