JPH0219600Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to a noise prevention structure for a blower.

(Prior Art) Conventionally, in order to prevent noise from a blower, glass wool 38 as shown in FIGS.
It is known to attach a sound absorbing material L to 1.

(Problem that the invention aims to solve) The conventional method of using upper air is effective in preventing noise, but the frictional resistance of the air increases and the flow rate ratio decreases, so it is necessary to increase the size of the device itself. However, there was a problem in terms of economy.

The present invention has been made in order to solve the above-mentioned problems, and aims to provide a blower having a noise prevention function that does not reduce the flow rate ratio of air, etc., is simple to manufacture, and is inexpensive.

(Means for Solving Problems) In order to achieve the above object, the present invention is a centrifugal blower that sucks air from the center and sends out air etc. in the circumferential direction. A porous, air-permeable sound absorbing material is formed so that the front and back sides of the impeller can be ventilated through the through holes drilled in the main plate, and a predetermined space is formed between the back side of the main plate and the casing of the blower. The porous sound-absorbing material is provided at a certain distance in front of the suction port of the blower so as to cover the suction port.

(Example) Next, an example of the present invention will be described with reference to the drawings.

In the figure, 1 is a blower of the present invention, which includes a casing part 2, an impeller part 3, a sound absorbing member 4 attached to the front surface of the casing part 2, and a sound absorbing part around the rotation axis (hub) 7 of the main plate 20 of the impeller part 3. 8.

Reference numeral 2 denotes a casing portion, which is formed by lying down in the shape of a generally short cylinder, and has a circular suction port 9 with the edge of the opening bent inward on the front surface, and an impeller portion 3, which will be described later, on the rear surface. It has an opening hole (not shown) to which a back plate 10 is attached for insertion and removal, an air outlet 11 is provided at one of the lower sides, and a pair of legs 12 are formed at both sides of the lower side. . In addition, the casing part 2
A screw hole 14 is provided near the circumference of the front surface, into which a sound absorbing member 4 to be attached to the front surface of the casing portion 2, which will be described later, is attached with a bolt 13 or the like. Further, the back plate 10 of the casing part 2 is formed into a disk shape, and a hole 15 is bored in the center through which the rotating shaft (hub) 7 of the impeller part 3 is inserted, and is fixed to the back side of the casing part 2 with bolts 16. A mounting hole 17 is provided at the outer peripheral edge.

18 is an impeller main body 18 of the impeller part 3,
It is formed from a side plate 19, a main plate 20, and a vane plate 21. The side plate 19 has an opening 6 formed in the center thereof with an edge bent outward, and the edge of the opening 6 is arranged so as to partially overlap and cover the suction port 9 of the casing part 2. It is. Also,
A rotary shaft (hub) 7 insertion hole 22, which will be described later, is bored in the center of the main plate 20, and a plurality of circular through holes 23 are formed concentrically around it, and the through holes 23 are formed around the center of the main plate 20. A sound absorbing part 8 around the rotating shaft (hub) 7 and a rotating shaft (hub) 7, which will be described later, are installed on the inside and outside of the
A plurality of mounting holes 24 are provided. Also, 8
is a sound-absorbing part, in which a disc-shaped sound-absorbing material m having a size that covers all the plurality of through holes 23 of the main plate 20 is attached to the back side of the main plate 20, and the sound-absorbing material m has a hole in the center. An insertion hole 25 for a rotating shaft (hub) 7, which will be described later, is formed, and mounting holes 26 for mounting the rotating shaft (hub) 7 and the main plate 20, which will be described later, are concentrically formed near the insertion hole 25 and near the circumference, respectively. It is set up in Further, the sound absorbing material m has a disc shape,
A sound absorbing portion 8 is constituted by a holding plate 27 having a through hole 28 formed by punching or the like in the same shape as the through hole 23 of the main plate 20, and a rivet 29
The through holes 23 and 28 of the main plate 20 and the holding plate 27 are aligned and fixed, and sound and air are fixed to the main plate 20 through the sound absorbing material m from the front side of the main plate 20 to the back side. Sound absorbing part 8 that allows the transmission of
An air layer A having a predetermined width is formed between the sound absorbing section 8, the casing section 2, and the back plate 10. Further, the sound absorbing material m is formed of, for example, an aluminum powder sintered sound absorbing material and has a porous and breathable structure, and the sound absorbing part 4 is formed of the suction port 9 of the casing part 2 and the side plate of the impeller part 3. It is configured so that the real back of the opening 6 has a position.

Reference numeral 7 denotes a rotation shaft (hub) of the impeller section 3, which has a cylindrical shape and has a flange portion 30 approximately in the center, and a drive shaft mounting hole 31 passing through the central shaft.
A key mechanism 32 is formed on the inner wall of the drive shaft mounting hole 31. The rotating shaft (hub) 7 is inserted from the inside (front side) of the impeller main body 18, and is perpendicular to the main plate 20 of the impeller main body 18 by means of rivets 29, etc., and the sound absorbing material m and the presser plate 27 are fixed together with the This rotating shaft (hub)
7 from the back side of the impeller part,
The drive shaft 34 of the drive device 33 is inserted and fixed with a key (not shown), and the drive shaft 34 and the impeller portion 5 are configured to rotate together.

n is a sound-absorbing material attached to the front of the suction port 9 of the casing part 2 of the sound-absorbing member 4, and is a porous, breathable material made of the same material as the sound-absorbing material m provided on the main plate 20 of the impeller part 3. It has a disk shape large enough to cover the front surface of the suction port 9, and has a plurality of mounting holes 36 passing through it so as to be held by a pressing member 35, which will be described later. The sound-absorbing material n is formed by press working or the like and has a disc shape, and the sound-absorbing member 4 is constituted by two holding members 35 having a frame radiating from the center in the circumferential direction and a predetermined space, and is riveted. 37 etc., and attached by bolts 13 etc. to the front of the suction port 9 of the casing part 2 so as to cover the suction port 9 at a fixed distance from the suction port 9 via supporting legs 38. Fixed.

Next, the operation and effects of this embodiment configured as described above will be explained.

Now, this embodiment is a centrifugal blower 1 that sucks air from the center and sends out air etc. in the circumferential direction. The material m is the main plate 2
The front side and the back side of the impeller 3 are formed so as to be ventilated through the through hole 23 drilled in the hole 23, and an air layer A of a predetermined width is provided between the back side of the main plate 20 and the casing 2 of the blower. In addition, the porous sound absorbing material n is attached at a certain distance in front of the suction port 9 of the blower 1 so as to cover the suction port 9.

Therefore, when this embodiment is operated, first, the noise generated inside the casing part 2 is repeatedly reflected as a sound wave on the inner wall surface of the casing part 2, and is mainly absorbed by air etc. which is opened on the front surface of the casing part 2. It is emitted as noise from the mouth 9.

In this case, part of the noise generated inside the casing part 2 is transmitted to the sound absorbing part 8 around the hub insertion hole 22 of the main plate 20 of the impeller part 3, which is located directly behind the suction port 9.
The sound is absorbed by

In addition, in this embodiment, porous aluminum powder sintered sound absorbing materials are used as the sound absorbing materials m and n, and sound energy due to noise is absorbed by the sound absorbing materials m and n.
It enters the ventilation hole of the sound absorbing materials m and n, but since the internal structure of the holes of the sound absorbing materials m and n are intricately interwoven and communicated three-dimensionally, the viscosity of the air remaining inside the hole changes it into thermal energy. The energy of sound is attenuated. In addition, while some of the sound is absorbed,
The sound is transmitted to the back side of the sound absorbing materials m and n, but in the case of the sound absorbing part 8 around the rotation axis (hub) 7 of the main plate 20, there is a total air A between the casing part 2 and the back plate 10, so the sound energy is absorbed by the air. The sound propagates through the layer A and is reflected on the casing back plate 10, and then passes through the sound absorbing material m again, so that the sound energy is further weakened and is emitted from the suction port 9 (see Fig. 9). .

Further, according to Holmhertz's sound absorption principle, the mass of air contained in the holes of the porous sound absorption member is caused by the elasticity of the air in the air layer A between the sound absorption part 8 and the back plate 10 of the casing part 2 to a predetermined spring. It vibrates, and in particular, it resonates with sounds of the same frequency as its spring constant, producing intense vibrations that create friction with the pore surface of the sound-absorbing material m, which converts sound energy into thermal energy. Noise is attenuated.

On the other hand, noise that is not attenuated by the sound absorbing part 8 of the main plate 20 of the impeller part 3 is emitted from the suction port 9 on the front surface of the casing part 12, but the sound absorbing member 4 attached to the front of the casing part 2 The sound energy is attenuated and absorbed together with the sound energy already attenuated by the sound absorption part 8 of the main plate 20 of the section 3 (first
(See figure 0). Note that the arrows in FIGS. 9 and 10 indicate the noise absorption situation.

(Effects of the invention) Now, according to the invention, among the noise generated inside the blower, the sound absorption part around the rotation axis of the main plate of the impeller and the sound absorption member in front of the suction port of the casing cause the noise generated inside the blower to be particularly absorbed from the suction port. It absorbs and attenuates the noise generated by the blower, and it does not increase the frictional resistance or decrease the flow rate when the blower sends air, so it can be said to be an extremely practical idea.

[Brief explanation of the drawing]

Fig. 1 to Fig. 10 show an embodiment of the present invention, Fig. 1 is an exploded perspective view of the blower, Fig. 2 is an exploded perspective view of the impeller and sound absorbing section from the back side, and Fig. 3 is an exploded perspective view of the impeller. Front view, Figure 4 is a front view of the sound absorbing material of the sound absorbing member,
Figure 5 is a front view of the holding plate, Figures 6 and 8 are front views of the holding member, Figure 7 is a front view of the sound absorbing material of the sound absorbing member, and Figures 9 and 10 are illustrations of the sound absorbing state. ,
FIGS. 11 and 12 show other embodiments. 1... Blower, 2... Casing, 3... Impeller, 7... Rotating shaft, 9... Suction port, 20... Main plate, 23... Through hole, A... Air layer, m, n...
Sound absorbing material.

Claims (1)

[Scope of utility model registration request] A centrifugal blower that sucks air from the center and sends out air, etc. in a peripheral direction, and a through hole made of a breathable porous sound-absorbing material in the main plate around the rotation axis of the main plate of the impeller of the blower. The front and back sides of the impeller are formed to be ventilable through the main plate, and an air layer of a predetermined width is provided between the back side of the main plate and the casing of the blower, and a certain distance is provided in front of the suction port of the blower. and the porous sound-absorbing material is provided so as to cover the suction port.