Blower device and method for manufacturing same

Abstract

This blower device has a fan part and a housing part. The fan part has an impeller that rotates around a central axis. The housing part houses the fan part. Here, the housing part has a cylindrical wall part. The cylindrical wall part extends along the central axis and covers the impeller from the outside in a radial direction. The impeller has a plurality of blade parts disposed in a circumferential direction. A cutting mark is formed in at least a part of an inner peripheral surface of the cylindrical wall part facing the blade parts in the radial direction or in an outer end part in the radial direction of the blade parts.

Description

Blower and manufacturing method thereof

[0001] The present invention relates to a blower and a method for manufacturing the same.

[0002] A conventional blower device includes a fan unit having an impeller that rotates around a central axis and a housing unit that houses the fan unit. The housing unit has a cylindrical wall that extends along the central axis and covers the impeller from the radial outside. The impeller has a plurality of blades arranged in the circumferential direction (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2000-179490

[0004] However, in conventional blowers, the blades can deform and bulge radially outward due to centrifugal force during rotation. In this case, if the radial gap between the impeller and the housing is small, the impeller and the housing can come into contact, potentially reducing the blowing performance of the blower. On the other hand, if the radial gap between the impeller and the housing is large, tip vortices can easily occur, potentially reducing the blowing performance of the blower.

[0005] An object of the present invention is to provide a blower device and a method for manufacturing a blower device that can prevent a decrease in blowing performance.

[0006] An exemplary blower device of the present invention has a fan section and a housing section. The fan section has an impeller that rotates around a central axis. The housing section accommodates the fan section. The housing section has a cylindrical wall section. The cylindrical wall section extends along the central axis and covers the impeller from the radially outer side. The impeller has a plurality of blade sections arranged in the circumferential direction. Cutting marks are formed on at least a portion of the inner surface of the cylindrical wall section that is radially opposite the blade sections or on the radially outer end of the blade sections.

[0007] An exemplary method for manufacturing a blower of the present invention is a method for manufacturing a blower including a fan section and a housing section, and includes, in order, a molding process and a cutting process. The fan section has an impeller that rotates around a central axis. The housing section has a cylindrical wall section that accommodates the fan section and covers the impeller from the radially outer side. The molding process molds the housing section. The cutting process cuts the inner circumferential surface of the cylindrical wall section. In the cutting process, a cutting blade inserted inside the cylindrical wall section is rotated around the central axis to cut the inner circumferential surface of the cylindrical wall section.

[0008] According to an exemplary embodiment of the present invention, it is possible to provide a blower device and a method for manufacturing a blower device that can prevent a decrease in blowing performance.

[0009] FIG. 1 is an overall perspective view of a blower device according to an embodiment of the present invention. FIG. 2 is a longitudinal cross-sectional view of a blower device according to an embodiment of the present invention. FIG. 3 is a longitudinal cross-sectional view of a housing portion of a blower device according to an embodiment of the present invention. FIG. 4 is a perspective view of a blower device according to an embodiment of the present invention. FIG. 5 is an explanatory diagram illustrating a manufacturing process of a housing portion of a blower device according to an embodiment of the present invention. FIG. 6 is an explanatory diagram illustrating a manufacturing process of a housing portion of a blower device according to an embodiment of the present invention. FIG. 7 is an explanatory diagram illustrating a manufacturing process of a housing portion of a blower device according to an embodiment of the present invention.

[0010] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. In this specification, the direction in which the central axis of the blower extends will be referred to simply as the "axial direction," the direction perpendicular to the central axis of the blower will be referred to simply as the "radial direction," and the direction along the arc centered on the central axis of the blower will be referred to simply as the "circumferential direction." Furthermore, for the sake of convenience, this specification will refer to the axial direction as the up-down direction, and the up-down direction in FIG. 2 as the up-down direction of the blower, and will describe the shape and positional relationship of each part. The "upper side" of the blower is the "intake side," and the "lower side" is the "exhaust side." Note that this definition of the up-down direction does not limit the orientation and positional relationship of the blower during use. In this specification, a cross section parallel to the axial direction will be referred to as a "longitudinal cross section." Furthermore, the term "parallel" used in this specification does not mean parallel in the strict sense, but also includes approximately parallel.

[0011] <1. Overall Configuration of Air Blower> Fig. 1 is an overall perspective view of an example of an air blower 1 according to an embodiment of the present invention, and Fig. 2 is a vertical cross-sectional view of the air blower 1. Note that the flange portion 22a is omitted in Fig. 2.

[0012] The blower device 1 includes a fan unit 10 and a housing unit 20. The fan unit 10 has an impeller 11 and a motor 12.

[0013] The housing 20 has an air flow path 21 therein. The air flow path 21 extends along the central axis J inside the housing 20. The air flow path 21 has an air intake port 211 at its upper end and an air outlet 212 at its lower end.

[0014] The housing 20 is a resin molded product (a molded product) and accommodates the impeller 11, the motor 12, and the circuit board 13. The housing 20 has a cylindrical wall 22, a base 23, a connecting portion 24, and a bearing holder 25.

[0015] The cylinder wall portion 22 extends along the central axis J and covers the impeller 11 from the radially outer side. The cylinder wall portion 22 has a cylindrical shape that extends up and down in the axial direction. The air flow path 21 is arranged radially inside the cylinder wall portion 22. An air intake port 211 is arranged at the upper axial end of the cylinder wall portion 22. An air outlet 212 is arranged at the lower axial end of the cylinder wall portion 22. The cylinder wall portion 22 also has flange portions 22a arranged at corners of the upper and lower ends (see Figure 1). The flange portions 22a have mounting holes 22b that penetrate in the axial direction. The blower device 1 can be screwed to a mounting surface via the mounting holes 22b.

[0016] The base portion 23 is disposed axially below the motor 12 and has a disk shape that extends radially about the central axis J. The connecting portions 24 extend radially outward from the radial outer surface of the base portion 23 and connect the base portion 23 to the cylindrical wall portion 22. A plurality of connecting portions 24 are arranged in the circumferential direction. Air flowing through the air flow passage 21 passes between adjacent connecting portions 24.

[0017] The bearing holder 25 is a metal member such as brass, and is molded integrally with the base portion 23. The bearing holder 25 protrudes axially upward from the upper surface of the base portion 23 and is cylindrical with the central axis J as its center. The bearing holder 25 holds a bearing 122 (described later) inside and constitutes a part of the motor 12. Note that instead of being molded as a separate member from the base portion 23, the bearing holder 25 may be molded integrally with the base portion 23 by resin molding.

[0018] The impeller 11 is disposed radially inside the cylindrical wall portion 22, axially above and radially outside the motor 12. The impeller 11 is a resin molded product (a molded product) and is rotated around the central axis J by the motor 12.

[0019] The impeller 11 has an impeller cup 111 and blade portions 112. The impeller cup 111 is fixed to the motor 12. The impeller cup 111 is a substantially cylindrical member having a lid on the axially upper side. The plurality of blade portions 112 are arranged in the circumferential direction on the outer surface of the impeller cup 111.

[0020] The motor 12 is fixed to the base portion 23 and housed in the housing portion 20. The motor 12 rotates the impeller 11 around the central axis J. The motor 12 has a shaft 121, a bearing 122, a bearing holder 25, a stator 123, and a rotor 124.

[0021] The shaft 121 is disposed along the central axis J. The shaft 121 is made of a metal such as stainless steel and is a columnar member extending up and down in the axial direction. The shaft 121 is supported by a bearing 122 so as to be rotatable around the central axis J.

[0022] The bearings 122 are arranged in at least one pair, one above and one below, in the axial direction. The bearings 122 are held inside the bearing holder 25. The bearings 122 are formed, for example, of ball bearings, but may also be formed of sleeve bearings or the like. The pair of bearings 122, one above and one below, in the axial direction, support the shaft 121 rotatably about the central axis J relative to the housing 20.

[0023] The stator 123 is fixed to the outer peripheral surface of the bearing holder 25. The stator 123 includes a stator core 1231, an insulator 1232, and a coil 1233.

[0024] The stator core 1231 is formed by stacking electromagnetic steel plates, such as silicon steel plates, one above the other. The insulator 1232 is formed from an insulating resin. The insulator 1232 is provided to surround the outer surface of the stator core 1231. The coil 1233 is formed from a conducting wire wound around the stator core 1231 via the insulator 1232.

[0025] The rotor 124 is disposed axially above and radially outward of the stator 123. The rotor 124 rotates about a central axis J relative to the stator 123. The rotor 124 includes a rotor yoke 1241 and a magnet 1242.

[0026] The rotor yoke 1241 is made of a magnetic material and is a substantially cylindrical member with a cover on the axially upper side. The rotor yoke 1241 is fixed to the shaft 121. The magnet 1242 is cylindrical and is fixed to the inner circumferential surface of the rotor yoke 1241. The magnet 1242 is disposed radially outside the stator 123.

[0027] The circuit board 13 is disposed axially below the impeller 11 and axially above the base portion 23. The circuit board 13 is, for example, in the shape of a disk extending radially about a central axis J. Lead wires of the coil 1233 are electrically connected to the circuit board 13. An electronic circuit for supplying a drive current to the coil 1233 is mounted on the circuit board.

[0028] In the blower 1 configured as described above, when a drive current is supplied to the coil 1233 of the motor 12 via the circuit board 13, a radial magnetic flux is generated in the stator core 1231. The magnetic field generated by the magnetic flux of the stator core 1231 interacts with the magnetic field generated by the magnet 1242, generating a torque in the circumferential direction of the rotor 124. This torque causes the rotor 124 and the impeller 11 to rotate about the central axis J. When the impeller 11 rotates, an airflow is generated by the multiple blades 112. In other words, the blower 1 can blow air by generating an airflow with the upper side serving as the intake side and the lower side serving as the exhaust side.

[0029] 2. Detailed Configuration of Housing Part Fig. 3 is a vertical cross-sectional view of the housing part 20. For the sake of explanation, the cutting marks 222a are shown with dotted patterns in Fig. 3. The flange part 22a is also omitted from Fig. 3.

[0030] The cylindrical wall portion 22 of the housing portion 20 has expanded diameter portions 221, 223 and a constant diameter portion 222. The constant diameter portion 222 has a constant inner diameter and extends in the axial direction (parallel to the central axis J). The expanded diameter portions 221, 223 are arranged adjacent to each other on both axial sides (axially upper and axially lower sides) of the constant diameter portion 222, and the inner diameter increases with increasing axial distance from the constant diameter portion 222. As a result, the inner circumferential surfaces of the expanded diameter portions 221, 223 incline radially outward as they extend axially outward.

[0031] The inner circumferential surface of the constant diameter portion 222 has cutting marks 222a. The inner circumferential surface of the expanded diameter portion 221 has an unmachined surface 221a without cutting marks 222a. The inner circumferential surface of the expanded diameter portion 223 has an unmachined surface 223a. That is, the cutting marks 222a are located on the inner circumferential surface of the constant diameter portion 222. As a result, the cutting marks 222a are located at the radially inner end on the inner circumferential surface of the cylindrical wall portion 22.

[0032] The unmachined surfaces 221a and 223a are located on the inner circumferential surfaces of the enlarged diameter portions 221 and 223, respectively. That is, the housing portion 20 has the unmachined surface 221a that does not have any cutting marks 222a.

[0033] As a result, cutting marks 222a are formed on at least a portion of the inner circumferential surface of the cylindrical wall portion 22 that faces the blade portion 112 in the radial direction. In this embodiment, the cutting marks 222a extend in the entire circumferential direction on the inner circumferential surface of the cylindrical wall portion 22. Here, the cutting marks 222a may extend continuously in the entire circumferential direction on the inner circumferential surface of the cylindrical wall portion 22, may extend discontinuously in the circumferential direction on a portion of the circumferential direction, or may extend continuously in only a portion of the circumferential direction. When the cutting marks 222a extend continuously in the entire circumferential direction on the inner circumferential surface of the cylindrical wall portion 22, cutting is performed over the entire circumferential direction, and variation in the inner diameter of the cutting marks 222a can be reduced. When the cutting marks 222a extend continuously and intermittently along a portion of the circumferential direction on the inner surface of the cylindrical wall portion 22, the amount of cutting to form the cutting marks 222a can be reduced, the cutting processing time required to form the cutting marks 222a can be reduced, and wear on the cutting blade 71a can be reduced.

[0034] The cutting marks 222a are formed by cutting the surface of the molded housing portion 20. The non-machined surfaces 221a and 223a are surfaces that were in contact with the mold during molding, and are not machined.

[0035] By cutting the uniform diameter portion 222, it is possible to reduce the variation in the inner diameter of the uniform diameter portion 222 relative to the variation in the dimensions of the molded housing portion 20. This ensures that a gap of a predetermined width is maintained between the blade portion 112 and the cylindrical wall portion 22. This prevents contact between the impeller 11 and the housing portion 20. This prevents a decrease in the air volume and static pressure of the blower 1, thereby preventing a decrease in blowing performance.

[0036] Furthermore, by reducing the minimum radial distance between the cylindrical wall portion 22 and the blade portion 112, it is possible to suppress the generation of tip vortices and improve the air volume and static pressure of the blower device 1. This further improves the blowing performance of the blower device 1.

[0037] Furthermore, the area where the cutting marks 222a are formed has a small surface roughness, allowing the airflow to flow smoothly in the axial direction, thereby further improving the air volume and static pressure of the blower device 1.

[0038] By forming the cutting marks 222a on the entire inner peripheral surface of the cylindrical wall portion 22 in the circumferential direction, it is possible to further improve the air volume and static pressure of the blower device 1. It is also possible to further prevent contact between the impeller 11 and the housing portion 20.

[0039] In this embodiment, the cutting marks 222a are formed on the entire surface of the same diameter portion 222, but they may be formed on only a portion of the same diameter portion 222. Depending on the shape of the cylindrical wall portion 22, forming the cutting marks 222a on the radially inner end portion of the cylindrical wall portion 22 can prevent contact between the impeller 11 and the housing portion 20.

[0040] (3. Manufacturing Method of Housing Portion) Fig. 4 is a flowchart showing the manufacturing process of the housing portion 20. Figs. 5, 6, and 7 are explanatory views illustrating the manufacturing process of the housing portion 20. Note that the flange portion 22a is omitted in Figs. 5 and 6.

[0041] 5, in step S1, the peripheral edge of mold 31 and the peripheral edge of mold 32 are brought into contact with each other in the vertical direction to form cavity 40 between mold 31 and mold 32. Cavity 40 has a shape corresponding to the shape of housing 20. Furthermore, bearing holder 25 is disposed in cavity 40 at a position corresponding to base 23.

[0042] In step S2, molten resin is injected into cavity 40. In step S3, the resin is cooled and hardened. As a result, housing portion 20 is formed in cavity 40. At this time, base portion 23 and bearing holder 25 are integrally molded. In step S4, as shown in FIG. 6, housing portion 20 is released from pair of molds 31, 32. At this time, the entire surface of housing portion 20 is an unmachined surface without cutting marks 222a.

[0043] In step S5, as shown in Fig. 7, the housing portion 20 is transported to a cutting device 70. The cutting device 70 has a cutting unit 71 and a table 72. The cutting unit 71 has a cutting blade 71a and a rotating body 71b. The rotating body 71b is cylindrical and rotatable around a central axis J. The rotating body 71b also has an insertion hole 71c extending axially upward from its lower surface. A plurality of cutting blades 71a are fixed circumferentially to the outer peripheral surface of the rotating body 71b.

[0044] The table 72 has an upper surface perpendicular to the axial direction, on which the transported housing 20 is placed. The table has a pin 72a that protrudes in the axial direction from the upper surface of the table. The pin 72a is inserted into the mounting hole 22b of the housing 20. This positions the housing 20 on the table 72.

[0045] After the housing 20 is placed on the table 72, the cutting portion 71 is inserted into the cylindrical wall 22. At this time, the bearing holder 25 is inserted into the insertion hole 71c. This allows the rotating body 71b to be inserted into the cylindrical wall 22 without coming into contact with the bearing holder 25.

[0046] Thereafter, the rotor 71b rotates about the central axis J, causing the cutting blade 71a to rotate about the central axis J. As a result, the inner peripheral surface of the cylindrical wall portion 22 is cut by the cutting blade 71a.

[0047] In step S6, the cutting blade 71a is rotated about the central axis J to cut the inner circumferential surface of the cylindrical wall portion 22. As a result, cutting marks 222a are formed on the inner circumferential surface of the same diameter portion 222. By rotating the cutting blade 71a about the central axis J to form the cutting marks 222a, cutting marks 222a that extend in the entire circumferential direction can be easily formed on the inner circumferential surface of the cylindrical wall portion 22.

[0048] As described above, the manufacturing method for the housing 20, which becomes part of the casing of the blower 1, includes, in order, a molding process, a conveying process, and a cutting process. In the molding process, the housing 20 is molded from resin (steps S1 to S4). In the conveying process, the housing 20 formed in the molding process is conveyed, and the cutting blade 71a is inserted into the cylindrical wall 22 (step S5). In the cutting process, the cutting blade 71a inserted into the cylindrical wall 22 is rotated around the central axis J to cut the inner circumferential surface of the cylindrical wall 22 (step S6). The conveying process allows the cutting process to be performed consecutively after the molding process, improving the manufacturing efficiency of the housing 20.

[0049] In this embodiment, the cutting marks 222a are formed by the cutting blade 71a, but the cutting marks 222a may be formed by using an abrasive material instead of the cutting blade 71a.

[0050] (4. Other) The above-described embodiment is merely an example of the present invention. The configuration of the embodiment may be modified as appropriate without departing from the technical spirit of the present invention. Furthermore, the embodiments may be combined to the extent possible. For example, in this embodiment, cutting marks 222a are formed on the inner circumferential surface of the cylindrical wall portion 22. However, cutting marks may also be formed on the radially outer end portions of the blade portions 112. By cutting the radially outer end portions of the blade portions 112, variation in the outer diameter of the blade portions 112 can be reduced relative to variation in the dimensions of the molded blade portions 112. This ensures that a predetermined gap is maintained between the blade portions 112 and the cylindrical wall portion 22. This prevents contact between the impeller 11 and the housing portion 20. This prevents a decrease in the air volume and static pressure of the blower 1, thereby preventing a decrease in blowing performance. Note that the areas of the blade portions 112 other than the radially outer end portions are unmachined surfaces without cutting marks.

[0051] At this time, it is preferable that the cutting marks are formed on the radially outer ends of all of the blade portions 112. This can further prevent the impeller 11 and the housing portion 20 from coming into contact with each other.

[0052] (5. Supplementary Note) As described above, a blower (1) according to one aspect of the present disclosure comprises a fan section (10) having an impeller (11) that rotates around a central axis (J), and a housing section (20) that houses the fan section, the housing section having a cylindrical wall section (22) that extends along the central axis and covers the impeller from the radial outside, the impeller having a plurality of blade sections (112) arranged in the circumferential direction, and cutting marks (222a) are formed on at least a part of the inner surface of the cylindrical wall section that faces the blade sections in the radial direction or on the radial outer end of the blade sections (first configuration).

[0053] In addition, in the above-mentioned first configuration, the housing portion and the impeller are molded products and have unmachined surfaces (221a, 223a) without cutting marks, and the cutting marks have a smaller surface roughness than the unmachined surfaces (second configuration).

[0054] In the first or second configuration, the cutting marks are located at the radially inner end of the inner circumferential surface of the cylindrical wall portion (third configuration).

[0055] In any one of the first to third configurations, the cutting marks extend over the entire circumferential direction on the inner circumferential surface of the cylindrical wall portion (fourth configuration).

[0056] In any one of the first to fourth configurations, the cutting marks are formed on the radially outer ends of all of the blade portions (fifth configuration).

[0057] In addition, in any of the first to fifth configurations, the cylindrical wall portion has a constant diameter portion (222) that has a constant inner diameter and extends in the axial direction, and expanded diameter portions (221, 223) that are arranged adjacent to the same diameter portion on both sides of the axial direction and whose inner diameter increases with increasing distance from the same diameter portion in the axial direction, and the cutting marks are located on the inner surface of the same diameter portion, and the non-machined surface is located on the inner surface of the expanded diameter portion (sixth configuration).

[0058] Furthermore, a manufacturing method of a blower (1) according to one aspect of the present disclosure is a manufacturing method of a blower comprising a fan section (10) having an impeller (11) that rotates around a central axis (J), and a housing section (20) that houses the fan section and has a cylindrical wall section (22) that covers the impeller from the radially outward side, the manufacturing method comprising a die molding process for molding the housing section and a cutting process for cutting the inner surface of the cylindrical wall section, in that order, in which a cutting blade (50) inserted inside the cylindrical wall section is rotated around the central axis to cut the inner surface of the cylindrical wall section (seventh configuration).

[0059] The seventh aspect of the present invention further includes a conveying step of conveying the housing portion formed by the mold forming step and inserting the cutting blade into the cylindrical wall portion (eighth aspect). The present invention can be used, for example, in a blower device for cooling a personal computer.

[0060] REFERENCE SIGNS LIST 1 blower device 10 fan section 11 impeller 12 motor 13 circuit board 20 housing section 21 air flow path 22 cylindrical wall section 22a flange section 22b mounting hole 23 base section 24 connecting section 25 bearing holding section 31, 32 mold 40 cavity 70 cutting device 71 cutting section 71a cutting blade 71b rotating body 71c insertion hole 72 table 72a pin 111 impeller cup 112 blade section 121 shaft 122 bearing 123 stator 124 rotor 211 air intake port 212 air outlet 221, 223 enlarged diameter section 221a, 223a non-machined surface 222 same diameter section 222a cutting marks 1231 Stator core 1232 Insulator 1233 Coil 1241 Rotor yoke 1242 Magnet J Central axis

Claims

1. A blower comprising: a fan section having an impeller rotating around a central axis; and a housing section accommodating the fan section, wherein the housing section has a cylindrical wall section extending along the central axis and covering the impeller from the radially outside, the impeller having a plurality of blade sections arranged in the circumferential direction, and cutting marks are formed on at least a part of an inner surface of the cylindrical wall section radially facing the blade sections or on the radially outer end sections of the blade sections.

2. The blower device according to claim 1, wherein the housing portion and the impeller are molded parts, have non-machined surfaces free of cutting marks, and the cutting marks have a smaller surface roughness than the non-machined surfaces.

3. A blower device as described in claim 1 or claim 2, wherein the cutting marks are located at the radially inner end on the inner circumferential surface of the cylindrical wall portion.

4. A blower device as described in claim 1 or claim 2, wherein the cutting marks extend circumferentially over the entire inner surface of the cylindrical wall portion.

5. A blower device as described in claim 1 or claim 2, wherein the cutting marks are formed on the radially outer ends of all of the blade portions.

6. The blower device described in claim 2, wherein the cylindrical wall portion has a constant diameter portion extending in the axial direction with a constant inner diameter, and expanded diameter portions arranged adjacent to both sides of the constant diameter portion in the axial direction and having an inner diameter that increases with increasing distance from the constant diameter portion in the axial direction, the cutting marks being located on the inner surface of the constant diameter portion, and the non-machined surface being located on the inner surface of the expanded diameter portion.

7. A manufacturing method for a blower including a fan section having an impeller that rotates about a central axis, and a housing section having a cylindrical wall section that houses the fan section and covers the impeller from the radial outside, the manufacturing method for a blower comprising, in order, a die molding step for molding the housing section with a die, and a cutting step for cutting the inner circumferential surface of the cylindrical wall section, wherein in the cutting step, a cutting blade inserted inside the cylindrical wall section is rotated about the central axis to cut the inner circumferential surface of the cylindrical wall section.

8. A method for manufacturing a blower, further comprising a conveying step of conveying the housing portion molded in the die molding step, and inserting the cutting blade into the inside of the cylindrical wall portion.

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