JP2015206294A - blower fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blower fan which is large in an air volume.SOLUTION: A blower fan 11 comprises an impeller, a motor part, a lower plate part 13, an upper plate part, and a sidewall part 14. An exhaust port 162 is formed at a sideway of the impeller, the sidewall part has a tongue part 141, a tangent which passes through a center shaft, and contacts with the tongue part is set as a virtual first linear line 41 in a plane view, a linear line vertically intersecting with the first virtual linear line is set as a virtual second linear line 42, a region in which the tongue part is located out of four regions which are partitioned by the virtual first linear line and the virtual second linear line is set as a first region 51, also set as a second region 52, a third region 53 and a fourth region 54 in this order from the first region toward a rotation direction downstream side of the impeller, the wall part is located at least in the whole area of the first region, the upper plate part has an internal peripheral edge part 131 which regulates an intake port 161, and a minimum distance between the internal peripheral edge part and the center shaft in the fourth region is shorter than a maximum distance between the internal peripheral edge part and the center shaft in either of the second region and the third region.

Description

  The present invention relates to a thin blower fan mounted on a notebook PC or the like.

  In recent years, in personal computers such as notebook PCs and tablets, cooling of the CPU is desired as the processing speed of the CPU increases. In particular, tablet-type personal computers are becoming thinner, and the density of electronic components mounted therein is high. That is, heat is likely to stay inside, and an improvement in cooling technology is desired.

For example, Japanese Patent Laid-Open No. 7-130924 discloses a method for cooling the inside of a personal computer. In a fan configured as described in Japanese Patent Laid-Open No. 7-130924, the heat sink is cooled by making the entire circumference an exhaust port and applying cooling air to the heat sink located at the periphery of the exhaust port. Further, by providing an intake port in the upper plate portion, the intake cooling air can be applied to the heat sink. Thereby, the air volume of the whole fan improves and it becomes possible to cool a wide range.
JP 7-130924 A

  In the free air state, the centrifugal fan configured as in Japanese Patent Laid-Open No. 7-130924 has a large amount of air passing through the fins of the heat sink, but when the component space in the electronic device is narrow, that is, when the static pressure is high. The air flow that flows backward tends to occur. When the air flow reverses, it becomes difficult to efficiently supply the cooling air to the heat sink. In other words, it is necessary to define a flow path through which air flows and to prevent backflow.

  An object of this invention is to provide the ventilation fan with much air volume.

  The blower fan includes an impeller, a motor part, a lower plate part, and a side wall part. The impeller has a plurality of blades that rotate around a central axis that faces in the vertical direction and that are arranged in the circumferential direction. The motor unit rotates the impeller. The lower plate portion covers the lower side of the impeller. The upper plate portion covers the upper side of the impeller. The side wall portion is located between the upper plate portion and the lower plate portion. An exhaust port is formed on the side of the impeller by the upper plate portion, the side wall portion, and the lower plate portion. The side wall portion has a tongue portion protruding between the exhaust port and the impeller. A tangent line passing through the central axis and in contact with the tongue when viewed in plan is defined as a virtual first straight line. A straight line passing through the central axis and perpendicularly intersecting the first virtual line when viewed in plan is defined as a virtual second straight line. Of the four areas divided by the virtual first straight line and the virtual second straight line, the area where the tongue is located is defined as the first area, and the second area, 3 areas and 4 areas. The side wall is located at least over the entire first region. The upper plate portion has an inner peripheral edge portion that defines an intake port that is a through hole passing through the central axis. The minimum distance between the inner peripheral edge portion and the central axis in the fourth region is smaller than the maximum distance between the inner peripheral edge portion and the central axis in either the second region or the third region.

  In the present invention, it is possible to provide a blower fan with a large air volume.

FIG. 1 is a cross-sectional view of a blower fan 1 according to a first exemplary embodiment of the present invention. FIG. 2 is a cross-sectional view of the vicinity of the motor unit 12. FIG. 3 is a plan view of the blower fan 1 with the upper plate portion 13 removed. FIG. 4 is a plan view of the blower fan 1. FIG. 5 is a top view showing a modification of the blower fan 1.

  In the present specification, the upper side of FIG. 1 in the central axis direction of the motor unit is simply referred to as “upper side”, and the lower side is simply referred to as “lower side”. Note that the vertical direction does not indicate the positional relationship or direction when incorporated in an actual device. A direction parallel to the central axis is referred to as an “axial direction”, a radial direction centered on the central axis is simply referred to as “radial direction”, and a circumferential direction centered on the central axis is simply referred to as “circumferential direction”.

    FIG. 1 is a cross-sectional view of a blower fan 1 according to a first exemplary embodiment of the present invention. The blower fan 1 in the present embodiment is a centrifugal fan, and is used, for example, for cooling a CPU or electronic components in a notebook personal computer. The blower fan 1 includes an impeller 11, a motor unit 12, an upper plate unit 13, a side wall unit 14, and a lower plate unit 15. The impeller 11 extends radially outward from the rotating portion 22 of the motor portion 12. The impeller 11 is rotated around the central axis J1 by the motor unit 12.

    In the blower fan 1, the impeller 11 is rotated about the central axis J <b> 1 by the motor unit 12, thereby generating an air flow.

  The impeller 11 is made of resin and includes a plurality of blades 112 arranged in the circumferential direction and a substantially annular blade support portion 111 that supports the plurality of blades 112. The inner peripheral surface of the blade support part 111 is fixed to the rotating part 22 of the motor part 12. The plurality of blades 112 extend radially outward from the outer peripheral surface of the blade support 111 around the central axis J1. The blade support 111 and the plurality of blades 112 are configured as a single member by resin injection molding.

  The upper plate portion 13 is a substantially plate-like member made of metal. The upper plate portion 13 is located above the motor portion 12 and the impeller 11 and covers the upper side of the impeller 11. The upper plate part 13 has one intake port 161 penetrating vertically. The intake port 161 overlaps a part of the impeller 11 and the motor unit 12 in the axial direction. The intake port 161 has a substantially circular shape that overlaps the central axis J1. The detailed shape of the intake port 161 will be described later. The upper plate part 13, the side wall part 14 and the lower plate part 15 accommodate the motor part 12 and the impeller 11.

  The lower plate portion 15 is a substantially plate-like member formed by pressing a metal plate. The lower plate portion 15 is located below the motor portion 12 and the impeller 11, covers the lower side of the impeller 11, and supports the motor portion 12. The material of the lower plate portion 15 may be copper, an aluminum alloy, iron, or an iron-based alloy (including SUS).

  The side wall part 14 is formed with resin. The side wall portion 14 is located between the upper plate portion 13 and the lower plate portion 15 and is located on the side of the impeller 11. The upper plate portion 13 is fixed to the upper end portion of the side wall portion 14 by screws or the like. The lower end portion of the side wall portion 14 is fastened to the lower plate portion 15 by insert molding. An exhaust port 162 is formed on the side of the impeller 11 by the upper plate portion 13, the side wall portion 14, and the lower plate portion. In the present embodiment, the side wall portion 14 is provided only in a part of the circumferential direction between the upper plate portion 13 and the lower plate portion 15. The side wall portion 14 may be provided by a technique other than insert molding, or may be formed of a material other than resin. Further, the method for fixing the upper plate portion 13 and the lower plate portion 15 to the side wall portion 14 is not limited to the above.

  FIG. 2 is a cross-sectional view of the vicinity of the motor unit 12. The motor unit 12 is an outer rotor type. The motor unit 12 includes a stationary unit 21 and a rotating unit 22. The stationary part 21 includes a bearing part 23, a lower plate part 15, a stator 210, and a circuit board 25.

  The bearing portion 23 is provided on the radially inner side than the stator 210. The bearing portion 23 includes a sleeve 231 and a bearing housing 232. The sleeve 231 has a substantially cylindrical shape centered on the central axis J1. The sleeve 231 is a metal sintered body. The sleeve 231 is impregnated with lubricating oil. A plurality of pressure adjusting circulation holes 275 extending in the axial direction are provided on the outer peripheral surface of the sleeve 231. The plurality of circulation holes 275 are provided at equal intervals in the circumferential direction. The bearing housing 232 is substantially cylindrical with a bottom, and includes a housing cylindrical portion 241 and a cap 242. The housing cylindrical portion 241 has a substantially cylindrical shape centered on the central axis J <b> 1 and covers the outer peripheral surface of the sleeve 231. The sleeve 231 is fixed to the inner peripheral surface of the housing cylindrical portion 241 with an adhesive. The bearing housing 232 is made of metal. The cap 242 is fixed to the lower end portion of the housing cylindrical portion 241. The cap 242 closes the lower portion of the housing cylindrical portion 241. The sleeve 231 may be fixed by other than an adhesive, and may be fixed to the inner peripheral surface of the housing cylindrical portion 241 by press-fitting, for example. The sleeve 231, the bearing housing 232, and the cap 242 may be formed of a material other than metal. For example, it may be made of brass.

The stator 210 is a substantially annular member centered on the central axis J1. The stator 210 includes a stator core 211 and a plurality of coils 212 configured on the stator core 211. The stator core 211 is formed by laminating thin silicon steel plates. The stator core 211 includes a substantially annular core back 211a and a plurality of teeth 211b protruding outward in the radial direction from the core back 211a. The plurality of coils 212 is configured by winding a conductive wire around each of the plurality of teeth 211b. A circuit board 25 is provided below the stator 210. The lead wire of the coil 212 is electrically connected to the circuit board 25. The circuit board 25 is an FPC (Flexible Print Circuit board).

  The rotating unit 22 includes a shaft 221, a thrust plate 224, a rotor holder 222, and a rotor magnet 223. The shaft 221 is provided around the central axis J1.

  As shown in FIG. 2, the rotor holder 222 has a substantially cylindrical shape with a lid centered on the central axis J1. The rotor holder 222 includes a magnet holding cylindrical portion 222a shown in FIG. 1, which is a cylindrical portion, a lid portion 222c, and a first thrust portion 222d. The magnet holding cylindrical portion 222a, the lid portion 222c, and the first thrust portion 222d are a continuous member. The first thrust portion 222d extends radially outward from the upper end portion of the shaft 221. The lid part 222c extends radially outward from the first thrust part 222d. The upper plate portion 13 is located above the lid portion 222c and the first thrust portion 222d. The lower surface of the lid portion 222 c is a substantially annular surface that surrounds the shaft 221. The first thrust portion 222d is opposed to the upper surface 231b of the sleeve 231 and the upper surface of the housing cylindrical portion 241 in the axial direction.

  The thrust plate 224 has a substantially disk-shaped portion that extends outward in the radial direction. The thrust plate 224 is fixed to the lower end portion of the shaft 221 and spreads radially outward from the lower end portion. The thrust plate 224 is accommodated in a plate accommodating portion 239 configured by a lower surface 231 c of the sleeve 231, an upper surface of the cap 242 and a lower portion of the inner peripheral surface of the housing cylindrical portion 241. The upper surface of the thrust plate 224 is a substantially annular surface surrounding the shaft 221. The upper surface of the thrust plate 224 is opposed to the lower surface 231 c of the sleeve 231, that is, the surface facing downward in the plate housing portion 239 in the axial direction. Hereinafter, the thrust plate 224 is referred to as a “second thrust portion 224”. Further, the lower surface of the second thrust part 224 faces the upper surface of the cap 242 of the bearing housing 232. The shaft 221 is inserted into the sleeve 231. The thrust plate 224 may be configured as a member connected to the shaft 221. The thrust plate 224 is made of a metal such as stainless steel, for example.

  The shaft 221 is configured as a member connected to the rotor holder 222. The shaft 221 and the rotor holder 222 are formed by cutting a metal member. That is, the lid portion 222c and the shaft 221 are continuous. The shaft 221 may be configured by a member separate from the rotor holder 222. In this case, the upper end portion of the shaft 221 is fixed to the lid portion 222c of the rotor holder 222. Further, as shown in FIG. 1, the rotor magnet 223 is fixed to the inner peripheral surface of the magnet holding cylindrical portion 222 a that extends downward in the axial direction from the radially outer end of the lid portion 222 c of the rotor holder 222. The shaft 221 is formed of a metal such as stainless steel, for example.

  The inner peripheral surface of the blade support portion 111 shown in FIG. 1 is fixed to the outer peripheral surface of the magnet holding cylindrical portion 222a of the rotor holder 222, and the plurality of blades 112 are located outside the outer peripheral surface of the magnet holding cylindrical portion 222a. The upper end portion of the shaft 221 is fixed to the impeller 11 via the rotor holder 222. The impeller 11 may be configured as a member connected to the rotor holder 222. In that case, the upper end portion of the shaft 221 is directly fixed to the impeller 11.

  As shown in FIG. 2, the rotor magnet 223 has a substantially cylindrical shape centered on the central axis J1. As described above, the rotor magnet 223 is fixed to the inner peripheral surface of the magnet holding cylindrical portion 222a. The rotor magnet 223 is provided outside the stator 210 in the radial direction.

  In the motor unit 12, when electric power is supplied to the stator 210, torque about the central axis J <b> 1 is generated between the rotor magnet 223 and the stator 210. The rotating mechanism 22 and the impeller 11 are supported by the bearing mechanism 4 so as to be rotatable about the central axis J1 with respect to the stationary part 21. Due to the rotation of the impeller 11, the air sucked from the air inlet 131 is compressed in the flow path formed between the upper plate portion 13, the lower plate portion and the side wall portion 14, and the impeller 11, And is discharged from the exhaust port 162.

  FIG. 3 is a plan view of the blower fan 1 with the upper plate portion 13 removed. The side wall part 14 has a tongue part 141 and a skirt part 142. The tongue 141 protrudes between the exhaust port 162 and the impeller 11. The skirt portion 142 extends from the tongue portion 141 to the downstream side in the rotation direction of the impeller 11, and the distance from the central axis J1 gradually increases as it proceeds downstream.

The blower fan 1 has a tangent line passing through the central axis J1 and in contact with the tongue portion 141 as a virtual first straight line 41 in plan view. A straight line passing through the central axis J1 and perpendicularly intersecting the virtual first straight line 41 is defined as a virtual second straight line 42. Of the four areas divided by the virtual first straight line 41 and the virtual second straight line 42, the area where the tongue 141 is located is in order from the first area 51 and the first area 51 toward the downstream side in the rotation direction of the impeller 11. A second area 52, a third area 53, and a fourth area 54 are assumed.

  In the present embodiment, the side wall 14 is located in the first region 51 or the second region 52. More preferably, the side wall portion 14 is located at least over the entire first region 51. Further, as will be described later, the first region 51 and the second region 52 may be disposed. Note that side walls are not arranged in the third region 53 and the fourth region 54. The side wall part 14 may be disposed only on a part of the second side wall part 52.

  FIG. 4 is a plan view of the blower fan 1. The upper plate portion 13 has an inner peripheral edge portion 131 that defines an intake port 161 that is a through hole passing through the central axis J1. The minimum distance between the inner peripheral edge 131 and the central axis J1 in the fourth area 54 is smaller than the maximum distance between the inner peripheral edge 131 and the central axis J1 in either the second area 52 or the third area 53.

  By forming an air flow path between the upper plate 13, the lower plate 15 and the side wall portion 14 and the impeller 11, the air sucked from the intake port 161 is compressed in the flow path so that the flow velocity is high. Thus, air is exhausted to the second region 52 or the third region 53. By discharging the air having a high flow velocity from the exhaust port 162, the heat source, that is, the electronic component provided around the exhaust port 162 of the blower fan 1 is further cooled.

  By discharging air with a high flow velocity to the second region 52 or the third region 53, the flow velocity gradually decreases toward the downstream side in the rotation direction. In particular, in the fourth region 54, the amount of the sucked air discharged from the exhaust port 162 decreases, so the air volume decreases. In the fourth region 54, the air sucked from the intake port 161 is not discharged from the exhaust port 162, but is pushed back by the backflowing air flow. Thereafter, the air pressure in the vicinity of the exhaust port 162 in the fourth region 54 decreases, and the air taken in from the intake port 161 is discharged from the exhaust port 162. By repeating this operation, a phenomenon occurs in which air repeatedly enters and exits between the exhaust port 162 and the intake port 161, and the air volume in the fourth region 54 is not stable.

  The maximum distance between the inner peripheral edge 131 and the central axis J1 in the fourth area 54 is smaller than the maximum distance between the inner peripheral edge 131 and the central axis J1 in either the second area 52 or the third area 53. Thus, the entry and exit of air between the exhaust port 162 and the intake port 161 is suppressed, the air volume is stabilized, and the air volume characteristics are improved.

  In the blower fan 1, the inner peripheral edge portion 131 includes a first inner peripheral edge portion 131a, a second inner peripheral edge portion 131b, and a connecting portion 131c. The first inner peripheral edge 131 a has an arc shape extending in the circumferential direction, and is provided at least in the fourth region 54. The second inner peripheral edge 131 b has an arc shape extending in the circumferential direction, and is provided at least in the second region 52. The connecting portion 131c connects both ends of the first inner peripheral edge 131a and the second inner peripheral edge 131b. At least two connecting portions 131c are provided. The connecting portion 131c gradually increases in radial distance from the central axis J1 as it goes from the first inner peripheral edge 131a to the second inner peripheral edge 131b. The shape of the connecting portion 131c does not necessarily have to gradually increase.

  In the present embodiment, the inner peripheral edge 131 is configured only by the first inner peripheral edge 131a, the second inner peripheral edge 131b, and the connecting portion 131c. However, the inner peripheral edge 131 may have a portion other than the first inner peripheral edge 131a, the second inner peripheral edge 131b, and the connecting portion 131c. For example, there may be a groove or a notch that is recessed radially outward from the inner end of the inner peripheral edge 131 in plan view. Further, there may be a protruding portion protruding radially inward from the inner end of the inner peripheral edge 131.

  The minimum radial distance from the central axis J1 of the first inner peripheral edge 131a is smaller than the maximum radial distance from the central axis J1 of the second inner peripheral edge 131b. More preferably, the maximum radial distance from the first inner peripheral edge 131a and the central axis J1 is smaller than the minimum distance between the second inner peripheral edge 131b and the central axis J1.

  Air that has been sucked from the intake port 161 because the minimum radial distance from the central axis J1 of the first inner peripheral edge 131a is smaller than the maximum radial distance from the central axis J1 of the second inner peripheral edge 131b. Is compressed in the flow path and the wind speed is increased, so that backflow of air from the flow path toward the outside of the cooling fan 1 can be suppressed. On the other hand, since the inner diameter of the second inner peripheral edge 131b is large and the air discharged from the exhaust ports 162 of the second region 52 and the third region 53 has a high flow velocity, the intake amount can be increased and the air amount can be increased. . Therefore, the heat source, that is, the electronic component provided around the exhaust port 162 of the blower fan 1 is further cooled.

  Further, since the maximum distance between the first inner peripheral edge 131a and the central axis J1 is smaller than the minimum radial distance from the second inner peripheral edge 131b and the central axis J1, the wind speed is further increased. Can be further suppressed, and the air volume can be further increased.

  In the blower fan 1, the sum of the circumferential lengths of the second inner peripheral edge portion 131b and the connecting portion 131c is longer than the circumferential length of the first inner peripheral edge portion 131a. More preferably, the circumferential length of the second inner circumferential edge 131b is longer than the circumferential length of the first inner circumferential edge 131a.

  By increasing the circumferential length of the second inner peripheral edge portion 131b and the connecting portion 131c, the area of the intake port 161 in the second region 52 or the third region 53 is increased. That is, it is possible to increase the intake air amount from the intake port 161 in the second region 52 and the third region 53 where the air speed is increased, and to increase the air amount. Therefore, the heat source, that is, the electronic component provided around the exhaust port 162 of the blower fan 1 is further cooled.

  As described above, the first inner peripheral edge 131 a is provided at least in the fourth region 54. More preferably, the first inner peripheral edge 131 a is provided in the fourth region 54 and the first region 51.

  By providing the first inner peripheral edge portion 131a in the fourth region 54 and the first region 51, the flow of air between the exhaust port 162 and the intake port 161 is suppressed, and the backflow can be suppressed.

  The first inner peripheral edge 131a may be disposed across the fourth region 54 and the first region 51. Further, the first inner peripheral edge 131 a may be disposed in the entire fourth region 54. The first inner peripheral edge 131a may be disposed in at least a part of the third region 53. More specifically, the first inner peripheral edge 131 a may be disposed across the fourth region 54 and the third region 53. The first inner peripheral edge 131a may be disposed in the first region 51, the fourth region 54, and the third region 53, and is disposed across the first region 51, the fourth region 54, and the third region 53. May be.

  As described above, the second inner peripheral edge 131 b is provided at least in the second region 52. Preferably, the second inner peripheral edge 131 b is provided in the second region 52 and the third region 53. More preferably, it is provided in the entire region of the second region 52 and the third region 53.

  By providing the second inner peripheral edge 131b in the second region 52 and the third region 53, the area of the intake port in the second region 52 or the third region 53 is increased. That is, it is possible to increase the intake air amount in the second region 52 and the third region 53 where the air speed is increased, and to increase the air volume. Therefore, the heat source, that is, the electronic component provided around the exhaust port 162 of the blower fan 1 is further cooled.

  Note that the second inner peripheral edge 131 b may be disposed across the second region 52 and the third region 53. Further, the second inner peripheral edge 131b may be disposed in the entire second region 52. The second inner peripheral edge 131b may be disposed in at least a part of the first region 51. More specifically, the first inner peripheral edge 131 a may be disposed across the second region 52 and the first region 51. The second inner peripheral edge 131b may be disposed in the first region 51, the second region 52, and the third region 53, and is disposed across the first region 51, the second region 52, and the third region 53. May be.

  In FIG. 4, the tongue part 141 and the skirt part 142 which are the side wall parts 14 are shown with a broken line. The distance in the radial direction from the first inner peripheral edge 131a and the central axis J1 on the virtual first straight line 41 is an imaginary distance passing through the downstream end 143 and the central axis J1 constituting the exhaust port 162 on the skirt 142 side. The distance on the third straight line 43 is smaller than the radial distance from the second inner peripheral edge 131 and the central axis J1.

  Since the distance between the first inner peripheral edge 131a and the central axis J1 is small, the air sucked from the intake port 161 is compressed in the flow path, and the wind speed is increased, so that the backflow can be suppressed. Further, the air discharged from the exhaust ports 162 of the second region 52 and the third region 53 has a high flow velocity, and since the inner diameter of the second inner peripheral edge 131b is large, the intake amount can be increased and the air amount can be increased. . Therefore, the heat source, that is, the electronic component provided around the exhaust port 162 of the blower fan 1 is further cooled.

  Furthermore, in a plan view, the first tangent line 71 that contacts the intake port 141 through the upstream end 144 of the side wall portion 14 that forms the exhaust port 162 on the tongue portion 141 side is in contact with the first inner peripheral edge 131a. A second tangent line 72 that contacts the intake port 161 through the downstream end 143 that forms the exhaust port 162 on the skirt 142 side of the side wall portion 14 is in contact with the second inner peripheral edge 131b. In the present embodiment, there are two second tangent lines 72. A second tangent line 72 on the upstream side in the rotation direction of the impeller 11 shown in FIG. 4 is in contact with the second inner peripheral edge 131b in the first region 51 or the second region 52. The second tangent line 72 on the downstream side in the rotation direction of the impeller 11 is in contact with the second inner peripheral edge 131 b in the second region 52 or the third region 53.

  Most of the air discharged from the exhaust port 162 on the tongue 141 side is air that has passed through the first inner peripheral edge 131a, and most of the air discharged from the exhaust port 162 on the base 142 side is the second inner peripheral edge. Air that has passed through 131b. That is, as described above, in the fourth region 54, since the amount of air that has passed through the side wall portion 14 is small, the wind speed becomes slow and the air flows backward. Therefore, the slowest part of the fourth region 54 is the upstream end 144 of the side wall 141 on the tongue 141 side, and the radial distance from the central axis J1 of the first inner peripheral edge 131a is small. Wind speed can be increased and backflow can be prevented. In addition, the air discharged from the exhaust port 162 on the side of the skirt 142 has a high flow velocity, and since the inner diameter of the second inner peripheral edge 131b is large, the intake amount can be increased and the air volume can be increased.

  In FIG. 4, some of the plurality of blades 112 of the impeller 11 hidden by the upper plate portion 13 in plan view are indicated by broken lines. The first inner peripheral edge 131a is located radially inward from the center of the outer end and inner end of the blade 112 in the radial direction.

  Since the first inner peripheral edge 131a is positioned radially inward from the center of the outer end and the inner end of the blade 112 in the radial direction, the area of the intake port in the area radially inward from the first inner peripheral edge 131a. Can be made smaller. Therefore, the air sucked from the intake port 161 is compressed in the flow path, and the wind speed increases, so that the backflow of air can be suppressed.

  The side wall 14 extends across the first region 51 and the second region 52.

  The side wall portion 14 extends across the first region 51 and the second region 52, so that the air sucked from the intake port 161 is interposed between the upper plate 13, the lower plate 15, the side wall portion 14, and the impeller 11. The air can be guided to the second region 52 through the formed air flow path. Accordingly, air having a high flow velocity can be discharged from the end portion 143 constituting the exhaust port 162 on the base portion 142 side.

  The side surface of the side wall portion 14 in the second region 52 on the flow path side is substantially straight. More specifically, the inner peripheral surface of the skirt portion 142 located in the second region 52 is substantially straight. However, the side surface on the flow path side of the side wall portion 14 in the second region 52 may not be substantially straight. For example, in a plan view, the side wall portion 14 in the second region 52 may be curved toward the third region 53 toward the downstream in the rotation direction.

  The side surface on the flow path side of the side wall portion 14 in the second region 52 is substantially straight, so that air having a high flow velocity is discharged by the second region 52 and the third region 53. By discharging the air having a high flow velocity from the exhaust port 162, the heat source, that is, the electronic component provided around the exhaust port 162 of the blower fan 1 is further cooled.

  The tongue portion 141 is positioned on the radially outer side than the first inner peripheral edge portion 131a, and the upper portion is covered with the upper plate portion 13.

  The tongue portion 141 is positioned on the radially outer side than the first inner peripheral edge portion 131a, and is covered with the upper plate portion 13, so that the intake port 161 is located in a region radially inward of the first inner peripheral edge portion 131a. The area of can be reduced. Therefore, the air sucked from the intake port 161 is compressed in the flow path, and the wind speed increases, so that the backflow of air can be suppressed.

  The tongue portion 141 has a proximity point (not shown) that is closest to the outer ends of the plurality of blades 112. The distance between the outer end of the blade 112 and the side surface of the side wall portion 14 on the flow path side gradually increases from the proximity point (not shown) toward the downstream side in the rotation direction.

  As the distance between the outer end of the blade 112 and the side surface on the flow path side of the side wall portion 14 gradually increases toward the downstream side in the rotation direction of the impeller 11, the upper plate 13, the lower plate 15, the side wall portion 14, and the impeller 11 The air compressed in the air flow path between is exhausted to the second region 52 and the third region 53 in a state where the flow velocity becomes higher toward the downstream in the rotation direction. By discharging the air having a high flow velocity from the exhaust port 162, the heat source, that is, the electronic component provided around the exhaust port 162 of the blower fan 1 is further cooled.

  FIG. 5 is a top view showing a modification of the blower fan 1. In the modification, the heat sink 6 is provided on the outer side in the radial direction from the outer ends of the plurality of blades 112 in the lower plate portion 15 in plan view. The heat sink 6 includes a plurality of cooling fins 61.

  The heat sink 6 may have any shape as long as it is configured to receive heat from the heating element by heat conduction and to transmit heat to the air sent by the rotation of the blower fan 1. For example, the lower plate portion 15 may have a plurality of cooling fins 61 that are in thermal contact with a heating element such as a CPU or an electronic component and extend upward from the upper surface of the lower plate portion 15. Further, the upper plate portion 13 may have a plurality of cooling fins 61 that are in thermal contact with a heating element such as a CPU or an electronic component and extend downward from the upper plate portion 13 in the axial direction. A gap through which air can pass is required between the cooling fins 61.

  Various changes can be made in the blower fan 1.

  The plurality of blades 112 may not be evenly arranged and may be unevenly distributed.

  As the motor, both a shaft rotating type and a shaft fixing type can be used. The motor can be either an outer rotor type or an inner rotor type.

  In the bearing mechanism 4, the radial dynamic pressure bearing portion may not be configured, and only at least one thrust dynamic pressure bearing portion may be configured.

  The bearing housing 232 does not necessarily have to be formed of a single member. For example, a bottomed substantially cylindrical bearing housing may be configured by fixing a substantially disk-shaped cap to the lower end of a substantially cylindrical housing cylindrical portion centered on the central axis J1. In this case, the housing cylindrical portion covers the outer peripheral surface of the sleeve 231, and the cap covers the lower surface of the sleeve 231. Further, the bearing portion 23 is not necessarily required to have a structure in which the sleeve 231 is inserted into the bearing housing 232, and may be constituted by a single member.

The configurations in the above-described embodiments and modifications may be combined as appropriate as long as they do not contradict each other.

The blower fan according to the present invention can be used for cooling a device inside a casing of a notebook PC or desktop PC, cooling other devices, supplying air to various objects, and the like.
Furthermore, it can be used for other purposes.

J1 Central shaft 1 Blower fan 4 Bearing mechanism 12 Motor part 13 Upper plate part 14 Side wall part 141 Tongue part 142 Bottom part 15 Lower plate part 161 Inlet port 162 Exhaust port 21 Stationary part 22 Rotating part 23 Bearing part 41 Virtual first straight line 42 Virtual second straight line 43 Virtual third straight line 44 Virtual fourth straight line 51 First region 52 Second region 53 Third region 54 Fourth region 6 Heat sink 61 Cooling fin

Claims (14)

An impeller having a plurality of blades arranged in the circumferential direction, which is a blower fan and rotates around a central axis facing in the vertical direction;
A motor section for rotating the impeller;
A lower plate covering the lower side of the impeller,
An upper plate covering the upper side of the impeller;
A side wall portion located between the upper plate portion and the lower plate portion;
With
The upper plate portion, the side wall portion and the lower plate portion constitute an exhaust port on the side of the impeller,
The side wall portion has a tongue protruding between the exhaust port and the impeller,
When viewed in plan,
A tangent line passing through the central axis and in contact with the tongue is a virtual first straight line,
A straight line passing through the central axis and perpendicularly intersecting the first imaginary straight line is a virtual second straight line,
Of the four regions divided by the virtual first straight line and the virtual second straight line, the region where the tongue portion is located is the first region, and the first region is arranged in order from the first region toward the downstream side in the rotation direction of the impeller. 2 region, 3rd region, 4th region,
The side wall portion is located at least over the entire first region,
The upper plate portion has an inner peripheral edge portion that defines an intake port that is a through hole passing through the central axis,
The minimum distance between the inner peripheral edge and the central axis in the fourth area is smaller than the maximum distance between the inner peripheral edge and the central axis in either the second area or the third area. The inner peripheral edge is
An arc shape extending in the circumferential direction, and at least a first inner peripheral edge provided in the fourth region;
An arc extending in the circumferential direction, having at least a second inner peripheral edge provided in the second region,
The blower fan according to claim 1, wherein a minimum distance from the central axis of the first inner peripheral edge is smaller than a maximum distance from the central axis of the second inner peripheral edge. The inner peripheral edge portion includes the first inner peripheral edge portion, the second inner peripheral edge portion, and a pair of connecting portions that connect both ends of the first inner peripheral edge portion and the second inner peripheral edge portion. ,
A maximum distance between the first inner peripheral edge and the central axis is smaller than a minimum distance between the second inner peripheral edge and the central axis;
The blower fan according to claim 2, wherein the connecting portion gradually increases in distance from the central axis as it goes from the first inner peripheral edge to the second inner peripheral edge.   The blower fan according to claim 2 or 3, wherein a sum of circumferential lengths of the second inner peripheral edge portion and the connecting portion is longer than a circumferential length of the first inner peripheral edge portion.   The blower fan according to claim 2, wherein the first inner peripheral edge is provided in the fourth region and the first region.   The blower fan according to claim 2, wherein the second inner peripheral edge is provided in the second region and the third region. The side wall portion includes the tongue portion, and a skirt portion that extends from the tongue portion to the downstream side in the rotation direction of the impeller and increases in distance from the central axis as it proceeds to the downstream side,
The distance between the first inner peripheral edge portion and the central axis on the virtual first straight line is on a virtual third straight line passing through the downstream end portion and the central axis constituting the exhaust port on the base portion side. The blower fan according to claim 2, wherein the blower fan is smaller than a distance between the second inner peripheral edge and the central axis. In plan view,
A first tangent line that is in contact with the intake port through the upstream end portion that constitutes the exhaust port on the tongue side of the side wall portion is in contact with the first inner peripheral edge portion.
The blower fan according to claim 7, wherein a second tangent line that contacts the intake port through the downstream end portion of the side wall portion is in contact with the second inner peripheral edge portion.   The blower fan according to any one of claims 2 to 8, wherein the first inner peripheral edge is located radially inward from the center of the outer ends and inner ends of the plurality of blades in the radial direction.   The blower fan according to claim 1, wherein the side wall portion extends across the first region and the second region.   The blower fan according to any one of claims 1 to 10, wherein the tongue portion is located radially outside of the first inner peripheral edge portion and is covered upward by the upper plate portion.   The blower fan according to claim 1, wherein a side surface of the side wall portion on the flow path side in the second region is substantially straight.   The tongue has a proximity point where the distance to the plurality of blades is closest, and the distance between the plurality of blades and the side surface of the side wall on the flow path side gradually increases from the proximity point toward the downstream side in the rotation direction. The blower fan according to claim 1, which expands.   The blower fan according to any one of claims 1 to 13, wherein a cooling fin is located in at least a part of the second region.

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