JPS61277900A - Air blower - Google Patents

Abstract

PURPOSE:To diminish noise by installing a sound absorbing member on the inner face of a casing confronting an air inlet so as to almost form a right angle to the direction of air flow from the inlet. CONSTITUTION:A sound absorbing member 11 is stuck to the entire inner surface confronting an air inlet in a casing. On the opposite side of the coating face, a concave part 12 with specific depth is formed, with an air layer part 13 thereby being constituted. Therefore, low frequency portion of noise is interfered and offset by the air layer part 13 of the concave part 12 in the sound absorbing member 11. Accordingly, noise can be greatly reduced, and small noise operation of the air blower becomes possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a blower configured to generate wind by rotating a fan disposed within a casing.

[Prior Art] Conventionally, for example, in an air conditioner for a car, inside air and outside air are selectively taken in by a single blower and discharged into the passenger compartment through a cooling unit or a heater core to adjust heating and cooling. I try to do it.

This blower consists of a fan placed inside a scroll casing that has an intake port and a discharge port.During operation, as the fan rotates, internal and external air is sucked in through the intake port, passes through the casing, and is discharged from the discharge port. It has become so.

[Problems to be solved by the invention] However, while the blower is operating, it is inevitable that noise will be generated within the scroll casing due to the generation of wind, and this has become a major obstacle in recent years when quiet operation is particularly required. It becomes.

Therefore, the present invention has been made to eliminate this obstacle, and its purpose is to significantly reduce noise inside the casing by providing a sound absorbing member in the casing so as to be substantially perpendicular to the direction of airflow flowing into the air intake port of the casing. An object of the present invention is to provide a blower that enables low-noise operation in order to achieve quiet operation of an automobile.

[Means for Solving the Problems] The present invention includes the following constituent requirements. In other words, (a) a casing having an air intake port formed in its center surface, and (b) an outlet having an opening surface substantially perpendicular to the opening surface of the air intake port formed on one side of the casing. Exit and 1. (c) a fan having a large number of blades disposed within the casing, the rotating surfaces of which are substantially parallel to the opening surface of the intake port, and rotationally driven by a motor;
A sound absorbing member is provided on at least an inner surface of the casing facing the intake port so as to be substantially perpendicular to the direction of air intake from the intake port of the casing.

[Operation] During operation, the propagation direction of the noise generated within the casing is directed approximately perpendicular to the sound absorbing member, so that the noise is directly and effectively absorbed by the sound absorbing member.

[Embodiment 1] An embodiment of the present invention will be described below based on the drawings. First, in an air conditioner for an automobile, a blower 1 is placed between a body (not shown) for switching between inside and outside air and a cooling unit or heater core (both not shown). 1, the scroll casing 2 has a circular intake port 3 at the center of its upper surface, and a discharge port 4 is formed within a rectangular cylindrical portion oriented substantially tangentially to the intake port 3. In this state, the opening surface of the intake port 3 of the scroll casing 2 and that of the discharge port 4 are substantially orthogonal, the intake port 3 is connected to the body, and the discharge port 4 is located opposite to the cooling unit and the heater core.

As shown in FIG. 2, the fan 5 consists of a funnel-shaped support tube 6 with a plurality of circular air holes 6a and a blade piece 7. The blade pieces 7 are arranged vertically at equal angular intervals on the periphery of the large-diameter side, forming a cylindrical shape as a whole and facing the intake port 3. Further, an opening 8 is formed in the casing 2 on the side facing the intake port 3, and a motor 9 is connected through the opening 8.
The motor shaft 10 is mounted so as to be positioned inside the support tube 6, and the upwardly oriented motor shaft 10 is directly connected to the smaller diameter side of the support tube 6.

Now, as shown in Fig. 3, the sound absorbing member 11 is made of a polyurethane foam coated with an ultra-thin Plus Deck film on one side to improve its weather resistance.
It is formed into a plate shape of 1IIIm, and is attached to the entire surface of the casing 2 on the side facing the intake port 3 so that the coating surface becomes the front surface. As shown in FIG. 2, this sound absorbing member 11 has a rectangular recess 12 having a predetermined depth formed on the side opposite to the coating surface, and a hollow air layer 13 is formed between the casing 2 and the recess 12. ing.

With the above configuration, when the fan 5 is rotated by the motor 9 to drive the blower 1, internal air or external air is sucked in from the intake port 3 through the switching body in the opposite direction, and passes through the casing 2. Then, it is discharged from the discharge port 4 and discharged into the vehicle interior via the cooling unit or heater core. This performs heating and cooling operation in the vehicle interior. During this operation, noise is generated within the casing 2 as the airflow is sucked through the intake port 3 of the casing 2. As a result of examining the causes of this noise, it was found that it can be broadly divided into the following three types. The second point is that as the fan 5 rotates, the airflow is intermittently pushed out from between the blades 7 and 70, so the airflow is directed to the nose section of the casing 2 (for convenience, the symbol N is shown in Figs. 1 and 3). This is due to discontinuous collision with the part where the rectangular tube part and the starting end of the casing 2 touch, as shown in the figure.
The second reason is that when the airflow passes between the blade pieces 7.7, a portion of the airflow separates from the surface of the blade piece 7, creating a vortex. Third, when air is taken in from the intake port 3, the airflow enters the inner surface of the casing 2 in a substantially vertical direction facing the intake port 3. It begins to rotate within the longitudinal section of
At this time, part of the airflow stagnates at the corner of the casing 2, resulting in a vortex. In this case, since the noise generally propagates substantially along the flow of the airflow, the propagation mostly goes from the air intake port 3 to the side of the casing 2 facing the air intake port 3. Therefore, the collision of the airflow against the nose part N for the first reason, the separation of the airflow from the blade piece 7 for the second reason, and the noise from the vortex generated in the casing 2 for the third reason, all of which occur in the casing 2 near the intake port 3.
The direction of propagation is approximately perpendicular to the sound absorbing member 11. Therefore, the noise based on the first, second, and third reasons described above is directly and effectively absorbed by the sound absorbing member 11, and the noise transmitted to the outside of the casing 2 is significantly reduced, making low-noise operation possible. It is particularly suitable for modern automobiles that require quiet operation.

By the way, in Figure 4, the vertical axis represents the noise level (dB) and the horizontal axis represents the noise frequency (Hz). I side 418m3 /h
This is a graph showing the relationship between noise level (dB) and noise frequency (tlz) when , the thin solid line indicates the general one,
The thick solid line represents the case of the present invention.

According to this, the present invention has a noise frequency of 200 to 315,112 and a noise frequency of 2,500 to 315 compared to general ones.
It can be seen that the low noise effect can be obtained over a wide range of 40 to 12,500 Hz, except for a small range of 0 Hz.

Moreover, in the case of the above embodiment, especially the blade piece 7 of the fan 5
While the noise generated by the separation of the airflow from the support tube 6 is effectively reduced by the air hole 6a provided in the support tube 6, the low frequency component of the noise is particularly reduced by the air layer 1 of the recess 12 provided in the sound absorbing member 11.
3, it is canceled out by interference and effectively reduced.

In the above embodiment, the support cylinder part 6 of the fan 5 has an air hole part 6a.
Although the shape is circular, it is needless to say that the air hole portion 6a is not limited to this shape, and the air hole portion 6a may be formed from an elongated slit oriented in the vertical direction. Further, the sound absorbing member 11 may be provided not only on the side of the casing 2 facing the intake port 3 but also on the inner surface of the casing 2 on the side where the intake port 3 exists in a facing state. In this case, the thickness of the sound absorbing member is smaller than that of the above example.
It should be about ou. Furthermore, the sound absorbing member may be constructed by mixing asphalt into a polyurethane foam to increase its rigidity, or may be formed from ceramic wool.

In addition, various changes may be made in the specific implementation without departing from the gist of the invention.

[Effects of the Invention] As described above, according to the present invention, since the sound absorbing member is provided so as to be substantially perpendicular to the direction of airflow inflow from the intake port, the noise generated within the casing is directly and It is possible to provide a blower that effectively absorbs noise, significantly reduces noise, and enables low-noise operation.

[BRIEF DESCRIPTION OF THE DRAWINGS] The drawings show one embodiment of the present invention, in which FIG. 1 is a perspective view of a blower, FIG. 2 is a longitudinal cross-sectional view of the blower, FIG. 3 is a cross-sectional view of the blower, and FIG. The figure shows noise level (dB) and noise frequency (H
2) is a graph showing the relationship with 2). In the diagram 2...Scroll casing (casing)
3...Intake port 4...Discharge port 5...Fan 6a...Air hole part 7...Blade piece 11...Sound absorbing member 13...Air layer part

Claims (1)

[Scope of Claims] (a) A casing having an air intake port formed in its center surface, and (b) a casing having an opening surface substantially perpendicular to the opening surface of the air intake port on one side of the casing. (c) a large number of vanes disposed within the casing, the rotating surfaces of which are substantially parallel to the opening surface of the intake port, and the fan is rotationally driven by a motor; (d) a sound absorbing member provided on at least the inner surface of the casing facing the air intake port so as to be substantially perpendicular to the direction of air intake from the air intake port of the casing.