JP2017160848A - Centrifugal blower - Google Patents

Abstract

In a centrifugal blower, noise and vibration are reduced when a drive source is operated. A casing 18 constituting a centrifugal blower 10 has a logarithmic spiral scroll wall 22 formed on the outer peripheral side of a fan 14, and air is interposed between the scroll wall 22 and the fan 14. And a scroll inner peripheral wall 26 formed on the inner peripheral side, and a scroll outer peripheral wall 28 connected to the winding end 26b of the scroll inner peripheral wall 26. Thereby, the length of the scroll wall 22 and the discharge passage 16 can be formed longer than that of the conventional centrifugal blower. [Selection] Figure 1

Description

  The present invention relates to a centrifugal blower, and more particularly to a centrifugal blower used in an air conditioner mounted on a vehicle.

  2. Description of the Related Art Conventionally, a vehicular air conditioner employs a centrifugal blower that includes a fan that takes in vehicle interior air or vehicle exterior air, a motor that rotates the fan, and a casing that surrounds the fan.

  In this centrifugal blower, for example, as disclosed in Patent Document 1, a blower fan is housed in a casing surrounded by a scroll wall, and a spiral passage is formed along the outer peripheral side of the blower fan. The Then, when the motor is driven, the blower fan rotates and air is taken into the inside from the opening of the bell mouth in the casing, and then circulates along the spiral passage.

JP 2001-277834 A

  In recent years, the centrifugal blower as described above has been required to be small and light, and this tends to make the scroll wall thinner, and the operating sound of the blower fan is likely to leak to the outside, leading to an increase in noise and vibration. There is a problem.

  In addition, even when reducing the size and weight, the required air blowing performance does not change, so the output of the blower is increased to increase the flow velocity, but this also increases the operating noise of the blower and reduces noise and vibration. Will be invited.

  The present invention has been made in consideration of the above-described problems, and an object thereof is to provide a centrifugal blower capable of reducing noise and vibration during operation of a drive source.

To achieve the above object, the present invention includes a casing having a spiral passage therein, a fan rotatably accommodated in the casing, and a drive source for rotating the fan. In a centrifugal blower equipped with a scroll wall whose radius changes in a logarithmic spiral toward the discharge port on the outer peripheral side,
The scroll wall includes an outer peripheral wall constituting the outer wall of the casing,
An inner peripheral wall formed on the inner side of the outer peripheral wall, the end of which is connected to the start of winding of the outer peripheral wall;
Consists of
An inner peripheral wall and an outer peripheral wall are formed continuously.

  According to the present invention, in the casing constituting the centrifugal blower, the scroll wall whose radius changes in a logarithmic spiral toward the discharge port is formed on the outer peripheral wall constituting the outer wall of the casing and on the inner side of the outer peripheral wall, The winding end is composed of an inner peripheral wall connected to the winding start of the outer peripheral wall.

  Therefore, compared with the conventional centrifugal blower, the passage length extending from the fan to the discharge port can be formed longer, and the change in the cross-sectional area of the passage with respect to the winding angle from the winding start to the winding end of the scroll wall can be achieved. Can be small. As a result, the flow of air flowing along the passage can be stabilized, so that noise and vibration generated in the vicinity of the fan due to the flow disturbance can be reduced. Further, since the scroll wall has a double structure from the outer peripheral wall and the inner peripheral wall, the radiated sound radiated with the rotation of the fan can be suitably blocked and attenuated, and the noise can be further reduced. .

  According to the present invention, the following effects can be obtained.

  That is, in the casing constituting the centrifugal blower, the scroll wall whose radius changes in a logarithmic spiral toward the discharge port is formed on the outer peripheral wall constituting the outer wall of the casing and the inner side of the outer peripheral wall, and the end of the winding is formed. Compared with the conventional centrifugal blower, the passage length extending from the fan to the discharge port can be made longer by configuring the inner peripheral wall connected to the winding start of the outer peripheral wall, and the scroll wall The change in the cross-sectional area of the passage with respect to the winding angle from the start of winding to the end of winding can be reduced. As a result, the flow of air flowing along the passage can be stabilized, and noise and vibration generated in the vicinity of the fan due to the flow disturbance can be reduced. Further, since the scroll wall has a double structure from the outer peripheral wall and the inner peripheral wall, the radiated sound radiated with the rotation of the fan can be cut off, and the noise can be further reduced.

FIG. 1A is an overall cross-sectional view of a centrifugal blower according to an embodiment of the present invention, and FIG. 1B is a characteristic diagram showing a relationship between a radius of a scroll wall and a winding angle.

  DESCRIPTION OF EMBODIMENTS Preferred embodiments of a centrifugal blower according to the present invention will be given and described in detail below with reference to the accompanying drawings. In FIG. 1, reference numeral 10 indicates a centrifugal blower according to an embodiment of the present invention.

  As shown in FIG. 1A, the centrifugal blower 10 includes a motor (drive source) 12 that is rotationally driven under an energization action, a fan 14 that is rotationally driven under the drive action of the motor 12, and an outer periphery of the fan 14. And a casing 18 having a spiral discharge passage 16 through which air flows.

  The motor 12 is provided, for example, at a substantially lower center portion of the casing 18, and is fixed so that the rotating shaft 20 protrudes into the casing 18. The rotating shaft 20 is connected to the central portion of the fan 14, and the fan 14 rotates integrally under the drive action of the motor 12.

  The casing 18 includes, for example, a scroll wall 22 formed so as to surround the outer peripheral side of the fan 14, and a linear portion 24 extending in a tangential direction from the winding end of the scroll wall 22.

  The scroll wall 22 has a scroll inner peripheral wall (inner peripheral wall) 26 formed inside, and a scroll outer peripheral wall (outer peripheral wall) 28 formed outside the scroll inner peripheral wall 26. In other words, the scroll outer peripheral wall 28 constitutes the outer wall of the casing 18, and the scroll inner peripheral wall 26 is formed therein.

  The scroll inner peripheral wall 26 has a winding start 26 a closest to the outer peripheral side of the fan 14 and is formed in a logarithmic spiral shape from the winding start 26 a to the winding end 26 b in a counterclockwise direction. It is connected to the winding start 28 a of the outer peripheral wall 28.

  Similarly to the scroll inner peripheral wall 26, the scroll outer peripheral wall 28 is formed in a counterclockwise logarithmic spiral shape, and its winding start 28a is connected to the winding end 26b of the scroll inner peripheral wall 26 so as to be continuous. The peripheral wall 26 is formed so as to cover the outer peripheral side from the winding start 26a to the winding end 26b.

  That is, the scroll wall 22 has a double structure in which the scroll inner peripheral wall 26 is provided inside the scroll outer peripheral wall 28.

  The winding angle θ of the scroll wall 22 composed of the scroll inner peripheral wall 26 and the scroll outer peripheral wall 28 (from the winding start 26a of the scroll inner peripheral wall 26 to the winding end 28b of the scroll outer peripheral wall 28) is the same as that of a conventional centrifugal blower. In comparison, the size is increased by the scroll inner peripheral wall 26, for example, about 1.5 to 2 times.

  On the other hand, a discharge passage 16 through which air is discharged is formed between the scroll inner peripheral wall 26 and the scroll outer peripheral wall 28, and the passage cross-sectional area of the scroll inner peripheral wall 26 scrolls from the winding start 26 a of the scroll inner peripheral wall 26. The outer peripheral wall 28 is formed so as to continuously increase toward the winding end 28b.

  The discharge passage 16 communicates with the discharge port 30 opened at the end of the linear portion 24, and the air flowing inside is discharged from the discharge port 30 to the outside.

  The centrifugal blower 10 according to the embodiment of the present invention is basically configured as described above. Next, its operation and effects will be described.

  First, the motor 12 is rotationally driven based on a control signal from a controller (not shown), and the fan 14 rotates integrally, whereby air is sucked into the fan 14 from an inlet (not shown) opened in the casing 18. .

  Then, after the air taken in the fan 14 is sent to the discharge passage 16 on the outer peripheral side and flows counterclockwise along the inner side of the scroll inner peripheral wall 26 in the discharge passage 16 and reaches the winding end 26b. The gas flows along the discharge passage 16 between the scroll outer peripheral wall 28 and the scroll inner peripheral wall 26, and is discharged to the outside from the discharge port 30 opened in the linear portion 24.

  As described above, in the present embodiment, in the casing 18 constituting the centrifugal blower 10, the scroll inner peripheral wall 26 is provided between the scroll outer peripheral wall 28 and the fan 14, and the winding start 28a of the scroll outer peripheral wall 28 is provided. By connecting, the winding angle θ of the scroll wall 22 is set larger than that of the conventional centrifugal blower.

  Thereby, compared with the conventional centrifugal blower, the discharge passage 16 extending from the fan 14 of the centrifugal blower 10 to the discharge port 30 can be formed longer, and as is understood from FIG. The radius L1 of the scroll wall 22 relative to the winding angle θ of the wall 22 (distance from the rotary shaft 20 to the scroll wall 22) change L1 (see the solid line) is compared with the radius change L2 of the conventional centrifugal blower (see the broken line). Be gentle.

  Therefore, when compared with a change in radius of the same scroll wall 22, the change in the cross-sectional area of the discharge passage 16 can be made smaller than that of a conventional centrifugal blower, and the flow of air flowing along the discharge passage 16 can be reduced. It can be stabilized. As a result, the disturbance of the air flow through the discharge passage 16 is suppressed, and accordingly, noise and vibration generated near the fan 14 due to the disturbance can be reduced.

  Moreover, since the scroll wall 22 has a double structure from the scroll outer peripheral wall 28 and the scroll inner peripheral wall 26, the sound radiated from the fan 14 when the centrifugal blower 10 is operated is preferably cut off and attenuated. Thus, noise can be further reduced.

  In addition, the centrifugal blower according to the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Centrifugal blower 12 ... Motor 14 ... Fan 16 ... Discharge passage 18 ... Casing 20 ... Rotating shaft 22 ... Scroll wall 24 ... Linear part 26 ... Scroll inner peripheral wall 26a, 28a ... Winding start 26b, 28b ... Winding end 28 ... Scroll Outer wall

Claims (1)

A casing having a spiral passage, a fan rotatably accommodated in the casing, and a drive source for rotating the fan, and a logarithmic spiral toward the discharge port on the outer peripheral side of the passage In a centrifugal blower having a scroll wall whose radius changes in a shape,
The scroll wall includes an outer peripheral wall constituting an outer wall of the casing;
An inner peripheral wall formed inside the outer peripheral wall, the end of which is connected to the start of winding of the outer peripheral wall;
Consists of
The centrifugal blower characterized in that the inner peripheral wall and the outer peripheral wall are formed continuously.

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