AU2014208727A1 - Cyclone separation device and electric vacuum cleaner using same - Google Patents

Abstract

This invention is provided with: an inlet (212) into which dust-containing air from an external air path flows; a swirl chamber (218), formed so as to have a substantially cylindrical shape, for swirling the dust-containing air which has flowed in from the inlet (212) and separating air and dust from each other; an outside-side-wall dust-collecting chamber (235) for collecting dust separated from the dust-containing air via a side wall opening (213) opening in a side wall (211a) of an upper cylindrical part (211) of the swirl chamber (218); and a discharge port (244) for discharging air separated from the dust-containing air in the swirl chamber. A rib (220) for suppressing the wind noise of the airflow passing through the side wall opening (213) is provided to the side wall opening (213).

Description

- 1 Description Title of Invention CYCLONE SEPARATION DEVICE AND ELECTRIC VACUUM CLEANER USING SAME Technical Field [0001] The present invention relates to a cyclone separation device and an electric vacuum cleaner using the cyclone separation device, and more particularly to a reduction in noise of the cyclone separation device. Background Art [0002] In a general cyclone separation device, air containing dust having flowed into a cyclone separation device is separated into dust and clean air by a centrifugal force in a swirl chamber. The separated dust is captured in a dust collection chamber, and clean air is discharged from the cyclone separation device through a discharge pipe. At this time, due to a high wind speed of a swirl airflow in the swirl chamber or the discharge pipe, noise caused by the swirl airflow is a problem. To reduce this noise, technologies are disclosed intended to prevent turbulence in a swirl chamber (including a communication air trunk that communicates with a dust collection chamber) or a discharge pipe.

-2 For example, Patent Literature 1 discloses a noise reducing rib that protrudes from an inner wall of a discharge pipe toward a center and includes a curved portion and a linear portion. Patent Literature 2 discloses a cyclone separation device including a vibration-proof rib in a discharge pipe for reducing vibration noise caused by vibration when air containing dust swirls in a swirl chamber. Further, Patent Literature 3 discloses an electric vacuum cleaner including serrations (teeth) in a communication port from a swirl chamber to a dust collection chamber. Citation List Patent Literature [0003] Patent Literature 1: Japanese Patent Laid-Open No. 2006-55622 Patent Literature 2: Japanese Patent Laid-Open No. 2011-212172 Patent Literature 3: Japanese Patent No. 4331656 Summary of Invention Problem to be Solved by the Invention [0004] However, the conventional technologies disclosed in Patent Literatures 1 and 2 described above have insufficient measures against airflow noise generated from a dust moving passage or a zero-order opening in a cyclone separation device including the dust moving passage from a swirl chamber to a dust collection chamber or the zero-order opening provided for separating relatively large dust from air containing dust.

-3 Also, Patent Literature 3 discloses providing serrations in a communication port from a swirl chamber to a dust collection chamber, but has insufficient measures against catching of hair or cotton dust or an increase in noise due to pressure loss because the serrations are provided in a middle of an air trunk of air containing dust. [0005] Also, in a cyclone separation device including a zero-order opening that separates relatively large dust from air containing dust swirling in a swirl chamber, airflow noise having a peak at a particular frequency component is generated when the air containing dust passes through the zero-order opening. [0006] The present invention is achieved to solve the above described problems, and has an object to provide a cyclone separation device that reduces airflow noise generated when air containing dust passes through a zero-order opening that separates relatively large dust from the air containing dust swirling in a swirl chamber, and prevents catching of dust or pressure loss in the zero-order opening, and an electric vacuum cleaner using the cyclone separation device. Means for Solving the Problem [0007] To solve the above described problems, it is sufficient to provide a cyclone separation device comprising: an inlet through which air containing dust from an external air trunk flows in; a swirl chamber that is formed to be substantially cylindrical, and swirls the air containing dust having flowed in through the inlet to separate air and dust; an out-of-side-wall dust collection chamber that accumulates the dust separated from the -4 air containing dust through a side wall opening that opens in a side wall of a cylindrical portion of the swirl chamber; and a discharge port that discharges the air separated from the air containing dust in the swirl chamber, wherein the side wall opening includes a rib that prevents wind noise of an airflow passing through the side wall opening. Advantageous Effect of Invention [0008] With the cyclone separation device and the electric vacuum cleaner using same according to the present invention, adopting the above described configuration can prevent wind noise of an airflow passing through a side wall opening. Brief Description of Drawings [0009] Figure 1 is a perspective view of an electric vacuum cleaner according to Embodiment 1 of the present invention. Figure 2 is a perspective view of a cleaner body of the electric vacuum cleaner according to Embodiment 1 of the present invention. Figure 3 is a top view of the cleaner body of the electric vacuum cleaner according to Embodiment 1 of the present invention. Figure 4 is an A-A sectional view of the cleaner body in Figure 3 of the electric vacuum cleaner according to Embodiment 1 of the present invention. Figure 5 is a perspective view of the cleaner body of the electric vacuum cleaner according to Embodiment 1 of the present invention, with a cyclone separation device being removed.

-5 Figure 6 is a top view of the cyclone separation device according to Embodiment 1 of the present invention. Figure 7 is a bottom view of the cyclone separation device according to Embodiment 1 of the present invention. Figure 8 is a B-B sectional view of the cyclone separation device in Figure 6 according to Embodiment 1 of the present invention. Figure 9 illustrates a configuration of a rib provided in a side wall opening that is an essential portion of the cyclone separation device according to Embodiment 1 of the present invention, with a dust collection portion case being removed. Figure 10 is a C-C sectional view of the cyclone separation device in Figure 9 according to Embodiment 1 of the present invention. Figure 11 illustrates a configuration of a rib provided in a side wall opening that is an essential portion of a cyclone separation device according to Embodiment 2 of the present invention, with a dust collection portion case being removed. Figure 12 illustrates an advantage of the cyclone separation devices according to Embodiments 1 and 2 of the present invention. Figure 13 illustrates an advantage of the cyclone separation devices according to Embodiments 1 and 2 of the present invention. Figure 14 illustrates an advantage of the cyclone separation device according to Embodiment 1 of the present invention. Figure 15 illustrates an advantage of the cyclone separation device according to Embodiment 1 of the present invention. Figure 16 illustrates an advantage of the cyclone separation device according to Embodiment 2 of the present invention.

-6 Figure 17 illustrates an advantage of the cyclone separation device according to Embodiment 2 of the present invention. Description of Embodiments [0010] Embodiment 1 Figure 1 is a perspective view of an electric vacuum cleaner according to Embodiment 1. Figure 2 is a perspective view of a cleaner body of the electric vacuum cleaner according to Embodiment 1 of the present invention. Figure 3 is a top view of the cleaner body of the electric vacuum cleaner according to Embodiment 1 of the present invention. Figure 4 is an A-A sectional view of the cleaner body in Figure 3 of the electric vacuum cleaner according to Embodiment 1 of the present invention. Figure 5 is a perspective view of the cleaner body of the electric vacuum cleaner according to Embodiment 1 of the present invention, with a cyclone separation device being removed. Figure 6 is a top view of the cyclone separation device according to Embodiment 1 of the present invention. Figure 7 is a bottom view of the cyclone separation device according to Embodiment 1 of the present invention. Figure 8 is a B-B sectional view of the cyclone separation device in Figure 6 according to Embodiment 1 of the present invention. Figure 9 illustrates a configuration of a rib provided in a side wall opening that is an essential portion of the cyclone separation device according to Embodiment 1 of the present invention, with a dust collection portion case being removed. Figure 10 is a C-C sectional view of the cyclone separation device in Figure 9 according to Embodiment 1 of the present invention. In the drawings, the same components are denoted by the same reference numerals. Figure 12 illustrates an advantage of the -7 cyclone separation devices according to Embodiments 1 and 2 of the present invention. Figure 13 illustrates an advantage of the cyclone separation devices according to Embodiments 1 and 2 of the present invention. Figure 14 illustrates an advantage of the cyclone separation device according to Embodiment 1 of the present invention. Figure 15 illustrates an advantage of the cyclone separation device according to Embodiment 1 of the present invention. [0011] Now, descriptions will be made with reference to Figures 1 to 10, and 12 to 15. An electric vacuum cleaner 1 according to Embodiment 1 includes a cleaner body 100, a suction hose 2 having a hose end 21 connected to the cleaner body 100, a connection pipe 3 having one end connected to the other end of the suction hose 2, a suction pipe 4 having one end connected to the other end of the connection pipe 3, and a suction port body 5 connected to the other end of the suction pipe 4. Hereinafter, with respect to the cleaner body 100, a direction of the suction hose 2 being connected is front, an opposite direction is rear, and right and left directions with respect to the front in the front-rear direction are right and left. [0012] The suction hose 2 is formed of a flexible bellows member. The connection pipe 3 is formed of a cylindrical member bent in a middle, and has a handle 31 held by a person who does cleaning for operation. The handle 31 has an operation switch 32 for controlling operations for starting or stopping driving or adjusting output of an electric blower 102 described later.

-8 The suction port body 5 sucks dust on a surface to be cleaned together with air from an opening formed downward, and includes a rotation brush (not shown) for scraping up dust on a floor or a carpet as a surface to be cleaned. A lead wire (not shown) is provided in the suction hose 2, the connection pipe 3, the suction pipe 4, and the suction port body 5, and transmits control signals from the operation switch 32 or electric power from the cleaner body 100 to the cleaner body 100 or the rotation brush in the suction port body 5. [0013] (Cleaner body) The cleaner body 100 includes an electric blower 102 that generates suction air using electric power supplied from a commercial power source through a power cord 101 (see Figure 4). A cyclone separation device 200 that separates dust and clean air from the suction air sucked together with dust from the surface to be cleaned by the electric blower 102 is removably mounted to the cleaner body 100 (see Figures 2 and 5). As described later, when the cyclone separation device 200 is mounted to the cleaner body 100, an air trunk is formed that passes through the suction port body 5, the suction pipe 4, the connection pipe 3, and the suction hose 2, then communicates with the cleaner body 100, the cyclone separation device 200, and the cleaner body 100 in this order, sucks air containing dust, separates dust and clean air, and discharges the clean air out of the cleaner body. [0014] In the front of the cleaner body 100, a hose connection port 103 is formed to which the hose end 21 of the suction hose 2 is connected.

-9 In a top surface of the cleaner body 100, a cyclone separation device housing portion 110 is formed that is substantially recessed and houses the cyclone separation device 200 obliquely with a front thereof downward. In a substantially middle of a bottom surface of the cyclone separation device housing portion 110, a handle housing portion 111 is formed that houses a cyclone separation device handle portion 201 (see Figure 5). [0015] On a rear right side of the cleaner body 100, a cyclone separation device connection port 104 is formed, and is connected to an inlet 212 (described later) through which air containing dust flows into the cyclone separation device 200. An intake duct 105 that provides communication between the hose connection port 103 and the cyclone separation device connection port 104 is formed in a right side of the cyclone separation device housing portion 110 (shown by a broken line in Figure 5). [0016] In a substantially middle in a lateral direction in the rear of the cleaner body 100, a cleaner body connection port 106 is formed adjacent to the cyclone separation device connection port 104, and is connected to a discharge port 244 (described later) through which clean air from which dust has been separated flows out of the cyclone separation device 200. The cleaner body connection port 106 communicates, via the electric blower 102, with an exhaust port (not shown) through which the clean air is exhausted to the outside of the cleaner body 100, and the cleaner body connection port 106, the electric blower 102, and the exhaust port constitute an exhaust air trunk (not shown). [0017] - 10 The cleaner body 100 includes a cleaner body handle 109 of a gate shape standing upward from opposite side surfaces. A cord reel that houses the power cord 101 is provided in the rear portion. A pair of wheels 107 with a fixed rotation axis are provided on a rear bottom surface. Further, a caster 108 with a rotatable rotation axis is provided on a front bottom surface. [0018] (Cyclone separation device) As shown in Figures 6 to 8, the cyclone separation device 200 has a generally substantially cylindrical shape, and includes a substantially cylindrical swirl portion case 210, a dust collection portion case 230 surrounding the swirl portion case 210, and a discharge portion case 240 connected to a top of the swirl portion case 210. [0019] The swirl portion case 210 includes the inlet 212, a swirl chamber 218, a side wall opening 213, and a rib 220 in claims as described later. The dust collection portion case 230 includes an out-of-side-wall dust collection chamber 235 in claims as described later. The discharge portion case 240 has a discharge port 244 in claims as described later. [0020] The swirl portion case 210 includes an upper cylindrical portion 211 having an open upper end and a substantially cylindrical upper portion, a conical portion 215 formed to be continuous with a lower end of the upper cylindrical portion 211, and a lower cylindrical portion 214 surrounding the conical portion 215. [0021] - 11 The inlet 212 through which air containing dust from the intake duct 105 as an external air trunk is formed above a side wall 211 a of the upper cylindrical portion 211. The side wall opening 213 is formed below the side wall 211 a of the upper cylindrical portion 211. The rib 220 described later is formed in the side wall opening 213. The lower cylindrical portion 214 that is cylindrical and has a lower end opening 214a in a lower end is formed continuously with the upper cylindrical portion 211 outside the conical portion 215. Further, a flange 21 lb that closes an upper end 233 of the dust collection portion case 230 described later is formed on an outer periphery of the upper cylindrical portion 211. [0022] An opening 215a is formed in a lower end of the conical portion 215, and located above the lower end opening 214a in the lower cylindrical portion 214. Insides of the upper cylindrical portion 211 and the conical portion 215 constitute the swirl chamber 218 that swirls air containing dust having flowed in through the inlet 212 to separate air and dust. A space surrounded by the lower cylindrical portion 214, a bottom 232 of the dust collection portion case 230 described later, and an outside of the conical portion 215 constitutes an out-of-conical-portion dust collection chamber 219. As described later, the discharge portion case 240 is connected to an upper end of the swirl portion case 210. [0023] The dust collection portion case 230 is a bottomed case having a substantially cylindrical outer wall portion 231 and the bottom 232, and has an open upper end 233. The upper end 233 is covered with the flange 21 lb formed on the outer periphery of the - 12 upper cylindrical portion 211 of the swirl portion case 210. A cylindrical bulkhead 232a stands on the bottom 232 so as to fit an inner peripheral wall of the lower end opening 214a in the lower cylindrical portion 214 of the swirl portion case 210. A seal member 234 such as packing is provided between a lower edge of the lower end opening 214a and the bottom 232. [0024] Also, a space formed between an inside of the outer wall portion 231 and an outside of the lower cylindrical portion 214 of the swirl portion case 210 constitutes the out-of-side-wall dust collection chamber 235, and relatively heavy dust having passed through the side wall opening 213 in the air containing dust swirling in the swirl chamber 218 accumulates in a lower portion of the out-of-side-wall dust collection chamber 235. [0025] The outer wall portion 231 has the cyclone separation device handle portion 201 for a user to carry the cyclone separation device 200 when discarding dust having accumulated on the bottom of the dust collection portion case 230 in the cyclone separation device 200. [0026] The dust collection portion case 230 is molded of highly transparent resin so that the user can check an amount of accumulating dust. At this time, the user sometimes feels uncomfortable because dust is clearly visible. To improve this, the dust collection portion case 230 may be molded of transparent resin, and a plated layer may be formed outside the transparent resin by half mirror deposition. [0027] The discharge portion case 240 includes a discharge pipe 241 and a lid 242.

- 13 The discharge pipe 241 includes a cylindrical portion 241a coaxial with a central axis of the upper cylindrical portion 211 of the swirl portion case 210, and a conical portion 241b continuous with a lower portion of the cylindrical portion 241a. Many micropores 241c are bored in a lower portion of the cylindrical portion 241a and a conical surface of the conical portion 241b. [0028] An inside of the lid 242 constitutes a discharge duct 243 having one end communicating with an upper end opening of the discharge pipe 241, and bent with respect to the central axis of the discharge pipe 241. The other end of the inside of the lid 242, that is, a discharge end of the discharge duct 243 constitutes a discharge port 244. The discharge port 244 is connected to the cleaner body connection port 106 of the cleaner body 100. [0029] (Rib provided in side wall opening) A configuration of the rib 220 formed in the side wall opening 213 that is an essential portion of the present invention will be described. As shown in Figure 9, the side wall opening 213 has a fan shape of a substantially quarter of a circle, and has a size of 45 mm in an axial direction of the upper cylindrical portion 211 and a size of 30 mm in a circumferential direction. An inner diameter of the upper cylindrical portion 211 is 80 mm. A thickness of the upper cylindrical portion 211 is 1.8 mm. [0030] As shown in Figures 9 and 10, the rib 220 prevents wind noise of an airflow passing through the side wall opening 213. The upper cylindrical portion 211 including - 14 the rib 220 is made of ABS resin, but may be made of thermoplastic resin such as polypropylene resin. The rib 220 extends tangentially of the side wall 211a along a swirl airflow from an upstream side of the swirl airflow in the swirl chamber 218 (a tangential height of 6 mm), and has a front end 221 that is a free end. An inner surface of the side wall 21 la and an inner surface of the rib 220 are smoothly continuous so that centers of curvature of the inner surfaces match a rotation axis of the upper cylindrical portion 211. An outer surface of the rib 220 is recessed toward the rotation axis of the upper cylindrical portion 211 from an outer surface of the side wall 211a. A thickness of the rib 220 is preferably 1 mm or less. As such, the thin rib 220 increases elasticity of the rib 220, and facilitates elastic deformation of the free end at the front end. [0031] As shown in Figure 9, notches 222 may be provided in an upper end and a lower end of the rib 220. Providing the notches 222 (each having a width of about 1 mm) in the upper end and the lower end further increases elasticity of the rib 220, and further facilitates elastic deformation of the free end at the front end. As described later, the elastic deformation can disturb a regular vortex generated by the airflow passing through the side wall opening 213, and reduce a noise level at a particular frequency. [0032] Next, an operation of the entire electric vacuum cleaner will be described. The power cord 101 included in the cleaner body 100 is connected to a receptacle, and the operation switch 32 is operated to drive the electric blower 102. Then, the electric blower 102 generates suction air, and air containing dust on the surface to be cleaned passes through the suction port body 5, the suction pipe 4, the connection pipe 3, - 15 and the suction hose 2, and is sucked from the hose connection port 103 into the cleaner body 100. Then, the air containing dust passes from the hose connection port 103 through the intake duct 105, and is sucked from the cyclone separation device connection port 104 through the inlet 212 into the cyclone separation device 200. The operation in the cyclone separation device 200 will be described later. [0033] Clean air from which dust has been separated in the cyclone separation device 200 passes through the discharge port 244 in the cyclone separation device 200, and is again sucked from the cleaner body connection port 106 into the cleaner body 100. The clean air having sucked into the cleaner body 100 passes through the electric blower 102, and is exhausted from the exhaust port to the outside of the cleaner body 100. [0034] Next, the operation in the cyclone separation device 200 will be described. The air containing dust sucked from the inlet 212 is introduced into the swirl chamber 218, and forms a swirl airflow that swirls along the side wall 21 la of the upper cylindrical portion 211 of the swirl portion case 210 (see a solid arrow in Figure 10). The swirl airflow flows downward (toward the conical portion 215) while forming a forced vortex region with a high flow rate near the central axis of the upper cylindrical portion 211 and a free vortex region with a low flow rate outside the forced vortex region. [0035] A centrifugal force is applied to the dust contained in the swirl airflow in the swirl chamber 218. For example, relatively large dust such as fiber dust or hair (such dust is hereinafter referred to as "dust a") falls in the swirl chamber 218 while being pressed against the side wall 211a of the upper cylindrical portion 211. When reaching the - 16 height of the side wall opening 213, the dust c is separated from the swirl airflow, and fed through the side wall opening 213 to the out-of-side-wall dust collection chamber 235. The dust a having entered the out-of-side-wall dust collection chamber 235 from the side wall opening 213 falls in the out-of-side-wall dust collection chamber 235 while moving in the same direction as the direction of the airflow swirling in swirl chamber 218, reaches a lowermost portion of the out-of-side-wall dust collection chamber 235, and is collected. [0036] On the other hand, dust that has not entered the out-of-side-wall dust collection chamber 235 from the side wall opening 213 travels downward while swirling in the swirl chamber 218 on the airflow in the swirl chamber 218. Relatively small dust such as sand dust or fine fiber dust (such dust is hereinafter referred to as "dust P") passes through the opening 215a, falls into the out-of-conical-portion dust collection chamber 219, and is captured. [0037] When the airflow swirling in the swirl chamber 218 reaches the lowermost portion of the swirl chamber 218, that is, the lower end of the conical portion 215, the airflow changes its traveling direction to an upward direction, and rises along the central axis of the swirl chamber 218. The dust a and the dust P are removed from the air that forms the rising airflow. The airflow from which the dust a and the dust P are removed (clean air) passes through the discharge pipe 241 and the discharge duct 243, and is discharged from the discharge port 244 to the outside of the cyclone separation device 200. [0038] - 17 Next, an operation of the rib 220 on the airflow passing through the side wall opening 213 will be described. Figures 12 and 13 show examples of measured values of frequency components at noise levels without the rib 220 in the side wall opening 213. Figures 14 and 15 show examples of measured values of frequency components at noise levels with the rib 220 in the side wall opening 213. In each drawing, the abscissa represents frequency in a range of 100 Hz to 10000 Hz. The ordinate represents noise level (dB). [0039] As a measurement condition, power consumption of the electric blower 102 is 850 W in each case. Figure 12 shows results of measurement at a position 1.5 m above a floor surface passing through a center in front-rear and lateral directions of the cleaner body 100, and Figure 13 shows results of measurement at a position 1.5 m left from the center in the front-rear and lateral directions of the cleaner body 100. [0040] An average value of noise levels measured by a power meter is 65.5 dB in Figure 12 and 65.2 dB in Figure 13. The average value is 65.2 dB in Figure 14 and 62.7 dB in Figure 15. As such, it is found that providing the rib 220 reduces the average value of the noise levels, and particularly reduces the average value of the noise levels in the left position from the center in the front-rear and lateral directions of the cleaner body 100. [0041] Also, noise levels at 1000 Hz as a particular frequency are compared (in the drawings, portions surrounded by ellipses). The frequency of 1000 Hz is chosen because noise having a peak at 1000 Hz is not generated when the side wall opening 213 is not formed in the side wall 211 a of the upper cylindrical portion 211, and also noise at - 18 the frequency of 1000 Hz offends the ear, and a reduction in noise level at 1000 Hz is aimed at. It is found that the noise levels at 1000 Hz in Figures 14 and 15 are reduced as compared to the noise levels at 1000 Hz in Figures 12 and 13. [0042] An action of the rib 220 will be described. When a swirl airflow flows from the side wall opening 213 formed in the side wall 21 la of the upper cylindrical portion 211 into the out-of-side-wall dust collection chamber 235, according to the same principle as whistling, the airflow flows tangentially from the upstream side of the swirl airflow in the side wall opening 213 at a fixed speed, and thus a Karman vortex with alternately changing swirl directions is generated from an edge of the side wall opening 213 on a downstream side of the swirl airflow, and periodically changes density of air. This generates large wind noise having a peak at a particular frequency component. [0043] When the rib 220 is provided at the edge of the side wall opening 213 on the upstream side of the swirl airflow, the front end 221 of the rib 220 is the free end, and thus the swirl airflow minutely vibrates the free end. This is because the thickness of the rib 220 of 1 mm or less increases elasticity. Thus, the airflow at the fixed speed flowing tangentially from the upstream side is disturbed to be irregular when passing through the rib 220, and wind noise does not have a peak at the particular frequency. [0044] Also, providing the notches 222 in the upper end and the lower end of the rib 220 further increases elasticity of the rib 220, and further facilitates elastic deformation of the - 19 free end at the front end. This further increases an effect of reducing wind noise at the particular frequency. [0045] The rib 220 extends tangentially of the side wall 21 la from the upstream side of the swirl airflow in the upper cylindrical portion 211 of the swirl chamber 218, and has the front end 221 that is the free end. This prevents catching of hair or cotton dust, and also prevents generation of noise due to pressure loss. [0046] As such, the cyclone separation device according to Embodiment 1 includes: the inlet through which air containing dust from the external air trunk flows in; the swirl chamber that is formed to be substantially cylindrical, and swirls the air containing dust having flowed in through the inlet to separate air and dust; the out-of-side-wall dust collection chamber that accumulates the dust separated from the air containing dust through the side wall opening that opens in the side wall of the cylindrical portion of the swirl chamber; and the discharge port that discharges the air separated from the air containing dust in the swirl chamber, and the side wall opening includes the rib that prevents wind noise of the airflow passing through the side wall opening. Thus, the swirl airflow minutely vibrates the free end of the rib, the airflow at the fixed speed flowing tangentially from the upstream side is disturbed to be irregular when passing through the rib, and wind noise does not have a peak at the particular frequency. This can prevent wind noise of the airflow passing through the side wall opening, and provide a cyclone separation device with little noise and an electric vacuum cleaner using same. [0047] - 20 Providing the notches in the upper end and the lower end of the rib further increases elasticity of the rib, and further facilitates elastic deformation of the free end at the front end. This further increases an effect of reducing wind noise at the particular frequency. [0048] The rib extends tangentially of the side wall of the swirl chamber from the upstream side of the swirl airflow in the upper cylindrical portion of the swirl chamber, and has the front end that is the free end. This prevents catching of hair or cotton dust, and also prevents generation of noise due to pressure loss. [0049] Embodiment 2 Figure 11 illustrates a configuration of a rib provided in a side wall opening that is an essential portion of a cyclone separation device according to Embodiment 2 of the present invention, with a dust collection portion case 230 being removed. Figure 16 illustrates an advantage of the cyclone separation device according to Embodiment 2 of the present invention. Figure 17 illustrates an advantage of the cyclone separation device according to Embodiment 2 of the present invention. In each drawing, the abscissa represents frequency in a range of 100 Hz to 10000 Hz. The ordinate represents noise level (dB). Embodiment 2 is different from Embodiment 1 only in the shape of the rib 220 provided in the side wall opening 213, and other configurations are the same as those in Embodiment 1. [0050] - 21 As shown in Figure 11, a rib 223 provided in the side wall opening 213 includes serrations alternately having peaks 223a and valleys 223b. A height from a bottom of the valley 223b to a top of the peak 223a is about 6 mm to 9 mm. Each serration is referred to as a chevron in heraldry. As shown in Figure 11, the rib 223 has five peaks 223a and six valleys 223b. The valleys at an upper end and a lower end of the rib 223 also serve as the notches 222 in Embodiment 1. [0051] Next, an operation of the rib 223 on the airflow passing through the side wall opening 213 will be described. Figures 16 and 17 show examples of measured values of frequency components at noise levels with the rib 223 in the side wall opening 213. A measurement condition is the same as described in Embodiment 1, and power consumption of the electric blower 102 is 850 W. Figure 16 shows results of measurement at a position 1.5 m above a floor surface passing through a center in front rear and lateral directions of the cleaner body 100, and Figure 17 shows results of measurement at a position 1.5 m left from the center in the front-rear and lateral directions of the cleaner body 100. Figures 16 and 17 are also compared with Figures 12 and 13 showing examples of measured values of frequency components at noise levels without the rib 223 in the side wall opening 213. [0052] As in Embodiment 1, an average value of noise levels measured by a power meter is 65.5 dB in Figure 12 without the rib 223 in the side wall opening, and 65.2 dB in Figure 13. The average value is 64.4 dB in Figure 16 and 61.2 dB in Figure 17. As such, it is found that providing the rib 223 reduces the average value of the noise levels, - 22 and particularly reduces the average value of the noise levels in the left position from the center in the front-rear and lateral directions of the cleaner body 100. [0053] Also as in Embodiment 1, noise levels at 1000 Hz as a particular frequency are compared (in the drawings, portions surrounded by ellipses). It is found that the noise levels at 1000 Hz in Figures 16 and 17 are reduced as compared to the noise levels at 1000 Hz in Figures 12 and 13. [0054] An action of the rib 223 will be described. As described in Embodiment 1, when a swirl airflow flows from the side wall opening 213 in the side wall 211 a of the upper cylindrical portion 211 into the out-of side-wall dust collection chamber 235, the airflow flows tangentially from the upstream side of the swirl airflow in the side wall opening 213 at a fixed speed, and thus a Karman vortex with alternately changing swirl directions is generated from an end of the side wall opening 213 on a downstream side of the swirl airflow, and periodically changes density of air. This generates large wind noise having a peak at a particular frequency component. [0055] When the rib 223 including serrations alternately having the peaks 223a and the valleys 223b is provided at the end of the side wall opening 213 on the upstream side of the swirl airflow, the front ends (peaks 223a) of the rib 223 are free ends, and thus the swirl airflow minutely vibrates the free ends. Also, providing notches 222 (each having a width of about 1 mm) in the upper end and the lower end of the rib 223 further - 23 increases elasticity of the rib 223, and further facilitates elastic deformation of the free ends at the front ends. [0056] Further, when the swirl airflow passes through the rib 223, a swirl airflow with a high flow rate in the swirl chamber 218 and a swirl airflow with a low flow rate in the out-of-side-wall dust collection chamber 235 are not mixed at one time, but are gradually mixed on a line connecting the peaks 223a and the valleys 223b, thereby preventing development of a vortex that causes noise. This can further reduce noise. [0057] Also, providing the notches 222 in the upper end and the lower end of the rib 223 further increases elasticity of the rib 223, and further facilitates elastic deformation of the free ends at the front ends. This further increases an effect of reducing wind noise at the particular frequency. [0058] The rib 223 extends tangentially of the side wall 211 a from the upstream side of the swirl airflow in the upper cylindrical portion 211 of the swirl chamber 218, and has the front ends (peaks 223 a) that are the free ends. This prevents catching of hair or cotton dust, and also prevents generation of noise due to pressure loss. [0059] In Embodiment 2, as in Embodiment 1, the thickness of the rib 223 is 1 mm or less, but may be 1.8 mm that is the same thickness as the upper cylindrical portion 211. This increases rigidity at the front ends of the rib 223 to reduce vibration, but the airflows are gradually mixed on the line connecting the peaks 223a and the valleys 223b, thereby preventing development of a vortex that causes noise.

- 24 [0060] As such, the cyclone separation device according to Embodiment 2 includes: the inlet through which air containing dust from the external air trunk flows in; the swirl chamber that is formed to be substantially cylindrical, and swirls the air containing dust having flowed in through the inlet to separate air and dust; the out-of-side-wall dust collection chamber that accumulates the dust separated from the air containing dust through the side wall opening that opens in the side wall of the cylindrical portion of the swirl chamber; and the discharge port that discharges the air separated from the air containing dust in the swirl chamber, and the side wall opening includes the rib that prevents wind noise of the airflow passing through the side wall opening, and the rib includes serrations alternately having the peaks and the valleys. Thus, the swirl airflow minutely vibrates the free ends of the rib, and the airflow at the fixed speed flowing tangentially from the upstream side is disturbed to be irregular when passing through the rib. Further, the airflows are gradually mixed on the line connecting the peaks and the valleys, thereby preventing development of a vortex that causes noise. Thus, wind noise does not have a peak at the particular frequency. This can prevent wind noise of the airflow passing through the side wall opening, and provide a cyclone separation device with little noise and an electric vacuum cleaner using same. [0061] Providing the notches in the upper end and the lower end of the rib further increases elasticity of the rib, and further facilitates elastic deformation of the free ends at the front ends. This further increases an effect of reducing wind noise at the particular frequency. [0062] - 25 The rib extends tangentially of the side wall of the swirl chamber from the upstream side of the swirl airflow in the upper cylindrical portion of the swirl chamber, and has the front ends that are the free ends. This prevents catching of hair or cotton dust, and also prevents generation of noise due to pressure loss. Description of Reference Characters [0063] 1; electric vacuum cleaner 2; suction hose 21; hose end 3; connection pipe 31; handle 32; operation switch 4; suction pipe 5; suction port body 100; cleaner body 101; power cord 102; electric blower 103; hose connection port 104; cyclone separation device connection port 105; intake duct 106; cleaner body connection port 107; wheel 108; caster - 26 109; cleaner body handle 110; cyclone separation device housing portion 111; handle housing portion 200; cyclone separation device 201; cyclone separation device handle portion 210; swirl portion case 211; upper cylindrical portion 211a; side wall 211b; flange 212; inlet 213; side wall opening 214; lower cylindrical portion 214a; lower end opening 215; conical portion 215a; opening 218; swirl chamber 219; out-of-conical-portion dust collection chamber 220; rib 221; front end 222; notch 223; rib 223a; peak 223b; valley 230; dust collection portion case - 27 231; outer wall portion 232; bottom 232a; bulkhead 233; upper end 234; seal member 235; out-of-side-wall dust collection chamber 240; discharge portion case 241; discharge pipe 241a; cylindrical portion 241b; conical portion 241c; micropore 242; lid 243; discharge duct 244; discharge port