GB2419811A

GB2419811A - Vacuum cleaner motor sound-proofing

Info

Publication number: GB2419811A
Application number: GB0509301A
Authority: GB
Inventors: Jang-Keun Oh
Original assignee: Samsung Gwangju Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2004-11-05
Filing date: 2005-05-06
Publication date: 2006-05-10
Anticipated expiration: 2025-05-06
Also published as: GB0509301D0; DE102005025665A1; DE102005025665B4; KR100667878B1; CN1770599A; KR20060046122A; JP4028872B2; GB2419811B; JP2006136187A; US20060096058A1; FR2877560A1; FR2877560B1; RU2299668C2; RU2005114753A

Abstract

A vacuum cleaner features a porous noise prevention board 53 in an exhaust passage, through which a portion, at least, of the exiting air passes. The arrangement may serve to reduce the overall noise output of the vacuum cleaner in use.

Description

EXHAUSTING APPARATUS OF MOTOR ASSEMBLY AND VACUUM

CLEANER HAVING THE SAME

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an exhausting apparatus of a motor assembly and a vacuum cleaner, and more particularly, to an exhausting apparatus which discharges air from a motor assembly and a vacuum cleaner having the same.

2. Description of the Related Art

Generally, a vacuum cleaner draws in dusts or contaminants into a dustcollecting area by a suction force generated by a driving motor of a driving chamber of a vacuum cleaner body. A high power motor with high RPM is used for the driving motor. The high power motor produces strong noise during driving thereof. As such, a structure for preventing noise is necessitated.

Korean Patent Laid-Open No. 1998-075351 entitled "Structure for Preventing Noise of Driving Motor of Vacuum Cleaner" discloses such a structure for preventing noise.

The schematic constructions are as follows. A vacuum cleaner 200 comprises a dust chamber 203 having a dust bag 201 and a driving chamber 207 mounting a driving motor 205 providing a suction force. The vacuum cleaner comprises a front cover 211 having a vibroisolating member 209 and enclosing a front portion of the driving motor 205, a first chamber 213 of which one end is fixed at the front cover and which is enclosing the outside of rear portion of the driving motor 205, a third chamber 217 of which one end is fixed at the first chamber 213 and which is spaced from outside of the first chamber 213 at a certain interval and receiving air from the first chamber 213 via a first -connection pipe 215, and a second chamber 223 disposed between the first chamber 213 and the third chamber 217 each at a certain interval and having a discharging opening 221 which is partitioned from the first chamber 213 and discharging air via a second connection pipe 219 from the third chamber 217 to the driving chamber 207.

Korean Patent Laid-Open No. 10-2004-80092 entitled "Structure for Reducing Noise of Vacuum Cleaner" also discloses a structure for preventing noise of a vacuum cleaner.

The schematic constructions are as follows. A motor case 230 comprises a front case 231 and a rear case 233 to reduce noise generated by a fan motor 241. The motor case 230 is mainly to reduce noise of vacuum cleaner 300 and fully covers the outside of fan motor 241.

As described above, Korean Patent Laid Open No. 1994-075351 discloses the first to the third chambers and Korean Patent Laid Open No. 102004-80092 discloses the front and rear case to reduce noise of a conventional vacuum cleaner.

Generally, polypropylene, robust to fire, is used for the member enclosing a fan motor in view of the preventing noise and safety to fire.

The polypropylene is appropriate for safety against fire, however, it cannot reduce the noise.

SUMMARY OF THE INVENTION

The present invention has been conceived to solve the above- mentioned problems occurring in the prior art, and an aspect of the present invention is to provide an exhausting apparatus of a motor assembly having a developed noise prevention effect by improving material and structure of a housing enclosing a driving motor.

Another aspect of the present invention is to provide a vacuum cleaner wherein the noise incurred during air flow is reduced by applying the exhausting apparatus to a vacuum cleaner.

In order to achieve the above aspects, there is provided an exhausting apparatus of a motor assembly comprising a motor assembly generating a suction force and having an air outlet; a motor housing enclosing the motor assembly and having an air discharging opening for exhausting air via the air outlet; and a porous noise prevention board configured in the exhausting passage formed by the motor housing.

The motor housing may have a porous noise prevention part at least at a portion, and at least a part of the air exhausting from the air outlet passes through the noise prevention part.

The noise prevention board may be made from a porous plastic of low density, the noise prevention part may be made from a porous plastic of high density, and the whole motor housing except for the noise prevention part may be made from plastic of high strength.

According to an embodiment of the present invention, the noise prevention board may be mounted at a discharging opening of the motor housing among the exhausting passages.

According to another embodiment of the present invention, the passage may comprise an inner passage configured in the motor housing and an outer passage configured at the outside, and the inner passage can be spirally formed to spirally discharge air exhausted from the air outlet of the motor assembly.

The motor housing may comprise an inner passage partition forming the passage and an outer passage partition, and at least a part of the inner passage partition can be made from a porous material. The noise prevention board may be made from a porous material of low density, the inner passage partition of the motor housing may be made from a porous material of high density, and the whole motor housing except for the inner passage partition may be made from a plastic of high strength.

In order to achieve the above aspects, there is provided a vacuum cleaner comprising: a cleaner body having a dust-collecting chamber and a motor chamber; a brush assembly connected with the dust-collecting chamber in fluid-communication and having an inlet flowing in contaminants-laden air; a motor assembly mounted in the motor chamber to generate a suction force and having an air outlet; a motor housing enclosing the motor assembly and having an discharging opening the air exhausted via the air outlet; and a porous noise prevention board mounted in the exhausting passage formed by the motor housing, wherein at least a portion of the motor housing comprises the porous noise prevention part, and at least a portion of air exhausted via the air outlet passes through the noise prevention part.

The noise prevention board may be mounted at the discharging opening of the motor housing among the passages. The noise prevention board may be made from a porous plastic of low density, the noise prevention part may be made from a porous plastic of high density, and the whole motor housing except for the noise prevention part may be made from a plastic of high strength.

The motor housing, the noise prevention board and the noise prevention part may be made from materials robust to fire. In order to achieve the above aspects, there is provided a method of reducing noise caused by a motor assembly that generates a suction force, comprising: passing a first portion of air discharged from the motor assembly through a first porous material having a first density; passing a second portion of air discharged from the motor assembly through a second porous material having a second density that is different from the first density; and exhausting the first and second portions of air to atmosphere.

Additionally, at least a portion of a motor housing may be formed to substantially enclose the motor assembly from the second porous material.

Additionally, at least a portion of the motor housing may be formed from a rigid material.

Additionally, at least a portion of the air discharged from the motor assembly may be guided in a spiral path about the motor assembly.

The spiral path may be at least partially defined by the second porous material.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of the present invention will be more apparent from the following detailed description taken with reference to the accompanying drawings, in which: FIG. I is a schematically perspective view of a vacuum cleaner according to an embodiment of the present invention; FIG. 2 is a sectional view of an exhausting apparatus of a motor housing according to an embodiment of the present invention; FIG. 3 is a partially cut, perspective view of an exhausting apparatus for a vacuum cleaner according to an embodiment of the present invention; FIG. 4 is a sectional view of an exhausting apparatus of a vacuum cleaner according to another embodiment of the present invention, wherein a motor housing has a spiral passage structure; FIG. 5 is a perspective view of the exhausting apparatus of FIG. 4; FIG. 6 is a sectional view of the exhausting apparatus taken along line I-I' of FIG. 5; FIG. 7 is a partially cut view of a portion mounting an impeller of FIG. 4; FIG. 8 is a view of an example of a conventional vacuum cleaner which is disclosed in the Korean Patent Laid-Open No. 10- 1998-075351; and FIG. 9 is a view of another example of a conventional vacuum cleaner which is disclosed in the Korean Patent Laid-Open No. 10- 2004-80092.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Certain embodiments of the present invention will be described in greater detail with reference to the accompanying drawings.

In the following description, same drawing reference numerals are used for the same elements even in different drawings. The matters defined in the description such as a detailed construction and elements are nothing but the ones provided to assist in a comprehensive understanding of the invention.

Thus, it is apparent that the present invention can be carried out without those defined matters. Also, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

An exhausting apparatus of motor assembly for generating a suction force can be used for various apparatuses which require suction force. For convenience of description, however, a vacuum cleaner will be explained wherein the exhausting apparatus of the motor assembly is applied as an

exemplary example.

FIG. I is a schematically perspective view of a vacuum cleaner according to an embodiment of the present invention, FIG. 2 is a sectional view of an exhausting apparatus of a motor housing according to an embodiment of the present invention and FIG. 3 is a partially cut, perspective view of an exhausting apparatus for a vacuum cleaner according to an embodiment of the present invention.

In the present embodiment, a canister type vacuum cleaner is explained, however, the exhausting apparatus of motor assembly of the present invention and vacuum cleaner having the same can be applied to various types of vacuum cleaner such as, for example, upright type and stick type vacuum cleaners.

Referring to FIGS. 1 to 3, a vacuum cleaner 20 comprises a cleaner body 28, a brush assembly 22, an exhausting apparatus 29 of a motor assembly, an extension pipe 24 and a flexible hose 26.

The cleaner body 28 comprises a dust-collecting chamber 1, a motor chamber 3 and a discharge opening or air outlet 5. The brush assembly 22 is connected with the dust-collecting chamber 1 of the cleaner body 28 in fluid- communication via the flexible hose 26, and has an inlet (not shown) drawing in contaminants-laden air.

The exhausting apparatus 29 of the motor assembly 30 comprises a motor assembly 30, a motor housing 50 and a noise prevention board 61. The motor housing 50 substantially encloses the motor assembly 30, and the noise prevention board 61 is disposed on an exhausting passage P. The motor assembly 30 comprises an impeller 31 which generates power to vacuum, an inlet 35a for drawing in air at a front side thereof, and an outlet 35b for exhausting air at a rear side thereof. The impeller 31 is an axial type wherein air mainly flows toward or in the direction of a driving axis 36.

The motor housing 50 substantially corresponds to the external appearance of the motor assembly 30 but is larger than the motor assembly 30 such that an exhausting passage P is formed to guide air exhausting from the outlet 35b of the motor assembly 30 to the outside of the vacuum cleaner. The exhausting passage P divides into an inner passage P1 and an outer passage P2. A discharging opening 51 forming a portion of the passage P and connecting the inner passage P1 to the outer passage P2 is configured along the direction of rotation of the driving axis 36 at a lower portion of the motor housing 50.

A noise prevention board 61 is disposed in the outer passage P2, preferably in proximity to or downstream of the discharging opening 51, and between the outer surface of the motor housing 50 and the cleaner body 10.

The noise prevention board 61 is made of a porous material to allow for the passage of air therethrough. Air passes through the porous noise prevention board 61, and, therefore, air flow lengthens, which results in noise reduction.

The porous material may be made from a suitable material, such as, for example, plastic, and a porous plastic material of low density is preferable.

A porous noise prevention part 53 is disposed at an upper portion of the motor housing 50, opposite to the discharging opening 51. A portion of air exhausted from the outlet 35b of the motor assembly 30 is discharged to the porous noise prevention part 53 such that an entire amount of discharging air can be easily maintained. Although air flowing via the exhausting passage P can be slightly stagnated due to the noise prevention board 61. Referring to FIG. 2, air is discharged via the noise prevention board 61 in a direction of the solid arrows (A direction), and the remaining air, which could not be discharged via the noise prevention board 61, is discharged via the noise prevention part 53 in a direction of the dotted arrows (B direction).

Preferably, the noise prevention part 53 may be made of porous plastic material of higher density than the noise prevention board 61. The amount of air discharging via the discharging opening 51 may be substantially the same as that via the noise prevention part 53.

The whole motor housing 50 could be made from a porous plastic material, however, the porous plastic material is inferior in strength. As such, to compensate for the lack of strength, the porous noise prevention part 53 is provided along one or more portions of the motor housing 50, and plastic of high strength or other rigid material, such as, for example, polypropylene, is provided along the other portions.

The porous plastic is preferably made with a uniform mixture of minute powder of magnesium and iron with polyethylene of high density.

In the above construction, the noise prevention board 61, the noise prevention part 53 and the motor housing 50 may be made from material robust to fire in view of the potential for overheating of the driving motor.

Referring to FIGS. 4 and 5, an exhausting apparatus 29' of the motor assembly 30 according to another embodiment of the present invention is shown. A whole passage F comprises an inner passage P1' and an outer passage P2', where the inner passage P1' of the motor housing 100 has a spiral-like configuration. FIG. 5 is a perspective view of the discharging apparatus of FIG. 4.

The motor assembly 30 and the motor housing 100 are mounted in a motor chamber 3. The motor assembly 30 has a similar structure as that in FIGS. 2 and 3, and therefore, the same reference numerals are used for the similar portions with FIGS. 2 and 3, and the detailed description thereof will be omitted for conciseness. However, FIGS. 4 and 5 depict the motor housing 100 which spirally guides air exhausting via the outlet 35b to discharge the air to the outside.

The motor housing 100 comprises an upper casing 110 and a lower casing 130. The upper and lower casings 110 and 130 have an impeller 31 of the motor assembly 30 and an impeller chamber 111 and 131 and a motor chamber 133 therein.

Interval maintenance parts or spacers 136a and 136b protrude from the front and the rear sides of the lower casing 130 of the motor housing 100. The interval maintenance parts 136a and 136b maintain a certain desired interval or spacing H between the lower casing 130 and a bottom part of the cleaner body 10, such that air discharging via the motor housing 100 can flow to the discharge opening or air outlet 5 at the rear side of the cleaner body 10.

FIG. 6 is a sectional view of the exhausting apparatus taken along line II' of FIG. 5, and FIG. 7 is a partially cut view of a portion mounting an impeller of FIG. 4.

Referring to FIGS. 6 and 7, the motor housing 100 has a spiral passage P1' through partitions 115, 117 and 135 to spirally guide air exhausted via the outlet 35b. A noise prevention board 150 is disposed between the partitions and 117 and is preferably substantially perpendicular to the partitions 115 and 117. The noise prevention board 150 is preferably made from a porous plastic and more preferably a porous plastic having a low density.

To compensate for the lack of discharging area due to the mounting of the noise prevention board 150 in the inner passage P1', the partition 115 nearest to the motor assembly 30 (refer to FIG. 4) is made from a porous plastic material of high density.

Based on the above structure, air exhausting via the outlet 35b of the motor assembly 30 is guided via the passage partitions 115, 117 and 135 to spirally flow in a direction of arrow D, and as the air passes through the noise prevention board 150, the noise is reduced. When the discharging area 1() becomes small due to the noise prevention board 150 and pressure in the motor housing 100 increases, the remaining air, which has not passed through the noise prevention board 150, is discharged in the direction of arrow E through the porous passage partitions 115 of high density.

The other portions of the motor housing 100 except for the passage partition 115 nearest to the motor assembly 30 is made from plastic of high strength or other rigid material, such as, for example, polypropylene, for maintaining strength.

The motor housing 100 comprising the passage partitions 115, 117 and including the afore.-described noise prevention board 150 may be made from material robust to fire against the potential of overheating due to highspeed rotation.

As described above, an exhausting apparatus according to the present invention has the motor housing 100 of porous material and the noise prevention board 150 of porous material in the passage such that the noise prevention effect can be increased or maximized.

Furthermore, noise can be reduced which incurred when air is discharged from the motor chamber 3 of the vacuum cleaner.

The foregoing embodiment and advantages are merely exemplary and are not to be construed as limiting the present invention. The present teaching can be readily applied to other types of apparatuses. Also, the description of the embodiments of the present invention is intended to be illustrative, and not to limit the scope of the claims, and many alternatives, modifications, and variations will be apparent to those skilled in the art.

Each feature disclosed in this specification (which term includes the claims) and/or shown in the drawings may be incorporated in the invention independently of other disclosed and/or illustrated features.

Statements in this specification of the "objects of the invention" relate to preferred embodiments of the invention, but not necessarily to all embodiments of the invention falling within the claims. Reference numerals appearing in the claims are illustrative only and the claims shall be interpreted as if they are not present.

The description of the invention with reference to the drawings is by way

of example only.

The text of the abstract filed herewith is repeated here as part of the

specification.

An exhausting apparatus of a motor assembly comprises a motor assembly generating a suction force and having an air outlet; a motor housing enclosing the motor assembly and having an air discharging opening for exhausting air via the air outlet; and a porous noise prevention board configured in the exhausting passage formed by the motor housing. The motor housing has a porous noise prevention part at least at a portion, and at least a part of air discharging from the air outlet passes through the noise prevention part. As such, a noise can be reduced when air is discharged.

Claims

CLAIMS: 1. An exhausting apparatus for a motor assembly that generates a

suction force and has an air outlet, the apparatus comprising: a motor housing at least substantially enclosing the motor assembly and having an air discharging opening in fluid communication with the air outlet for exhausting air; an exhausting passage formed at least in part by the motor housing and in fluid communication with the air discharging opening; and a porous noise prevention board disposed in the exhausting passage, wherein at least a first portion of the air from the air outlet passes through the porous noise prevention board.
2. The apparatus according to claim 1, wherein at least a portion of the motor housing has a porous noise prevention part, and wherein at least a second portion of the air from the air outlet passes through the porous noise prevention part.
3. The apparatus according to claim 2, wherein the porous noise prevention board is made from a porous plastic of low density, the porous noise prevention part is made from a porous plastic of high density, and the motor housing except for the porous noise prevention part is made from a plastic of high strength.
4. The apparatus according to claim 3, wherein a first amount of air passing through the porous noise prevention board is substantially the same as a second amount of air passing through the porous noise prevention part.
5. The apparatus according to claim 2, wherein the porous noise prevention board is in proximity to the air discharging opening of the motor housing in the exhausting passage.
6. The apparatus according to claim 5, wherein the porous noise prevention board is made from a porous plastic of low density, the porous noise prevention part is made from a porous plastic of high density, and the motor housing except for the porous noise prevention part is made from a plastic of high strength.
7. The apparatus according to claim 2, wherein the exhausting passage comprises an inner passage disposed in the motor housing and an outer passage disposed outside of the motor housing, and wherein the inner passage is spirally formed to spirally discharge the air from the air outlet.
8. The apparatus according to claim 7, wherein the motor housing comprises an inner passage partition and an outer passage partition so as to at least partially form the exhausting passage, and at least a portion of the inner passage partition is made from a porous material.
9. The apparatus according to claim 8, wherein the porous noise prevention board is made from a porous material of low density, the inner passage partition of the motor housing is made from a porous material of high density, and the motor housing except for the inner passage partition is made from a plastic of high strength.
10. A vacuum cleaner comprising: a cleaner body having a dust-collecting chamber and a motor chamber; a brush assembly connected with the dust-collecting chamber in fluid- communication and having an inlet for contaminants-laden air; a motor assembly mounted in the motor chamber to generate a suction force and having an air outlet; a motor housing at least substantially enclosing the motor assembly and having a discharging opening to exhaust the air discharged from the air outlet; an exhausting passage formed at least in part by the motor housing; and a porous noise prevention board in the exhausting passage, wherein at least a portion of the motor housing comprises a porous noise prevention part, and at least a portion of the air from the air outlet passes through the porous noise prevention part.
11. The cleaner according to claim 10, wherein the porous noise prevention board is mounted in proximity to the discharging opening of the motor housing in the exhausting passage.
12. The cleaner according to claim 10, wherein the porous noise prevention board is made from a porous plastic of low density, the porous noise prevention part is made from a porous plastic of high density, and the motor housing except for the porous noise prevention part is made from a plastic of high strength.
13. The cleaner according to claim 11, wherein the porous noise prevention board is made from a porous plastic of low density, the porous noise prevention part is made from a porous plastic of high density, and the motor housing except for the porous noise prevention part is made from a plastic of high strength.
14. The cleaner according to claim 12, wherein a first amount of air passing through the porous noise prevention board is substantially the same as a second amount of air passing through the porous noise prevention part.
15. The cleaner according to claim 13, wherein a first amount of air passing through the porous noise prevention board is substantially the same as a second amount of air passing through the porous noise prevention part.
16. A method of reducing noise caused by a motor assembly that generates a suction force, the method comprising: passing a first portion of air discharged from the motor assembly through a first porous material having a first density; passing a second portion of air discharged from the motor assembly through a second porous material having a second density that is different from the first density; and exhausting the first and second portions of air to atmosphere.
17. The method of claim 16, further comprising forming at least a portion of a motor housing that substantially encloses the motor assembly from the second porous material.
18. The method of claim 17, further comprising forming at least a portion of the motor housing from a rigid material.
19. The method of claim 16, further comprising guiding at least a portion of the air discharged from the motor assembly in a spiral path about the motor assembly.
20. An exhaust arrangement for a motor assembly substantially as described herein with reference to and/or as illustrated in any of Figures 1 to 7 of the accompanying drawings.

* * *.* * * *
21. A vacuum cleaner substantially as described herein with reference to and/or as illustrated in any of Figures 1 to 7 of the accompanying drawings.

20. The method of claim 19, wherein the spiral path is at least partially defined by the second porous material.

21. An exhaust arrangement for a motor assembly substantially as described herein with reference to and/or as illustrated in any of Figures 1 to 7 of the accompanying drawings.

22. A vacuum cleaner substantially as described herein with reference to and/or as illustrated in any of Figures 1 to 7 of the accompanying drawings.

Amendments to the claims have been filed as follows 1. An exhausting apparatus for a motor assembly that generates a suction force and has an air outlet, the apparatus comprising: a motor housing at least substantially enclosing the motor assembly and having an air discharging opening in fluid communication with the air outlet for exhausting air; an exhausting passage formed at least in part by the motor housing and in fluid communication with the air discharging opening; and a porous noise prevention board disposed in the exhausting passage, wherein a first portion of the air from the air outlet passes through the porous noise prevention board; wherein at least a portion of the motor housing has a porous noise prevention part, and wherein a second portion of the air from the air outlet passes through the porous noise prevention part.

* S - - - - S...

2. The apparatus according to claim 1, wherein the porous noise prevention board is made from a porous plastic of low density, the porous * noise prevention part is made from a porous plastic of high density, and the motor housing except for the porous noise prevention part is made from a plastic of high strength.

3. The apparatus according to claim 2, wherein a first amount of air passing through the porous noise prevention board is substantially the same as a second amount of air passing through the porous noise prevention part.

4. The apparatus according to claim 1, wherein the porous noise prevention board is in proximity to the air discharging opening of the motor housing in the exhausting passage.

5. The apparatus according to claim 4, wherein the porous noise prevention board is made from a porous plastic of low density, the porous noise prevention part is made from a porous plastic of high density, and the motor housing except for the porous noise prevention part is made from a plastic of high strength.

6. The apparatus according to claim 1, wherein the exhausting passage comprises an inner passage disposed in the motor housing and an outer passage disposed outside of the motor housing, and wherein the inner passage is spirally formed to spirally discharge the air from the air outlet.

7. The apparatus according to claim 6, wherein the motor housing comprises an inner passage partition and an outer passage partition so as to at least partially form the exhausting passage, and at east a portion of the inner passage partition is made from a porous material.

"s 8. The apparatus according to claim 7, wherein the porous noise prevention board is made from a porous material of low density, the inner passage partition of the motor housing is made from a porous material of high density, and the motor housing except for the inner passage partition is made

. from a plastic of high strength. * S..CLME: S S S * SS

9. A vacuum cleaner comprising: a cleaner body having a dust-collecting chamber and a motor chamber; a brush assembly connected with the dust-collecting chamber in fluid- communication and having an inlet for contaminants-laden air; a motor assembly mounted in the motor chamber to generate a suction force and having an air outlet; a motor housing at least substantially enclosing the motor assembly and having a discharging opening to exhaust the air discharged from the air outlet; an exhausting passage formed at least in part by the motor housing; and a porous noise prevention board disposed in the exhausting passage wherein a first portion of the air from the air outlet passes through the porous noise prevention board; wherein at least a portion of the motor housing comprises a porous noise prevention part, and wherein a second portion of the air from the air outlet passes through the porous noise prevention part.

10. The cleaner according to claim 9, wherein the porous noise prevention board is mounted in proximity to the discharging opening of the motor housing in the exhausting passage.

11. The cleaner according to claim 9, wherein the porous noise prevention board is made from a porous plastic of low density, the porous noise prevention part is made from a porous plastic of high density, and the motor housing except for the porous noise prevention part is made from a plastic of high strength.

12. The cleaner according to claim 10, wherein the porous noise : * prevention board is made from a porous plastic of low density, the porous :::.:. noise prevention part is made from a porous plastic of high density, and the motor housing except for the porous noise prevention part is made from a plastic of high strength.

I..... * I

13. The cleaner according to claim 11, wherein a first amount of air I..

passing through the porous noise prevention board is substantially the same as a second amount of air passing through the porous noise prevention part.

14. The cleaner according to claim 12, wherein a first amount of air passing through the porous noise prevention board is substantially the same as a second amount of air passing through the porous noise prevention part.

15. A method of reducing noise caused by a motor assembly that generates a suction force, the method comprising: passing a first portion of air discharged from the motor assembly through a first porous material having a first density; passing a second portion of air discharged from the motor assembly through a second porous material having a second density that is different from the first density; and exhausting the first and second portions of air to atmosphere. \1

16. The method of claim 15, further comprising forming at least a portion of a motor housing that substantially encloses the motor assembly from the second porous material.

17. The method of claim 16, further comprising forming at least a portion of the motor housing from a rigid material.

18. The method of claim 15, further comprising guiding at least a portion of the air discharged from the motor assembly in a spiral path about the motor assembly.

19. The method of claim 18, wherein the spiral path is at least partially defined by the second porous material. * ** * * *