Blower device

Abstract

This blower device is configured so that the size thereof can be reduced compared to conventional blower devices without causing a decrease in blower device performance.　This blower device (100) comprises a shaft (210), a yoke (230) fixed to the shaft (210), and an impeller (300) fixed to the yoke (230). The yoke (230) has a cylindrical section (231) extending in the direction of the axis of rotation (X-axis) of the impeller (300). The cylindrical section (231) has a through hole (234) penetrating in the radial direction of the impeller (300), with a section of the impeller (300) entering the through hole (234).

Description

blower

[0001] The present invention relates to a blower device.

[0002] An outer rotor type fan with a simple structure that is waterproof and dustproof has been proposed. This fan has a magnet fixed to the inner circumferential surface of the cylindrical part of the rotor yoke, and a part of the hub of the impeller is inserted into a through-hole provided in the disk-shaped top plate of the rotor yoke (see, for example, Patent Document 1).

[0003] JP 2013-188091 A

[0004] However, in the blower of Patent Document 1, part of the hub is inserted into a through hole provided in the top plate of the rotor yoke, which makes the blower longer overall in the axial direction of the shaft, making it difficult to reduce the height of the entire blower and make it smaller.

[0005] Furthermore, since the stator coil is located below the top plate of the rotor yoke, if the motor is to be made smaller without changing the structure, the stator coil must be made smaller, which inevitably results in a decrease in performance.

[0006] An example of an object of the blower of the present invention is to make the blower even smaller than conventional blowers without reducing the performance of the blower.

[0007] The blower device of the present invention comprises a shaft, a yoke fixed to the shaft, and an impeller fixed to the yoke, wherein the yoke has a cylindrical portion extending in the direction of the rotation axis of the impeller, the cylindrical portion having a through hole extending radially through the impeller, and a portion of the impeller inserts into the through hole.

[0008] FIG. 1 is a cross-sectional view showing the configuration of a blower according to an embodiment that is an example of the present invention; FIG. 2 is a perspective view showing the configuration of a yoke according to an embodiment that is an example of the present invention when viewed from the downstream side (A), and the configuration of the yoke when viewed from the upstream side (B); FIG. 3 is a perspective view showing the configuration of a combined body of an impeller and a yoke of a blower according to an embodiment that is an example of the present invention when viewed from the upstream side; FIG. 4 is a perspective view showing the configuration of a combined body of an impeller and a yoke of a blower according to an embodiment that is an example of the present invention when viewed from the downstream side; FIG. 5 is a partial enlarged view showing a state in which a part of the impeller according to an embodiment that is an example of the present invention is inserted into a through-hole of the yoke.

[0009] An embodiment of the present invention will now be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the configuration of a blower according to an embodiment of the present invention. FIG. 2 is a perspective view showing a configuration of a yoke according to an embodiment of the present invention as viewed from the downstream side (A) and a configuration of the yoke as viewed from the upstream side (B). FIG. 3 is a perspective view showing the configuration of a combined body of an impeller and a yoke of a blower according to an embodiment of the present invention as viewed from the upstream side. FIG. 4 is a perspective view showing the configuration of a combined body of an impeller and a yoke of a blower according to an embodiment of the present invention as viewed from the downstream side. FIG. 5 is a perspective view showing the configuration of an impeller of a blower according to an embodiment of the present invention. FIG. 6 is a partial enlarged view showing a state in which a portion of the impeller according to an embodiment of the present invention is inserted into a through-hole of the yoke.

[0010] In the description of the embodiments of the present invention, for convenience of explanation, the direction of arrow a along axis X will be referred to as the upstream side or one side. The direction of arrow b along axis X will be referred to as the downstream side or the other side. Here, the direction of arrows ab will be referred to as the upstream / downstream direction or the axial direction. However, the upstream side and the downstream side do not necessarily coincide with the vertical direction. Furthermore, the direction of arrows c and d will be referred to as the radial direction, and the direction of arrow c away from axis X will be referred to as the outer side or one radial side, and the direction of arrow d approaching axis X will be referred to as the inner side or the other radial side. Furthermore, the direction of rotation around axis X will be referred to as the circumferential direction.

[0011] As shown in FIG. 1, the fan motor 100 serving as a blower according to this embodiment is an axial flow fan that blows air from the upstream side (the direction of arrow a) to the downstream side (the direction of arrow b) in the X-axis direction, and has an overall rectangular cylindrical shape that is roughly square when viewed from above.

[0012] The fan motor 100 includes a motor 200, an impeller 300 disposed upstream (in the direction of arrow a) of a shaft 210 of the motor 200, and a casing 400 that houses the motor 200 and the impeller 300.

[0013] Impeller 300 is composed of hub 311 and blades 312, and is driven to rotate by motor 200. Fan motor 100 has an upstream opening 401 for drawing air through impeller 300 from the upstream side in the X-axis direction (the direction of arrow a), and a downstream opening 402 for discharging air through impeller 300.

[0014] The casing 400 of the fan motor 100 comprises a side wall 410 that surrounds the impeller 300 from the radially outer side (direction of arrow c), a base 420 formed at the end on the downstream side (direction of arrow b) and that holds the fan motor 100, and spokes 430 consisting of a plurality of stator blades (fixed blades) that connect the side wall 410 and the base 420 in the radial direction (direction of arrows cd).

[0015] The side wall 410, base 420, and spokes 430 of the casing 400 are integrally formed by injection molding of a synthetic resin such as glass fiber reinforced polybutylene terephthalate, although the side wall 410, base 420, and spokes 430 of the casing 400 may be formed of other materials.

[0016] The side wall 410 of the casing 400 is a tube or cylindrical body that defines an air tunnel of the fan motor 100. The side wall 410 has an upstream opening 401 and a downstream opening 402, and also has a cylindrical inner circumferential surface 410a centered on the axis X serving as the rotation axis. The diameter of the inner circumferential surface 410a of the side wall 410 is large enough so that it does not come into contact with the radially outer ends (in the direction of arrow c) of the blades 312 of the impeller 300.

[0017] That is, a predetermined gap is formed between the radially outer ends (in the direction of arrow c) of the blades 312 of the impeller 300 and the inner circumferential surface 410a of the side wall 410. The side wall 410 also functions as a guard portion that protects the impeller 300.

[0018] The base 420 of the casing 400 is formed by an approximately disk-shaped base 420a, a cylindrical outer wall 420b extending a predetermined length from the radially outer end (arrow c direction) of the base 420a toward the upstream side (arrow a direction), and a cylindrical inner wall 420c protruding a predetermined length from the radially inner end (arrow d direction) on the other radial side of the base 420a toward the upstream side (arrow a direction).

[0019] The inner peripheral wall 420c and the outer peripheral wall 420b of the base 420 are disposed on either side of the base portion 420a in the radial direction, and the inner peripheral wall 420c is formed longer (higher) in the X-axis direction than the outer peripheral wall 420b.

[0020] In addition, the inner wall 420c of the base 420 has an end face (hereinafter referred to as the "upper end face") on the upstream side (direction of arrow a), and the inner end of the circuit board 500 is placed on this upper end face and fixed integrally thereto by adhesive or the like.

[0021] The circuit board 500 is made of a thin, annular member and is a printed wiring board having a single layer or multiple wiring layers on which electronic components that constitute a motor drive control circuit (not shown) that rotates and drives the rotor 240 of the motor 200 are mounted.

[0022] A plurality of spokes 430 are integrally formed on the radially outer surface (direction of arrow c) of the outer peripheral wall 420b of the base 420 (hereinafter referred to as the "outer peripheral surface") of the base 420. The outer peripheral wall 420b of the base 420 is supported by the side wall 410 of the casing 400 via the spokes 430. In other words, the base 420 and the side wall 410 of the casing 400 are integrally connected via the plurality of spokes 430.

[0023] The motor 200 includes a shaft 210 , a rotor 240 disposed on the upstream side of the shaft 210 (in the direction of the arrow a), a bearing device 260 , and a stator 250 .

[0024] Shaft 210 is a cylindrical member rotatably held by upstream bearing 263 and downstream bearing 264. The upstream end (direction of arrow a) of shaft 210 is integrally joined to shaft holding portion 233 of rotor yoke 230 by press-fitting, adhesive bonding, or the like.

[0025] The bearings 263 and 264 are, for example, ball bearings. However, the bearings 263 and 264 are not limited to ball bearings and may be various other bearings, such as sleeve bearings. Furthermore, a coil spring sp for applying preload to the bearing 263 is interposed around the shaft holder 233 between the upstream end of the bearing 263 and the disk portion 232 of the rotor yoke 230.

[0026] The bearing device 260 has an upstream bearing 263, a downstream bearing 264, and a holding member 262 that holds the two bearings 263, 264. The holding member 262 is made of metal, and has a generally hollow cylindrical shape as a whole.

[0027] The holding member 262 is press-fitted into the inner circumferential surface (the radially inner surface) of the inner circumferential wall 420c of the base 420. Note that the holding member 262 may be formed integrally with the base 420 in a state where it is inserted into the inner circumferential wall 420c.

[0028] Bearing 263 is disposed on the upstream side (direction of arrow a) of shaft 210 and rotatably supports the upstream side (direction of arrow a) of shaft 210 with respect to holding member 262. Bearing 264 is disposed on the downstream side (direction of arrow b) of shaft 210 and rotatably supports the downstream side (direction of arrow b) of shaft 210 with respect to holding member 262. Thus, shaft 210 is supported rotatably relative to holding member 262 via the two bearings 263 and 264.

[0029] Motor 200 is an outer rotor type single-phase brushless DC motor, and includes rotor 240 and stator 250. Note that motor 200 is not limited to being a single-phase brushless DC motor, and may be another motor, such as a three-phase brushless DC motor.

[0030] The rotor 240 is fixed to the upstream side (direction of arrow a) of the shaft 210. The rotor 240 has a rotor yoke 230 and a magnet mg. The rotor yoke 230 has a cylindrical portion 231, a disk portion 232, and a shaft holder 233.

[0031] The cylindrical portion 231 of the rotor yoke 230 is a cylindrical portion made of a soft magnetic material and arranged coaxially with the shaft 210. As shown in Fig. 1, a cylindrical magnet mg is fixed integrally to the inner circumferential surface (the radially inner surface) of the cylindrical portion 231 and coaxially with the cylindrical portion 231. The cylindrical portion 231 functions as a portion that prevents leakage of the magnetic field of the magnet mg.

[0032] The disk portion 232 of the rotor yoke 230 is an approximately disk-shaped portion that extends from the upstream end of the cylindrical portion 231 radially inward (in the direction of arrow d) toward the shaft 210 and blocks the upstream side of the cylindrical portion 231 (in the direction of arrow a).

[0033] The shaft holder 233 is a generally cylindrical portion that protrudes a predetermined length from the radially inner end (in the direction of arrow d) of the disk portion 232 toward the downstream bearing 263 (in the direction of arrow b). The inner diameter of the shaft holder 233 is formed slightly smaller than the outer diameter of the shaft 210.

[0034] Shaft 210 is press-fitted into the inner peripheral surface (the surface facing radially inward (in the direction of arrow d)) of shaft holder 233, thereby integrally fixing rotor yoke 230 and shaft 210. Cylindrical portion 231 and disk portion 232 of rotor yoke 230 are integrally fixed to the inner peripheral surface of hub 311 of impeller 300 by insert molding or the like.

[0035] Furthermore, as shown in Figures 2(A) and (B), the rotor yoke 230 has multiple (e.g., five) through holes 234 that penetrate radially through the cylindrical portion 231 at the upstream end (direction of arrow a) of the cylindrical portion 231 and at the radially outer end (direction of arrow c) of the disk portion 232, i.e., at the corner where the cylindrical portion 231 and the disk portion 232 intersect.

[0036] These through holes 234 are rectangular in plan view, and are holes through which molten resin enters when rotor yoke 230 and hub 311 of impeller 300 are integrally insert-molded. After protrusions 350 (FIGS. 1, 5, and 6) of hub 311 are formed by insert molding, through holes 234 also serve as inlets into which protrusions 350 enter. In this case, five through holes 234 are provided, but the number is not limited to five and any number may be used.

[0037] The stator 250 (FIG. 1) is attached to the outer peripheral surface (the radially outer surface) of the holding member 262. However, the stator 250 may be attached directly to the base 420 without using the holding member 262.

[0038] The stator 250 has a stator core 251 formed by a laminate of a plurality of electromagnetic steel sheet cores made of soft magnetic material, an insulator 252 made of an insulating material attached to the stator core 251, and a coil (not shown) wound around the stator core 251 via the insulator 252. The stator core 251 and the coil are insulated by the insulator 252.

[0039] When motor 200 is operated, rotor 240 rotates together with shaft 210 due to the electromagnetic interaction between rotor 240 and stator 250, impeller 300 fixed integrally to rotor 240 rotates, and air (hereinafter also referred to as "air flow") is sent from the upstream side (direction of arrow a) to the downstream side (direction of arrow b) by the action of multiple blades 312. Therefore, fan motor 100 functions as a blower.

[0040] As shown in Figures 3 and 4, the impeller 300 includes a hub 311 having a cup shape with a bottom and a cross section that is approximately an inverted U-shape, and a plurality of blades 312 arranged at regular intervals around the outer peripheral surface, which is the radially outer surface of the hub 311.

[0041] Hub 311 has opening 311a at its upstream end (arrow a direction) in the axial direction, and the upstream end face (arrow a direction) of shaft 210 and disk portion 232 are exposed through opening 311a (FIG. 1) (FIG. 3). The state in which impeller 300 and rotor yoke 230 are fixed together is referred to as a combined body 360, and will be used in the following description.

[0042] The plurality of blades 312 of the impeller 300 constituting the combined body 360 all have the same shape and are evenly spaced at equal intervals in the circumferential direction of the hub 311. The hub 311 and the plurality of blades 312 are integrally formed by injection molding of a synthetic resin such as glass fiber reinforced polybutylene terephthalate.

[0043] As shown in Figure 1, the hub 311 of the impeller 300 covers the outer peripheral surface of the cylindrical portion 231 on the radially outer side (in the direction of arrow c), and is fixed to the radially outer end (in the direction of arrow c) of the upper end surface 232u on the upstream side (in the direction of arrow a) of the disk portion 232 of the rotor yoke 230, and to the outer peripheral surface of the cylindrical portion 231.

[0044] As shown in Figure 5, the hub 311 of the impeller 300 forms a cup shape with a bottom and a cross section that is approximately an inverted U-shape, and has a cylindrical portion 330 formed coaxially with the shaft 210, and a disk-shaped upper cover portion 340 extending from the upstream end (direction of arrow a) of the cylindrical portion 330 toward the shaft 210.

[0045] The upper cover portion 340 of the hub 311 has an opening 311a (FIG. 1) of a predetermined radius centered on the X-axis, and the upstream end face (direction of arrow a) of the shaft 210 and the disk portion 232 of the rotor yoke 230 are exposed through the opening 311a (FIGS. 1 and 3).

[0046] 6, the cylindrical portion 330 of the hub 311 has protrusions 350 that fit into a plurality of (e.g., five) through holes 234 provided in the cylindrical portion 231 of the rotor yoke 230. The protrusions 350 are formed in a circular shape with a generally rectangular cross section that fits from the through holes 234 of the cylindrical portion 231 of the rotor yoke 230 toward the shaft 210 and extends in the circumferential direction.

[0047] The protrusion 350 has an inner peripheral surface 350n on the radially inward side (direction of arrow d), and has an annular locking portion 352 that extends from the inner peripheral surface 350n at the upstream end (direction of arrow a) of the protrusion 350 so as to protrude slightly radially inward (direction of arrow d) toward the shaft 210. Note that the protrusion 350 refers to the portion surrounded by the dashed line and the inner peripheral surface 350n in FIG. 6 .

[0048] The upper end surface 352u of this locking portion 352 on the upstream side (direction of arrow a) abuts against the lower end surface 232d on the downstream side (direction of arrow b) of the disk portion 232 of the rotor yoke 230, preventing the hub 311 from coming off upstream (direction of arrow a) when the impeller 300 rotates.

[0049] In addition, the protrusion 350 has an annular protruding portion 353 that extends slightly downstream (in the direction of arrow b) along the X-axis direction beyond the upper end surface 231u on the upstream side (in the direction of arrow a) of the cylindrical portion 231 of the rotor yoke 230.

[0050] The protruding portion 353 is flush with the inner peripheral surface 350n of the protruding portion 350. The outer diameter r1 of the protruding portion 353 is smaller than the inner diameter r2 of the cylindrical portion 231 of the rotor yoke 230. The protruding portion 353 has a flat lower end surface 353d on the downstream side (direction of arrow b), and this lower end surface 353d is adjacent to the upper end surface mgu on the upstream side (direction of arrow a) of the magnet mg with a small gap therebetween. However, this is not limited to this, and the lower end surface 353d of the protruding portion 353 may also abut against the upper end surface mgu on the upstream side (direction of arrow a) of the magnet mg.

[0051] The protrusion portion 350 is spaced a predetermined distance d1 (r2-r1) between the inner surface 231n on the radially inner side (direction of arrow d) of the cylindrical portion 231 of the rotor yoke 230 and the outer surface 353g on the radially outer side (direction of arrow c) of the protruding portion 353.

[0052] As a result, a pocket space 350p as an annular groove is formed between the protruding portion 353 of the protrusion 350, the cylindrical portion 231 of the rotor yoke 230, and the upper end surface mgu of the magnet mg.

[0053] In practice, the cylindrical portion 231 of the rotor yoke 230 is inserted into the hub 311 in a mold, and the molten resin of the hub 311 is poured into the through hole 234 of the cylindrical portion 231 to form the protrusion 350 having the locking portion 352 and the protruding portion 353.

[0054] In the above configuration, in the fan motor 100, the protrusion 350 on the hub 311 of the impeller 300 is formed integrally with the through hole 234 of the cylindrical portion 231 of the rotor yoke 230, and therefore, when the impeller 300 rotates, the impeller 300 can be prevented from coming out of the rotor yoke 230 due to centrifugal force.

[0055] Furthermore, in fan motor 100, instead of providing a through hole in disk portion 232 of rotor yoke 230 and having part of hub 311 of impeller 300 fit into it as in the conventional case, protrusion 350, which is part of hub 311, fits into through hole 234 in cylindrical portion 231 of rotor yoke 230. This prevents fan motor 100 from being too long overall in the X-axis direction of shaft 210, allowing for a reduced overall height and compact size.

[0056] Furthermore, in the fan motor 100, when the magnet mg is fixed to the inner circumferential surface 231n of the cylindrical portion 231 of the rotor yoke 230 with an adhesive or the like, the lower end surface 353d of the protruding portion 353 of the protrusion 350 can be brought into contact with the upper end surface mgu of the magnet mg. This makes it easy to determine the height in the X-axis direction of the magnet mg when fixing it to the inner circumferential surface 231n of the cylindrical portion 231 in the fan motor 100.

[0057] When the lower end surface 353d of the protruding portion 353 of the protrusion 350 is adjacent to or abuts against the upper end surface mgu of the magnet mg, a pocket space 350p having a rectangular cross section and an annular shape is formed by the three elements of the cylindrical portion 231, the protruding portion 353, and the magnet mg.

[0058] The magnet mg is pressed against the inner peripheral surface 231n of the cylindrical portion 231 and pushed up from the downstream side (arrow b direction) to the upstream side (arrow a direction) until it is adjacent to or abuts against the lower end surface 353d of the protruding portion 353.

[0059] At this time, the adhesive present between the inner surface 231n of the cylindrical portion 231 and the magnet mg is squeezed by the magnet mg and pushed up upstream (in the direction of arrow a), so that the pushed-up adhesive can be stored in the pocket space 350p.

[0060] In addition, when the magnet mg is fixed to the inner surface 231n of the cylindrical portion 231 by pressing it in rather than using adhesive, burrs and the like present at the upper end of the magnet mg can be accommodated in the pocket space 350p instead of using adhesive.

[0061] Incidentally, even when the magnet mg is fixed to the inner peripheral surface 231n of the cylindrical portion 231 with an adhesive, the pocket space 350p of the protrusion 350 can naturally accommodate not only the adhesive but also burrs.

[0062] In the fan motor 100, not only is the locking portion 352 of the protrusion 350 provided on the hub 311 of the impeller 300 locked to the disk portion 232 of the rotor yoke 230, but the disk portion 232 is also sandwiched between the upper cover portion 340 of the rotor yoke 230 and the locking portion 352 of the protrusion 350.

[0063] As a result, the hub 311 of the impeller 300 and the disk portion 232 of the rotor yoke 230 are firmly fixed together, preventing the impeller 300 from slipping out of the rotor yoke 230 upstream in the X-axis direction (in the direction of arrow a) when the impeller 300 rotates.

[0064] Although the preferred embodiment of the fan of the present invention has been described above, the fan of the present invention is not limited to the configuration of the above embodiment. For example, although the fan motor 100 is an outer rotor type motor, the motor of the present invention may be an inner rotor type motor.

[0065] Furthermore, in the present invention, a case has been described in which the through-hole 234 is rectangular in plan view at the end of the disk portion 232 on the outer side in the radial direction (in the direction of the arrow c), i.e., at the corner where the cylindrical portion 231 intersects with the disk portion 232. However, the present invention is not limited to this, and a through-hole having a circular shape in plan view or any other shape may be provided in a part of the cylindrical portion 231, and the protrusion 350 of the hub 311 may fit into the through-hole.

[0066] In addition, those skilled in the art can appropriately modify the blower device of the present invention and change the combination of various components in accordance with conventionally known knowledge. As long as such modifications still include the components of the present invention, they are of course included in the scope of the present invention.

[0067] 100...fan motor, 200...motor, 210...shaft, 230...rotor yoke, 231...cylindrical portion, 231n...inner peripheral surface, 232...disk portion, 232u...upper end surface, 232d...lower end surface, 233...shaft holding portion, 234...through hole, 240...rotor, 250...stator, 251...stator core, 252...insulator, 260...bearing device, 262...holding member, 263, 264...bearings, 300...impeller, 311...hub, 311a...opening, 312...vanes, 330...cylinder portion, 340...upper cover portion, 350...protrusion portion, 350n...inner surface, 350p...pocket space, 352...engaging portion, 352u...upper end surface, 353...protruding portion, 353g...outer surface, 353d...lower end surface, 360...connector, 400...casing, 401, 402...opening, 410...side wall, 410a...inner surface, 420...base, 420a...base portion, 420b...outer wall, 420c...inner wall, 430...spokes, 500...circuit board, sp...coil spring, mg...magnet, mgu...upper end surface.

Claims

1. A blower comprising: a shaft; a yoke fixed to the shaft; and an impeller fixed to the yoke, wherein the yoke has a cylindrical portion extending in the direction of a rotation axis of the impeller, the cylindrical portion having a through hole passing through in the radial direction of the impeller, and a part of the impeller fits into the through hole.

2. The blower device according to claim 1, wherein the impeller has a protrusion extending radially of the impeller toward the shaft, the protrusion fitting into the through hole.

3. The blower device according to claim 2, wherein the end of the protrusion has an annular protrusion extending in the direction of the rotation shaft.

4. The blower device of claim 3, wherein the impeller has an annular groove recessed in the direction of the rotation axis, the groove being formed between the protrusion and the inner surface of the cylindrical portion in the radial direction, and a magnet is fixed to the inner surface of the cylindrical portion, the magnet being adjacent to the groove.

5. The blower device according to claim 4, wherein the magnet is in contact with an axial end face of the protrusion.

6. The blower device according to claim 4 or 5, wherein the groove portion is an annular pocket space capable of accommodating adhesive used when fixing the magnet to the inner circumferential surface of the cylindrical portion.

Images