JPH04203399A - Centrifugal blower for vehicle - Google Patents

Abstract

PURPOSE:To provide a low noise by a method wherein a lower bottom wall of a scroll casing is provided with a flat plate-like porous material, a reverse side shaft end of a motor main body is extended up to a substantial same position as that of a lower surface of a centrifugal blower or a scroll casing is extended up to a slight projected position. CONSTITUTION:A lower bottom wall of a scroll casing is provided with a flat plate-like porous material 10. A scroll casing is extended up to a substantial same position as that of the lower surface of a centrifugal blower at a reversing fan shaft end of a main body 5 of a motor or slightly projected by using a resin housing 11 for holding the main body 5 of the motor. The porous material 10 is combined with the scroll casing 12 to add a sound reducing function, the porous material is held between the scroll casing 3 and the extended scroll casing 12 and fixed to cause a simplification of structure and an assembling of the structure to be improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a low-noise structure of an automatic air conditioner, and is particularly useful for reducing the noise of a centrifugal blower. related to scroll casing structure.

The present invention is applicable to a wide range of applications, including centrifugal blowers for use in home use, which require low noise, as well as automatic air conditioners, and centrifugal blowers for cooling electronic computers.

[Prior Art] As described in Utility Model Application No. 48-63305, a conventional centrifugal blower consists of a fan, a scroll casing that houses the fan, and a motor that rotates the fan. The structure sucks air from one side of the fan,
It was designed to blow air in the radial direction of the fan. This scroll casing has a function of gradually restoring the dynamic pressure generated by the rotation of the fan to static pressure within the scroll casing. However, this structure reduces air pulsation noise generated by the fan, noise caused by separation, and turbulence noise within the scroll casing1]
The husband had not been. However, Jikoko 57-24
! 'i [i (: automatic 1'l as described in issue
In commercial air conditioners, an indoor/outdoor air switching box has been devised as an indirect step to reduce these radiated sounds.・
On the other hand, as described in JP-A No. 63-DO/115, a sound absorbing material in which a non-porous elastic material is added to the surface of a porous elastic material is added to the scroll casing with the aim of reducing noise as I-1 ( There are also examples of low-noise 1" I2 achieved by subtracting 1.
When using a motor having a commutator on the fan side as shown in No. 3640 and Utility Model Application No. 62-98459, M
At the same time, the motor noise generated by the commutator and brush sliding is carried by the fan rotation and is emitted from the scroll casing's discharge 111. There was a problem that it was dissipated into the room.

[Problem to be Solved by the Invention 1 -I- The conventional technology described in Japanese Utility Model Application Publication No. 48-63305 does not solve the problem of air pulsation generated by a fan. There was a problem in that noise generated by vortices due to separation, turbulence noise within the scroll casing, etc. were generated, and the noise of the entire blower became considerably large. In addition, in automatic heavy-duty air conditioners such as those described in Utility Model Publication No. 57-24566, the inside/outside air switching box has to be devised in order to defeat these lawsuits. Multi-force, highly versatile, inexpensive automatic! In addition, these centrifugal blowers were disclosed in Japanese Unexamined Patent Application Publication No. 1983-10.
When using a motor with rectification f on the fan side shown in No. 36, Utility Model Application No. 62 984591;-,
1);j As mentioned above, the motor noise generated by the rectification t and the brush sliding is carried by the discharge air due to the rotation of the fan and is emitted from the discharge L1 of the scroll casing. There was a problem that 1 was transmitted indoors and was dissipated into the room, and only the wind noise was dealt with by devising the above-mentioned internal/external air switching box. As described in No. 90415, this is an example in which a sound-absorbing material is attached to a scroll casing for the purpose of reducing noise, but the flexible polyurethane foam that is generally used as a sound-absorbing material is 100011z or higher.
Although the sound absorption effect is high for high frequencies of I 000
It is less effective for low frequencies below 11z. The example described in JP-A No. 63-90415 states that in order to eliminate the problem in ``U'', the vibration energy of sound waves over a wide range of frequencies can be absorbed by laminating two types of FF materials as sound absorbing materials. It is being However, when using this sound absorbing material, although it is possible to absorb the vibration energy of sound waves at low frequencies because it is a porous material, the sound waves do not reach the deep layer, and on the contrary, It is reflected, and the effect of the porous elastic material provided on the side of the layer is almost lost, and the effect of the porous elastic material alone cannot be obtained.
1. It does not reduce high frequency sounds. Furthermore, in order to maximize the effect of pasting the sound-absorbing material on the scroll casing, the work of pasting the sound-absorbing material on the scroll casing should be done all around the inner wall surface of the scroll casing. It is expensive because it cannot be pasted, and at the same time, it is always in contact with the air passage surface, so it has problems such as the need to take measures to prevent it from peeling off after pasting.

[F stage for solving problems] Misfire 1! If is particularly important for automatic IJ (centrifugal blowers) that use a motor that produces rectified r-J on the fan side, in order to obtain a highly reliable and inexpensive air conditioner by reducing noise and simplifying the structure. , one i' Di-shaped porous body is provided on the lower bottom wall side of the scroll casing, and in order to more effectively reduce the motor noise generated from the motor body and the I! The scroll casing is extended to a point where the shaft end is approximately at the same position as the centrifugal blower 1ζ, or at the lower 11) position.

The scroll casing is partially formed of a resin housing that holds the motor body, and there is a
It has a simple structure in which a plate-shaped porous body is arranged, and the plate-shaped porous body is clamped and fixed between the resin housing and the scroll casing from 4-F or 6-1, and the plate-shaped porous body The body is located on the upper bottom wall of the conventional centrifugal blower.

[Function] By adopting the structure described in t)8, the present invention eliminates the pulsating sound of air generated in the scroll casing in which the qI-plate-like porous body is the upper bottom wall surface of the centrifugal blower, and the rotation of the fan. vortex noise caused by separation, turbulence noise inside the casing,
Sound waves combined with motor noise carried by the wind pass through the porous body, and 1) middle and high frequency bands of the sound waves are reduced. Further, the sound waves reach the scroll casing inner wall 1hi formed by the flat porous body and the resin housing 1111, are reflected, and 1); Sound in the low frequency band also gradually attenuates. In addition, since the deck-like porous body is clamped and fixed from the top, it is easy to assemble and will not fall off due to wind pressure. Is there any other noise radiated directly from the motor body?
In 1-, the scroll casing is extended to a position where the end of the shaft on the side opposite to the fan of the motor body is almost at the same position as the surface of the centrifugal blower, or at a position where it protrudes from the surface of the centrifugal blower. It is similarly attenuated by the inner wall surface of the scroll casing.

[Example 1] Hereinafter, an example of the present invention will be described using FIG. 1. 3. FIG. 1 shows a cross-sectional view of the present invention. Automatic small centrifugal blower 1
In general, it has an inside/outside air switching box 2 for selectively opening/closing air outside the vehicle interior and 11 (inside the vehicle) in its two parts, and includes a scroll casing 3 and a box housed within the scroll casing. It consists of a fan 4 and a motor 5 that rotates the fan. 11 (Outdoor, +1 [Indoor air is sucked in through the selectively opened and closed inside/outside air switching box 2, introduced into the scroll casing 3 through the suction +16 of the scroll casing 3, and blown out in the radial direction of the fan 4. , the air is discharged to the discharge [13A] of the scroll casing 3.This scroll casing has the function of converting the dynamic pressure generated by the rotation of the fan into static pressure.The motor main body 5 is placed on the side of the fan 4. Commutator-7
, has a brush 8, and when the brush 8 is energized, the rotation t9 is 1 (one rotation, and the fan 4 attached to the tip of the rotor 9
It has a structure that drives. In this centrifugal blower, the present invention provides a flat porous body 10 on the lower bottom wall side of the scroll casing, so that the shaft end of the motor body 5 on the side opposite to the fan is at a rotational position approximately equal to the surface Δ of the centrifugal blower. Or Young 1: Move the scroll casing to the protruding position of the motor body 5.
A tri-sound function is added by combining the porous body 10 and the extended scroll casing I2, and the porous body is extended with the scroll casing 3. By sandwiching and fixing the screws between the scroll casings 12, the structure is simplified and assembly is improved. Furthermore, by using the porous body as an elastic body containing activated carbon or a honeycomb-shaped porous body containing a deodorizing agent, it is possible to obtain a structure that has both a deodorizing function and a sound deadening function.

That is, in FIG. 1, the scroll casing 3 is the first scroll casing, and the resin housing 11 that holds the motor body 5 is the second scroll casing 8 that covers the third side of the star scroll casing 8 = roll casing. 12, and has a structure in which a porous body 10 is provided between the first scroll casing 3 and the second scroll casing 12. 7. A contact portion between the first scroll casing 3 and the second scroll casing 12 11 plate-like frame I' that holds the porous body 10 inside.
, 3 are sandwiched, the first scroll casing 3
and a spring 1/ that fastens the second scroll casing 12.
It is fixed at the same time at I. The second scroll casing 12 formed of the housing 11 made of the wood 11 has a shape of 11 (11 during wartime) to avoid interference between the two parts and to match the desired frequency reduction described later. The first scroll casing can vary:
It is not necessary to match the shape of 3. 1); J.11 The porous body 10 held in the plate-like frame 12 is made of a material in which the gaps between aggregates of delicate or fine particles or the air bubbles in the foam are continuous, or , an elastic body containing the same type of activated carbon, or a honeycomb-shaped porous body containing a deodorizing agent, and the sound waves incident on the surface of these materials propagate through the air in the gaps and enter the interior of the material, causing viscosity and heat. The energy is lost through conduction. This is the principle of sound absorption by porous materials. Generally speaking, the thicker the porous material, the greater the sound absorption effect; The sound absorption band is the middle and high frequency band, which reduces the harsh sounds of wind noise and motor noise, and the transmitted low frequency band is 1); 2
The inner wall 16 of the scroll casing 12 reflects the reflection, and the porous body lO! I' gradually decreases as it interacts with l-. In the present invention, by providing the inner wall surface (3) of the second scroll casing 12 that almost covers the rear motor of this porous body, it is possible to reduce noise in all frequency bands, and at the same time, the thickness of the porous body This makes it possible to freely change the amount of reduction by selecting the material. The principle behind this will be explained below. As the fan 4 rotates, it produces various sounds such as pulsating air, dry air due to separation of blades, turbulent air noise, and sliding noise between motor commutator 7 and brushes 8. The sound waves mix between the first scroll casing 3 and the second scroll casing 1.
It passes through a porous body 10 provided at the contact portion between the two. At that time, the sound mainly in the middle and high frequency bands is reduced by the action described in 1.1.After that, the sound waves that enter based on the principle of an extinguisher are formed by the resin housing 11; It was reflected by the inner wall surface 13 of the second scroll casing 12 and passed through the porous body 10 mentioned earlier. The l'9 wave is 71-ini 1
As a result, especially the low frequency band that was not attenuated by the porous body 10 is gradually attenuated.

As described above, by forming a scroll casing in which the porous body 10 and the second scroll casing 12 are combined, the power can be reduced by 1iJ in all frequency bands.11. You can also freely adjust the amount of reduction.

Furthermore, by using the porous body as an elastic body containing activated carbon or a honeycomb-shaped porous body containing a deodorizing agent, a structure that has both a deodorizing function and a sound muffling function can be obtained. Next, the structure of the assembly of the second scroll casing 12 formed by the porous body IO and the resin housing 11 will be explained in detail. The figure shows how the motor body 5 and the porous body 10 are assembled. The outer periphery of the iron plate yoke 15 of the motor body 5 is press-fitted into the small protrusion 17 of the cylindrical body 16 provided at the center of the resin housing 11. will be determined.

The resin housing 11 has a cylindrical body 16 provided in the center.
It constitutes a bag-shaped second scroll casing 12 extending from the casing. The bottom wall surface of the bag-shaped second scroll casing 12 is located at the same position as the shaft end of the tipped motor body 5 or at a position that slightly protrudes from the shaft end of the motor body 5. 10 and a second scroll casing 12. Therefore, the noise emitted from the cylindrical body 16 provided at the center of the resin housing II of the motor body 5 is also absorbed and reflected by these muffler members, making it difficult for the noise to be radiated to the outside.・On the other hand, the porous body IO is
The first scroll casing; as described above, is fixed to the holding part 181i11 provided on the side edge of the porous body 10 of No. 3, but the porous body 10 is an elastic body such as urethane foam. In this case, as shown in FIG. 2, it is held by a frame 13 having a necessary minimum number of grooves on the outside. Below 1
- By having a structure like this, the frame body 13 that holds the porous body 10 inside can easily be placed between the first scroll casing 3 and the second scroll casing 12. It is securely fixed. Moreover, since the frame body 13 is configured to be able to be separated and independent from the first scroll casing;
Synthetic resin foams such as polypropylene type, polyamide type, polystyrene type, NBI≧, 5I3R, natural rubber type rubber foams, glass wool, etc. can be easily used.
It is possible to assemble it.

Figure 3 shows the noise measurement results of the centrifugal blower equipped with the above-mentioned silencing function.

The overall measurement position was 1 m from suction 1-1. Third
In the figure, the black circles indicate the conventional scroll casing, and the white circles indicate the results of noise frequency analysis of the scroll casing structure of the present invention. From this diagram, l OOOllz
It can be seen that the noise is reduced over a wide range from 10KIIz to 10KIIz. FIG. 4 shows the noise inq determination result when the thickness of the poroelasticity -14 material is approximately twice that of FIG. 3. In this case, as in Fig. 3, the black circles indicate the conventional scroll casing, and the white circles indicate the results of frequency analysis of the scroll casing structure of the present invention. , plus 1KIIy
, the following frequency bands can be reduced, lK117. The noise in the following frequency band also has an increased one-generation attenuation compared to FIG. As can be seen from this one experimental result, when a porous body and a scroll casing are combined,
The high frequency band can be reliably reduced, and the thickness of the porous body can be reduced.
The low frequency band is also reduced by improving the materials, etc. jrf
Becomes Noh.

[Effects of the Invention] According to the present invention, a porous body is provided between the first scroll casing and the second scroll casing, and an air layer is formed between the porous body and the second scroll casing. The pulsating sound of the air generated inside the scroll casing of 1, the heating caused by the separation of the blades as the fan rotates, the turbulence noise inside the casing, the motor sliding noise, etc.
A miscellaneous combination of sound waves passes through a porous body,
]-Among the recorded sound waves, the middle and high frequency bands are reduced in -L. Furthermore, the waves reach the inner wall of the second scroll casing, are reflected, and interfere with each other within this porous body, causing the low frequency band that has not been reduced in the first place. i
'li also reduces. As a result, noise in the entire frequency band has been reduced by 11 times. Furthermore, when forming the second scroll casing, the part of the resin housing that holds the motor body was extended to cover the body provided in the center of the motor body, so noise from the motor body was also minimized. 2
It has become possible to muffle and reflect sound within the scroll casing and suppress sound dissipated to the outside.Furthermore, the porous body can be separated and manufactured and assembled independently. Since the structure is such that the clamp is locked between the scroll casing and the second scroll casing, various porous bodies can be selected. It is something that can be fixed.
In an embodiment of the invention, the second scroll casing includes:
Although the part of the resin housing that holds the motor body is extended, this effect will not be impaired even if the casing is separated from the resin housing.

[Brief explanation of the drawing]

Figure 1 shows the automatic system of the present invention! Figure 2 is a cross-sectional view of a centrifugal blower for IC, Figure 2 is a diagram showing the assembly of the resin housing that holds the motor body of the present invention and the porous body of the motor body, and Figure 3 is a diagram showing the noise of a centrifugal blower with a noise reduction function. 1"? 8111 Figure 4 is a diagram showing the noise measurement results of a centrifugal blower when the thickness of the poroelastic material is increased. l...Centrifugal blower for automobiles, 2.・・Inside/outside air switching box,
: 3... First scroll casing, 4... Fan, 5... Motor body, 7... Rectifier r-18...
Brush, 9... Rotation f, 10... Porous body, l]
...Resin housing that holds the motor body 5, 12
...Second scroll casing.

Claims (3)

[Claims] 1. In a centrifugal blower for an automobile that includes a fan, a motor that rotates the fan, and a through-roll casing that houses the fan, in which the commutator of the motor is on the fan side, the lower bottom wall side of the scroll casing is porous. A centrifugal blower for automobiles characterized by low noise by providing a body. 2. In claim 1, in which the suction port of the scroll casing draws air from above the fan, the shaft end of the motor body on the side opposite to the fan is located at the lower bottom wall surface of the scroll casing at approximately the same position as the lower surface of the centrifugal blower, or slightly protrudes from the bottom wall surface of the scroll casing. A centrifugal blower for an automobile is characterized in that the radiated noise of the motor body can be reduced at the same time as the wind-related noise by arranging it in a position where 3. An air conditioner for an automobile according to claim 1, wherein an inside/outside air switching box is attached to the upper surface of the scroll casing.