CN106560115B

CN106560115B - Air supply device

Info

Publication number: CN106560115B
Application number: CN201610849772.1A
Authority: CN
Inventors: 友寄泰秀; 冈本佑介
Original assignee: Maxell Holdings Ltd
Current assignee: Maxell Ltd
Priority date: 2015-10-05
Filing date: 2016-09-26
Publication date: 2021-01-26
Anticipated expiration: 2036-09-26
Also published as: CN106560115A; JP2017070337A; JP6704232B2

Abstract

The invention provides an air supply device, which can restrain noise generated by fan blades of an air supply fan. A blower fan (4) is provided inside a cylindrical housing (6) having an inlet (6a) and an outlet (6 b). The blower fan (4) is configured by arranging a plurality of fan blades (4a) around a fan boss (4 b). A front concave flange (85) and a rear concave flange (86) for reducing fan noise are formed at the blade front edge of the sheet (4a) and the blade rear edge of the fan blade (4a), respectively. The adjacent pitch (P1) of the recessed portions (85a) of the front recessed flange (85) is set to be larger than the adjacent pitch (P2) of the recessed portions (86a) of the rear recessed flange (86).

Description

Air supply device

Technical Field

The present invention relates to an air blower mounted on a hair dryer or the like, and more particularly to an air blower capable of reducing the noise level of air blowing noise during use.

Background

In connection with the present invention, patent document 1 discloses a structure of a blower fan in which a plurality of fan blades are provided on the outer periphery of a fan boss. The axial fan, in which a plurality of blades are integrally provided on the outer periphery of the projection, is provided inside the cylindrical casing. The plurality of blades have a pressure surface on the side of pressing air and a negative pressure surface on the opposite side.

Documents of the prior art

Patent document 1: japanese laid-open patent publication No. 9-191924

In the axial flow fan of patent document 1, since the trailing edge of the blade is formed of a single arc, the airflow on the pressure surface side and the airflow on the negative pressure surface side join together almost simultaneously, and the vortex becomes large, which causes noise.

Disclosure of Invention

The invention aims to provide an air supply device capable of suppressing noise generated by fan blades of an air supply fan.

The air blower of the present invention includes an air blower fan 4 inside a cylindrical casing 6 having an inlet 6a and an outlet 6 b. The blower fan 4 is configured by arranging a plurality of fan blades 4a around a fan boss 4 b. A front concave flange 85 and a rear concave flange 86 for reducing fan noise are formed at the blade front edge of the fan blade 4a and the blade rear edge of the fan blade 4a, respectively.

The adjacent pitch P1 of the recessed portion 85a of the front concave flange 85 is set to be greater than the adjacent pitch P2 of the recessed portion 86a of the rear concave flange 86.

The concave-convex depth j1 of the front concave flange 85 is set to be smaller than the concave-convex depth j2 of the rear concave flange 86.

Also, the concave portion 85a of the front concave flange 85 and the concave portion 86a of the rear concave flange 86 are formed by curved edges, respectively. The radius of curvature k1 of the concave portion 85a of the front concave flange 85 is set to be larger than the radius of curvature k2 of the concave portion 86a of the rear concave flange 86.

The fan blades 4a are formed of a fiber-reinforced plastic material.

The effects of the invention are as follows.

In the blower device of the present invention, if the front concave flange 85 and the rear concave flange 86 are formed on the blade front edge and the blade rear edge of the fan blade 4a, respectively, the fan noise when the blower fan 4 is driven to rotate can be reduced. Specifically, when the air is pressed by the pressing surface of the fan blade 4a, the forward recessed flange 85 can disperse the pressing reaction force of the air acting on the blade front edge by the recessed portion 85a and the raised portion 85b of the forward recessed flange 85, and can suppress the generation of noise due to the blade front edge vibrating in the blade thickness direction. Further, the timing at which the airflow is pressed by the pressing surface of the blade front edge is shifted between the concave portion 85a and the convex portion 85b, so that the entire blade front edge can be suppressed from vibrating in the blade thickness direction at the same time.

Similarly, when the rear concave flange 86 is provided, when the airflow on the pressure surface side and the airflow on the negative pressure surface side merge at the blade trailing edge, the merged flow occurs earlier at the concave portion 86a and later at the convex portion 86b, and the two airflows gradually merge. As a result, the rear vortex generated at the blade trailing edge is subdivided, and the velocity loss of the blade rear flow is reduced. Therefore, it is possible to simultaneously suppress noise generated by the vibration of the blade leading edge and noise in the case where the velocity loss of the blade backward flow is large, and it is possible to reduce fan noise.

When the adjacent pitch P1 of the recessed portions 85a of the front concave flange 85 is set to be larger than the adjacent pitch P2 of the recessed portions 86a of the rear concave flange 86, the area of the projecting portions 85b of the front concave flange 85 can be increased, the structural strength of the projecting portions 85b can be improved, and the occurrence of noise due to vibration of the projecting portions 85b in the blade thickness direction can be further effectively suppressed.

If the concave-convex depth j1 of the front concave flange 85 is set to be smaller than the concave-convex depth j2 of the rear concave flange 86, the concave-convex depth j1 is small and accordingly is difficult to deflect, and the occurrence of noise due to vibration of the convex portion 85b of the front concave flange 85 in the blade thickness direction can be further effectively suppressed.

If the bending radius k1 of the concave portion 85a of the front concave flange 85 is set to be larger than the bending radius k2 of the concave portion 86a of the rear concave flange 86, the change in the cross section of the convex portion 85b of the front concave flange 85 can be made gentle, and the structural strength can be improved, and accordingly, the occurrence of noise due to vibration of the convex portion 85b of the front concave flange 85 in the blade thickness direction can be further effectively suppressed.

If the fan blades 4a are formed of a fiber-reinforced plastic material, the structural strength of the fan blades 4a can be increased to make them less likely to vibrate, and fan noise caused by the vibration of the fan blades 4a can be reduced, as compared to the case where the fan blades 4a are formed of only a plastic material. Further, if the gap between the housing 6 and the fan blades 4a changes in size with a change in the rotational speed, the gap becomes a cause of noise. In this configuration, even if the rotation speed is changed, since the fan blades 4a are reinforced, the deformation of the fan blades 4a due to the centrifugal force, that is, the change in the size of the gap can be suppressed, and the noise in the gap portion can be suppressed as much as possible.

Drawings

Fig. 1 is a longitudinal sectional view of a blowing structure of a blower on which a blowing device of the present invention is mounted.

Figure 2 is a side view of a hair dryer.

Fig. 3 is an exploded rear view showing components on the suction grill side of the blower.

Fig. 4 is a partially cut-away exploded side view showing a peripheral structure of the suction grill.

FIG. 5 is a longitudinal sectional view showing a detailed structure of the gas suction body.

Fig. 6 is a sectional view showing an attachment structure of the suction grill.

Fig. 7 is a partially cut-away side view showing an attachment structure of the rear cylinder.

Fig. 8 is a sectional view taken along line a-a of fig. 1.

Fig. 9 is a rear view of the blower fan.

Fig. 10 is an enlarged rear view showing a detailed configuration of the fan blade.

Fig. 11 is an explanatory diagram showing the relative dimensions of the air blowing structure portion.

In the figure:

1-main body case, 4-blower fan, 5-motor, 6-fan case (casing), 9-rear opening, 11-suction grille, 12-suction body, 23-11 ventilation grid, 24-11 assembly part, 25-23 ventilation hole, 29-suction inlet, 30-rectification grid, 45-front cylinder, 46-rear cylinder, 48-second filter screen, 53-main cylinder, 54, 55-cover wall, 60-inner clamping wall, 61-outer clamping wall, 68-press ring, 85-front concave flange, 86-rear concave flange.

Detailed Description

(embodiment) fig. 1 to 11 show an embodiment in which the air blowing device of the present invention is applied to a hair dryer. The front-back, left-right, and up-down in the present invention follow the intersecting arrows shown in fig. 2, and the display of the front-back, left-right, and up-down marked in the vicinity of the arrows. In fig. 2, the hair dryer includes a main body casing 1 formed of a hollow tube, and a handle 3 connected to the main body casing 1 so as to be foldable about a shaft 2.

In fig. 1 and 2, the main body casing 1 is formed in a hollow tubular shape by joining the left and right divided

casings

1a and 1b and the upper casing 1c, and has a rear opening 9 at a rear end thereof and a blow-out port 13 at a front end thereof. An axial flow type blower fan 4 for blowing dry air, a motor 5 for driving the fan 4 to rotate, and a cylindrical fan case (casing) 6 for supporting the fan 4 and the fan 5 are disposed in the main body case 1, and a heating unit 7 is provided adjacent to an outlet 6b of the fan case 6. That is, the fan casing 6 is disposed in the main body casing 1 with the inlet 6a and the outlet 6b thereof positioned between the rear opening 9 and the air outlet 13 of the main body casing 1. As shown in fig. 1, a screw boss 26 is provided on the lower surface of the cylindrical wall of the fan case 6, and the fan case 6 is fixed to the main body case 1 by fastening the screw boss 26 to the left divided case 1b with a screw 27. The left and right divided

cases

1a and 1b are fastened and fixed by screws not shown.

The air blowing device of the present invention includes a fan case 6, a motor 5 supported by the fan case 6, and an air blowing fan 4 fixed to a rotation shaft of the motor 5. In the present embodiment, if the fan case 6 is omitted and the main body case 1 also serves as the fan case (casing) 6, the main body case 1 can be replaced with the fan case 6. The blower fan 4 integrally includes a fan boss 4b and four fan blades 4 a. A plurality of flow straightening vanes 15 are provided on the outlet 6b side of the fan housing 6, and a motor bracket 16 is provided at the center portion thereof. The motor 5 is attached to a bracket 16, and the blower fan 4 is fixed to an output shaft protruding from a rear end of the bracket 16. That is, the motor 5 and the blower fan 4 are supported by the fan case 6 via the motor bracket 16 and the flow straightener 15. The airflow that is pressurized and twisted by the blower fan 4 is rectified into a linear flow by the rectifying blades 15, and then guided to be sent toward the heating unit 7. A switch knob 8 for starting the motor 5 or switching the state of power supply to the heating unit 7 is provided on the front surface of the handle 3. An air volume switching knob 10 for changing the driving rotation speed of the motor 5 to switch the air volume of the blower fan 4 is provided behind the handle 3. In fig. 1, a suction grill 11 covering the inlet 6a of the fan casing 6 and a cylindrical air intake body 12 are disposed between the inlet 6a of the fan casing 6 and the rear opening 9 of the main body casing 1. A blow-out nozzle 14 (see fig. 2) is mounted on the blow-out port 13 of the main body casing 1.

In the hair dryer configured as described above, in order to greatly suppress noise when the blower fan 4 is driven and reduce the overall noise when in use, the suction grill 11 and the suction body 12 are arranged in this order between the blower fan 4 and the rear opening 9, in the order of the suction grill 11 and the suction body 12. As shown in fig. 3 and 4, the suction grill 11 integrally includes a partially spherical (concave curved) ventilation grid 23 bulging toward the blower fan 4, and a mounting portion 24 protruding toward the peripheral edge of the ventilation grid 23. The suction grill 11 is formed into a tea net shape by punching a perforated metal blank made of an aluminum plate, a thin steel plate, a stainless steel thin plate, or the like, and a set of vent holes 25 are formed in the vent net 23. In this embodiment, the vent hole 25 is formed only on the side of the concave curved surface of the vent net 23, and the vent hole 25 avoids the flange-shaped fitting portion 24 and the portion formed at the boundary portion between the concave curved surface and the fitting portion 24 (see fig. 5), but the vent hole 25 may be formed in the fitting portion 24.

The suction body 12 is composed of a front cylinder 45 and a rear cylinder 46 each made of a plastic molded product, and the rear cylinder 46 is provided with a suction port 29. A sieve 30 serving also as a first filter 47 and a second filter 48 are disposed in the vicinity of the front cylinder 45 and the rear cylinder 46 facing the suction port 29. The front cylinder 45 is a cylindrical body having front and rear openings, and has a cylinder wall with a diameter gradually increasing toward the fan housing 6, and is configured as an expanded cylinder wall (cylinder wall) 32 in which the cylinder wall from the inlet to the delivery outlet (outlet) 31 is gently curved.

A frame structure for receiving the second filter 48 is provided at a portion of the front cylinder 45 adjacent to the rear cylinder 46. As shown in fig. 3, the frame structure is composed of a circular center receiving frame 49 and an X-shaped support frame 50 for supporting the frame 49, and the center receiving frame 49 and the support frame 50 are flush with the tube end surface 51 of the front tube 45. The getter body 12 performs two functions simultaneously: the front barrel 45 has a function of reducing turbulent noise by a rectifying effect; and the function of the flow straightening net 30 and the second filter 48 to prevent hair, dust, and the like from being sucked into the fan housing 6. The rectifying mesh 30 preferably exhibits a rectifying effect, but may be a protective structure capable of preventing only the intrusion of hair or fingers.

The second filter 48 is formed of a flexible sheet-like material that can freely flex. More specifically, the filter is formed of a commercially available resin mesh in which thin plastic wires are crossed, and includes a set of vent holes 48a that are sufficiently smaller than the first filter 47, thereby preventing hairs and small dust from entering the inside of the fan housing 6. As shown in fig. 5, the second filter 48 is formed into a shallow dish shape by heating, and is integrated with the front barrel 45 by thermally welding the end surfaces thereof to the center frame 49, the support frame 50, and the barrel end surface 51. In a state where the intake air 12 is fitted to the rear opening 9 of the main body case 1, the front and rear surfaces of the second filter 48 are firmly held by the plastic center receiving frame 49 and the support frame 50 and the flow straightening net 30. That is, the second filter mesh 48 made of a flexible sheet-like soft material is firmly held by the center receiving frame 49 and the support frame 50, which are harder than the filter mesh 48, and the flow adjusting grid 30. Therefore, even when wind pressure due to the blowing action of the blower fan 4 or vacuum pressure of the vacuum cleaner acts on the second filter 48, the second filter 48 can be prevented from being largely deformed and damaged.

As shown in fig. 7, the rear tube 46 integrally includes a double-tube-shaped tube main portion 53 and cover

walls

54 and 55 projecting upward and downward from the tube main portion 53, and the inner wall of the tube main portion 53 serves as a bell-mouth-shaped suction port 29. By forming the suction port 29 in a bell mouth shape in this way, the flow of air sucked into the air intake body 12 can be smoothed, and the silencing effect can be improved. The suction port 29 and the above-mentioned expanding cylinder wall 32 are smoothly continuous, and the cross sections thereof are gentle S-shapes. The above-described rectification mesh 30 is integrally formed at the adjacent end of the rear tube 46 adjacent to the front tube 45. As shown in fig. 3, the rectifying mesh 30 is composed of quadruple circular rectifying ribs 56 arranged concentrically, and X-shaped intersecting ribs 57 supporting the rectifying ribs 56.

In order to improve the flow regulation effect of the suction port 29 and the silencing effect, as shown in fig. 5, the thickness T of the ventilation grid 23 of the suction grill 11 is set to be smaller than the rib length L1 in the ventilation direction of the flow regulation rib 56. In order to reliably exhibit the rectifying effect and to prevent the air inlet 29 from being blocked and the air resistance from increasing, the rib thickness L2 of the rectifying rib 56 is set to be smaller than the rib length L1 in the air flow direction of the rectifying rib 56.

Next, a fixing structure of the suction grill 11 to the fan casing 6, a connecting structure of the front cylinder 45 and the rear cylinder 46, a mounting structure of the rear cylinder 46 to the rear opening 9, and the like will be described.

As shown in fig. 5 and 6, the mounting portion 24 of the suction grill 11 is formed in a multiple cylindrical shape by an inner engaging wall 60 at the periphery of the ventilation grid 23 and an outer engaging wall 61 continuously bent in an L-shape from the inner engaging wall 60. Further, engaging claws 62 are integrally provided at four positions around the outer engaging wall 61, and engaging ribs 63 for engaging the engaging claws 62 are circumferentially projected on the outer peripheral surface of the fan housing 6. The suction grill 11 is integrated with the fan case 6 so as to be inseparable from the fan case 6 and so as not to be movable relative thereto by fitting the outer engagement wall 61 to the outer surface of the inlet 6a of the fan case 6 and engaging the engagement claws 62 with the engagement ribs 63. Since the inner engaging wall 60 and the outer engaging wall 61 sandwich the cylindrical wall of the fan housing 6 between the inside and the outside in this state, the suction grill 11 can be fixed to the fan housing 6 in a state of being immovable in the radial direction with respect to the fan housing 6, and in addition, the structural strength of the fan housing 6 is enhanced by the outer engaging wall 61 which is in close contact with the peripheral surface of the housing, and the generation of vibration noise of the fan housing 6 which receives vibration of the motor 5 can be suppressed. As shown in fig. 6, after the outer engaging wall 61 is assembled to the fan case 6, the claw tip of the engaging claw 62 is bent to engage with the engaging rib 63.

As shown in fig. 4, four rectangular coupling claws 64 are provided on the peripheral surface of the adjacent portion of the front tube 45 adjacent to the fan case 6 so as to project forward, and a rectangular coupling hole 65 is formed in the wall surface of each coupling claw 64. Coupling projections 66 that engage with the coupling holes 65 are formed at four positions on the circumferential surface of the fan housing 6. After the mounting portion 24 of the suction grill 11 is mounted to the fan case 6, the coupling claws 64 of the front cylinder 45 are brought into contact with the circumferential surface of the fan case 6, and the coupling holes 65 are press-fitted and engaged with the coupling projections 66, whereby the front cylinder 45 can be fixed to the fan case 6. In this attached state, the fitting portion 24 of the suction grill 11 is sandwiched and fixed between the cylinder end surface of the discharge port 31 of the front cylinder 45 and the fan housing 6, and therefore the suction grill 11 can be further firmly fixed. As can be understood from the above description, the suction grill 11 and the front barrel 45 are fixed to the fan case 6 so as not to be separable.

As shown in fig. 5, a pressing ring 68 is provided at a portion of the front cylinder 45 adjacent to the rear cylinder 46. The pressing ring 68 integrally includes a cylindrical wall 69 covering the peripheral edge of the second filter 48, and a coupling seat 70 receiving the front end of the suction port 29 of the rear cylinder 46. In order to temporarily fix the pressing ring 68 to the front tube 45, engaging holes 71 are formed at four positions of the tube wall 69, and ribs 72 corresponding to the engaging holes 71 are provided on the circumferential surface of the front tube 45. The pressing ring 68 is fitted to the front tube 45, and the rib 72 is dropped and engaged with the engagement hole 71, whereby the pressing ring 68 can be temporarily fixed to the front tube 45. In this state, the rear cylinder 46 is fitted to the rear opening 9 of the main body case 1, whereby the fixed pressing ring 68 can be pressed toward the front cylinder 45 by the rear cylinder 46. Therefore, when the hair dryer is used, the pressing ring 68 can be firmly fixed while being prevented from moving in the front-rear direction and the radial direction. Further, the second filter 48 fixed to the front tube 45 is firmly fixed by the press ring 68, and the second filter 48 can be reliably prevented from being separated from the front tube 45.

In a state where the press ring 68 is pressed and fixed by the rear cylinder 46, a gap E is secured between the cylinder end surface 51 of the front cylinder 45 and the cylinder end of the rear cylinder 46 facing the cylinder end surface 51. Since the gap E is sufficiently larger than the thickness of the second filter 48, even in a state where the pressing ring 68 is pressed and fixed to the cylinder end surface 51, the peripheral edge of the second filter 48 is not pressed by the cylinder end of the rear cylinder 46, and stress applied to the peripheral edge of the second filter 48 can be eliminated. Therefore, the peripheral edge portion of the second filter 48 that can be visually observed through the suction port 29 can be prevented from being damaged early.

As shown in fig. 7, in order to detachably attach the rear cylinder 46 to the rear opening 9, a positioning rib 74 is formed along the peripheral edges of the cylinder main portion 53 and the upper and

lower cover walls

54 and 55 of the rear cylinder 46. Locking claws 75 are formed at the left and right centers of the upper end of the upper cover wall 54, and fastening pieces 76 are formed at the left and right centers of the lower end of the lower cover wall 55. A pair of right and left engaging claws 77 are formed at the upper and lower centers of the tube main portion 53. On one side of the rear opening 9, positioning grooves 78 corresponding to the positioning ribs 74 are formed along the periphery thereof, locking grooves 79 for engaging the locking claws 75 are formed in the left and right center of the upper case 1c, and screw seats 80 are formed at the lower end of the left split case 1 b. Further, an engagement stepped portion 81 corresponding to the engagement claw 77 is formed in the upper and lower center of the left and right divided

cases

1a, 1 b.

By locking the locking claws 75 in the locking grooves 79, engaging the positioning ribs 74 with the positioning grooves 78, and press-fitting the engagement claws 77 in the engagement stepped portions 81 as shown in fig. 8, the rear tube 46 can be fitted to the rear opening 9 to close the rear surface of the main body casing 1. In this state, since the fastening pieces 76 enter the inner surface of the rear opening 9 and vertically face the screw seats 80, the rear cylinder 46 can be fixed to the body case 1 by screwing screws (countersunk screws) 82 inserted through the screw seats 80 into the fastening pieces 76. By loosening the screw 82 as necessary to remove the rear cylinder 46 from the rear opening 9, the rear cylinder 46 and the pressing ring 68 can be water-washed, and dust and the like adhering to the second filter 48 can be removed. As described above, in the state where the air intake body 12 is attached to the main body case 1, most of the air intake body protrudes rearward from the rear opening 9, and the rear opening 9 is closed by the rear cylinder 46. The attachment portion 24 of the suction grill 11 is located forward of the tube front end of the suction body 12.

In order to suppress the swirl and separation generated by the fan blades 4a of the blower fan 4 or the blade noise generated by the vibration of the fan blades 4a, the fan blades 4a are configured as follows. As shown in fig. 9 and 10, a front concave flange 85 is provided on the blade front edge on the downstream side in the rotational direction of the fan blade 4a, and a rear concave flange 86 is provided on the blade rear edge on the upstream side in the rotational direction of the fan blade 4 a. The arrow in fig. 9 indicates the rotation direction of the blower fan 4. The front concave flange 85 is formed by concave portions 85a and convex portions 85b which are gently curved, and the rear concave flange 86 is formed by concave portions 86a and convex portions 86b which have a larger number of concave and convex portions than the front concave flange 85. The blower fan 4 is entirely made of a fiber-reinforced plastic material, and the structural strength of the fan blades 4a is increased so as to be hard to vibrate. As the reinforcing fiber, glass fiber, carbon fiber, boron fiber, aramid fiber, or the like can be applied.

In this way, if the front concave flange 85 is formed in a wave shape by the plurality of concave portions 85a and the plurality of convex portions 85b, when air is pressed by the pressing surface (the side facing the flow straightener 15) of the fan blade 4a, the pressing reaction force of the air acting on the blade front edge is dispersed, and the blade front edge can be suppressed from vibrating in the blade thickness direction to generate noise. Further, the timing at which the airflow is pressed by the pressing surface of the blade front edge is shifted between the concave portion 85a and the convex portion 85b, and the entire blade front edge is also suppressed from vibrating in the blade thickness direction at the same time.

Similarly, if the rear concave flange 86 is formed by the plurality of concave portions 86a and convex portions 86b, when the airflow on the pressure surface side and the airflow on the suction surface (the side facing the suction grill 11) side merge at the blade trailing edge, the merged flow occurs earlier at the concave portions 86a and later at the convex portions 86b, and the two airflows gradually merge. As a result, the rear vortex generated at the blade trailing edge is subdivided, and the velocity loss of the blade rear flow is reduced. Therefore, it is possible to simultaneously suppress noise generated by the vibration of the blade leading edge and noise in the case where the velocity loss of the blade backward flow is large, and it is possible to reduce fan noise.

In order to further secure the vibration restricting effect by the front concave flange 85 and the subdividing effect of the rear vortex by the rear concave flange 86, the relationship between the front concave flange 85 and the rear concave flange 86 is set as follows. As shown in fig. 10, the adjacent pitch P1 of the recessed portion 85a of the front concave flange 85 is set to be larger than the adjacent pitch P2 of the recessed portion 86a of the rear concave flange 86. The concave-convex depth j1 of the front concave flange 85 is set to be smaller than the concave-convex depth j2 of the rear concave flange 86. The radius of curvature k1 of the concave portion 85a of the front concave flange 85 is set to be larger than the radius of curvature k2 of the concave portion 86a of the rear concave flange 86. As a result, the number of the convex portions 85b of the front concave flange 85 is two, and the number of the convex portions 86b of the rear concave flange 86 is three. That is, the number of the convex portions 86b of the rear concave flange 86 is set larger than the number of the convex portions 85b of the front concave flange 85.

When the adjacent pitch P1 of the recessed portions 85a of the front concave flange 85 is set to be larger than the adjacent pitch P2 of the recessed portions 86a of the rear concave flange 86, the area of the raised portions 85b of the front concave flange 85 can be increased, and the structural strength of the raised portions 85b can be improved. Accordingly, the generation of noise due to the vibration of the convex portion 85b in the blade thickness direction can be further effectively suppressed.

If the concave-convex depth j1 of the front concave flange 85 is set to be smaller than the concave-convex depth j2 of the rear concave flange 86, the concave-convex depth j1 is small and accordingly is difficult to deflect, and the occurrence of noise due to vibration of the convex portion 85b of the front concave flange 85 in the blade thickness direction can be further effectively suppressed. The radius of curvature k1 of the concave portion 85a of the front concave flange 85 is set to be larger than the radius of curvature k2 of the concave portion 86a of the rear concave flange 86 for the same reason.

As described above, the blowing noise of the blower fan 4 having the front concave flange 85 and the rear concave flange 86 formed on the fan blades 4a was measured and compared with the blowing noise of the blower fan of the conventional structure, and it was confirmed how much the blowing noise can be reduced. Specifically, a blower for measurement in which a curved suction grill is attached to the rear end of the main body casing is prepared, and a conventional blower fan in which the front concave flange 85 and the rear concave flange 86 are not formed is assembled to measure the blowing noise, and the blower fan 4 according to the present invention is replaced to measure the blowing noise and compare the blowing noise of the two. For measuring the blowing noise, a microphone of a noise meter was disposed at a position 1m away from the rear end of the main body casing 1, and the noise level was measured so that the rotation speeds of both were the same. As a result, it was confirmed that the blower incorporating the blower fan 4 of the present invention can reduce the blowing noise as compared with the blower incorporating the blower fan of the conventional structure.

As described above, the main body casing 1 is formed in a hollow cylindrical shape by joining the left and right divided

casings

1a and 1b and the upper casing 1c, and as shown in fig. 1, large gaps are formed between the upper casing 1c and the fan casing 6 and between the lower portions of the left and right divided

casings

1a and 1b and the fan casing 6. With these gaps, a power supply control board (control board) 90 is disposed in the lower gap, and a temperature control board (control board) 91 is disposed in the upper gap. A mode switch 92 is attached to the temperature control board 91, and the switch 92 can be switched by a button 93 provided on the upper surface of the upper case 1 c. As shown in fig. 2, a discharge electrode 94 for generating ions is provided above the heating unit 7. As described above, by arranging the

control boards

90 and 91 in the gap space between the main body casing 1 and the fan casing 6 in advance, the

control boards

90 and 91 block the blowing noise outside the fan casing 6 from diffusing outside the main body casing, and the quietness can be improved.

When the switch knob 8 is operated to turn on, a commercial ac current is supplied to the power supply control board 90, and the current for operating the motor 5, the heating unit 7, the discharge electrode 94, and the like is adjusted. The power supply/control board 90 switches the driving rotation speed of the motor 5 according to the on/off signal of the airflow rate switching button 10. When the button 93 is operated and the mode changeover switch 92 is turned on, the amount of heat generated by the heating unit 7 is maximized, and hot air at 100 degrees celsius can be sent from the air outlet 13. Thereafter, hot air at 80 degrees celsius or 60 degrees celsius can be sent from the air outlet 13 each time the button 93 is operated to turn on, and when the button 93 is operated again to turn on, the energization of the heating means 7 is cut off, and dry air at normal temperature is sent from the air outlet 13. Thereafter, the same temperature control is repeated.

According to the blower configured as described above, the air flow sucked from the suction port 29 by the blower fan 4 during use is rectified while passing through the rectification grid 30, the second filter 48, and the expanded cylindrical wall 32, and flows toward the suction grill 11. At this time, the airflow having passed through the expanded cylindrical wall 32 is sucked into the blower fan 4 while being again rectified by the ventilation grid 23, but the sucked airflow is basically sucked from the peripheral portion of the ventilation grid 23 which faces the front and rear of the rotation region of the fan blades 4 a. This is because the negative pressure is larger as the portion facing the rotation region of the fan blade 4a is closer, and the negative pressure is smaller at the portion facing the front and rear of the fan boss 4 b.

However, the curved top 40 of the ventilation grid 23 is sufficiently short of the fan boss 4b adjacent to other grid locations. Therefore, the air flow reaching the vicinity of the curved ceiling portion 40 does not have a space between the curved ceiling portion 40 and the fan boss 4b, and therefore, the generation of a vortex caused by the stagnation of the air flow can be prevented, and the generation of turbulent noise can be greatly reduced. In the vicinity of the oblique side portion of the trapezoidal fan boss 4b, a flow of air (radiation airflow) drawn in the radial direction toward the rotation region of the fan blade 4a is formed. This radiation airflow serves to smoothly send the air between the curved top portion 40 and the fan boss 4b into the rotating region of the fan blades 4a, and also serves to eliminate the occurrence of eddy currents due to the airflow staying between the fan boss 4b and the curved top portion 40. In this way, the suction grill 11 is provided to reduce generation of turbulent noise caused by stagnation of the airflow.

In addition to the noise reduction structure described above, in the blower of the embodiment, the relational dimensions and the like of the blower fan 4, the suction grill 11, and the air intake body 12 are set as follows in order to further effectively reduce the turbulent noise.

As shown in fig. 11, when the facing distance between the curved top portion 40 of the ventilation grid 23 of the suction grid 11 and the fan boss 4b of the blower fan 4 is a and the front-rear distance from the attachment portion 24 of the suction grid 11 to the curved top portion 40 of the ventilation grid 23 is b, the suction grid 11 is disposed such that the facing distance a and the front-rear distance b satisfy the inequality (a < b).

When the front-rear distance b is set to be larger than the facing distance a as described above, it is possible to eliminate the formation of a stagnation space in which turbulent noise is likely to occur between the ventilation grid 23 and the fan boss 4b, and to increase the degree of curvature of the concave ventilation grid 23. Further, the larger the degree of curvature of the ventilation grid 23, the larger the area of the peripheral portion of the ventilation grid 23 facing the region of high flow velocity of the air flow, and the throughput of the air flow at the center of the ventilation grid 23 can be reduced. Therefore, the air flow can be prevented from staying in the space between the ventilation grid 23 and the fan boss 4b to generate a vortex, and the generation of turbulent noise can be reliably prevented. For this reason, the suction grill 11 is disposed so as to satisfy the inequality (a < b).

Moreover, if the radius of curvature of the ventilation grid 23 is large, the degree of curvature becomes small, and the area of the peripheral portion of the ventilation grid 23 facing the region of high flow velocity of the air flow becomes small, so that the throughput of the air flow at the center of the ventilation grid 23 increases. In the above-described embodiment, the front-rear distance b is set to be about 5 times the opposing distance a, so that the area of the peripheral portion of the ventilation mesh 23 facing the region where the flow velocity of the air flow is large is sufficiently large.

When the front-rear distance from the mounting portion 24 of the suction grill 11 to the curved top portion 40 of the ventilation grid 23 is b and the front-rear distance from the opening surface of the suction port 29 of the suction body 12 to the ventilation holes 25 of the ventilation grid 23 of the suction grill 11 is e, the suction grill 11 is disposed such that the front-rear distance b and the front-rear distance e satisfy the inequality (b < e).

As described above, if the front-rear distance e is set to be greater than the front-rear distance b, the airflow sucked from the suction port 29 and reaching the ventilation grid 23 is rectified by the front cylinder 45 and the suction port 29 and the rectification grid 30, and the occurrence of turbulent flow inside the front cylinder 45 can be suppressed. Further, the rotational noise of the blower fan 4 and the blade noise of the fan blades 4a can be attenuated by the expanding cylindrical wall 32. Therefore, in addition to the suppression effect of the turbulent noise of the ventilation grid 23, the noise attenuation effect of the front cylinder 46 can be utilized to reduce the overall noise of the blower.

When a front-rear distance from an opening surface of the suction port 29 of the suction body 12 to the mounting portion 24 of the suction grill 11 is denoted by d and an opposing distance between the mounting portion 24 of the suction grill 11 and the fan blades 4a of the blower fan 4 is denoted by c, the suction grill 11 is disposed such that the front-rear distance d and the opposing distance c satisfy an inequality (c < d). In fig. 11, symbol f denotes the front-rear dimension from the rear end of the suction port 29 of the rear cylinder 46 to the mounting portion 24 of the suction grill 11.

As described above, if the front-rear distance d is set to be larger than the facing distance c, the airflow sucked from the suction port 29 and reaching the blade edges of the fan blades 4a is rectified by the three of the rectifying grid 30, the front cylinder 45, and the ventilation grid 23, and the occurrence of turbulence in the interior of the intake body 12 and the interior of the fan casing 6 facing the ventilation grid 23 can be suppressed. Further, the rotational noise of the blower fan 4 and the blade noise of the fan blades 4a can be attenuated by the ventilation grid 23 and the air intake body 12. Therefore, the noise of the blower as a whole can be reduced by the noise attenuation effect of the air intake body 12 in addition to the suppression effect and the noise attenuation effect of the turbulent noise of the air flow grid 23.

When the opening area of the suction port 29 of the suction body 12 is C and the opening area of the delivery port 31 is D, the opening area C and the opening area D are set to satisfy an inequality (C < D). When the opening area D of the delivery port 31 is set larger than the opening area C in this way, the rotational noise of the blower fan 4 and the blade noise of the fan blades 4a passing through the ventilation grid 23 leaking to the side of the suction port 29 are enclosed in the suction port 29 having a small opening area, and the amount of noise emitted from the suction port 29 can be reduced, thereby further reducing the overall noise of the hair dryer. Further, by reducing the flow velocity of the air flow immediately before the air flow enters the ventilation grid 23 from the outlet 31, it is possible to suppress the generation of a vortex in the vicinity of the passing air flow after passing through the ventilation holes 25 of the ventilation grid 23, and accordingly, it is possible to reduce the overall noise of the blower.

In the above-described embodiment, the rear cylinder 46 of the suction body 12 is detachably attached to the main body casing 1, but it is not essential, and the suction body 12 may be attached to the main body casing 1 in a state of being fixed only to the main body casing 1. The suction grill 11 is not necessarily formed of a metal plate, and may be formed of a plastic molded product. In this case, the engagement claws 62 may be formed in a hook shape in advance, and the engagement claws 62 may be engaged with the engagement ribs 63 while being elastically deformed. The ventilation mesh 23 is not necessarily a concave curved shape formed by one curved surface, and may be formed by a curved surface in which a plurality of curved surfaces are overlapped in a multi-step shape. If necessary, the cross section of the ventilation mesh 23 may be a curved surface bent into a wave shape. The second filter 48 is not necessarily thermally welded to the center bearing frame 49, the support frame 50, and the cylinder end surface 51, and may be fixed by adhesion with an adhesive.

The present invention is widely applied to hair curlers, circulators, and the like, in addition to hair dryers.

Claims

1. A blower device comprising a blower fan (4) inside a cylindrical casing (6) having an inlet (6a) and an outlet (6b),

the blower fan (4) is configured by arranging a plurality of fan blades (4a) around a fan boss (4b),

a front concave flange (85) is formed on the front edge of the fan blade (4a), and a rear concave flange (86) is formed on the rear edge of the fan blade (4a),

the concave portion (85a) of the front concave flange (85) and the concave portion (86a) of the rear concave flange (86) are formed by curved edges,

a radius (k1) of curvature of a recessed portion (85a) of the front concave flange (85) is set to be larger than a radius (k2) of curvature of a recessed portion (86a) of the rear concave flange (86).

2. The air supply arrangement according to claim 1,

the adjacent pitch (P1) of the recessed portions (85a) of the front recessed flange (85) is set to be larger than the adjacent pitch (P2) of the recessed portions (86a) of the rear recessed flange (86).

3. The air supply apparatus according to claim 1 or 2,

the concave-convex depth (j1) of the front concave flange (85) is set to be smaller than the concave-convex depth (j2) of the rear concave flange (86).

4. The air supply apparatus according to claim 1 or 2,

the fan blades (4a) are formed from a fibre reinforced plastics material.