Blower

Abstract

Provided is a blower having a simpler structure and improved air blowing efficiency.　A centrifugal fan (100) comprises: an upper casing (110); a lower casing (130); a plurality of columns (116) that connect the upper casing (110) and the lower casing (130); a flow path (120) provided between the plurality of columns (116) in the radial direction; an impeller (200) disposed in the flow path (120); and a motor (300) that rotatably supports the impeller (200). The plurality of columns (116) are provided with through holes (118) into which bolts for attachment to an attachment target are inserted.

Description

Air blower

[0001] The present invention relates to an air blower, and particularly to a technique for improving productivity and air blowing efficiency by integrating a fixed structure.

[0002] Conventionally, as an air blower, for example, a centrifugal blower disclosed in Patent Document 1 is known. In this centrifugal blower, an upper case 20 having a suction port 16 and a lower case 30 are connected by a connecting member 40, and an impeller 10 rotated by a motor is disposed between the upper and lower cases 20, 30. Further, a support column 50 is disposed between the upper and lower cases 20, 30 to determine the distance between the two. In this air blower, the air sucked from the suction port 16 by the rotation of the impeller 10 is blown out from a blowout port formed in a portion of the side surface excluding the connecting member 40 and the support column 50.

[0003] Japanese Patent Application Laid-Open No. 2022-94632

[0004] By the way, in order to attach the centrifugal blower as described above to the device to be attached, through holes are formed in the upper and lower cases 20, 30, bolts are inserted, and the bolts are tightened and attached to screw holes provided in the device to be attached. In such a configuration, the structure becomes complicated, and in addition to the connecting member 40 and the support column 50 on the side surface, the bolts become a wind resistance, and the air blowing efficiency of the centrifugal blower becomes insufficient.

[0005] An object of the present invention is to provide an air blower that can simplify the structure, improve productivity, and improve air blowing efficiency in view of the above circumstances.

[0006] The present invention includes a first casing, a second casing provided on the opposite side of the first casing in the axial direction, a plurality of columns connecting the first casing and the second casing, a flow path provided between the plurality of columns in the radial direction, an impeller disposed in the flow path, and a motor that rotatably supports the impeller, and the plurality of columns are provided with through holes into which fixing members are inserted.

[0007] According to the centrifugal blower having the above configuration, the structure can be simplified, productivity can be improved, and air blowing efficiency can be improved.

[0008] This is a perspective view showing a centrifugal fan of the first embodiment. (A) is a plan view showing the centrifugal fan of the embodiment, and (B) is a side view. (A) is a cross-sectional view taken along line III-III in Figure 2(A), and (B) is an enlarged view of the portion indicated by arrow B in (A). This is a cross-sectional view taken along line IV-IV in Figure 2(A). (A) is a perspective view showing the upper casing in the embodiment, and (B) is a side view. (A) is a plan view showing the lower casing in the embodiment, and (B) is a view taken in the direction of arrow B in (A). (A) is a perspective view showing the impeller in the embodiment, and (B) is a plan view.

[0009] Figures 1 to 4 show the overall configuration of a centrifugal fan (centrifugal blower) 100 according to an embodiment of the present invention. The centrifugal fan 100 comprises a casing 150 composed of an upper casing (first casing) 110 and a lower casing (second casing) 130. As shown in Figure 3, the casing 150 is equipped with a motor 300 and an impeller 200 rotated by the motor 300. The individual components of the centrifugal fan 100 will be described below.

[0010] In the following explanation, the direction of the shaft 310 of the centrifugal fan 100 will be referred to as the "axial direction," and the direction perpendicular to the axial direction will be referred to as the "radial direction." Furthermore, terms indicating direction, such as "up" and "down," attached to the components will refer to the directions shown in Figure 3.

[0011] The upper casing 110 is made of resin and has a rectangular (approximately square) shape in plan view. A circular suction port 111 is formed in the center of the upper casing 110. As shown in Figure 5, the upper casing 110 is provided with a base 112 that forms an approximately positive contour. A flat third annular plate 113 is formed on the radially inward side of the base 112. In addition, the base 112 has a plurality of radial ribs 113a that extend radially from the periphery of the third annular plate 113, and a plurality of concentric ribs 113b that connect the radial ribs 113a to each other.

[0012] A second annular plate 114 is formed on the radially inner side of the third annular plate 113, which is raised one step in the axial direction relative to the base 112. A first annular plate 115 is formed on the radially inner side of the second annular plate 114, which is raised one step further in the axial direction. The back surface of the second annular plate 114 is an inclined surface 114a whose thickness increases towards the radially outer side (see Figure 4).

[0013] As shown in Figure 4, a first annular groove 115a is formed around the entire circumference of the back surface of the first annular plate 115, and a second annular groove 114b is formed around the entire circumference of the inclined surface 114a on the back surface of the second annular plate 114. Furthermore, a third annular groove 114c is formed around the entire circumference radially outward of the second annular groove 114b. In other words, the upper casing 110 is provided with first, second, and third annular grooves 115a, 114b, and 114c that are recessed in the axial direction away from the impeller 200.

[0014] As shown in Figure 5, columns 116 extending downward in the axial direction are formed at the four corners of the upper casing 110. A cylindrical surface 116a and a flat surface 116b, which has a flat surface on part of the corner of the base 112, are formed on the outer circumference of the columns 116. The flat surface 116b is oriented along the diagonal of the upper casing 110, and a convex portion 117 projecting radially outward is formed at the position of the base 112. As shown in Figure 3(B), the convex portion 117 has an engaging surface 117a that is substantially perpendicular to the flat surface 116b and an inclined surface 117b whose axial thickness decreases as it extends radially outward.

[0015] A through-hole 118 is formed in the column 116, penetrating it in the axial direction. Additionally, an annular projection 116c, smaller in diameter than the column 116, is formed on the lower end surface of the column 116. The through-hole 118 penetrates the annular projection 116c.

[0016] Next, the lower casing (second casing) 130 will be described with reference to Figure 6. The lower casing 130 is made of resin and has the same plan view shape as the upper casing 110. The lower casing 130 is provided with a base 132 that forms a substantially positive directional contour. A housing portion 133, which is substantially circular in plan view and has a bottomed cylindrical shape, is formed radially inward of the base 132, and an annular projection 134 that protrudes axially upward is formed in the center of the housing portion 133.

[0017] The bottom surface of the housing section 133 has multiple radial ribs 133a and multiple concentric ribs 133b connecting the radial ribs 133a to each other. In addition, the outer circumference of the housing section 133 has multiple ribs 135, the parts connected to the outer circumference forming a roughly triangular shape.

[0018] Holes 136 that penetrate axially are formed at the four corners of the base 132. As shown in Figure 3, a metal collar 137 is integrally molded with the lower casing 130 by insert molding in the axial middle portion of the hole 136.

[0019] A projection 138 is formed adjacent to the radially outer side of the hole 136, projecting upward in the axial direction. In side view, the projection 138 is rectangular in shape and oriented along the diagonal of the lower casing 130. As shown in Figure 3(B), a rectangular hole (opening) 138a is formed at the upper end of the projection 138, and above the hole 138a, an inclined surface 138b is formed that slopes downward toward the radially inward side.

[0020] The annular projection 116c formed on the column 116 of the upper casing 110 fits into the hole 136 of the lower casing 130. As a result, the through hole 118 of the column 116 is centered with the hole 136 of the lower casing 130. The centrifugal fan 100 is then attached by inserting a bolt (fixing member) from below through the hole 136 and the through hole 118 and screwing it into a screw hole (which may also be a bolt hole) provided in the device to be attached.

[0021] The protrusion 117 of the column 116 of the upper casing engages with the hole 138a of the projection 138 of the lower casing 130. This connects the upper casing 110 and the lower casing 130. In this case, when the upper casing 110 is brought close to the lower casing 130, the inclined surface 117b of the protrusion 117 slides against the inclined surface 138b of the projection 138, pushing the projection 138 radially outward, and the engaging surface 117a enters the hole 138a, causing the projection 138 to elastically return and the protrusion 117 to engage with the hole 138a. In this state, the flat surface 116b of the column 116 comes into contact with the projection 138.

[0022] The portion of the casing 150 excluding the column 116 on its side forms a gap between the upper casing 110 and the lower casing 130, and this gap serves as the outlet 119 for the air generated by the rotation of the impeller 200 (see Figure 4). The space from the impeller 200 to the outlet 119 forms the airflow path 120.

[0023] As shown in Figures 4 and 7, the impeller 200 consists of a cup-shaped hub 210, a plurality of blades 220 extending outward from near the outer circumference of the upper surface of the hub 210 inclined radially, a disc-shaped base 230 positioned at the lower end of the blades 220, and an annular shroud 240 positioned at the upper end of the blades 220.

[0024] Figure 7(A) shows the state in which the shaft 310 of the motor 300 is fixed to the sleeve 213 of the impeller 200. All the blades 220 are the same shape and are evenly arranged in the circumferential direction. The hub 210, the blades 220, the base 230, and the shroud 240 are integrally formed by resin injection molding. In Figure 7(A), the blades 220 rotate in a clockwise direction, blowing air radially outward.

[0025] The rotor yoke 211 is integrally molded with the impeller 200 by insert molding on the inner circumferential surface of the cylindrical portion formed on the lower side of the hub 210 and on the inclined surface extending from the inner circumferential surface toward the center. An annular rotor magnet 212, which is a permanent magnet, is fixed to the inner circumferential surface of the cylindrical portion of the rotor yoke 211 by means of adhesive or other means. The rotor magnet 212 is magnetized in an alternating pattern of opposite polarity (SNSN...) along the circumferential direction.

[0026] As shown in Figure 4, the shroud 240 comprises a disc-shaped portion (hereinafter referred to as the parallel plate 241) that is substantially parallel to the base 230, and a portion (hereinafter referred to as the inclined plate 242) that slopes upward from the parallel plate 241 toward the center. A first annular projection 243 projecting upward in the axial direction is formed on the radially inner edge of the top surface of the inclined plate 242. A second annular projection 244 projecting upward in the axial direction is formed on the radially outer side of the first annular projection 243, and a third annular projection (second annular projection) 245 projecting upward in the axial direction is formed on the radially outer side of the second annular projection 244.

[0027] The distances from the base 230 to the upper ends of the second and third annular projections 244 and 245 are the same and smaller than the distance from the base 230 to the upper end of the first annular projection 243. The first annular projection 243 is housed in the first annular groove 115a of the upper casing 110 with a gap, the second annular projection 244 is housed in the second annular groove 114b with a gap, and the third annular projection 245 is housed in the third annular groove 114c with a gap.

[0028] A metal sleeve 213 is integrally molded with the impeller 200 by insert molding in the central part of the hub 210. The shaft 310 of the motor 300 is fixed to the sleeve 213 by means of press-fitting or other means. In the axial direction, an annular groove is provided in the central part of the sleeve 213 that is recessed in the radial direction, and the resin material forming the impeller 200 fits into this annular groove, thereby firmly fixing the impeller 200 and the sleeve 213.

[0029] The motor 300 will be described with reference to Figure 4. A stator core 320 is positioned radially inside the rotor magnet 212, with a predetermined gap between them. The stator core 320 is made of laminated thin sheets of soft magnetic material such as electromagnetic steel, and is constructed by having a plurality of teeth 322 protrude radially outward from an annular core back 321.

[0030] An insulating resin insulator 330 is integrally molded with the stator core 320 by insert molding. Alternatively, the insulator 330 may be molded as two separate upper and lower parts and attached to the stator core 320. A coil 323 is wound around each tooth 322 of the stator core 320 via the insulator 330.

[0031] A cylindrical bearing holder 340 made of metal (for example, brass) is integrally molded with the lower casing 130 by insert molding on the annular projection 134 of the lower casing 130. The stator core 320 is fitted onto the outer circumference of the bearing holder 340. A stepped portion 341 projecting radially is formed on the outer surface of the bearing holder 340, and the inner circumference of the stator core 320 rests on this stepped portion 341.

[0032] A pair of ball bearings 350 are arranged inside the bearing holder 340, spaced apart in the vertical direction, and a shaft 310 is rotatably supported by the ball bearings 350. A stepped portion 342 projecting radially is formed on the inner circumferential surface of the bearing holder 340, and a coil spring 360 is interposed between the stepped portion 342 and the lower ball bearing 350. This applies preload to the lower ball bearing 350.

[0033] A circuit board (hereinafter referred to as the circuit board 370) is positioned below the ball bearing 350. The drive circuit is wired to the circuit board 370, and a wire drawn from the coil 323 is connected to the drive circuit. In addition, a wire for connecting to an external power supply is connected to the drive circuit, and the wire is drawn out to the outside through an opening 139 (see Figure 3) formed in the housing portion 133 of the lower casing 130.

[0034] As shown in Figure 2, a connecting portion 140, whose internal hollow portion covers the opening 139, is connected to the housing portion 133 of the lower casing 130, and a connector housing 142 is connected to the connecting portion 140 via an extension tube 141 that allows for electrical connections such as lead wires. The conductor drawn out from the opening 139 is pulled out to the connector housing 142 through the connecting portion 140 and the extension tube 141, and connected to a plurality of terminals that are insert-molded into the connector housing 142. When the centrifugal fan 100 is mounted on, for example, an automobile, the connector housing 142 is exposed on, for example, the side of the vehicle to which it is mounted, and a socket connected to an external power supply is inserted into the connector housing 142.

[0035] In the centrifugal fan 100 with the above configuration, a through hole 118 is formed in the column 116 that connects the upper and lower casings 110 and 130. Therefore, the centrifugal fan 100 can be attached by inserting a bolt through the through hole 118 and screwing it into a screw hole provided on the mounting object. Thus, since the column 116 performs two functions, the configuration is simplified and production efficiency is improved, and since the column 116 is the only component that blocks the wind, the airflow efficiency can be improved.

[0036] In this configuration, where the upper and lower casings 110 and 130 are connected only by the column 116, the flow path 120 can be widened, but the rigidity of the casing 150 against vertical stress is reduced, raising concerns that the casing 150 and a part of the impeller 200 may come into contact. In this regard, in the above embodiment, the upper casing 110 is provided with first, second, and third annular grooves 115a, 114b, and 114c that are recessed in the axial direction away from the impeller 200, and the impeller 200 is provided with first, second, and third annular protrusions 243, 244, and 245 that are housed in these annular grooves 115a, 114b, and 114c, so that a distance can be secured between the upper casing 110 and the impeller 200, and contact between the two can be prevented.

[0037] On the other hand, increasing the distance between the upper casing 110 and the impeller 200 makes it easier for air to backflow. However, in the above embodiment, since multiple annular protrusions 243, 244, and 245 are housed in multiple annular grooves 115a, 114b, and 114c, the pressure loss between the impeller 200 and the upper casing 110 can be increased, thereby suppressing air backflow and the noise generated by the backflow.

[0038] In the above embodiment, the distances from the base 230 to the upper ends of the second and third annular projections 244 and 245 of the impeller 200 are the same and set to be smaller than the distance from the base 230 to the upper end of the first annular projection 243. As a result, the axial height of the portion of the upper casing 110 facing the second and third annular projections 244 and 245 can be reduced, contributing to miniaturization.

[0039] In the above embodiment, the upper casing 110 and the lower casing 130 are connected to each other by engaging the protrusion 117 of the column 116 of the upper casing with the hole 138a of the projection 138 of the lower casing 130, thus ensuring a wide airflow path 120. Moreover, in the above embodiment, the position of the projection 138 as viewed from the impeller 200 is on the back side of the column 116, so the projection 138 does not obstruct the airflow.

[0040] In the above embodiment, the axial width of the third annular projection 245 is wider than the width of the first and second annular projections 243 and 244. This effectively suppresses backflow of wind and reduces pressure loss.

[0041] The present invention is not limited to the above embodiments and can be modified in various ways as follows: i) The present invention is not limited to radial centrifugal fans as in the above embodiments, but can be applied to axial flow fan motors and centrifugal fans equipped with a spiral casing that blow air in a tangential direction.

[0042] ii) In the above embodiment, the connector housing 142 is connected to the lower casing 130 via the connecting portion 140 and the extension pipe 141, but the connector housing 142 may be connected directly to the lower casing 130.

[0043] iii) In the present invention, since the upper and lower casings 110 and 130 are coupled to each other by inserting a fixing member through the through-hole 118 of the column 116 and attaching it to the attachment target, the convex portion 117 of the upper casing 110 and the protrusion 138 of the lower casing 130 may be omitted.

[0044] iv) In the above embodiment, the third annular groove 114c is formed in the upper casing 110 and the third annular protrusion 245 is formed in the shroud 240, but both may be omitted. Further, the first and second annular grooves 115a and 114b and the first and second annular protrusions 243 and 244 can also be omitted.

[0045] The present invention can be used in the technical field of a centrifugal fan as a blower widely used for cooling, ventilation, air conditioning of home appliances, OA equipment, industrial equipment, and air conditioning and blowing for vehicles.

[0046] 100...Centrifugal fan, 110...Upper casing (first casing), 111...Inlet, 112...Base, 113...Third annular plate, 113a...Radial ribs, 113b...Concentric ribs, 114...Second annular plate, 114a...Inclined surface, 114b...Second annular groove, 114c...Third annular groove, 115...First annular plate, 115a...First annular groove, 116...Column, 116a...Cylindrical surface 116b...flat surface, 116c...annular projection, 117...protrusion, 117a...engaging surface, 117b...inclined surface, 118...through hole, 119...air outlet, 120...flow channel, 130...lower casing (second casing), 132...base, 133...housing section, 133a...radial ribs, 133b...concentric ribs, 134...annular projection, 135...rib, 136...hole, 137...collar, 138 ...projection, 138a...hole (opening), 138b...inclined surface, 139...opening, 140...connecting part, 141...extension tube, 142...connector housing, 150...casing, 200...impeller, 210...hub, 211...rotor yoke, 212...rotor magnet, 213...sleeve, 220...blade, 230...base, 240...shroud, 241...parallel plate, 242...inclined plate, 243...first annular projection, 244...second annular projection, 245...third annular projection (second annular projection), 300...motor, 310...shaft, 320...stator core, 322...teeth, 323...coil, 330...insulator, 340...bearing holder, 341...stepped section, 350...ball bearing, 342...stepped section, 360...coil spring, 370...circuit board.

Claims

1. A blower comprising: a first casing; a second casing provided on the opposite side of the first casing in the axial direction; a plurality of columns connecting the first casing and the second casing; a flow path provided between the plurality of columns in the radial direction; an impeller disposed in the flow path; and a motor that rotatably supports the impeller, wherein the plurality of columns are provided with through holes into which fixing members are inserted.

2. The blower according to claim 1, wherein the first casing is provided with a groove recessed in the axial direction away from the impeller, and a portion of the impeller is housed in the groove.

3. The blower according to claim 2, wherein the impeller comprises a base, a shroud, and a plurality of blades sandwiched in the axial direction between the base and the shroud, the shroud has a top surface facing the first casing in the axial direction, the top surface has a first annular projection as part of the impeller and a second annular projection radially outward from the first annular projection, and the first casing has a first annular groove for accommodating the first annular projection and a second annular groove for accommodating the second annular projection.

4. The blower according to claim 3, wherein a plurality of the second annular projections are provided, and the distance from the base to the ends of the plurality of the second annular projections is the same in the axial direction.

5. The blower according to claim 1 or 2, wherein the column has a protrusion as an engaging portion projecting radially, and the second casing has an opening as an engaging portion penetrating radially, and the protrusion engages with the opening.

6. The blower according to claim 5, wherein, in the radial direction, the protrusion and the opening are located on the rear side of the column when viewed from the impeller side.

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