US20130136631A1 - Fan - Google Patents
Fan Download PDFInfo
- Publication number
- US20130136631A1 US20130136631A1 US13/612,138 US201213612138A US2013136631A1 US 20130136631 A1 US20130136631 A1 US 20130136631A1 US 201213612138 A US201213612138 A US 201213612138A US 2013136631 A1 US2013136631 A1 US 2013136631A1
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- United States
- Prior art keywords
- holder
- thrust
- space
- cap
- circumferential surface
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D25/00—Pumping installations or systems
- F04D25/02—Units comprising pumps and their driving means
- F04D25/06—Units comprising pumps and their driving means the pump being electrically driven
- F04D25/0606—Units comprising pumps and their driving means the pump being electrically driven the electric motor being specially adapted for integration in the pump
- F04D25/0613—Units comprising pumps and their driving means the pump being electrically driven the electric motor being specially adapted for integration in the pump the electric motor being of the inside-out type, i.e. the rotor is arranged radially outside a central stator
- F04D25/0626—Details of the lubrication
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K5/00—Casings; Enclosures; Supports
- H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
- H02K5/16—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields
- H02K5/167—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields using sliding-contact or spherical cap bearings
- H02K5/1675—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields using sliding-contact or spherical cap bearings radially supporting the rotary shaft at only one end of the rotor
Definitions
- the present invention relates to a fan arranged to produce an air current.
- a fan motor disclosed in JP-UM-B 06-31199 includes a case, a stator, a sleeve, a shaft, an annular member, a rotor, and a plurality of blades.
- the stator is arranged on an outer circumference of an inner tubular portion of the case.
- the sleeve is fitted into the inner tubular portion and fixed thereto.
- the shaft is inserted in the sleeve.
- Grooves arranged to generate a dynamic pressure are defined in an outer circumferential surface of the shaft.
- the annular member is fitted on a lower end portion of the shaft and fixed thereto.
- the annular member is arranged axially opposite a lower surface of the sleeve.
- Each of a gap defined between the sleeve and the shaft and a gap defined between the sleeve and the annular member is filled with a lubricating fluid.
- the rotor is fixed to an upper end portion of the shaft.
- a magnet is fixed to an inner circumference of a cylindrical attachment member of the rotor, and is arranged radially opposite the stator.
- the blades are fixed to an outer circumference of the attachment member.
- a radial dynamic pressure bearing is defined by a combination of the shaft and the sleeve
- a thrust dynamic pressure bearing is defined by a combination of the sleeve and the annular member.
- a difference in pressure may occur between an upper surface of the lubricating fluid, which is defined in the gap between the sleeve and the shaft, and a lower surface of the lubricating fluid, which is defined in a gap defined between a lower surface of the sleeve and an upper surface of the annular member or its vicinity. This pressure difference may cause a leakage of the lubricating fluid.
- a fan includes a plurality of blades and a motor arranged to rotate the blades about a central axis.
- the motor includes a stationary portion including a stator; a rotating portion including a rotor magnet arranged radially outside the stator; and a bearing mechanism arranged to support the rotating portion such that the rotating portion is rotatable with respect to the stationary portion.
- the rotating portion includes a rotor holder arranged in a shape of a covered cylinder, and including an outer circumferential surface on which the blades are arranged.
- the bearing mechanism includes a shaft; a sleeve in which the shaft is inserted; a holder arranged to hold the sleeve; and a thrust plate fixed to a lower end portion of the shaft on a lower side of the sleeve.
- the shaft and the sleeve are arranged to together define a radial gap therebetween, the radial gap including a radial bearing portion arranged to support the shaft in a radial direction.
- the thrust plate and the holder are arranged to together define a lower seal portion therebetween, the lower seal portion having a lower surface of a lubricating oil defined therein, while the holder and the sleeve are arranged to together define an upper seal portion therebetween, the upper seal portion having an upper surface of the lubricating oil defined therein.
- the holder includes a connection channel defining portion arranged to define a connection channel to connect an upper space defined between the upper seal portion and an inside of the rotor holder with a lower space at which the lower seal portion is arranged.
- a fan includes a plurality of blades and a motor arranged to rotate the blades about a central axis.
- the motor includes a stationary portion including a stator; a rotating portion including a rotor magnet arranged radially outside the stator; and a bearing mechanism arranged to support the rotating portion such that the rotating portion is rotatable with respect to the stationary portion.
- the rotating portion includes a rotor holder arranged in a shape of a covered cylinder, and including an outer circumferential surface on which the blades are arranged.
- the bearing mechanism includes a shaft; a sleeve in which the shaft is inserted; a holder arranged to hold the sleeve; and a thrust plate fixed to a lower end portion of the shaft on a lower side of the sleeve.
- the holder includes a cylindrical first holder arranged to cover an outer circumferential surface of the sleeve and an outer circumferential surface of the thrust plate, the first holder including an annular upper portion arranged to project radially inward on an upper side of the sleeve; and a second holder including an inner circumferential surface having an outer circumferential surface of the first holder fixed thereto, the second holder having the stator arranged on a radially outer side thereof.
- the shaft and the sleeve are arranged to together define a radial gap therebetween, the radial gap including a radial bearing portion arranged to support the shaft in a radial direction.
- the thrust plate and the first holder are arranged to together define a lower seal portion therebetween, the lower seal portion having a lower surface of a lubricating oil defined therein, while the shaft and the annular upper portion are arranged to together define an upper seal portion therebetween, the upper seal portion having an upper surface of the lubricating oil defined therein.
- the second holder includes a connection channel defining portion arranged to define a connection channel to connect an upper space defined between the upper seal portion and an inside of the rotor holder with a lower space at which the lower seal portion is arranged.
- a fan includes a plurality of blades and a motor arranged to rotate the blades about a central axis.
- the motor includes a stationary portion including a stator; a rotating portion including a rotor magnet arranged radially outside the stator; and a bearing mechanism arranged to support the rotating portion such that the rotating portion is rotatable with respect to the stationary portion.
- the stationary portion includes a bushing arranged to hold the stator on a radially outer side thereof.
- the rotating portion includes a rotor holder arranged in a shape of a covered cylinder, and including an outer circumferential surface on which the blades are arranged.
- the bearing mechanism includes a shaft; a bearing portion in which the shaft is inserted; a thrust plate fixed to a lower end portion of the shaft on a lower side of the sleeve; a thrust portion arranged to extend radially outward from an upper portion of the shaft; and a rotor cylindrical portion arranged to extend axially downward from the thrust portion.
- the shaft and the bearing portion are arranged to together define a radial gap therebetween, the radial gap including a radial bearing portion arranged to support the shaft in a radial direction.
- the thrust plate and the bearing portion are arranged to together define a lower seal portion therebetween, the lower seal portion having a lower surface of a lubricating oil defined therein, while the bearing portion and the rotor cylindrical portion are arranged to together define an upper seal portion therebetween, the upper seal portion having an upper surface of the lubricating oil defined therein.
- the bushing includes a connection channel defining portion arranged to define a connection channel to connect an upper space defined between the upper seal portion and an inside of the rotor holder with a lower space at which the lower seal portion is arranged.
- a reduction in a difference in pressure between the upper and lower spaces is achieved, and this contributes to preventing a leakage of the lubricating oil.
- FIG. 1 is a cross-sectional view of a fan according to a first preferred embodiment of the present invention.
- FIG. 2 is a cross-sectional view illustrating a bearing mechanism of the fan in an enlarged form.
- FIG. 3 is a cross-sectional view illustrating the bearing mechanism in an enlarged form.
- FIG. 4 is a horizontal cross-sectional view of the bearing mechanism.
- FIG. 5 is a plan view of a thrust plate of the bearing mechanism.
- FIG. 6 is a horizontal cross-sectional view of a holder according to a modification of the first preferred embodiment.
- FIG. 7 is a cross-sectional view of a bearing mechanism according to another modification of the first preferred embodiment.
- FIG. 8 is a cross-sectional view of a bearing mechanism according to yet another modification of the first preferred embodiment.
- FIG. 9 is a cross-sectional view of a bearing mechanism according to yet another modification of the first preferred embodiment.
- FIG. 10 is a horizontal cross-sectional view of a holder of the bearing mechanism illustrated in FIG. 9 .
- FIG. 11 is a cross-sectional view of a fan according to a second preferred embodiment of the present invention.
- FIG. 12 is a cross-sectional view of a fan according to a third preferred embodiment of the present invention.
- FIG. 13 is a cross-sectional view illustrating a bearing mechanism of the fan in an enlarged form.
- FIG. 14 is a cross-sectional view of a bearing mechanism according to a modification of the third preferred embodiment.
- FIG. 15 is a cross-sectional view of a fan according to a fourth preferred embodiment of the present invention.
- FIG. 16 is a cross-sectional view of a fan according to a modification of the fourth preferred embodiment.
- FIG. 17 is a cross-sectional view of a fan according to another modification of the fourth preferred embodiment.
- a vertical direction is defined as a direction in which a central axis of a motor extends, and that an upper side and a lower side along the central axis in FIG. 1 are referred to simply as an upper side and a lower side, respectively. It should be noted, however, that the above definitions of the vertical direction and the upper and lower sides should not be construed to restrict relative positions or directions of different members or portions when the motor is actually installed in a device.
- axial direction a direction parallel to the central axis
- radial direction a direction parallel to the central axis
- radial direction a direction parallel to the central axis
- radial direction a direction parallel to the central axis
- radial direction a direction parallel to the central axis
- radial direction a direction parallel to the central axis
- radial direction a direction parallel to the central axis
- radial direction centered on the central axis
- circumferential direction a circumferential direction about the central axis
- FIG. 1 is a cross-sectional view of an axial fan 1 according to a first preferred embodiment of the present invention.
- the axial fan 1 will be referred to simply as the “fan 1 ”.
- the fan 1 includes a motor 11 , an impeller 12 , a housing 13 , and a plurality of support ribs 14 .
- the housing 13 is arranged to surround an outer circumference of the impeller 12 .
- the support ribs 14 are arranged in a circumferential direction.
- the housing 13 and the motor 11 are connected to each other through the support ribs 14 .
- the impeller 12 is made of a resin, and includes a rotor holder 121 and a plurality of blades 122 .
- the rotor holder 121 is substantially in the shape of a covered cylinder.
- the rotor holder 121 is arranged to cover an outer side of the motor 11 .
- the rotor holder 121 is arranged to define a portion of a rotating portion 2 of the motor 11 , which will be described below.
- the rotor holder 121 includes a top plate portion 123 , a side wall portion 124 , and a tubular bushing 125 .
- the top plate portion 123 is arranged to spread perpendicularly to a central axis J 1 .
- the side wall portion 124 is arranged to extend downward from an outer edge portion of the top plate portion 123 .
- the bushing 125 is made of a metal, and is fixed to a surface which defines a central hole of the top face portion 123 .
- the blades 122 are arranged to extend radially outward from an outer circumferential surface of the side wall portion 124 with the central axis J 1 as a center.
- the rotor holder 121 and the blades 122 are defined as a single member by a resin injection molding process.
- the fan 1 is arranged to produce an air current traveling downward from above through rotation of the impeller 12 about the central axis J 1 caused by the motor 11 .
- the motor 11 is a single-phase or three-phase motor of an outer-rotor type.
- the motor 11 includes the rotating portion 2 , a stationary portion 3 , and a bearing mechanism 401 .
- the rotating portion 2 is supported by the bearing mechanism 401 to be rotatable with respect to the stationary portion 3 .
- the rotating portion 2 includes the rotor holder 121 , a substantially cylindrical metallic yoke 21 , and a rotor magnet 22 .
- the rotor holder 121 is arranged substantially in the shape of a covered cylinder.
- the yoke 21 is fixed to an inside of the side wall portion 124 of the rotor holder 121 .
- the rotor magnet 22 is fixed to an inner circumferential surface of the yoke 21 .
- the stationary portion 3 includes a base portion 31 , a stator 32 , and a circuit board 33 .
- the stator 32 is arranged on an outer circumference of the bearing mechanism 401 .
- the stator 32 includes a stator core 321 and a plurality of coils 322 arranged on the stator core 321 .
- the stator core 321 is defined by laminated magnetic steel sheets.
- the circuit board 33 is fixed below the coils 322 . Lead wires from the coils 322 are attached to pins (not shown) inserted in holes of the circuit board 33 , so that the stator 32 and the circuit board 33 are electrically connected with each other. Note that the lead wires from the coils 322 may be directly connected to the circuit board 33 .
- a turning force is generated between the rotor magnet 22 and the stator 32 , which is arranged radially inside the rotor magnet 22 .
- a Hall element 331 and a drive circuit are mounted on an upper surface of the circuit board 33 .
- the Hall element 331 is arranged under the rotor magnet 22 to detect changes in magnetic flux which accompany rotation of the rotor magnet 22 .
- a magnetic attraction force which attracts the rotor magnet 22 downward is produced between the rotor magnet 22 and the stator 32 . This contributes to reducing a force that acts to lift the impeller 12 relative to the stationary portion 3 .
- the bearing mechanism 401 includes a shaft 41 , an annular thrust plate 42 , a sleeve 44 , a thrust cap 45 , i.e., a cap member, a holder 46 , and a lubricating oil 47 .
- the shaft 41 is inserted in the sleeve 44 .
- An upper portion of the shaft 41 is fixed to the top face portion 123 through the bushing 125 . Note that the upper portion of the shaft 41 may be directly fixed to the top face portion 123 without the bushing 125 intervening therebetween.
- the thrust plate 42 is fixed to a lower end portion of the shaft 41 on a lower side of the sleeve 44 .
- the thrust plate 42 is arranged to extend radially outward from an outer circumferential surface of the shaft 41 .
- the thrust plate 42 includes an inclined surface 421 defined between an outer circumferential surface and a lower surface thereof.
- the inclined surface 421 is arranged to be inclined radially inward with decreasing height.
- the sleeve 44 is a metallic sintered body impregnated with the lubricating oil 47 .
- the sleeve 44 is held inside the holder 46 , which is substantially cylindrical in shape.
- the holder 46 , the base portion 31 , and the support ribs 14 are defined as a single member.
- the holder 46 is arranged to extend upward from a central portion of the base portion 31 .
- the holder 46 , the base portion 31 , and the support ribs 14 are made of a resin. Note that the holder 46 , the base portion 31 , and the support ribs 14 may be made of a metal.
- An upper portion of the holder 46 includes an upper annular portion 461 and an upper cylindrical portion 462 .
- the upper annular portion 461 is arranged in an annular shape centered on the central axis J 1 , and is arranged on an upper side of the sleeve 44 .
- the upper cylindrical portion 462 is arranged to extend upward from an outer edge portion of the upper annular portion 461 .
- the holder 46 further includes a connection channel defining portion 5 .
- the connection channel defining portion 5 is arranged to define a connection channel 51 in the holder 46 .
- a radially inner portion of the stator core 321 is fixed to an outer circumferential surface of the holder 46 . Note that each of the shaft 41 and the thrust plate 42 defines a portion of the rotating portion 2 , while each of the sleeve 44 , the thrust cap 45 , and the holder 46 defines a portion of the stationary portion 3 .
- FIG. 2 is a cross-sectional view illustrating a portion of the bearing mechanism 401 in an enlarged form.
- Each of an upper portion and a lower portion of the sleeve 44 is fixed to an inner circumferential portion of the holder 46 .
- a portion of the inner circumferential portion of the holder 46 which is arranged to be in radial contact with the upper portion of the sleeve 44 will be hereinafter referred to as an “upper contact portion 463 ”.
- a portion of the inner circumferential portion of the holder 46 which is arranged to be in radial contact with the lower portion of the sleeve 44 will be hereinafter referred to as a “lower contact portion 464 ”.
- An outer circumferential surface of the sleeve 44 includes an inclined surface 441 arranged to be inclined radially inward with increasing height between the upper and lower contact portions 463 and 464 .
- An upper seal gap 611 which is arranged to gradually increase in radial width with increasing height, is defined between the inclined surface 441 of the sleeve 44 and an inner circumferential surface 46 a of the holder 46 .
- An upper seal portion 61 a which is arranged to retain the lubricating oil 47 through capillary action, is defined in the upper seal gap 611 .
- An upper surface of the lubricating oil 47 is defined in the upper seal portion 61 a.
- FIG. 3 is a diagram illustrating an upper portion of the fan 1 in an enlarged form.
- FIG. 4 is a cross-sectional view of the bearing mechanism 401 taken along line A-A in FIG. 3 .
- the upper contact portion 463 of the holder 46 includes cut portions 463 a each of which extends in a vertical direction. Each cut portion 463 a is arranged to define an airway 651 extending in the vertical direction between the upper contact portion 463 and the outer circumferential surface of the sleeve 44 .
- the airway 651 is arranged to bring the upper seal gap 611 into communication with a space 656 defined between an upper surface of the sleeve 44 and a lower surface of the upper annular portion 461 .
- the bushing 125 is arranged above the holder 46 .
- a horizontal gap 652 extending in directions perpendicular to the central axis J 1 is defined between a lower surface of the bushing 125 and an upper surface of the upper annular portion 461 .
- a vertical gap 653 extending in an axial direction is defined between an outer circumferential surface of the bushing 125 and an inner circumferential surface of the upper cylindrical portion 462 .
- the vertical gap 653 is arranged in an annular shape centered on the central axis J 1 .
- the upper seal gap 611 is arranged to be in communication with a space above the stator 32 illustrated in FIG.
- the upper seal gap 611 , the airways 651 , the space 656 , the horizontal gap 652 , and the vertical gap 653 that is, a space enclosed by the sleeve 44 , the holder 46 , the shaft 41 , and the bushing 125 , will be hereinafter referred to collectively as an “upper space 61 ”.
- the upper space 61 may include a space defined in the vicinity of the vertical gap 653 between the rotor holder 121 and an inner circumferential portion of the stator 32 illustrated in FIG. 1 .
- the thrust cap 45 is arranged in the shape of a disk, and is fixed to a lower portion of the holder 46 below the thrust plate 42 .
- the thrust cap 45 is arranged to close a lower opening of the holder 46 .
- the bearing mechanism 401 includes a space 62 enclosed by the thrust cap 45 , the thrust plate 42 , the holder 46 , and the shaft 41 .
- the space 62 which is defined above the thrust cap 45 , will be hereinafter referred to as a “lower space 62 ”.
- a portion of the lower space 62 which is defined between the inclined surface 421 of the thrust plate 42 and the inner circumferential surface 46 a of the holder 46 will be referred to as a “lower seal gap 621 ”.
- the lower seal gap 621 is arranged to gradually increase in radial width with decreasing height.
- a lower seal portion 62 a which is arranged to retain the lubricating oil 47 through capillary action, is defined in the lower seal gap 621 .
- a lower surface of the lubricating oil 47 is defined in the lower seal portion 62 a.
- the connection channel 51 which is defined by the connection channel defining portion 5 , includes a vertical hole 511 , an upper horizontal hole 512 , and a lower horizontal hole 513 .
- the vertical hole 511 is arranged to extend in the vertical direction in the holder 46 .
- the upper horizontal hole 512 is arranged to extend radially inward from a top portion of the vertical hole 511 .
- An end opening of the upper horizontal hole 512 i.e., an upper end opening of the connection channel 51 , is defined in a middle portion of the inner circumferential surface 46 a of the holder 46 .
- the upper horizontal hole 512 is joined to the upper seal gap 611 on an upper side of the upper seal portion 61 a .
- the lower horizontal hole 513 is arranged to extend radially inward from a bottom portion of the vertical hole 511 .
- An end opening of the lower horizontal hole 513 i.e., a lower end opening of the connection channel 51 , is defined in a lower portion of the inner circumferential surface 46 a of the holder 46 .
- the lower horizontal hole 513 is joined to the lower space 62 on a lower side of the lower seal portion 62 a .
- the upper and lower spaces 61 and 62 are connected with each other through the connection channel 51 .
- a seal member 311 which is a nameplate, is attached to a lower surface of the base portion 31 on a lower side of the thrust cap 45 .
- the fan 1 includes a space 622 enclosed by the seal member 311 , a lower surface of the thrust cap 45 , and an inner circumferential surface of the base portion 31 .
- the space 622 which is defined below the thrust cap 45 , will be hereinafter referred to as a “below-cap space 622 ”.
- a thrust gap 64 arranged to extend radially is defined between an upper surface of the thrust plate 42 and a lower surface of the sleeve 44 .
- FIG. 5 is a plan view of the thrust plate 42 .
- the upper surface of the thrust plate 42 includes a thrust dynamic pressure groove array 641 arranged in a herringbone pattern.
- a thrust bearing portion 64 a arranged to generate, during the drive of the motor 11 , a thrust dynamic pressure acting on the lubricating oil 47 through the thrust dynamic pressure groove array 641 is defined in the thrust gap 64 .
- a radial gap 66 arranged to extend in the axial direction is defined between an inner circumferential surface of the sleeve 44 and the outer circumferential surface of the shaft 41 .
- a radial bearing portion 66 a arranged to generate a radial dynamic pressure acting on the lubricating oil 47 during the drive of the motor 11 is defined in the radial gap 66 .
- a top portion of the sleeve 44 includes an upper-side groove portion 442 arranged to extend radially.
- An upper plate 48 which is arranged in an annular shape, is arranged on the upper surface of the sleeve 44 .
- a communicating channel 654 arranged to extend radially is defined between the upper-side groove portion 442 and the upper plate 48 .
- the communicating channel 654 serves to guide a portion of the lubricating oil 47 which soaks out of the top portion of the sleeve 44 into the radial gap 66 , and also to prevent a leakage of the lubricating oil 47 through the top portion of the sleeve 44 . Note that a portion of the lubricating oil 47 which is in the communicating channel 654 may sometimes flow toward the upper seal gap 611 .
- a so-called labyrinth structure is defined by provision of the horizontal and vertical gaps 652 and 653 .
- the thrust plate 42 is stably supported in the axial direction with respect to the stationary portion 3 through the thrust bearing portion 64 a , while the shaft 41 is stably supported in a radial direction through the radial bearing portion 66 a .
- Use of the bearing mechanism using fluid dynamic pressure in the fan 1 contributes to reducing a production cost of the fan 1 as compared to the case where a ball bearing is used therein, and also to reducing noise during the drive of the fan.
- the fan 1 has been described above.
- the upper space 61 which is arranged between the upper seal portion 61 a and an inside of the rotor holder 121 , is joined to the lower space 62 through the connection channel 51 .
- a difference in pressure between the upper and lower spaces 61 and 62 can thus be reduced or eliminated. This contributes to preventing the lubricating oil 47 from leaking out of the upper and lower seal portions 61 a and 62 a .
- Provision of the thrust cap 45 between the lower space 62 and a space downstream of the fan 1 contributes to more effective prevention of occurrence of a difference in pressure between the upper and lower spaces 61 and 62 .
- FIG. 6 is a horizontal cross-sectional view illustrating a holder 46 according to a modification of the first preferred embodiment.
- the holder 46 includes a plurality of connection channel defining portions 5 defined therein. Each of the connection channel defining portions 5 is arranged to define a connection channel 51 .
- the connection channels 51 are arranged at regular intervals in the circumferential direction. Provision of the plurality of connection channels 51 leads to more secure prevention of occurrence of a difference in pressure between an upper space 61 and a lower space 62 illustrated in FIG. 2 .
- FIG. 7 is a cross-sectional view of a bearing mechanism 401 according to a modification of the first preferred embodiment.
- a holder 46 includes a connection channel defining portion 5 a arranged to define a connection channel 51 a .
- the connection channel 51 a includes a vertical groove 514 , an upper horizontal hole 512 , and a lower horizontal hole 513 .
- the vertical groove 514 is arranged to extend in the vertical direction in an outer circumferential surface of the holder 46 on a radially inner side of a stator 32 .
- the vertical groove 514 and an inner circumferential portion of a stator core 321 are arranged to together define a vertical hole 514 a , which is a portion of the connection channel 51 a .
- the vertical groove 514 is arranged to connect the upper and lower horizontal holes 512 and 513 with each other.
- the upper horizontal hole 512 is arranged to extend in a radial direction through the holder 46 on an upper side of the vertical groove 514 .
- a radially inner end opening of the upper horizontal hole 512 is defined in a middle portion of an inner circumferential surface 46 a of the holder 46 , and is joined to an upper seal gap 611 .
- the lower horizontal hole 513 is arranged to extend in the radial direction through the holder 46 on a lower side of the vertical groove 514 .
- a radially inner end opening of the lower horizontal hole 513 is defined in a lower portion of the inner circumferential surface 46 a of the holder 46 , and is joined to a lower seal gap 621 .
- connection channel 51 a contributes to preventing occurrence of a difference in pressure between an upper space 61 and a lower space 62 .
- the vertical groove 514 , the upper horizontal hole 512 , and the lower horizontal hole 513 can be defined easily by moving a portion of a mold radially outward when the holder 46 is molded by a resin injection molding process.
- FIG. 8 is a cross-sectional view of a bearing mechanism 401 according to another modification of the first preferred embodiment.
- a holder 46 includes a connection channel defining portion 5 b arranged to define a connection channel 51 b .
- the connection channel 51 b includes a holder groove 515 and a holder through hole 516 .
- the holder groove 515 is arranged to extend in the vertical direction in an outer circumferential surface of the holder 46 on a radially inner side of an inner circumferential surface of a stator 32 .
- the holder through hole 516 is arranged to extend in the vertical direction through the holder 46 , from a lower end of the holder groove 515 to a lower end of an outer circumferential portion of the holder 46 .
- the holder groove 515 and the inner circumferential surface of the stator 32 are arranged to together define a portion of the connection channel 51 b.
- the holder through hole 516 is arranged radially outward of a thrust cap 45 .
- a portion of the holder 46 which is radially outward of the thrust cap 45 includes a groove portion 516 a arranged to extend in the axial direction continuously from a lower end of the holder through hole 516 .
- the groove portion 516 a is arranged to define a portion of the connection channel 51 b between the holder 46 and the thrust cap 45 .
- a portion of the connection channel 51 b is defined between the groove portion 516 a and an outer circumferential surface of the thrust cap 45 .
- the thrust cap 45 includes a cap through hole 451 arranged to extend in the vertical direction through the thrust cap 45 .
- a lubricating oil 47 is injected into the bearing mechanism 401 through the cap through hole 451 .
- An inner circumferential portion of a stator core 321 includes a cut portion 321 a arranged to extend in the vertical direction.
- the cut portion 321 a may be used for circumferential positioning of each of the magnetic steel sheets.
- the cut portion 321 a and the holder groove 515 are arranged to overlap with each other in a radial direction.
- the holder groove 515 may not necessarily be arranged to overlap with the cut portion 321 a of the stator core 321 in the radial direction, and that the holder groove 515 may be arranged to overlap with another portion of the inner circumferential portion of the stator core 321 in the radial direction.
- an upper space 61 which includes a space above a surface of the lubricating oil 47 in an upper seal gap 611 , is joined to a lower space 62 through the connection channel 51 b , a below-cap space 622 , and the cap through hole 451 , and this contributes to preventing occurrence of a difference in pressure between the upper and lower spaces 61 and 62 .
- FIG. 9 is a cross-sectional view of a bearing mechanism 401 according to yet another modification of the first preferred embodiment.
- FIG. 10 is a cross-sectional view of a holder 46 taken along line B-B in FIG. 9 .
- the holder 46 includes a connection channel defining portion 5 c arranged to define a connection channel 52 .
- the connection channel 52 is a vertical hole extending in the vertical direction.
- a radially inner portion of the connection channel 52 includes a slit-like portion arranged to extend in the vertical direction (hereinafter referred to as a “slit portion 521 ”).
- the circumferential width of the slit portion 521 is arranged to be considerably smaller than the circumferential width of a portion of the connection channel 52 which is radially outward of the slit portion 521 .
- the connection channel 52 is arranged to join a portion of an upper seal gap 611 which is above an upper seal portion 61 a to a portion of a lower seal gap 621 which is below a lower seal portion 62 a . This contributes to preventing occurrence of a difference in pressure between an upper space 61 and a lower space 62 .
- the slit portion 521 is arranged to have a sufficiently small circumferential width to prevent entry of a lubricating oil 47 into the connection channel 52 .
- FIG. 11 is a diagram illustrating a fan 1 according to a second preferred embodiment of the present invention.
- a thrust cap 45 of the fan 1 includes a cap through hole 451 arranged to extend in the vertical direction through the thrust cap 45 .
- a base portion 31 includes a base through hole 312 arranged to extend in the vertical direction through the base portion 31 .
- a circuit board 33 includes a board through hole 332 arranged to extend in the vertical direction through the circuit board 33 .
- the base through hole 312 and the board through hole 332 are arranged to coincide with each other when viewed in the axial direction. Note that these through holes 312 and 332 may not necessarily be arranged to coincide with each other when viewed in the axial direction.
- An upper portion of a holder 46 includes a horizontal hole 517 arranged to extend in a radial direction therethrough. A radially inner end opening of the horizontal hole 517 is defined in an inner circumferential surface of an upper contact portion 463 .
- the horizontal hole 517 is joined to an upper seal gap 611 through an airway 651 .
- one end portion of a tube 16 made of a resin is inserted into the horizontal hole 517 through a circumferential gap defined between adjacent coils 322 of a stator 32 .
- the tube 16 is inserted through the board through hole 332 and the base through hole 312 , and an opposite end portion of the tube 16 is inserted into the cap through hole 451 .
- the fan 1 according to the second preferred embodiment is otherwise similar in structure to the fan 1 according to the first preferred embodiment.
- an upper space 61 and a lower space 62 are connected with each other, and this contributes to preventing occurrence of a difference in pressure between the upper and lower spaces 61 and 62 .
- Prevention of the occurrence of a difference in pressure between the upper and lower spaces 61 and 62 leads to prevention of a leakage of a lubricating oil 47 .
- other preferred embodiments of the present invention described below are also preferred.
- FIG. 12 is a diagram illustrating a fan 1 a according to a third preferred embodiment of the present invention.
- a bearing mechanism 402 of the fan 1 a includes a shaft 41 , a sleeve 44 , a holder 7 , a thrust plate 42 , a thrust cap 45 , and a lubricating oil 47 .
- the shaft 41 is inserted in the sleeve 44 .
- the sleeve 44 is a sintered body impregnated with the lubricating oil 47 .
- the thrust plate 42 is fixed to a lower end portion of the shaft 41 .
- the holder 7 includes a first holder 71 and a second holder 72 .
- the first holder 71 is arranged substantially in the shape of a cylinder centered on a central axis J 1 , and is arranged to hold the sleeve 44 .
- Each of an outer circumferential surface of the sleeve 44 and an outer circumferential surface of the thrust plate 42 is covered by the first holder 71 . That is, an inner circumferential surface of the first holder 71 is arranged radially outside the outer circumferential surface of the sleeve 44 and the outer circumferential surface of the thrust plate 42 .
- the first holder 71 includes an annular portion 711 arranged to project radially inward on an upper side of the sleeve 44 .
- the portion 711 will be hereinafter referred to as an “annular upper portion 711 ”.
- the second holder 72 is arranged substantially in the shape of a cylinder centered on the central axis J 1 .
- An outer circumferential surface of the first holder 71 is fixed to an inner circumferential surface of the second holder 72 .
- a stator 32 is fixed to an outer circumferential surface of the second holder 72 .
- the second holder 72 includes a connection channel defining portion 73 arranged to define a connection channel 730 .
- the fan 1 a is similar in structure to the fan 1 according to the first preferred embodiment except in the structure of the bearing mechanism 402 . Accordingly, like members or portions are designated by like reference numerals, and redundant description is omitted.
- a radial bearing portion 66 a is defined in a radial gap 66 defined between an inner circumferential surface of the sleeve 44 and an outer circumferential surface of the shaft 41 .
- an upper seal gap 611 is defined between an inner circumferential surface of the annular upper portion 711 and the outer circumferential surface of the shaft 41 .
- the upper seal gap 611 is arranged to gradually increase in radial width with increasing height.
- An upper seal portion 61 a arranged to retain the lubricating oil 47 is defined in the upper seal gap 611 .
- An upper surface of the lubricating oil 47 is defined in the upper seal portion 61 a .
- a lower seal gap 621 is defined between an inclined surface 421 of the thrust plate 42 and a lower portion of the inner circumferential surface of the first holder 71 .
- the lower seal gap 621 is arranged to gradually increase in radial width with decreasing height.
- a lower seal portion 62 a arranged to retain the lubricating oil 47 is defined in the lower seal gap 621 .
- a lower surface of the lubricating oil 47 is defined in the lower seal portion 62 a.
- a minute gap 74 extending in the axial direction is defined between an upper portion of the outer circumferential surface of the first holder 71 and an upper portion of the inner circumferential surface of the second holder 72 .
- the minute gap 74 is joined to the upper seal portion 61 a through a horizontal gap 652 defined between a lower surface of a bushing 125 and an upper surface of the annular upper portion 711 .
- the upper space 61 may include a space defined between the rotor holder 121 and an inner circumferential portion of the stator 32 .
- the connection channel 730 includes a vertical hole 731 , an upper horizontal hole 732 , and a lower horizontal hole 733 .
- the vertical hole 731 is arranged to extend in the vertical direction in the second holder 72 .
- the upper horizontal hole 732 is arranged to extend radially inward from a top portion of the vertical hole 731 .
- An end opening of the upper horizontal hole 732 i.e., an upper end opening of the connection channel 730 , is defined in the upper portion of the inner circumferential surface of the second holder 72 , and is joined to the minute gap 74 .
- the thrust cap 45 is fixed to a lower portion of the second holder 72 .
- An inner circumferential portion of the second holder 72 includes a groove portion arranged to extend in the radial direction on an upper side of the thrust cap 45 .
- This groove portion is arranged to define the lower horizontal hole 733 between the thrust cap 45 and the inner circumferential portion of the second holder 72 .
- the lower horizontal hole 733 is arranged to extend radially inward from a bottom portion of the vertical hole 731 .
- An end opening of the lower horizontal hole 733 i.e., a lower end opening of the connection channel 730 , is defined in a lower portion of the inner circumferential surface of the second holder 72 .
- a lower space 62 is defined by a combination of the thrust cap 45 , the thrust plate 42 , the holder 7 , and the shaft 41 .
- the upper space 61 which is arranged between the upper seal portion 61 a and an inside of the rotor holder 121 , is connected with the lower space 62 through the connection channel 730 , and this contributes to preventing occurrence of a difference in pressure between the upper and lower spaces 61 and 62 .
- FIG. 14 is a cross-sectional view of a bearing mechanism 402 according to a modification of the third preferred embodiment.
- a second holder 72 includes a connection channel defining portion 73 a arranged to define a connection channel 730 a .
- the connection channel 730 a includes a vertical groove 734 and a vertical hole 735 .
- the vertical groove 734 is defined in an outer circumferential surface of the second holder 72 .
- the vertical groove 734 and an inner circumferential surface of a stator 32 are arranged to together define a vertical hole which is continuous with the vertical hole 735 above the vertical hole 735 .
- the vertical hole 735 is arranged to extend in the vertical direction through an outer circumferential portion of the second holder 72 on a lower side of the vertical groove 734 .
- a thrust cap 45 includes a cap through hole 451 arranged to extend in the vertical direction through the thrust cap 45 .
- a seal member 311 is attached to a lower surface of a base portion 31 , so that a below-cap space 622 is defined below the thrust cap 45 .
- a lower space 62 is joined to an upper space 61 through the cap through hole 451 , the below-cap space 622 , and the connection channel 730 a in a manner similar to that illustrated in FIG. 8 .
- FIG. 15 is a diagram illustrating a fan 1 b according to a fourth preferred embodiment of the present invention.
- the fan 1 b includes a rotating portion 2 a , a stationary portion 3 a , and a bearing mechanism 403 .
- the bearing mechanism 403 includes a shaft 41 , a bearing portion 49 , a thrust plate 42 , and a thrust cap 45 .
- the bearing portion 49 includes a tubular sleeve 491 and a holder 492 .
- the holder 492 is arranged to cover an outer circumferential surface of the sleeve 491 .
- the shaft 41 is inserted in the sleeve 491 .
- the thrust plate 42 is fixed to a lower end portion of the shaft 41 .
- An upper surface of the thrust plate 42 is arranged axially opposite a lower surface of the sleeve 491 .
- a lower seal portion 62 a is defined between an outer edge portion of the thrust plate 42 and a lower end portion of the holder 492 .
- a lower surface of a lubricating oil 47 is defined in the lower seal portion 62 a .
- a lower space 62 is defined by a combination of the thrust plate 42 , the bearing portion 49 , and the thrust cap 45 .
- a rotor holder 121 a of the rotating portion 2 a includes a first rotor member 126 and a second rotor member 127 .
- the first rotor member 126 includes a thrust portion 126 b .
- the thrust portion 126 b is arranged in a substantially annular shape centered on a central axis J 1 , and is arranged to extend radially outward from an upper portion of the shaft 41 .
- the second rotor member 127 is attached to an outer circumferential surface of the first rotor member 126 .
- the second rotor member 127 includes a cylindrical portion 127 a .
- a rotor magnet 22 is fixed to an inner circumferential surface of the cylindrical portion 127 a .
- Blades 122 are arranged on an outer circumferential surface of the cylindrical portion 127 a.
- the first rotor member 126 further includes a rotor cylindrical portion 126 a .
- the rotor cylindrical portion 126 a is a cylindrical portion arranged to extend axially downward from the thrust portion 126 b on a radially outer side of the holder 492 .
- An upper seal gap 611 is defined between an inner circumferential surface of the rotor cylindrical portion 126 a and an upper portion of an outer circumferential surface of the holder 492 .
- the upper seal gap 611 is arranged to gradually increase in radial width with decreasing height.
- An upper seal portion 61 a is defined in the upper seal gap 611 .
- a surface of a lubricating oil 47 is defined in the upper seal portion 61 a.
- the stationary portion 3 a includes a substantially cylindrical bushing 31 a .
- the bushing 31 a is arranged to extend upward from a central portion of a base portion 31 .
- the bushing 31 a and the base portion 31 are defined by a single member.
- the thrust cap 45 is fixed to a lower portion of the bushing 31 a , and a lower opening of the bushing 31 a is closed by the thrust cap 45 .
- a stator 32 is fixed to an outer circumferential surface of the bushing 31 a .
- the holder 492 is fixed to an inner circumferential surface of the bushing 31 a .
- the bushing 31 a includes a projecting portion 313 and a connection channel defining portion 34 arranged to define a connection channel 340 .
- the projecting portion 313 is arranged to extend upward on a radially outer side of the rotor cylindrical portion 126 a .
- a vertical gap 655 arranged to extend in the axial direction is defined between the rotor cylindrical portion 126 a and the projecting portion 313 , and this contributes to preventing evaporation of the lubricating oil 47 out of the upper seal portion 61 a .
- the holder 492 includes a recessed portion, which is recessed radially inward, defined in a middle portion of the outer circumferential surface thereof.
- the vertical gap 655 is joined to the upper seal gap 611 through a space 623 enclosed by the recessed portion of the holder 492 , a lower portion of the rotor cylindrical portion 126 a , and a portion of the bushing 31 a which is radially inward of the projecting portion 313 .
- the vertical gap 65 , the space 623 , and the upper seal gap 611 (more precisely, a space below the surface of the lubricating oil 47 in the upper seal gap 611 ) will be hereinafter referred to collectively as an “upper space 61 ”.
- the connection channel 340 includes a vertical hole 341 and a lower horizontal hole 342 .
- the vertical hole 341 is arranged to extend in the axial direction on a radially inner side of the projecting portion 313 .
- An upper end opening of the vertical hole 341 is joined to the upper space 61 .
- the thrust cap 45 is fixed to the lower portion of the bushing 31 a .
- An inner circumferential portion of the bushing 31 a includes a groove portion shaped like a cut and arranged to extend in a radial direction on an upper side of the thrust cap 45 . This groove portion is arranged to define the lower horizontal hole 342 between the thrust cap 45 and the inner circumferential portion of the bushing 31 a .
- the lower horizontal hole 342 is arranged to extend radially inward from a lower end of the vertical hole 341 .
- An end opening of the lower horizontal hole 342 i.e., a lower end opening of the connection channel 340 , is defined in the inner circumferential surface of the bushing 31 a .
- the lower space 62 is joined to the lower horizontal hole 342 .
- an upper thrust bearing portion 661 a which is arranged to support the first rotor member 126 in the axial direction, is defined in an upper thrust gap 661 defined between a lower surface of the thrust portion 126 b and an upper surface of the sleeve 491 .
- the first rotor member 126 thus plays a part in defining the upper thrust bearing portion 661 a .
- a lower thrust bearing portion 662 a which is arranged to support the thrust plate 42 in the axial direction, is defined in a lower thrust gap 662 defined between the lower surface of the sleeve 491 and the upper surface of the thrust plate 42 .
- a radial bearing portion 66 a which is arranged to support the shaft 41 in the radial direction, is defined in a radial gap 66 defined between an outer circumferential surface of the shaft 41 and an inner circumferential surface of the sleeve 491 .
- the upper space 61 which is arranged between the upper seal portion 61 a and an inside of the rotor holder 121 a , is connected with the lower space 62 , which is arranged above the thrust cap 45 , through the connection channel 340 , and this contributes to preventing occurrence of a difference in pressure between the upper and lower spaces 61 and 62 .
- the upper thrust bearing portion may be defined between the first rotor member 126 and an upper surface of the holder 492 . The same is true with the case of FIG. 16 , which will be described below.
- FIG. 16 is a cross-sectional view of a bearing mechanism 403 according to a modification of the fourth preferred embodiment.
- a connection channel 340 a defined by a connection channel defining portion 34 a of a bushing 31 a includes a bushing groove 343 and a bushing through hole 344 .
- the bushing groove 343 is arranged to extend in the vertical direction in an outer circumferential surface of the bushing 31 a on a radially inner side of an inner circumferential surface of a stator 32 .
- the bushing through hole 344 is arranged to extend in the vertical direction through an outer circumferential portion of the bushing 31 a from a lower end of the bushing groove 343 to a lower end of the outer circumferential portion of the bushing 31 a .
- the bushing groove 343 and the inner circumferential surface of the stator 32 are arranged to together define a vertical hole which is continuous with the bushing through hole 344 above the bushing through hole 344 .
- a thrust cap 45 includes a cap through hole 451 .
- a below-cap space 622 is defined between the thrust cap 45 and a seal member 311 attached to a lower surface of a base portion 31 below the thrust cap 45 .
- a lower space 62 is connected with an upper space 61 through the cap through hole 451 , the below-cap space 622 , and the connection channel 340 a.
- FIG. 17 is a diagram illustrating a bearing mechanism 403 according to another modification of the fourth preferred embodiment.
- the bearing mechanism 403 includes a bearing portion 493 , which is a single sleeve made of a metal. An outer circumferential surface of the bearing portion 493 is fixed to a bushing 31 a .
- a radial bearing portion 66 a is defined in a radial gap 66 defined between an inner circumferential surface of the bearing portion 493 and an outer circumferential surface of a shaft 41 , which is inserted in the bearing portion 493 .
- An upper thrust bearing portion 661 a is defined in an upper thrust gap 661 defined between an upper surface of the bearing portion 493 and a lower surface of a first rotor member 126 .
- the bearing mechanism 403 does not include a lower thrust bearing portion.
- the bearing mechanism 403 according to the present modification of the fourth preferred embodiment is otherwise similar in structure to the bearing mechanism 403 of the fan 1 b illustrated in FIG. 15 .
- a connection channel 340 because of provision of a connection channel 340 , an upper space 61 and a lower space 62 are connected with each other, and this contributes to preventing occurrence of a difference in pressure between the upper and lower spaces 61 and 62 .
- a portion of the holder 46 which is on an upper side of the upper horizontal hole 512 , a portion of the holder 46 which is on a lower side of the lower horizontal hole 513 , and a portion of the holder 46 which is arranged between the above two portions and includes the connection channel defining portion 5 may be defined by separate members. In this case, the connection channel defining portion 5 can be defined more easily.
- a tube 16 may be arranged to join the upper and lower spaces 61 and 62 to each other.
- a modification of the fourth preferred embodiment In a modification of the fan 1 a illustrated in FIG. 12 , a groove portion arranged to extend in the vertical direction and define a connection channel may be defined in the inner circumferential surface of the second holder 72 . The same is true of each of modifications of the bushings 31 a illustrated in FIGS. 15 and 17 , respectively.
- the present invention is applicable to fans arranged to produce air currents.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
- General Details Of Gearings (AREA)
- Sealing Of Bearings (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
- Sliding-Contact Bearings (AREA)
Abstract
A fan includes blades and a motor. The motor includes a rotor holder; a shaft; a sleeve; a holder; and a thrust plate. A radial bearing portion arranged to support the shaft in a radial direction is defined in a radial gap defined between the shaft and the sleeve. A lower seal portion having a lower surface of a lubricating oil defined therein is defined between the thrust plate and the holder, while an upper seal portion having an upper surface of the lubricating oil defined therein is defined between the holder and the sleeve. The holder includes a connection channel defining portion arranged to define a connection channel to connect an upper space defined between the upper seal portion and an inside of the rotor holder with a lower space at which the lower seal portion is arranged.
Description
- 1. Field of the Invention
- The present invention relates to a fan arranged to produce an air current.
- 2. Description of the Related Art
- Cooling fans arranged to cool electronic components have typically been installed inside cases of a variety of electronic devices. A fan motor disclosed in JP-UM-B 06-31199 includes a case, a stator, a sleeve, a shaft, an annular member, a rotor, and a plurality of blades. The stator is arranged on an outer circumference of an inner tubular portion of the case. The sleeve is fitted into the inner tubular portion and fixed thereto. The shaft is inserted in the sleeve. Grooves arranged to generate a dynamic pressure are defined in an outer circumferential surface of the shaft. The annular member is fitted on a lower end portion of the shaft and fixed thereto. The annular member is arranged axially opposite a lower surface of the sleeve. Each of a gap defined between the sleeve and the shaft and a gap defined between the sleeve and the annular member is filled with a lubricating fluid. The rotor is fixed to an upper end portion of the shaft. A magnet is fixed to an inner circumference of a cylindrical attachment member of the rotor, and is arranged radially opposite the stator. The blades are fixed to an outer circumference of the attachment member. In the fan motor, a radial dynamic pressure bearing is defined by a combination of the shaft and the sleeve, while a thrust dynamic pressure bearing is defined by a combination of the sleeve and the annular member.
- During drive of a fan disclosed in JP-UM-B 06-31199, a difference in pressure may occur between an upper surface of the lubricating fluid, which is defined in the gap between the sleeve and the shaft, and a lower surface of the lubricating fluid, which is defined in a gap defined between a lower surface of the sleeve and an upper surface of the annular member or its vicinity. This pressure difference may cause a leakage of the lubricating fluid.
- A fan according to a preferred embodiment of the present invention includes a plurality of blades and a motor arranged to rotate the blades about a central axis. The motor includes a stationary portion including a stator; a rotating portion including a rotor magnet arranged radially outside the stator; and a bearing mechanism arranged to support the rotating portion such that the rotating portion is rotatable with respect to the stationary portion. The rotating portion includes a rotor holder arranged in a shape of a covered cylinder, and including an outer circumferential surface on which the blades are arranged. The bearing mechanism includes a shaft; a sleeve in which the shaft is inserted; a holder arranged to hold the sleeve; and a thrust plate fixed to a lower end portion of the shaft on a lower side of the sleeve. The shaft and the sleeve are arranged to together define a radial gap therebetween, the radial gap including a radial bearing portion arranged to support the shaft in a radial direction. The thrust plate and the holder are arranged to together define a lower seal portion therebetween, the lower seal portion having a lower surface of a lubricating oil defined therein, while the holder and the sleeve are arranged to together define an upper seal portion therebetween, the upper seal portion having an upper surface of the lubricating oil defined therein. The holder includes a connection channel defining portion arranged to define a connection channel to connect an upper space defined between the upper seal portion and an inside of the rotor holder with a lower space at which the lower seal portion is arranged.
- A fan according to another preferred embodiment of the present invention includes a plurality of blades and a motor arranged to rotate the blades about a central axis. The motor includes a stationary portion including a stator; a rotating portion including a rotor magnet arranged radially outside the stator; and a bearing mechanism arranged to support the rotating portion such that the rotating portion is rotatable with respect to the stationary portion. The rotating portion includes a rotor holder arranged in a shape of a covered cylinder, and including an outer circumferential surface on which the blades are arranged. The bearing mechanism includes a shaft; a sleeve in which the shaft is inserted; a holder arranged to hold the sleeve; and a thrust plate fixed to a lower end portion of the shaft on a lower side of the sleeve. The holder includes a cylindrical first holder arranged to cover an outer circumferential surface of the sleeve and an outer circumferential surface of the thrust plate, the first holder including an annular upper portion arranged to project radially inward on an upper side of the sleeve; and a second holder including an inner circumferential surface having an outer circumferential surface of the first holder fixed thereto, the second holder having the stator arranged on a radially outer side thereof. The shaft and the sleeve are arranged to together define a radial gap therebetween, the radial gap including a radial bearing portion arranged to support the shaft in a radial direction. The thrust plate and the first holder are arranged to together define a lower seal portion therebetween, the lower seal portion having a lower surface of a lubricating oil defined therein, while the shaft and the annular upper portion are arranged to together define an upper seal portion therebetween, the upper seal portion having an upper surface of the lubricating oil defined therein. The second holder includes a connection channel defining portion arranged to define a connection channel to connect an upper space defined between the upper seal portion and an inside of the rotor holder with a lower space at which the lower seal portion is arranged.
- A fan according to yet another preferred embodiment of the present invention includes a plurality of blades and a motor arranged to rotate the blades about a central axis. The motor includes a stationary portion including a stator; a rotating portion including a rotor magnet arranged radially outside the stator; and a bearing mechanism arranged to support the rotating portion such that the rotating portion is rotatable with respect to the stationary portion. The stationary portion includes a bushing arranged to hold the stator on a radially outer side thereof. The rotating portion includes a rotor holder arranged in a shape of a covered cylinder, and including an outer circumferential surface on which the blades are arranged. The bearing mechanism includes a shaft; a bearing portion in which the shaft is inserted; a thrust plate fixed to a lower end portion of the shaft on a lower side of the sleeve; a thrust portion arranged to extend radially outward from an upper portion of the shaft; and a rotor cylindrical portion arranged to extend axially downward from the thrust portion. The shaft and the bearing portion are arranged to together define a radial gap therebetween, the radial gap including a radial bearing portion arranged to support the shaft in a radial direction. The thrust plate and the bearing portion are arranged to together define a lower seal portion therebetween, the lower seal portion having a lower surface of a lubricating oil defined therein, while the bearing portion and the rotor cylindrical portion are arranged to together define an upper seal portion therebetween, the upper seal portion having an upper surface of the lubricating oil defined therein. The bushing includes a connection channel defining portion arranged to define a connection channel to connect an upper space defined between the upper seal portion and an inside of the rotor holder with a lower space at which the lower seal portion is arranged.
- According to preferred embodiments of the present invention, a reduction in a difference in pressure between the upper and lower spaces is achieved, and this contributes to preventing a leakage of the lubricating oil.
- The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.
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FIG. 1 is a cross-sectional view of a fan according to a first preferred embodiment of the present invention. -
FIG. 2 is a cross-sectional view illustrating a bearing mechanism of the fan in an enlarged form. -
FIG. 3 is a cross-sectional view illustrating the bearing mechanism in an enlarged form. -
FIG. 4 is a horizontal cross-sectional view of the bearing mechanism. -
FIG. 5 is a plan view of a thrust plate of the bearing mechanism. -
FIG. 6 is a horizontal cross-sectional view of a holder according to a modification of the first preferred embodiment. -
FIG. 7 is a cross-sectional view of a bearing mechanism according to another modification of the first preferred embodiment. -
FIG. 8 is a cross-sectional view of a bearing mechanism according to yet another modification of the first preferred embodiment. -
FIG. 9 is a cross-sectional view of a bearing mechanism according to yet another modification of the first preferred embodiment. -
FIG. 10 is a horizontal cross-sectional view of a holder of the bearing mechanism illustrated inFIG. 9 . -
FIG. 11 is a cross-sectional view of a fan according to a second preferred embodiment of the present invention. -
FIG. 12 is a cross-sectional view of a fan according to a third preferred embodiment of the present invention. -
FIG. 13 is a cross-sectional view illustrating a bearing mechanism of the fan in an enlarged form. -
FIG. 14 is a cross-sectional view of a bearing mechanism according to a modification of the third preferred embodiment. -
FIG. 15 is a cross-sectional view of a fan according to a fourth preferred embodiment of the present invention. -
FIG. 16 is a cross-sectional view of a fan according to a modification of the fourth preferred embodiment. -
FIG. 17 is a cross-sectional view of a fan according to another modification of the fourth preferred embodiment. - It is assumed herein that a vertical direction is defined as a direction in which a central axis of a motor extends, and that an upper side and a lower side along the central axis in
FIG. 1 are referred to simply as an upper side and a lower side, respectively. It should be noted, however, that the above definitions of the vertical direction and the upper and lower sides should not be construed to restrict relative positions or directions of different members or portions when the motor is actually installed in a device. Also note that a direction parallel to the central axis is referred to by the term “axial direction”, “axial”, or “axially”, that radial directions centered on the central axis are simply referred to by the term “radial direction”, “radial”, or “radially”, and that a circumferential direction about the central axis is simply referred to by the term “circumferential direction”, “circumferential”, or “circumferentially”. -
FIG. 1 is a cross-sectional view of anaxial fan 1 according to a first preferred embodiment of the present invention. Hereinafter, theaxial fan 1 will be referred to simply as the “fan 1”. Thefan 1 includes amotor 11, animpeller 12, ahousing 13, and a plurality ofsupport ribs 14. Thehousing 13 is arranged to surround an outer circumference of theimpeller 12. Thesupport ribs 14 are arranged in a circumferential direction. Thehousing 13 and themotor 11 are connected to each other through thesupport ribs 14. - The
impeller 12 is made of a resin, and includes arotor holder 121 and a plurality ofblades 122. Therotor holder 121 is substantially in the shape of a covered cylinder. Therotor holder 121 is arranged to cover an outer side of themotor 11. Therotor holder 121 is arranged to define a portion of arotating portion 2 of themotor 11, which will be described below. Therotor holder 121 includes atop plate portion 123, aside wall portion 124, and atubular bushing 125. Thetop plate portion 123 is arranged to spread perpendicularly to a central axis J1. Theside wall portion 124 is arranged to extend downward from an outer edge portion of thetop plate portion 123. Thebushing 125 is made of a metal, and is fixed to a surface which defines a central hole of thetop face portion 123. Theblades 122 are arranged to extend radially outward from an outer circumferential surface of theside wall portion 124 with the central axis J1 as a center. Therotor holder 121 and theblades 122 are defined as a single member by a resin injection molding process. - The
fan 1 is arranged to produce an air current traveling downward from above through rotation of theimpeller 12 about the central axis J1 caused by themotor 11. - The
motor 11 is a single-phase or three-phase motor of an outer-rotor type. Themotor 11 includes therotating portion 2, astationary portion 3, and abearing mechanism 401. The rotatingportion 2 is supported by thebearing mechanism 401 to be rotatable with respect to thestationary portion 3. The rotatingportion 2 includes therotor holder 121, a substantially cylindricalmetallic yoke 21, and arotor magnet 22. Therotor holder 121 is arranged substantially in the shape of a covered cylinder. Theyoke 21 is fixed to an inside of theside wall portion 124 of therotor holder 121. Therotor magnet 22 is fixed to an inner circumferential surface of theyoke 21. - The
stationary portion 3 includes abase portion 31, astator 32, and acircuit board 33. Thestator 32 is arranged on an outer circumference of thebearing mechanism 401. Thestator 32 includes astator core 321 and a plurality ofcoils 322 arranged on thestator core 321. Thestator core 321 is defined by laminated magnetic steel sheets. Thecircuit board 33 is fixed below thecoils 322. Lead wires from thecoils 322 are attached to pins (not shown) inserted in holes of thecircuit board 33, so that thestator 32 and thecircuit board 33 are electrically connected with each other. Note that the lead wires from thecoils 322 may be directly connected to thecircuit board 33. During drive of themotor 11, a turning force is generated between therotor magnet 22 and thestator 32, which is arranged radially inside therotor magnet 22. - A
Hall element 331 and a drive circuit (not shown) are mounted on an upper surface of thecircuit board 33. TheHall element 331 is arranged under therotor magnet 22 to detect changes in magnetic flux which accompany rotation of therotor magnet 22. - A magnetic attraction force which attracts the
rotor magnet 22 downward is produced between therotor magnet 22 and thestator 32. This contributes to reducing a force that acts to lift theimpeller 12 relative to thestationary portion 3. - The
bearing mechanism 401 includes ashaft 41, anannular thrust plate 42, asleeve 44, athrust cap 45, i.e., a cap member, aholder 46, and a lubricatingoil 47. Theshaft 41 is inserted in thesleeve 44. An upper portion of theshaft 41 is fixed to thetop face portion 123 through thebushing 125. Note that the upper portion of theshaft 41 may be directly fixed to thetop face portion 123 without thebushing 125 intervening therebetween. Thethrust plate 42 is fixed to a lower end portion of theshaft 41 on a lower side of thesleeve 44. Thethrust plate 42 is arranged to extend radially outward from an outer circumferential surface of theshaft 41. Thethrust plate 42 includes aninclined surface 421 defined between an outer circumferential surface and a lower surface thereof. Theinclined surface 421 is arranged to be inclined radially inward with decreasing height. - The
sleeve 44 is a metallic sintered body impregnated with the lubricatingoil 47. Thesleeve 44 is held inside theholder 46, which is substantially cylindrical in shape. Theholder 46, thebase portion 31, and thesupport ribs 14 are defined as a single member. Theholder 46 is arranged to extend upward from a central portion of thebase portion 31. Theholder 46, thebase portion 31, and thesupport ribs 14 are made of a resin. Note that theholder 46, thebase portion 31, and thesupport ribs 14 may be made of a metal. An upper portion of theholder 46 includes an upperannular portion 461 and an uppercylindrical portion 462. The upperannular portion 461 is arranged in an annular shape centered on the central axis J1, and is arranged on an upper side of thesleeve 44. The uppercylindrical portion 462 is arranged to extend upward from an outer edge portion of the upperannular portion 461. Theholder 46 further includes a connectionchannel defining portion 5. The connectionchannel defining portion 5 is arranged to define aconnection channel 51 in theholder 46. A radially inner portion of thestator core 321 is fixed to an outer circumferential surface of theholder 46. Note that each of theshaft 41 and thethrust plate 42 defines a portion of therotating portion 2, while each of thesleeve 44, thethrust cap 45, and theholder 46 defines a portion of thestationary portion 3. -
FIG. 2 is a cross-sectional view illustrating a portion of thebearing mechanism 401 in an enlarged form. Each of an upper portion and a lower portion of thesleeve 44 is fixed to an inner circumferential portion of theholder 46. A portion of the inner circumferential portion of theholder 46 which is arranged to be in radial contact with the upper portion of thesleeve 44 will be hereinafter referred to as an “upper contact portion 463”. A portion of the inner circumferential portion of theholder 46 which is arranged to be in radial contact with the lower portion of thesleeve 44 will be hereinafter referred to as a “lower contact portion 464”. An outer circumferential surface of thesleeve 44 includes aninclined surface 441 arranged to be inclined radially inward with increasing height between the upper andlower contact portions - An
upper seal gap 611, which is arranged to gradually increase in radial width with increasing height, is defined between theinclined surface 441 of thesleeve 44 and an innercircumferential surface 46 a of theholder 46. Anupper seal portion 61 a, which is arranged to retain the lubricatingoil 47 through capillary action, is defined in theupper seal gap 611. An upper surface of the lubricatingoil 47 is defined in theupper seal portion 61 a. -
FIG. 3 is a diagram illustrating an upper portion of thefan 1 in an enlarged form.FIG. 4 is a cross-sectional view of thebearing mechanism 401 taken along line A-A inFIG. 3 . Theupper contact portion 463 of theholder 46 includes cutportions 463 a each of which extends in a vertical direction. Eachcut portion 463 a is arranged to define anairway 651 extending in the vertical direction between theupper contact portion 463 and the outer circumferential surface of thesleeve 44. Theairway 651 is arranged to bring theupper seal gap 611 into communication with aspace 656 defined between an upper surface of thesleeve 44 and a lower surface of the upperannular portion 461. - As illustrated in
FIG. 3 , thebushing 125 is arranged above theholder 46. Ahorizontal gap 652 extending in directions perpendicular to the central axis J1 is defined between a lower surface of thebushing 125 and an upper surface of the upperannular portion 461. Avertical gap 653 extending in an axial direction is defined between an outer circumferential surface of thebushing 125 and an inner circumferential surface of the uppercylindrical portion 462. Thevertical gap 653 is arranged in an annular shape centered on the central axis J1. Theupper seal gap 611 is arranged to be in communication with a space above thestator 32 illustrated inFIG. 1 through theairways 651, thespace 656, a gap defined between theshaft 41 and an inner edge of the upperannular portion 461, thehorizontal gap 652, and thevertical gap 653. Theupper seal gap 611, theairways 651, thespace 656, thehorizontal gap 652, and thevertical gap 653, that is, a space enclosed by thesleeve 44, theholder 46, theshaft 41, and thebushing 125, will be hereinafter referred to collectively as an “upper space 61”. Note that theupper space 61 may include a space defined in the vicinity of thevertical gap 653 between therotor holder 121 and an inner circumferential portion of thestator 32 illustrated inFIG. 1 . - As illustrated in
FIG. 2 , thethrust cap 45 is arranged in the shape of a disk, and is fixed to a lower portion of theholder 46 below thethrust plate 42. Thethrust cap 45 is arranged to close a lower opening of theholder 46. Thebearing mechanism 401 includes aspace 62 enclosed by thethrust cap 45, thethrust plate 42, theholder 46, and theshaft 41. Thespace 62, which is defined above thethrust cap 45, will be hereinafter referred to as a “lower space 62”. A portion of thelower space 62 which is defined between theinclined surface 421 of thethrust plate 42 and the innercircumferential surface 46 a of theholder 46 will be referred to as a “lower seal gap 621”. Thelower seal gap 621 is arranged to gradually increase in radial width with decreasing height. Alower seal portion 62 a, which is arranged to retain the lubricatingoil 47 through capillary action, is defined in thelower seal gap 621. A lower surface of the lubricatingoil 47 is defined in thelower seal portion 62 a. - The
connection channel 51, which is defined by the connectionchannel defining portion 5, includes avertical hole 511, an upperhorizontal hole 512, and a lowerhorizontal hole 513. Thevertical hole 511 is arranged to extend in the vertical direction in theholder 46. The upperhorizontal hole 512 is arranged to extend radially inward from a top portion of thevertical hole 511. An end opening of the upperhorizontal hole 512, i.e., an upper end opening of theconnection channel 51, is defined in a middle portion of the innercircumferential surface 46 a of theholder 46. The upperhorizontal hole 512 is joined to theupper seal gap 611 on an upper side of theupper seal portion 61 a. The lowerhorizontal hole 513 is arranged to extend radially inward from a bottom portion of thevertical hole 511. An end opening of the lowerhorizontal hole 513, i.e., a lower end opening of theconnection channel 51, is defined in a lower portion of the innercircumferential surface 46 a of theholder 46. The lowerhorizontal hole 513 is joined to thelower space 62 on a lower side of thelower seal portion 62 a. In thebearing mechanism 401, the upper andlower spaces connection channel 51. - A
seal member 311, which is a nameplate, is attached to a lower surface of thebase portion 31 on a lower side of thethrust cap 45. Thefan 1 includes aspace 622 enclosed by theseal member 311, a lower surface of thethrust cap 45, and an inner circumferential surface of thebase portion 31. Thespace 622, which is defined below thethrust cap 45, will be hereinafter referred to as a “below-cap space 622”. - A
thrust gap 64 arranged to extend radially is defined between an upper surface of thethrust plate 42 and a lower surface of thesleeve 44.FIG. 5 is a plan view of thethrust plate 42. The upper surface of thethrust plate 42 includes a thrust dynamicpressure groove array 641 arranged in a herringbone pattern. Athrust bearing portion 64 a arranged to generate, during the drive of themotor 11, a thrust dynamic pressure acting on the lubricatingoil 47 through the thrust dynamicpressure groove array 641 is defined in thethrust gap 64. - A
radial gap 66 arranged to extend in the axial direction is defined between an inner circumferential surface of thesleeve 44 and the outer circumferential surface of theshaft 41. Aradial bearing portion 66 a arranged to generate a radial dynamic pressure acting on the lubricatingoil 47 during the drive of themotor 11 is defined in theradial gap 66. As illustrated inFIG. 3 , a top portion of thesleeve 44 includes an upper-side groove portion 442 arranged to extend radially. Anupper plate 48, which is arranged in an annular shape, is arranged on the upper surface of thesleeve 44. A communicatingchannel 654 arranged to extend radially is defined between the upper-side groove portion 442 and theupper plate 48. - The communicating
channel 654 serves to guide a portion of the lubricatingoil 47 which soaks out of the top portion of thesleeve 44 into theradial gap 66, and also to prevent a leakage of the lubricatingoil 47 through the top portion of thesleeve 44. Note that a portion of the lubricatingoil 47 which is in the communicatingchannel 654 may sometimes flow toward theupper seal gap 611. In thebearing mechanism 401, a so-called labyrinth structure is defined by provision of the horizontal andvertical gaps radial gap 66 from traveling out of thebearing mechanism 401, and to reducing evaporation of the lubricatingoil 47 out of thebearing mechanism 401. - During drive of the
fan 1 illustrated inFIG. 1 , thethrust plate 42 is stably supported in the axial direction with respect to thestationary portion 3 through thethrust bearing portion 64 a, while theshaft 41 is stably supported in a radial direction through theradial bearing portion 66 a. Use of the bearing mechanism using fluid dynamic pressure in thefan 1 contributes to reducing a production cost of thefan 1 as compared to the case where a ball bearing is used therein, and also to reducing noise during the drive of the fan. - The
fan 1 according to the first preferred embodiment has been described above. In thefan 1, theupper space 61, which is arranged between theupper seal portion 61 a and an inside of therotor holder 121, is joined to thelower space 62 through theconnection channel 51. A difference in pressure between the upper andlower spaces oil 47 from leaking out of the upper andlower seal portions thrust cap 45 between thelower space 62 and a space downstream of thefan 1 contributes to more effective prevention of occurrence of a difference in pressure between the upper andlower spaces -
FIG. 6 is a horizontal cross-sectional view illustrating aholder 46 according to a modification of the first preferred embodiment. Theholder 46 includes a plurality of connectionchannel defining portions 5 defined therein. Each of the connectionchannel defining portions 5 is arranged to define aconnection channel 51. Theconnection channels 51 are arranged at regular intervals in the circumferential direction. Provision of the plurality ofconnection channels 51 leads to more secure prevention of occurrence of a difference in pressure between anupper space 61 and alower space 62 illustrated inFIG. 2 . -
FIG. 7 is a cross-sectional view of abearing mechanism 401 according to a modification of the first preferred embodiment. Aholder 46 includes a connectionchannel defining portion 5 a arranged to define a connection channel 51 a. The connection channel 51 a includes avertical groove 514, an upperhorizontal hole 512, and a lowerhorizontal hole 513. Thevertical groove 514 is arranged to extend in the vertical direction in an outer circumferential surface of theholder 46 on a radially inner side of astator 32. Thevertical groove 514 and an inner circumferential portion of astator core 321 are arranged to together define a vertical hole 514 a, which is a portion of the connection channel 51 a. Thevertical groove 514 is arranged to connect the upper and lowerhorizontal holes - The upper
horizontal hole 512 is arranged to extend in a radial direction through theholder 46 on an upper side of thevertical groove 514. A radially inner end opening of the upperhorizontal hole 512 is defined in a middle portion of an innercircumferential surface 46 a of theholder 46, and is joined to anupper seal gap 611. The lowerhorizontal hole 513 is arranged to extend in the radial direction through theholder 46 on a lower side of thevertical groove 514. A radially inner end opening of the lowerhorizontal hole 513 is defined in a lower portion of the innercircumferential surface 46 a of theholder 46, and is joined to alower seal gap 621. - In the
bearing mechanism 401, provision of the connection channel 51 a contributes to preventing occurrence of a difference in pressure between anupper space 61 and alower space 62. In the case of thebearing mechanism 401, thevertical groove 514, the upperhorizontal hole 512, and the lowerhorizontal hole 513 can be defined easily by moving a portion of a mold radially outward when theholder 46 is molded by a resin injection molding process. -
FIG. 8 is a cross-sectional view of abearing mechanism 401 according to another modification of the first preferred embodiment. InFIG. 8 , the shape of a portion of thebearing mechanism 401 beyond a cross section of thebearing mechanism 401 is also depicted. The same is true ofFIG. 9 , which will be described below. Aholder 46 includes a connectionchannel defining portion 5 b arranged to define aconnection channel 51 b. Theconnection channel 51 b includes aholder groove 515 and a holder throughhole 516. Theholder groove 515 is arranged to extend in the vertical direction in an outer circumferential surface of theholder 46 on a radially inner side of an inner circumferential surface of astator 32. The holder throughhole 516 is arranged to extend in the vertical direction through theholder 46, from a lower end of theholder groove 515 to a lower end of an outer circumferential portion of theholder 46. Theholder groove 515 and the inner circumferential surface of thestator 32 are arranged to together define a portion of theconnection channel 51 b. - The holder through
hole 516 is arranged radially outward of athrust cap 45. A portion of theholder 46 which is radially outward of thethrust cap 45 includes agroove portion 516 a arranged to extend in the axial direction continuously from a lower end of the holder throughhole 516. Thegroove portion 516 a is arranged to define a portion of theconnection channel 51 b between theholder 46 and thethrust cap 45. A portion of theconnection channel 51 b is defined between thegroove portion 516 a and an outer circumferential surface of thethrust cap 45. - The
thrust cap 45 includes a cap throughhole 451 arranged to extend in the vertical direction through thethrust cap 45. When thebearing mechanism 401 is manufactured, a lubricatingoil 47 is injected into thebearing mechanism 401 through the cap throughhole 451. - An inner circumferential portion of a
stator core 321 includes acut portion 321 a arranged to extend in the vertical direction. When a plurality of magnetic steel sheets are placed one upon another to define thestator core 321, thecut portion 321 a may be used for circumferential positioning of each of the magnetic steel sheets. In thebearing mechanism 401, thecut portion 321 a and theholder groove 515 are arranged to overlap with each other in a radial direction. Note that theholder groove 515 may not necessarily be arranged to overlap with thecut portion 321 a of thestator core 321 in the radial direction, and that theholder groove 515 may be arranged to overlap with another portion of the inner circumferential portion of thestator core 321 in the radial direction. - In the
bearing mechanism 401, anupper space 61, which includes a space above a surface of the lubricatingoil 47 in anupper seal gap 611, is joined to alower space 62 through theconnection channel 51 b, a below-cap space 622, and the cap throughhole 451, and this contributes to preventing occurrence of a difference in pressure between the upper andlower spaces -
FIG. 9 is a cross-sectional view of abearing mechanism 401 according to yet another modification of the first preferred embodiment.FIG. 10 is a cross-sectional view of aholder 46 taken along line B-B inFIG. 9 . Theholder 46 includes a connectionchannel defining portion 5 c arranged to define aconnection channel 52. Theconnection channel 52 is a vertical hole extending in the vertical direction. A radially inner portion of theconnection channel 52 includes a slit-like portion arranged to extend in the vertical direction (hereinafter referred to as a “slit portion 521”). - As illustrated in
FIG. 10 , the circumferential width of theslit portion 521 is arranged to be considerably smaller than the circumferential width of a portion of theconnection channel 52 which is radially outward of theslit portion 521. As illustrated inFIG. 9 , theconnection channel 52 is arranged to join a portion of anupper seal gap 611 which is above anupper seal portion 61 a to a portion of alower seal gap 621 which is below alower seal portion 62 a. This contributes to preventing occurrence of a difference in pressure between anupper space 61 and alower space 62. In thebearing mechanism 401, theslit portion 521 is arranged to have a sufficiently small circumferential width to prevent entry of a lubricatingoil 47 into theconnection channel 52. -
FIG. 11 is a diagram illustrating afan 1 according to a second preferred embodiment of the present invention. Athrust cap 45 of thefan 1 includes a cap throughhole 451 arranged to extend in the vertical direction through thethrust cap 45. Abase portion 31 includes a base throughhole 312 arranged to extend in the vertical direction through thebase portion 31. Acircuit board 33 includes a board throughhole 332 arranged to extend in the vertical direction through thecircuit board 33. The base throughhole 312 and the board throughhole 332 are arranged to coincide with each other when viewed in the axial direction. Note that these throughholes - An upper portion of a
holder 46 includes ahorizontal hole 517 arranged to extend in a radial direction therethrough. A radially inner end opening of thehorizontal hole 517 is defined in an inner circumferential surface of anupper contact portion 463. Thehorizontal hole 517 is joined to anupper seal gap 611 through anairway 651. In thefan 1, one end portion of atube 16 made of a resin is inserted into thehorizontal hole 517 through a circumferential gap defined betweenadjacent coils 322 of astator 32. Thetube 16 is inserted through the board throughhole 332 and the base throughhole 312, and an opposite end portion of thetube 16 is inserted into the cap throughhole 451. Thefan 1 according to the second preferred embodiment is otherwise similar in structure to thefan 1 according to the first preferred embodiment. - In the second preferred embodiment, because of provision of the
tube 16, which is a connection channel defining portion, anupper space 61 and alower space 62 are connected with each other, and this contributes to preventing occurrence of a difference in pressure between the upper andlower spaces lower spaces oil 47. The same is true of other preferred embodiments of the present invention described below. -
FIG. 12 is a diagram illustrating a fan 1 a according to a third preferred embodiment of the present invention. Abearing mechanism 402 of the fan 1 a includes ashaft 41, asleeve 44, aholder 7, athrust plate 42, athrust cap 45, and a lubricatingoil 47. Theshaft 41 is inserted in thesleeve 44. Thesleeve 44 is a sintered body impregnated with the lubricatingoil 47. Thethrust plate 42 is fixed to a lower end portion of theshaft 41. - The
holder 7 includes afirst holder 71 and asecond holder 72. Thefirst holder 71 is arranged substantially in the shape of a cylinder centered on a central axis J1, and is arranged to hold thesleeve 44. Each of an outer circumferential surface of thesleeve 44 and an outer circumferential surface of thethrust plate 42 is covered by thefirst holder 71. That is, an inner circumferential surface of thefirst holder 71 is arranged radially outside the outer circumferential surface of thesleeve 44 and the outer circumferential surface of thethrust plate 42. Thefirst holder 71 includes anannular portion 711 arranged to project radially inward on an upper side of thesleeve 44. Theportion 711 will be hereinafter referred to as an “annularupper portion 711”. - The
second holder 72 is arranged substantially in the shape of a cylinder centered on the central axis J1. An outer circumferential surface of thefirst holder 71 is fixed to an inner circumferential surface of thesecond holder 72. Astator 32 is fixed to an outer circumferential surface of thesecond holder 72. Thesecond holder 72 includes a connectionchannel defining portion 73 arranged to define aconnection channel 730. The fan 1 a is similar in structure to thefan 1 according to the first preferred embodiment except in the structure of thebearing mechanism 402. Accordingly, like members or portions are designated by like reference numerals, and redundant description is omitted. - A
radial bearing portion 66 a is defined in aradial gap 66 defined between an inner circumferential surface of thesleeve 44 and an outer circumferential surface of theshaft 41. On an upper side of theradial gap 66, anupper seal gap 611 is defined between an inner circumferential surface of the annularupper portion 711 and the outer circumferential surface of theshaft 41. Theupper seal gap 611 is arranged to gradually increase in radial width with increasing height. Anupper seal portion 61 a arranged to retain the lubricatingoil 47 is defined in theupper seal gap 611. An upper surface of the lubricatingoil 47 is defined in theupper seal portion 61 a. Alower seal gap 621 is defined between aninclined surface 421 of thethrust plate 42 and a lower portion of the inner circumferential surface of thefirst holder 71. Thelower seal gap 621 is arranged to gradually increase in radial width with decreasing height. Alower seal portion 62 a arranged to retain the lubricatingoil 47 is defined in thelower seal gap 621. A lower surface of the lubricatingoil 47 is defined in thelower seal portion 62 a. - Referring to
FIG. 13 , aminute gap 74 extending in the axial direction is defined between an upper portion of the outer circumferential surface of thefirst holder 71 and an upper portion of the inner circumferential surface of thesecond holder 72. Theminute gap 74 is joined to theupper seal portion 61 a through ahorizontal gap 652 defined between a lower surface of abushing 125 and an upper surface of the annularupper portion 711. Theupper seal gap 611, theminute gap 74, thehorizontal gap 652, and avertical gap 653 defined between an outer circumferential surface of thebushing 125 and the upper portion of the inner circumferential surface of thesecond holder 72, that is, a space enclosed by theshaft 41, theholder 7, and arotor holder 121, will be hereinafter referred to collectively as an “upper space 61”. Note that theupper space 61 may include a space defined between therotor holder 121 and an inner circumferential portion of thestator 32. - The
connection channel 730 includes avertical hole 731, an upperhorizontal hole 732, and a lowerhorizontal hole 733. Thevertical hole 731 is arranged to extend in the vertical direction in thesecond holder 72. The upperhorizontal hole 732 is arranged to extend radially inward from a top portion of thevertical hole 731. An end opening of the upperhorizontal hole 732, i.e., an upper end opening of theconnection channel 730, is defined in the upper portion of the inner circumferential surface of thesecond holder 72, and is joined to theminute gap 74. - The
thrust cap 45 is fixed to a lower portion of thesecond holder 72. An inner circumferential portion of thesecond holder 72 includes a groove portion arranged to extend in the radial direction on an upper side of thethrust cap 45. This groove portion is arranged to define the lowerhorizontal hole 733 between thethrust cap 45 and the inner circumferential portion of thesecond holder 72. The lowerhorizontal hole 733 is arranged to extend radially inward from a bottom portion of thevertical hole 731. An end opening of the lowerhorizontal hole 733, i.e., a lower end opening of theconnection channel 730, is defined in a lower portion of the inner circumferential surface of thesecond holder 72. Alower space 62 is defined by a combination of thethrust cap 45, thethrust plate 42, theholder 7, and theshaft 41. - In the third preferred embodiment, the
upper space 61, which is arranged between theupper seal portion 61 a and an inside of therotor holder 121, is connected with thelower space 62 through theconnection channel 730, and this contributes to preventing occurrence of a difference in pressure between the upper andlower spaces -
FIG. 14 is a cross-sectional view of abearing mechanism 402 according to a modification of the third preferred embodiment. Asecond holder 72 includes a connection channel defining portion 73 a arranged to define aconnection channel 730 a. Theconnection channel 730 a includes avertical groove 734 and avertical hole 735. Thevertical groove 734 is defined in an outer circumferential surface of thesecond holder 72. Thevertical groove 734 and an inner circumferential surface of astator 32 are arranged to together define a vertical hole which is continuous with thevertical hole 735 above thevertical hole 735. Thevertical hole 735 is arranged to extend in the vertical direction through an outer circumferential portion of thesecond holder 72 on a lower side of thevertical groove 734. Athrust cap 45 includes a cap throughhole 451 arranged to extend in the vertical direction through thethrust cap 45. Aseal member 311 is attached to a lower surface of abase portion 31, so that a below-cap space 622 is defined below thethrust cap 45. Alower space 62 is joined to anupper space 61 through the cap throughhole 451, the below-cap space 622, and theconnection channel 730 a in a manner similar to that illustrated inFIG. 8 . -
FIG. 15 is a diagram illustrating afan 1 b according to a fourth preferred embodiment of the present invention. Thefan 1 b includes arotating portion 2 a, a stationary portion 3 a, and abearing mechanism 403. Thebearing mechanism 403 includes ashaft 41, a bearingportion 49, athrust plate 42, and athrust cap 45. The bearingportion 49 includes atubular sleeve 491 and aholder 492. Theholder 492 is arranged to cover an outer circumferential surface of thesleeve 491. Theshaft 41 is inserted in thesleeve 491. Thethrust plate 42 is fixed to a lower end portion of theshaft 41. An upper surface of thethrust plate 42 is arranged axially opposite a lower surface of thesleeve 491. In thebearing mechanism 403, alower seal portion 62 a is defined between an outer edge portion of thethrust plate 42 and a lower end portion of theholder 492. A lower surface of a lubricatingoil 47 is defined in thelower seal portion 62 a. Alower space 62 is defined by a combination of thethrust plate 42, the bearingportion 49, and thethrust cap 45. - A
rotor holder 121 a of therotating portion 2 a includes afirst rotor member 126 and asecond rotor member 127. Thefirst rotor member 126 includes athrust portion 126 b. Thethrust portion 126 b is arranged in a substantially annular shape centered on a central axis J1, and is arranged to extend radially outward from an upper portion of theshaft 41. Thesecond rotor member 127 is attached to an outer circumferential surface of thefirst rotor member 126. Thesecond rotor member 127 includes a cylindrical portion 127 a. Arotor magnet 22 is fixed to an inner circumferential surface of the cylindrical portion 127 a.Blades 122 are arranged on an outer circumferential surface of the cylindrical portion 127 a. - The
first rotor member 126 further includes a rotorcylindrical portion 126 a. The rotorcylindrical portion 126 a is a cylindrical portion arranged to extend axially downward from thethrust portion 126 b on a radially outer side of theholder 492. Anupper seal gap 611 is defined between an inner circumferential surface of the rotorcylindrical portion 126 a and an upper portion of an outer circumferential surface of theholder 492. Theupper seal gap 611 is arranged to gradually increase in radial width with decreasing height. Anupper seal portion 61 a is defined in theupper seal gap 611. A surface of a lubricatingoil 47 is defined in theupper seal portion 61 a. - The stationary portion 3 a includes a substantially
cylindrical bushing 31 a. Thebushing 31 a is arranged to extend upward from a central portion of abase portion 31. Thebushing 31 a and thebase portion 31 are defined by a single member. On a lower side of thethrust plate 42, thethrust cap 45 is fixed to a lower portion of thebushing 31 a, and a lower opening of thebushing 31 a is closed by thethrust cap 45. Astator 32 is fixed to an outer circumferential surface of thebushing 31 a. Theholder 492 is fixed to an inner circumferential surface of thebushing 31 a. Thebushing 31 a includes a projectingportion 313 and a connectionchannel defining portion 34 arranged to define aconnection channel 340. The projectingportion 313 is arranged to extend upward on a radially outer side of the rotorcylindrical portion 126 a. Avertical gap 655 arranged to extend in the axial direction is defined between the rotorcylindrical portion 126 a and the projectingportion 313, and this contributes to preventing evaporation of the lubricatingoil 47 out of theupper seal portion 61 a. Theholder 492 includes a recessed portion, which is recessed radially inward, defined in a middle portion of the outer circumferential surface thereof. Thevertical gap 655 is joined to theupper seal gap 611 through aspace 623 enclosed by the recessed portion of theholder 492, a lower portion of the rotorcylindrical portion 126 a, and a portion of thebushing 31 a which is radially inward of the projectingportion 313. The vertical gap 65, thespace 623, and the upper seal gap 611 (more precisely, a space below the surface of the lubricatingoil 47 in the upper seal gap 611) will be hereinafter referred to collectively as an “upper space 61”. - The
connection channel 340 includes avertical hole 341 and a lowerhorizontal hole 342. Thevertical hole 341 is arranged to extend in the axial direction on a radially inner side of the projectingportion 313. An upper end opening of thevertical hole 341 is joined to theupper space 61. Thethrust cap 45 is fixed to the lower portion of thebushing 31 a. An inner circumferential portion of thebushing 31 a includes a groove portion shaped like a cut and arranged to extend in a radial direction on an upper side of thethrust cap 45. This groove portion is arranged to define the lowerhorizontal hole 342 between thethrust cap 45 and the inner circumferential portion of thebushing 31 a. The lowerhorizontal hole 342 is arranged to extend radially inward from a lower end of thevertical hole 341. An end opening of the lowerhorizontal hole 342, i.e., a lower end opening of theconnection channel 340, is defined in the inner circumferential surface of thebushing 31 a. Thelower space 62 is joined to the lowerhorizontal hole 342. - In the
bearing mechanism 403, an upper thrust bearing portion 661 a, which is arranged to support thefirst rotor member 126 in the axial direction, is defined in anupper thrust gap 661 defined between a lower surface of thethrust portion 126 b and an upper surface of thesleeve 491. Thefirst rotor member 126 thus plays a part in defining the upper thrust bearing portion 661 a. A lowerthrust bearing portion 662 a, which is arranged to support thethrust plate 42 in the axial direction, is defined in alower thrust gap 662 defined between the lower surface of thesleeve 491 and the upper surface of thethrust plate 42. Aradial bearing portion 66 a, which is arranged to support theshaft 41 in the radial direction, is defined in aradial gap 66 defined between an outer circumferential surface of theshaft 41 and an inner circumferential surface of thesleeve 491. - In the fourth preferred embodiment, in a manner similar to that of the first preferred embodiment, the
upper space 61, which is arranged between theupper seal portion 61 a and an inside of therotor holder 121 a, is connected with thelower space 62, which is arranged above thethrust cap 45, through theconnection channel 340, and this contributes to preventing occurrence of a difference in pressure between the upper andlower spaces bearing mechanism 403, the upper thrust bearing portion may be defined between thefirst rotor member 126 and an upper surface of theholder 492. The same is true with the case ofFIG. 16 , which will be described below. -
FIG. 16 is a cross-sectional view of abearing mechanism 403 according to a modification of the fourth preferred embodiment. Aconnection channel 340 a defined by a connection channel defining portion 34 a of abushing 31 a includes abushing groove 343 and a bushing throughhole 344. Thebushing groove 343 is arranged to extend in the vertical direction in an outer circumferential surface of thebushing 31 a on a radially inner side of an inner circumferential surface of astator 32. The bushing throughhole 344 is arranged to extend in the vertical direction through an outer circumferential portion of thebushing 31 a from a lower end of thebushing groove 343 to a lower end of the outer circumferential portion of thebushing 31 a. More precisely, thebushing groove 343 and the inner circumferential surface of thestator 32 are arranged to together define a vertical hole which is continuous with the bushing throughhole 344 above the bushing throughhole 344. Athrust cap 45 includes a cap throughhole 451. A below-cap space 622 is defined between thethrust cap 45 and aseal member 311 attached to a lower surface of abase portion 31 below thethrust cap 45. - In the
bearing mechanism 403, alower space 62 is connected with anupper space 61 through the cap throughhole 451, the below-cap space 622, and theconnection channel 340 a. -
FIG. 17 is a diagram illustrating abearing mechanism 403 according to another modification of the fourth preferred embodiment. Thebearing mechanism 403 includes a bearingportion 493, which is a single sleeve made of a metal. An outer circumferential surface of the bearingportion 493 is fixed to abushing 31 a. Aradial bearing portion 66 a is defined in aradial gap 66 defined between an inner circumferential surface of the bearingportion 493 and an outer circumferential surface of ashaft 41, which is inserted in the bearingportion 493. An upper thrust bearing portion 661 a is defined in anupper thrust gap 661 defined between an upper surface of the bearingportion 493 and a lower surface of afirst rotor member 126. Note that thebearing mechanism 403 does not include a lower thrust bearing portion. Thebearing mechanism 403 according to the present modification of the fourth preferred embodiment is otherwise similar in structure to thebearing mechanism 403 of thefan 1 b illustrated inFIG. 15 . In the case also ofFIG. 17 , because of provision of aconnection channel 340, anupper space 61 and alower space 62 are connected with each other, and this contributes to preventing occurrence of a difference in pressure between the upper andlower spaces - While preferred embodiments of the present invention have been described above, it is to be understood that the present invention is not limited to the above-described preferred embodiments, and that a variety of modifications are possible. For example, in a modification of the
bearing mechanism 401 illustrated inFIG. 2 , a portion of theholder 46 which is on an upper side of the upperhorizontal hole 512, a portion of theholder 46 which is on a lower side of the lowerhorizontal hole 513, and a portion of theholder 46 which is arranged between the above two portions and includes the connectionchannel defining portion 5 may be defined by separate members. In this case, the connectionchannel defining portion 5 can be defined more easily. - In a modification of the third preferred embodiment, a
tube 16 may be arranged to join the upper andlower spaces FIG. 12 , a groove portion arranged to extend in the vertical direction and define a connection channel may be defined in the inner circumferential surface of thesecond holder 72. The same is true of each of modifications of thebushings 31 a illustrated inFIGS. 15 and 17 , respectively. - Features of the above-described preferred embodiments and the modifications thereof may be combined appropriately as long as no conflict arises.
- The present invention is applicable to fans arranged to produce air currents.
Claims (26)
1. A fan comprising:
a plurality of blades; and
a motor arranged to rotate the blades about a central axis; wherein
the motor includes:
a stationary portion including a stator;
a rotating portion including a rotor magnet arranged radially outside the stator; and
a bearing mechanism arranged to support the rotating portion such that the rotating portion is rotatable with respect to the stationary portion;
the rotating portion includes a rotor holder arranged in a shape of a covered cylinder, and including an outer circumferential surface on which the blades are arranged;
the bearing mechanism includes:
a shaft;
a sleeve in which the shaft is inserted;
a holder arranged to hold the sleeve; and
a thrust plate fixed to a lower end portion of the shaft on a lower side of the sleeve;
the shaft and the sleeve are arranged to together define a radial gap therebetween, the radial gap including a radial bearing portion arranged to support the shaft in a radial direction;
the thrust plate and the holder are arranged to together define a lower seal portion therebetween, the lower seal portion having a lower surface of a lubricating oil defined therein, while the holder and the sleeve are arranged to together define an upper seal portion therebetween, the upper seal portion having an upper surface of the lubricating oil defined therein; and
the holder includes a connection channel defining portion arranged to define a connection channel to connect an upper space defined between the upper seal portion and an inside of the rotor holder with a lower space at which the lower seal portion is arranged.
2. The fan according to claim 1 , wherein a lower surface of the sleeve and an upper surface of the thrust plate are arranged to together define a lower thrust gap therebetween, the lower thrust gap including a lower thrust bearing portion arranged to support the thrust plate in an axial direction.
3. The fan according to claim 1 , wherein
an outer circumferential surface of the sleeve and an inner circumferential surface of the holder are arranged to together define an upper seal gap therebetween, the upper seal gap being arranged to gradually increase in radial width with increasing height, the upper seal gap including the upper seal portion defined therein; and
the upper space is a space enclosed by the sleeve, the holder, the shaft, and the rotor holder.
4. The fan according to one of claims 1 and 3 , wherein an upper end opening of the connection channel defining portion is defined in the inner circumferential surface of the holder.
5. The fan according to one of claims 1 and 3 , wherein a lower end opening of the connection channel defining portion is defined in the inner circumferential surface of the holder.
6. The fan according to one of claims 1 and 3 , wherein
the bearing mechanism further includes a thrust cap arranged to close a lower opening of the holder; and
the lower space is arranged on an upper side of the thrust cap.
7. The fan according to claim 6 , wherein
the thrust cap includes a cap through hole arranged to extend in a vertical direction through the thrust cap; and
the lower space is connected with the upper space through the cap through hole and the connection channel.
8. The fan according to claim 7 , further comprising a seal member arranged on a lower side of the thrust cap to define a space between the thrust cap and the seal member, wherein
the connection channel includes:
a holder groove arranged to extend in the vertical direction in an outer circumferential surface of the holder on a radially inner side of an inner circumferential surface of the stator; and
a holder through hole arranged to extend through the holder from the holder groove to a lower end of the holder; and
the lower space is connected with the upper space through the cap through hole, the space defined between the thrust cap and the seal member, the holder through hole, and the holder groove.
9. The fan according to any one of claims 1 to 3 , wherein
a plurality of connection channel defining portions are provided; and
each of the connection channel defining portions is arranged to define one of a plurality of connection channels arranged at regular intervals in a circumferential direction.
10. A fan comprising:
a plurality of blades; and
a motor arranged to rotate the blades about a central axis; wherein
the motor includes:
a stationary portion including a stator;
a rotating portion including a rotor magnet arranged radially outside the stator; and
a bearing mechanism arranged to support the rotating portion such that the rotating portion is rotatable with respect to the stationary portion;
the rotating portion includes a rotor holder arranged in a shape of a covered cylinder, and including an outer circumferential surface on which the blades are arranged;
the bearing mechanism includes:
a shaft;
a sleeve in which the shaft is inserted;
a holder arranged to hold the sleeve; and
a thrust plate fixed to a lower end portion of the shaft on a lower side of the sleeve;
the holder includes:
a cylindrical first holder arranged to cover an outer circumferential surface of the sleeve and an outer circumferential surface of the thrust plate, the first holder including an annular upper portion arranged to project radially inward on an upper side of the sleeve; and
a second holder including an inner circumferential surface having an outer circumferential surface of the first holder fixed thereto, the second holder having the stator arranged on a radially outer side thereof;
the shaft and the sleeve are arranged to together define a radial gap therebetween, the radial gap including a radial bearing portion arranged to support the shaft in a radial direction;
the thrust plate and the first holder are arranged to together define a lower seal portion therebetween, the lower seal portion having a lower surface of a lubricating oil defined therein, while the shaft and the annular upper portion are arranged to together define an upper seal portion therebetween, the upper seal portion having an upper surface of the lubricating oil defined therein; and
the second holder includes a connection channel defining portion arranged to define a connection channel to connect an upper space defined between the upper seal portion and an inside of the rotor holder with a lower space at which the lower seal portion is arranged.
11. The fan according to claim 10 , wherein a lower surface of the sleeve and an upper surface of the thrust plate are arranged to together define a lower thrust gap therebetween, the lower thrust gap including a lower thrust bearing portion arranged to support the thrust plate in an axial direction.
12. The fan according to claim 10 , wherein
an inner circumferential surface of the annular upper portion and an outer circumferential surface of the shaft are arranged to together define an upper seal gap therebetween, the upper seal gap being arranged to gradually increase in radial width with increasing height, the upper seal gap including the upper seal portion defined therein; and
the upper space is a space enclosed by the shaft, the holder, and the rotor holder.
13. The fan according to any one of claims 10 to 12 , wherein an upper end opening of the connection channel defining portion is defined in the inner circumferential surface of the second holder.
14. The fan according to any one of claims 10 to 12 , wherein a lower end opening of the connection channel defining portion is defined in the inner circumferential surface of the second holder.
15. The fan according to any one of claims 10 to 12 , wherein
the bearing mechanism further includes a thrust cap arranged to close a lower opening of the holder; and
the lower space is arranged on an upper side of the thrust cap.
16. The fan according to claim 15 , wherein
the thrust cap includes a cap through hole arranged to extend in a vertical direction through the thrust cap; and
the lower space is connected with the upper space through the cap through hole and the connection channel.
17. The fan according to claim 16 , further comprising a seal member arranged on a lower side of the thrust cap to define a space between the thrust cap and the seal member, wherein
the connection channel includes:
a holder groove arranged to extend in the vertical direction in an outer circumferential surface of the second holder on a radially inner side of an inner circumferential surface of the stator; and
a holder through hole arranged to extend through the second holder from the holder groove to a lower end of the second holder; and
the lower space is connected with the upper space through the cap through hole, the space defined between the thrust cap and the seal member, the holder through hole, and the holder groove.
18. The fan according to any one of claims 10 to 12 , wherein
a plurality of connection channel defining portions are provided; and
each of the connection channel defining portions is arranged to define one of a plurality of connection channels arranged at regular intervals in a circumferential direction.
19. A fan comprising:
a plurality of blades; and
a motor arranged to rotate the blades about a central axis; wherein
the motor includes:
a stationary portion including a stator;
a rotating portion including a rotor magnet arranged radially outside the stator; and
a bearing mechanism arranged to support the rotating portion such that the rotating portion is rotatable with respect to the stationary portion;
the stationary portion includes a bushing arranged to hold the stator on a radially outer side thereof;
the rotating portion includes a rotor holder arranged in a shape of a covered cylinder, and including an outer circumferential surface on which the blades are arranged;
the bearing mechanism includes:
a shaft;
a bearing portion in which the shaft is inserted;
a thrust plate fixed to a lower end portion of the shaft on a lower side of the sleeve;
a thrust portion arranged to extend radially outward from an upper portion of the shaft; and
a rotor cylindrical portion arranged to extend axially downward from the thrust portion;
the shaft and the bearing portion are arranged to together define a radial gap therebetween, the radial gap including a radial bearing portion arranged to support the shaft in a radial direction;
the thrust plate and the bearing portion are arranged to together define a lower seal portion therebetween, the lower seal portion having a lower surface of a lubricating oil defined therein, while the bearing portion and the rotor cylindrical portion are arranged to together define an upper seal portion therebetween, the upper seal portion having an upper surface of the lubricating oil defined therein; and
the bushing includes a connection channel defining portion arranged to define a connection channel to connect an upper space defined between the upper seal portion and an inside of the rotor holder with a lower space at which the lower seal portion is arranged.
20. The fan according to claim 19 , wherein a lower surface of the bearing portion and an upper surface of the thrust plate are arranged to together define a lower thrust gap therebetween, the lower thrust gap including a lower thrust bearing portion arranged to support the thrust plate in an axial direction.
21. The fan according to one of claims 19 and 20 , wherein
the bearing portion includes:
a tubular sleeve; and
a holder arranged to cover an outer circumferential surface of the sleeve; and
an upper surface of the sleeve and a lower surface of the thrust portion are arranged to together define an upper thrust bearing portion therebetween, the upper thrust bearing portion being arranged to support the thrust portion in an axial direction.
22. The fan according to one of claims 19 and 20 , wherein a lower end opening of the connection channel defining portion is defined in an inner circumferential surface of the bushing.
23. The fan according to one of claims 19 and 20 , wherein
the bearing mechanism further includes a thrust cap arranged to close a lower opening of the bushing; and
the lower space is arranged on an upper side of the thrust cap.
24. The fan according to claim 23 , wherein
the thrust cap includes a cap through hole arranged to extend in a vertical direction through the thrust cap; and
the lower space is connected with the upper space through the cap through hole and the connection channel.
25. The fan according to claim 24 , further comprising a seal member arranged on a lower side of the thrust cap to define a space between the thrust cap and the seal member, wherein
the connection channel includes:
a bushing groove arranged to extend in the vertical direction in an outer circumferential surface of the bushing on a radially inner side of an inner circumferential surface of the stator; and
a bushing through hole arranged to extend through the bushing from the bushing groove to a lower end of the bushing; and
the lower space is connected with the upper space through the cap through hole, the space defined between the thrust cap and the seal member, the bushing through hole, and the bushing groove.
26. The fan according to one of claims 19 and 20 , wherein
a plurality of connection channel defining portions are provided; and
each of the connection channel defining portions is arranged to define one of a plurality of connection channels arranged at regular intervals in a circumferential direction.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2011-255845 | 2011-11-24 | ||
JP2011255845A JP2013108470A (en) | 2011-11-24 | 2011-11-24 | Fan |
Publications (1)
Publication Number | Publication Date |
---|---|
US20130136631A1 true US20130136631A1 (en) | 2013-05-30 |
Family
ID=48467062
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/612,138 Abandoned US20130136631A1 (en) | 2011-11-24 | 2012-09-12 | Fan |
Country Status (3)
Country | Link |
---|---|
US (1) | US20130136631A1 (en) |
JP (1) | JP2013108470A (en) |
CN (2) | CN103133373B (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2013108470A (en) * | 2011-11-24 | 2013-06-06 | Nippon Densan Corp | Fan |
CN205123443U (en) * | 2015-09-29 | 2016-03-30 | 佛山市启正电气有限公司 | But ceiling -fan motor of direct mount flabellum |
CN105827033B (en) * | 2016-05-23 | 2018-10-16 | 珠海格力节能环保制冷技术研究中心有限公司 | A kind of electric machine support and use its motor |
Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3960468A (en) * | 1946-07-16 | 1976-06-01 | The United States Of America As Represented By The United States Energy Research And Development Administration | Fluid lubricated bearing assembly |
US4801252A (en) * | 1984-05-09 | 1989-01-31 | Papst-Motoren Gmbh & Co. Kg | Slide bearing unit for small size fan |
US6672767B2 (en) * | 2001-06-27 | 2004-01-06 | Nidec Corporation | Dynamic bearing device and motor having the same |
US20050117822A1 (en) * | 2003-12-02 | 2005-06-02 | Abin Chen | Bearing for heat dissipating fan |
US7431506B2 (en) * | 2004-12-14 | 2008-10-07 | Foxconn Technology Co., Ltd. | Motor with fluid dynamic bearing and fan employing the motor |
US20090046960A1 (en) * | 2006-03-02 | 2009-02-19 | Ntn Corporation | Fluid dynamic bearing device |
US20100054965A1 (en) * | 2008-08-29 | 2010-03-04 | Nidec Corporation | Bearing structure, motor, and fan apparatus |
US20100166344A1 (en) * | 2006-06-07 | 2010-07-01 | Ntn Corporation | Fluid dynamic bearing device and method of manufacturing the same |
US7819585B2 (en) * | 2004-05-25 | 2010-10-26 | Ntn Corporation | Fluid dynamic bearing apparatus and a motor using the same |
US20110007989A1 (en) * | 2009-07-13 | 2011-01-13 | Alphana Technology Co., Ltd. | Disk drive device provided with fluid dynamic bearing unit |
US20110097025A1 (en) * | 2008-07-08 | 2011-04-28 | Ntn Corporation | Fluid dynamic bearing device |
US20130101450A1 (en) * | 2011-10-24 | 2013-04-25 | Nidec Corporation | Motor and fan |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2003139129A (en) * | 2001-10-30 | 2003-05-14 | Nippon Densan Corp | Dynamic pressure bearing, spindle motor using the bearing, and disc drive device having the spindle motor |
US7473034B2 (en) * | 2005-07-28 | 2009-01-06 | Panasonic Corporation | Hydrodynamic bearing device, motor, and disk driving apparatus |
DE102007019642B4 (en) * | 2007-04-26 | 2014-09-04 | Minebea Co., Ltd. | Fluid dynamic storage system |
JP2013108470A (en) * | 2011-11-24 | 2013-06-06 | Nippon Densan Corp | Fan |
-
2011
- 2011-11-24 JP JP2011255845A patent/JP2013108470A/en active Pending
-
2012
- 2012-09-12 US US13/612,138 patent/US20130136631A1/en not_active Abandoned
- 2012-11-14 CN CN201210457268.9A patent/CN103133373B/en not_active Expired - Fee Related
- 2012-11-14 CN CN2012206005912U patent/CN203146365U/en not_active Expired - Lifetime
Patent Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3960468A (en) * | 1946-07-16 | 1976-06-01 | The United States Of America As Represented By The United States Energy Research And Development Administration | Fluid lubricated bearing assembly |
US4801252A (en) * | 1984-05-09 | 1989-01-31 | Papst-Motoren Gmbh & Co. Kg | Slide bearing unit for small size fan |
US6672767B2 (en) * | 2001-06-27 | 2004-01-06 | Nidec Corporation | Dynamic bearing device and motor having the same |
US20050117822A1 (en) * | 2003-12-02 | 2005-06-02 | Abin Chen | Bearing for heat dissipating fan |
US7819585B2 (en) * | 2004-05-25 | 2010-10-26 | Ntn Corporation | Fluid dynamic bearing apparatus and a motor using the same |
US7431506B2 (en) * | 2004-12-14 | 2008-10-07 | Foxconn Technology Co., Ltd. | Motor with fluid dynamic bearing and fan employing the motor |
US20090046960A1 (en) * | 2006-03-02 | 2009-02-19 | Ntn Corporation | Fluid dynamic bearing device |
US20100166344A1 (en) * | 2006-06-07 | 2010-07-01 | Ntn Corporation | Fluid dynamic bearing device and method of manufacturing the same |
US20110097025A1 (en) * | 2008-07-08 | 2011-04-28 | Ntn Corporation | Fluid dynamic bearing device |
US20100054965A1 (en) * | 2008-08-29 | 2010-03-04 | Nidec Corporation | Bearing structure, motor, and fan apparatus |
US20110007989A1 (en) * | 2009-07-13 | 2011-01-13 | Alphana Technology Co., Ltd. | Disk drive device provided with fluid dynamic bearing unit |
US20130101450A1 (en) * | 2011-10-24 | 2013-04-25 | Nidec Corporation | Motor and fan |
Also Published As
Publication number | Publication date |
---|---|
CN103133373A (en) | 2013-06-05 |
JP2013108470A (en) | 2013-06-06 |
CN103133373B (en) | 2016-03-30 |
CN203146365U (en) | 2013-08-21 |
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Legal Events
Date | Code | Title | Description |
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AS | Assignment |
Owner name: NIDEC CORPORATION, JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:HIRAYAMA, MASASHI;TESHIMA, HIROYOSHI;REEL/FRAME:028953/0022 Effective date: 20120827 |
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STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |