Fan motor

Abstract

Provided is a fan motor capable of improving QP characteristics by effectively suppressing diffusion and backflow of air.　This fan motor (100) comprises, in the rotation axis direction, a base (135), a shroud (123), and an impeller (160) disposed between the base (135) and the shroud (123). The impeller (160) comprises a plurality of blades (164), and the shroud (123) comprises a flat surface (126) facing the blades (164). A first surface (164a) of each of the blades (164) facing the shroud (123) extends along an inclined surface (126a) of the shroud (123), an inclined surface (136a) of the base (135) facing the impeller (160) extends along the inclined surface (164a) of the shroud (123), and a second surface (164b) of each of the blades (164) facing the base (135) extends along the inclined surface (136a) of the base (135).

Description

Fan motor

[0001] The present invention relates to a fan motor, and particularly to a technique for suppressing diffusion and reverse flow of air from an impeller.

[0002] As a blower widely used for cooling, ventilation, air conditioning of home appliances, OA equipment, industrial equipment, and air conditioning and air blowing for vehicles, a fan motor is known. As this type of fan motor, a casing is composed of an upper casing and a lower casing, an impeller and a motor are housed inside the casing, the impeller rotates by driving of the motor, and air inhaled from a suction port is blown outward from a blowout port formed over the entire circumference of the side surface of the casing as the impeller rotates (for example, see Patent Document 1).

[0003] In the fan motor of Patent Document 1, a wall housing portion is formed in an upper shroud formed in the upper casing, and a wall that protrudes axially upward at the peripheral edge of the impeller and is housed in the wall housing portion is formed to form a labyrinth structure, thereby suppressing reverse flow of air.

[0004] Japanese Patent Application Laid-Open No. 2019-157656

[0005] In a fan motor, there is a strong demand for effectively suppressing diffusion and reverse flow of air to improve PQ characteristics. One object of the present invention is to provide a fan motor capable of improving PQ characteristics by suppressing diffusion and reverse flow of air.

[0006] The present invention includes, in the rotational axis direction, a base, a shroud, and an impeller disposed between the base and the shroud, the impeller includes a plurality of blades, the shroud includes a plane facing the blades, a first surface of the blades facing the shroud extends along the plane of the shroud, a plane of the base facing the impeller extends along the plane of the shroud, and a second surface of the blades facing the base extends along the plane of the base.

[0007] According to the present invention, diffusion and reverse flow of air can be effectively suppressed to improve PQ characteristics.

[0008] This is a perspective view showing a fan motor according to an embodiment of the present invention. This is a plan view showing a fan motor according to an embodiment. This is a cross-sectional view (A) taken along line III-III in Figure 2, and a partially enlarged view (B) of (A). This is a perspective view showing an impeller in an embodiment. This is a plan view showing an impeller in an embodiment. This is a cross-sectional view taken along line VI-VI in Figure 5. This is a graph showing the relationship between airflow and static pressure in an embodiment of the present invention.

[0009] 1. Figure 1 is a perspective view showing a fan motor 100 according to an embodiment of the present invention, and Figure 2 is a plan view. The fan motor 100 includes a casing 110 composed of a resin upper casing 120 and a resin lower casing 130. The casing 110 has a rectangular shape (including a nearly square shape) in plan view, but is not limited to this, and may be circular.

[0010] Legs 121 are formed at the four corners of the upper casing 120, projecting downwards. The legs 121 are formed by creating roughly rectangular notches at the corners of the upper casing 120 and extending downwards from the edges of the notches.

[0011] The lower casing 130 has a projection 131 that protrudes upward, and the upper end of the projection 131 is connected to the lower end of the leg 121. The projection 131 has the same axial cross-sectional shape as the leg 121. The upper end of the projection 131 has a step 131a formed on the inner circumference side, which is lowered by one step. On the other hand, the lower end of the leg 121 has a step 121a formed on the inner circumference side, which protrudes by one step downward. The steps 121a and 131a are fitted together and joined to each other, for example, by adhesive.

[0012] A through hole 132 is formed on the radially outer side of the projection 131, and a metal collar 133 is fixed around the through hole 132. The collar 133 is integrally formed with the lower casing 130 by insert molding. For example, a bolt is inserted through the through hole 132 and tightened into a screw hole in the device to which the fan motor 100 is to be mounted.

[0013] A circular intake port 122 is formed in the center of the upper casing 120. In addition, outlet ports 112 are formed around the entire circumference of the casing 110, excluding the legs 121 and projections 131. In other words, multiple outlet ports 112 are formed between adjacent projections 131. Inside the casing 110, a flow path 111 is formed by a base 135 and a shroud 123, which will be described later, connecting the intake port 122 and the outlet ports 112. An impeller 160 is positioned in the flow path 111 in a rotatable manner. When the impeller 160 rotates clockwise in the figure, air is drawn in from the intake port 122 by the action of the blades 164 of the impeller 160. The drawn-in air passes between the blades 164 and is blown out radially outward from the impeller 160, passing through the flow path 111 and being discharged from the outlet ports 112.

[0014] As shown in Figure 3, a motor 140 is positioned in the center of the casing 110. The motor 140 is an outer rotor type brushless DC motor. In this description, the direction of the motor 140's shaft 141 is referred to as the "axial direction," the direction perpendicular to the axial direction is referred to as the "radial direction," and the direction in which the shaft 141 rotates is referred to as the "circumferential direction." Also, terms indicating directions such as "up" and "down" are based on Figure 3.

[0015] An annular projection 134 is formed in the center of the lower casing 130, projecting upward in the axial direction. A cylindrical metal bearing holder 142 is fixed to the annular projection 134 with adhesive. Ball bearings 143 are fixed to both sides of the bearing holder 142 in the axial direction by means of press-fitting, adhesive, or other means. The shaft 141 is fixed to the ball bearings 143 in a rotatable manner by means of press-fitting, adhesive, or other means.

[0016] A rotor yoke 144 made of a soft magnetic material (iron) is fixed to the upper end of the shaft 141 by means of press-fitting or other means. The rotor yoke 144 is a bottomed cylindrical shape, and an annular rotor magnet 145 is fixed to the inner circumferential surface of its cylindrical portion with adhesive. The rotor magnet 145 is magnetized in such a way that the polarity of the magnetic poles alternates between NSNS... along the circumferential direction. A coil spring 146 is interposed between the rotor yoke 144 and the ball bearing 143 to apply preload to the ball bearing 143.

[0017] A stator 150 is fixed to the outer circumference of the bearing holder 142. The stator 150 consists of a stator core 151, an insulator 152, and a stator coil 153. The stator core 151 has a structure in which multiple thin sheets of soft magnetic material such as electromagnetic steel are laminated and crimped together. The stator core 151 has multiple pole teeth 151b that extend radially outward from a core back portion 151a which has an annular shape.

[0018] A resin insulator 152 is integrally molded onto the stator core 151 by insert molding, and a stator coil 153 is wound around multiple pole teeth 151b via the insulator 152. The insulator 152 insulates the stator core 151 from the stator coil 153. The insulator 152 may be made by bonding together separate parts that are separated in the axial direction.

[0019] The core back portion 151a has an opening that penetrates axially, and the opening of the core back portion 151a is fitted to the outer circumferential surface of the bearing holder 142, and the lower end surface of the core back portion 151a is placed on the annular projection 134 of the lower casing 130, thereby axially positioning the stator core 151. However, this is not the only option; the outer circumferential surface of the bearing holder 142 may be press-fitted into the opening of the core back portion 151a.

[0020] The rotor magnet 145 is positioned opposite the outer circumferential surface of the pole teeth 151b of the stator core 151, with a gap (magnetic gap) between the outer circumferential surface of the pole teeth 151b and the rotor magnet 145. In other words, in the radial direction, the outer circumferential surface of the pole teeth 151b and the rotor magnet 145 face each other with a magnetic gap in between. A circuit board 154 is positioned below the insulator 152. The circuit board 154 is electrically connected to the stator coil 153, and by periodically switching the polarity of the current applied to the stator coil 153 using a drive circuit formed on the circuit board 154, a driving force is generated that causes the rotor magnet 145 to rotate around the shaft 141, and the impeller 160 rotates.

[0021] 2. The impeller 160 in this embodiment will be described with reference to the impeller configuration diagrams 3 to 6. Before describing the impeller 160, the parts of the casing 110 located opposite the blades 164 of the impeller 160 will be described. As shown in Figure 3, in the radial direction, the upper casing 120 is provided with a shroud 123 facing the intake port 122.

[0022] The shroud 123 comprises a bell mouth 124 with a circular arc cross-section formed on the upper edge of the inner circumference, an inner circumference portion 125 with a cylindrical curved surface that continues axially downward from the bell mouth 124, and a plane 126 that extends radially outward from the lower end of the inner circumference portion 125 and faces the lower casing 130. The plane 126 comprises an inclined surface (plane) 126a whose axial thickness increases as it extends radially outward, and a second plane 126b that extends radially outward from the inclined surface 126a.

[0023] The lower casing 130 is provided with a base 135 at its peripheral edge. The base 135 has a plane 136 facing the upper casing 120, and the plane 136 has an inclined surface 136a whose axial thickness decreases as it extends radially outward, a second plane 136b extending radially inward from the inclined surface 136a, and a third plane 136c extending radially outward from the inclined surface 136a. Air is blown radially by this third plane 136c and the second plane 126b of the shroud 123. The inclined surface 136a of the base 135 is parallel to the inclined surface 126a of the shroud 123. A recess 137 is formed on the radially inward side of the second plane 136b, which is recessed axially downward.

[0024] Next, the impeller 160 will be described. In Figure 4, reference numeral 161 denotes a cylinder. The cylinder 161 is a bottomed cylindrical shape, and the impeller 160 is rotatably supported by the motor 140 by placing the cylinder 161 over the rotor yoke 144 and bonding it. An annular plate 162 is formed on the outer circumferential surface of the cylinder 161, extending radially outward and axially downward. The annular plate 162 has an arc-shaped cross-section that is convex axially downward, and extends to a position radially inward from the inclined surface 136a of the base 135.

[0025] The annular plate 162 has a flat surface 163 facing the lower casing 130, and the flat surface 163 comprises a curved surface 163a with an arc-shaped cross-section and a horizontal surface 163b extending radially outward from the curved surface 163a. ​​The horizontal surface 163b faces the second flat surface 136b of the base 135 (see Figure 3(B)).

[0026] Multiple blades 164 are integrally formed on the upper surface of the annular plate 162. All blades 164 have the same shape and are evenly arranged in the circumferential direction, facing the outer circumference of the cylinder 161 with a constant gap in the radial direction. Furthermore, the blades 164 are backward-facing blades that are curved so as to be concave in the opposite direction to the direction of rotation, and are arranged at an inclination in the direction of rotation indicated by arrow R in Figure 5 relative to the annular plate 162, and also at an inclination downward toward the radially outward direction, as shown in Figure 6.

[0027] Each blade 164 has a first surface 164a facing upward in the axial direction, and this first surface 164a is provided on each of the multiple blades 164, forming the same shape. Furthermore, each blade 164 has a second surface 164b facing downward in the axial direction, and this second surface 164b is provided on each of the multiple blades 164, forming the same shape. The first surface 164a and the second surface 164b are parallel to each other.

[0028] The first surface 164a of the blade 164 extends along the inclined surface 126a of the shroud 123. This creates an airflow path between the first surface 164a and the inclined surface 126a. The inclined surface 136a of the base 135, which faces the blade 164, also extends along the inclined surface 126a of the shroud 123. The second surface 164b of the blade 164 extends along the inclined surface 136a of the base 135. This creates an airflow path between the second surface and the inclined surface 136a.

[0029] A ring 165 is integrally formed on the periphery of the first surface 164a of the blade 164. This connects the blades 164 to each other. In the radial direction, an annular plate 162 extends to a position midway between the ring 165 and the outer surface of the cylinder 161. Thus, the blades 164 are firmly connected to the cylinder 161, as they are connected to each other at their periphery by the ring 165 and to each other at their inner circumference by the annular plate 162. The top surface 165a of the ring 165 faces the second plane 126b of the shroud 123.

[0030] In the fan motor 100 with the above configuration, the first surface 164a of the blade 164 extends along the inclined surface 126a of the shroud 123, and the second surface 164b of the blade 164 extends along the inclined surface 136a of the base 135. Therefore, by appropriately adjusting the gap between the base 135 and shroud 123, which form the space in which the blade 164 rotates, and the blade 164 facing them, the airflow generated by the blade 164 can be increased as much as possible, and the backflow of air from the gap and the diffusion of air in directions other than centrifugal can be suppressed. P is static pressure (Pa), Q is airflow (m³). ３ The PQ characteristics can be improved when the value is set to ( / min).

[0031] In particular, in the fan motor 100 with the above configuration, the blades 164 are angled downwards with radial outward orientation, so the orientation of the blades 164 is obtuse with respect to the direction of the air flowing in axially from the intake port 122. As a result, the air drawn in axially from the intake port 122 flows in a direction that is inclined downwards with respect to the horizontal direction, so the deflection of the airflow is gentle and the resistance the air receives from the flow path 111 is small, and therefore the PQ characteristics can be further improved.

[0032] Furthermore, in the above embodiment, an air passage is formed between the first surface 164a of the blade 164 and the inclined surface 126a of the shroud 123, and an air passage is formed between the second surface 164b of the blade 164 and the inclined surface 136a of the base 135. As a result, air flows towards the outlet 112 through these passages, suppressing air diffusion and backflow.

[0033] In the above embodiment, the annular plate 162 extends to a position radially inward from the inclined surface 136a of the base 135. Therefore, in the radial direction, the annular plate 162 faces the inclined surface 136a with a gap between them. As a result, the action of the vanes 164 is fully exerted, contributing to the improvement of the PQ characteristics. Furthermore, since the annular plate 162 has a cross-sectional shape that is convex downward in the axial direction, the air drawn in from the intake port 122 is smoothly deflected radially outward.

[0034] In the above embodiment, a recess 137 is formed radially inward of the base 135. The annular plate 162 of the impeller 160 is positioned axially above the recess 137, and air passes over the annular plate 162. Therefore, the recess 137 can contribute to reducing the weight of the fan motor 100 without causing turbulence in the airflow.

[0035] 3. Examples of Modifications The present invention is not limited to the above embodiments, and various modifications are possible as follows: i) The blade 164 can be extended horizontally without being tilted downward.

[0036] ii) The annular plate 162 may be omitted, and the blades 164 may be formed directly on the outer surface of the cylinder 161. In this case, the inclined surface 136a of the base 135 can be extended to the cylinder 161. iii) The shape of the blades 164 is not limited to backward-facing blades and is arbitrary. iv) The present invention is not limited to radial fan motors as in the above embodiments, but can be applied to axial flow fan motors and centrifugal fans.

[0037] 4. Examples The relationship between airflow rate, wind pressure, and wind speed was investigated by operating the fan motor 100 of the above embodiment. For comparison, the same was investigated with a comparative example to which the present invention was not applied. The results are shown in Figure 7. As shown in Figure 7, it was confirmed that the fan motor of the present invention has a larger airflow rate than the comparative example, and that the wind pressure and wind speed relative to the airflow rate are significantly improved.

[0038] This invention can be used in fan motors used for air supply, ventilation, cooling, etc., in home appliances, office automation equipment, and air conditioning systems for industrial and vehicle use.

[0039] 100...Fan motor, 110...Casing, 111...Flow path, 112...Outlet, 120...Upper casing, 121...Legs, 121a...Step, 122...Inlet, 123...Shroud, 124...Bell mouth, 125...Inner circumference, 126...Plane, 126a...Inclined surface (plane), 126b...Second plane, 130...Lower casing, 131...Protrusion, 131a...Step, 132...Through hole, 133...Collar, 134...Annular projection, 135...Base, 136...Plane, 136a...Inclined surface, 136b...Second plane, 136c...Third plane, 137...Recess, 140...Mo 141...Shaft, 142...Bearing holder, 143...Ball bearing, 144...Rotor yoke, 145...Rotor magnet, 146...Coil spring, 150...Stator, 151...Stator core, 151a...Core back section, 151b...Poles, 152...Insulator, 153...Stator coil, 154...Circuit board, 160...Impeller, 161...Cylinder, 162...Annular plate, 163...Plane, 163a...Curved surface, 163b...Horizontal surface, 164...Blade, 164a...First surface, 164b...Second surface, 165...Ring, 165a...Top surface, R...Arrow.

Claims

1. A fan motor comprising, in the direction of rotation axis, a base, a shroud, and an impeller disposed between the base and the shroud, wherein the impeller has a plurality of blades, the shroud has a plane facing the blades, the first surface of the blades facing the shroud extends along the plane of the shroud, the plane of the base facing the impeller extends along the plane of the shroud, and the second surface of the blades facing the base extends along the plane of the base.

2. The fan motor according to claim 1, wherein the plane of the shroud facing the blades is an inclined surface, the first surface of the blades facing the shroud is inclined along the inclined surface of the shroud, the plane of the base facing the blades is inclined along the inclined surface of the shroud, and the second surface of the blades facing the base is inclined along the inclined surface of the base.

3. In the radial direction, the inner circumference of the shroud is located between the outer and inner circumferences of the blades, and the inner circumference of the shroud forms an inclined surface of the shroud, as described in claim 2.

4. The fan motor according to claim 1 or 2, wherein the plane of the shroud and the plane of the base form a radially extending flow path.

5. The fan motor according to claim 2, wherein the impeller comprises a cylinder rotatably supported by a motor and an inclined plate extending radially outward from the outer circumferential surface of the cylinder toward the lower side in the direction of rotation and perpendicular to the direction of rotation, and the blades are formed on the axial upper surface of the inclined plate.

6. The fan motor according to claim 5, wherein a recess is provided on the radially inner side of the base, opposite to the inclined plate, and recesses downward in the direction of the rotation axis.

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