JP2014190231A - Centrifugal blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce blowing noise and improve blowing efficiency in a centrifugal blower installed in a vehicle air conditioner.SOLUTION: A centrifugal blower includes a flexible porous body 5 provided on a tongue portion 3d, extending in an axial direction of a fan 2, and thicker as closer to an opposite side to an inlet port 3b.

Description

  The present invention relates to a centrifugal blower.

  A vehicle air conditioner generally includes a centrifugal blower for blowing air and a heat unit that uses the blown air as conditioned air. A centrifugal blower mounted on such a vehicle air conditioner generally includes a fan having a plurality of blades and a scroll casing that houses the fan.

  The scroll casing includes a discharge passage formed in a spiral shape so as to surround the fan in a rotational direction, a suction port formed at a position spaced axially with respect to the fan, and a tangential direction of the discharge passage in the fan A discharge port that discharges air flowing through the discharge passage to the outside, and a tongue that is positioned between the discharge port and the fan and protrudes toward the inside of the discharge passage. I have.

Japanese Patent Laid-Open No. 05-195995

  However, at the tongue of the centrifugal fan, the air flow is separated from the inner wall surface of the casing, thereby causing periodic pressure fluctuations. For this reason, blowing noise is generated and the blowing efficiency is reduced. Furthermore, the centrifugal blower has a structure in which air is taken into the casing from the axial direction of the fan, and since air is biased to the side opposite to the suction port, the pressure on the side opposite to the suction port is higher than that on the suction port side. A secondary flow is generated by this pressure difference, and the blowing efficiency is lowered.

  The present invention has been made in view of the above-described problems, and an object thereof is to reduce blowing noise and improve blowing efficiency in a centrifugal blower installed in a vehicle air conditioner.

  In order to achieve the above object, in the present invention, a centrifugal blower including a fan that blows air sucked in from an axial direction outward in a radial direction and a scroll casing that houses the fan, wherein the scroll casing includes the above-described scroll casing, A discharge passage formed in a spiral shape so as to surround the fan in the rotational direction, a suction port formed at a position axially separated from the fan, and a tangential direction of the discharge passage, A discharge port that opens toward the rear side in the rotation direction and discharges the air flowing through the discharge passage to the outside, and a tongue that is positioned between the discharge port and the fan and protrudes toward the inside of the discharge passage And a flexible porous body that is provided on the tongue and extends in the axial direction of the fan and becomes thicker toward the opposite side of the suction port. The adopted.

  According to the present invention, a flexible porous body that extends in the axial direction of the fan with respect to the tongue and becomes thicker toward the opposite side of the suction port is provided. By providing such a porous body on the tongue, it is possible to reduce friction of blowing air in the vicinity of the tongue, and to suppress separation of the air flow at the tongue. For this reason, it is possible to prevent the occurrence of periodic pressure fluctuations, reduce the blowing noise, and improve the blowing efficiency.

  Further, according to the present invention, the flexible porous body becomes thicker toward the side opposite to the suction port. For this reason, when the pressure on the side opposite to the suction port in the scroll casing is increased, the pressing force against the thick portion of the porous body is increased and the thick portion is crushed. As a result, the internal space on the side opposite to the suction port of the scroll casing becomes wider as the porous body is crushed, and the pressure on the side opposite to the suction port is reduced. For this reason, it is prevented that the pressure in the scroll casing becomes uniform or close to uniform, and a secondary flow is generated. Therefore, according to this invention, the fall of the ventilation efficiency by the secondary flow generated by the pressure difference inside a scroll casing can be prevented, and ventilation efficiency can be improved.

  As described above, according to the present invention, in the centrifugal blower installed in the vehicle air conditioner, it is possible to reduce the blowing noise and improve the blowing efficiency.

(A) is a perspective view which shows schematic structure of the centrifugal blower in one Embodiment of this invention, (b) is the sectional view on the AA line of (a) in the state where the fan is not rotationally driven, (C) has shown the sectional view on the AA line of (a) in the state in which the fan is rotationally driven.

  Hereinafter, an embodiment of a centrifugal blower according to the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size.

  (A) of FIG. 1 is a perspective view which shows schematic structure of the centrifugal blower 1 of this embodiment. As shown in this figure, the centrifugal blower 1 of the present embodiment includes a fan 2, a scroll casing 3, a motor 4, and a porous body 5.

  The fan 2 is a component in which a large number of blades 2b are arranged in a ring around the shaft portion 2a. The fan 2 is rotationally driven to blow air sucked from the upper side in the axial direction outward in the radial direction.

  The scroll casing 3 is a component that houses the fan 2 and in which an air flow path is formed. The scroll casing 3 has a discharge passage 3a, a suction port 3b, a discharge port 3c, and a tongue 3d.

  The discharge passage 3a is a portion formed in a spiral shape so as to surround the fan 2 in the rotation direction. The suction port 3 b is formed at a position separated from the fan 2 in the axial direction, and is an opening for taking outside air into the scroll casing 3. The discharge port 3 c is opened toward the rear side in the rotation direction of the fan 2 in the tangential direction of the discharge passage 3 a and discharges the air flowing through the discharge passage 3 a to the outside of the scroll casing 3. The tongue 3d is located between the discharge port 3c and the fan 2 and protrudes toward the inside of the discharge passage 3a.

  The motor 4 is connected to the shaft portion 2 a of the fan 2, generates rotational power based on an external command, and transmits this power to the fan 2 to rotate the fan 2. The motor 4 is installed on the opposite side of the inlet 3 b of the scroll casing 3.

  The porous body 5 is affixed to the discharge port 3c side of the tongue 3d, extends in the axial direction of the fan 2, and as shown in FIG. 1 (a), moves toward the side opposite to the suction port 3b. It has a shape that becomes thick. The porous body 5 is made of a flexible material having resilience, and is made of, for example, sponge urethane foam.

  1B and 1C are cross-sectional views taken along line AA in FIG. 1A, FIG. 1B shows a state where the fan 2 is not driven to rotate, and FIG. The state where the fan 2 is rotationally driven by the motor 4 is shown.

  As shown in FIG. 1B, when the fan 2 is not driven to rotate, the porous body 5 has an initial shape. That is, the porous body 5 has a thick shape on the side opposite to the inlet 3b of the scroll casing 3 when the fan 2 is not driven to rotate.

  When the fan 2 is rotationally driven by the motor 4, the air X is taken into the scroll casing 3 from the suction port 3b of the scroll casing 3, blown radially outward by the fan 2, and finally discharged from the discharge port 3c. Is done.

  When the fan 2 is rotationally driven by the motor 4, the air X flowing into the scroll casing 3 is biased to the opposite side to the suction port 3b, and the pressure on the suction port 3b side in the scroll casing 3 is higher than that on the suction port 3b side. Get higher. Thereby, the pressing force applied to the thick portion of the porous body 5 increases, and the thick portion of the porous body 5 is crushed as shown in FIG. For this reason, the internal space on the opposite side to the suction port 3b of the scroll casing 3 expands, and the pressure in the internal space on the opposite side to the suction port 3b decreases. As a result, the pressure in the scroll casing 3 is made uniform.

  According to the centrifugal blower 1 of the present embodiment as described above, the flexibility that extends in the axial direction of the fan 2 with respect to the tongue 3d and becomes thicker toward the opposite side to the suction port 3b. The porous body 5 is provided. By providing such a porous body 5 on the tongue portion 3d, the friction of air blowing in the vicinity of the tongue portion 3d is reduced, and the air flow can be prevented from peeling off at the tongue portion 3d. For this reason, it is possible to prevent the occurrence of periodic pressure fluctuations, reduce the blowing noise, and improve the blowing efficiency.

  Moreover, according to the centrifugal blower 1 of this embodiment, it becomes thick as the flexible porous body 5 goes to the opposite side to the inlet 3b. For this reason, when the pressure on the opposite side of the suction port 3b in the scroll casing 3 is increased, the pressing force against the thick portion of the porous body 5 is increased, and the thick portion is crushed. As a result, the internal space of the scroll casing 3 on the side opposite to the suction port 3b becomes wider as the porous body is crushed, and the pressure on the side opposite to the suction port 3b is reduced. For this reason, it is prevented that the pressure in the scroll casing 3 becomes uniform or close to uniform and a secondary flow is generated. Therefore, according to the centrifugal blower 1 of this embodiment, the fall of the ventilation efficiency by the secondary flow generated by the pressure difference inside the scroll casing 3 can be prevented, and the ventilation efficiency can be improved.

  Thus, according to the centrifugal blower 1 of this embodiment, in the centrifugal blower installed in the vehicle air conditioner, it is possible to reduce the blowing noise and improve the blowing efficiency.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  For example, in the above-described embodiment, the configuration in which the porous body 5 becomes thicker from the opposite side from the suction port 3b has been described. However, the present invention is not limited to this, and a porous body having a shape that does not become thicker from the suction port 3b toward the opposite side may be used. Even in such a case, it is possible to prevent the air flow from being peeled off at the tongue portion 3d.

  DESCRIPTION OF SYMBOLS 1 ... Centrifugal blower, 2 ... Fan, 2a ... Shaft part, 2b ... Blade, 3 ... Scroll casing, 3a ... Discharge passage, 3b ... Suction port, 3c ... Discharge port, 3d ... Tongue Part, 4 ... motor, 5 ... porous body, X ... air

Claims (1)

A centrifugal blower comprising a fan that blows air sucked in from an axial direction radially outward, and a scroll casing that houses the fan,
The scroll casing is
A discharge passage formed in a spiral shape so as to surround the fan in the rotation direction;
A suction port formed at a position axially separated from the fan;
The discharge passage is tangential to the discharge passage and opened toward the rear side in the rotation direction of the fan, and is located between the discharge port and the fan. A tongue protruding toward the inside of the discharge passage,
A centrifugal blower comprising: a flexible porous body that is provided on the tongue and extends in the axial direction of the fan and becomes thicker toward the opposite side of the suction port.

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