Centrifugal Blower

Abstract

To provide a centrifugal blower capable of easily insulating a common line connection part from other member, as well as, capable of securely maintaining the insulation state of the common line connection part.SOLUTION: A centrifugal blower is a centrifugal blower housing an impeller, a motor for rotating an impeller and a circuit board 144 for controlling driving of the motor inside a lower casing. The motor is arranged on one end part side in an axial direction of the circuit board 144, and an end cap 160 is provided on the other end part side in the axial direction of the circuit board 144. The end cap 160 includes: an inside annular part 162 extending in the axial direction; and pocket parts 163 projecting radially inward from an inner-peripheral surface of the inside annular part 162. The motor is a three-phase brushless motor and includes common line connection parts 143a with a three-phase coil wound in a star connection. The common line connection parts 143a project toward the other end part side in the axial direction from the circuit board 144 and are housed respectively in the pocket parts 163 of the end cap 160.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a centrifugal blower that can easily insulate a common wire connection portion in a motor that rotates an impeller. [Background technology]

[0002] Centrifugal fans are widely used for blowing, ventilating, cooling, etc. in home appliances, office equipment, and industrial and vehicle air conditioners (see, for example, Patent Document 1). As shown in Fig. 10, the centrifugal fan disclosed in Patent Document 1 includes a casing 10, inside which are housed an impeller 20 with a plurality of blades 21 and a motor 30 that rotates the impeller 20.

[0003] Here, a three-phase brushless motor may be used as the motor 30. Known methods for connecting the coils of a brushless motor are delta connection and star connection (Y connection), and when the coils of the U-phase, V-phase, and W-phase of a three-phase brushless motor are star-connected, the coils are connected by a common wire that serves as the neutral point, and this common wire must be insulated from other components.

[0004] In order to insulate the common wire from other components, an insulating tube is generally placed over the joint of the common wire, but for example, Patent Document 2 proposes a method that does not use an insulating tube. Figures 11 and 12 show a brushless motor having such a common wire joint, in which a common wire joint fixing groove 6D is formed in an insulating wall portion 6C formed integrally with an insulating cover 2B, and the common wire joint 4 is fixed by being pressed into the common wire joint fixing groove 6D. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-016152 A [Patent Document 2] Japanese Patent Application Publication No. 4-317534 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when the brushless motor described in Patent Document 2 is used as the motor of the centrifugal blower described in Patent Document 1, it is necessary to bend the common wire coupling portion 4 multiple times in order to press the common wire coupling portion 4 into the common wire coupling portion fixing groove 6D. Also, if the common wire coupling portion 4 is not pressed sufficiently into the common wire coupling portion fixing groove 6D, the common wire coupling portion 4 may protrude from the common wire coupling portion fixing groove 6D in the axial direction, and insulation from other members may not be ensured.

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide a centrifugal blower which not only does not require covering the common wire coupling part in the motor for rotating the impeller with an insulating tube, but also can easily insulate the common wire coupling part from other components and reliably maintain the insulated state of the common wire coupling part. [Means for solving the problem]

[0008] The present invention relates to a centrifugal blower that houses an impeller inside a casing, a motor for rotating the impeller, and a circuit board having a circuit for controlling and driving the motor, the motor being disposed on one axial end side of the circuit board, and an end cap being provided on the other axial end side of the circuit board, the end cap having an annular portion extending in the axial direction and a cylindrical portion protruding radially inward from an inner circumferential surface of the annular portion, the motor being a three-phase brushless motor having a stator, the stator having a three-phase coil wound in a star connection and a common line coupling portion, the common line coupling portion being connected to the circuit board, Through protruding toward the other axial end death, A centrifugal blower is housed in the cylindrical portion of the end cap.

[0009] According to the present invention, since the common line coupling portion protrudes from the circuit board toward the other axial end side and is housed in the cylindrical portion of the end cap, the common line coupling portion can be insulated from other members simply by inserting the common line coupling portion into the cylindrical portion, improving workability. Therefore, the common line coupling portion can be easily insulated from other members. In addition, since the common line coupling portion is surrounded by the cylindrical portion, the insulated state can be reliably maintained.

[0010] Here, the orientation of the cylindrical portion is arbitrary, but it is preferable that the cylindrical portion extends in the axial direction. In this embodiment, the common line coupling portion drawn from the coil can be inserted into the cylindrical portion by moving it in the axial direction relative to the cylindrical portion without bending it, thereby further improving workability.

[0011] The casing may have an upper casing and a lower casing, and the end cap may be attached to the lower casing. In this case, a flange protruding radially outward may be formed on the edge of the end cap, and a boss of the lower casing may be inserted into a through hole formed in the flange and then crimped to fix the end cap to the lower casing. Effect of the Invention

[0012] According to the present invention, a centrifugal blower is provided which not only does not require covering the common wire connection part of the motor for rotating the impeller with an insulating tube, but also makes it possible to easily insulate the common wire connection part from other components and reliably maintain the insulation state of the common wire. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2A is a rear view of a centrifugal blower according to an embodiment of the present invention, and FIG. 2B is an enlarged view of a portion indicated by arrow B in FIG. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 3 is an enlarged view of a main part of FIG. 2. [Figure 4] FIG. 4 is an enlarged view of a portion indicated by an arrow IV in FIG. [Diagram 5] FIG. 2 is a perspective view showing a lower casing of the embodiment. [Figure 6] FIG. 6 is an enlarged view of a portion indicated by an arrow VI in FIG. 5. [Figure 7] 6A is an enlarged view of a portion indicated by arrow VII in FIG. 5, and FIG. 6B is a cross-sectional view taken along line BB in FIG. [Figure 8] FIG. 2 is a perspective view showing an end cap in the embodiment. [Figure 9] FIG. 4 is a back view showing the end cap in the embodiment. [Figure 10] FIG. 1 is a cross-sectional view showing a conventional centrifugal fan (Patent Document 1). [Figure 11] FIG. 1 is a perspective view showing a stator of a conventional brushless motor (Patent Document 2). [Figure 12] FIG. 12 is a perspective view showing a main part of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] 1. Configuration of centrifugal blower Fig. 1 is a rear view of a centrifugal blower 100 of the first embodiment, Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1, and Fig. 3 is an enlarged view of a main part of Fig. 2. The centrifugal blower 100 includes an impeller 120 that includes an inner space on the axial center side and a plurality of blades 121 arranged in an annular portion around the inner space and that rotates to exhaust air in a centrifugal direction from the inner space through the plurality of blades 121, a spiral-shaped casing 110 that houses the impeller 120 inside in a freely rotatable state, and an intake port 114 that is an opening provided at a position facing the inner space of the impeller 120 and that introduces air into the inner space of the impeller 120.

[0015] The centrifugal blower 100 includes a casing 110. As shown in FIG. 2, the casing 110 includes an upper casing 111 molded from resin and a lower casing 112 molded from resin. As shown in FIG. 5, claws 112a protruding radially outward are formed at equal intervals in the circumferential direction on the lower edge of the outer periphery of the lower casing 112. On the other hand, as shown in FIG. 1, a rectangular frame-shaped engagement portion 111a is formed on the outer periphery of the upper casing 111, and the claws 112a are inserted into and engaged with the engagement portion 111a, thereby joining the upper casing 111 and the lower casing 112. As shown in FIG. 2, an impeller 120 having a plurality of blades 121 is rotatably housed inside the casing 110.

[0016] In this embodiment, since the main components are included in the lower casing 112, the lower casing 112 is shown upside down in Fig. 2 and Fig. 3. Therefore, in the following description, terms indicating directions such as "upper" and "lower" are used to indicate the directions in Fig. 2 and Fig. 3.

[0017] A spiral flow passage 113 (see FIG. 2) is formed inside the casing 110. The flow passage 113 has a structure in which the cross-sectional area gradually increases from the start point where the gap between the impeller 120 and the casing 110 is smallest, moving in the clockwise circumferential direction from there. An outlet 115 is formed at the end of the flow passage 113. That is, the spiral flow passage 113 has a structure in which the cross-sectional area gradually increases toward the outlet 115.

[0018] The upper casing 111 has a suction port 114 that opens in the axial direction. Here, the axis refers to the shaft 151 of the impeller 120, and the axial direction refers to the direction in which it extends. The lower casing 112 has fixing legs 116 for mounting and fixing to another device or housing, and is also equipped with a motor 130 (see FIG. 2) for rotating the impeller 120. In FIG. 1(A), reference numeral 116a denotes a metallic collar.

[0019] As shown in Fig. 2, impeller 120 is fixed to shaft 151 of motor 130, and when motor 130 rotates, impeller 120 rotates. When impeller 120 rotates, air is sucked in from suction port 114 and guided to the inside of impeller 120 (internal space on the axial center side). This air is blown out in the centrifugal direction from the inside of impeller 120 by the action of blades 121. The air blown out from impeller 120 flows through spiral flow passage 113 toward discharge port 115 in Fig. 1, and is exhausted from discharge port 115.

[0020] Impeller 120 has a cup-shaped hub 122 that forms the top surface, a plurality of blades 121 arranged in an axially upright state on the outer annular portion of hub 122, and an annular connecting ring 123 that connects the ends of the plurality of blades 121 opposite to hub 122. All of the blades 121 have the same shape, have a forward-facing blade shape that is concave with respect to the rotation direction of impeller 120, and are evenly arranged in the circumferential direction. An inner space is provided inside the plurality of blades 121 (toward the center of the shaft), and when impeller 120 rotates, air is blown out from this inner space in the centrifugal direction through the blades 121.

[0021] 3, the hub 122 has a boss portion 124 at its center that protrudes downward in a convex shape, and a through hole 124a is formed in the boss portion 124. A cylindrical metallic (e.g., brass) bush 125 is fixed to the inner periphery of the through hole 124a by insert molding, and a shaft 151 of the motor 130 is press-fitted into the bush 125, thereby connecting the impeller 120 to the shaft 151. The shaft 151 is the rotating shaft of the motor 130, and by connecting with the impeller 120, it also serves as the rotating shaft of the impeller 120. The hub 122, the plurality of blades 121, and the connecting ring 123 are integrally formed of resin.

[0022] 2.Motor configuration The motor 130 is an inner rotor type three-phase brushless motor, and includes a cup-shaped housing 131 made of a magnetic metal material. A stator 140 is disposed on the inner circumferential surface of the housing 131. The stator 140 includes a stator core 141 formed by laminating a predetermined number of cores made of electromagnetic steel sheets, an insulator 142 attached to the stator core 141, a coil 143 wound around the stator core 141 via the insulator 142, and a circuit board 144 disposed above the insulator 142. The stator core 141 has a plurality of teeth extending radially inward from a ring-shaped core back portion, and three-phase (U-phase, V-phase, W-phase) coils 143 are wound around the teeth in a star connection (Y-connection) via the insulator 142.

[0023] A rotor 150 is disposed inside the stator core 141. The rotor 150 includes a metallic shaft 151, a cup-shaped rotor yoke 152 coupled to the upper end of the shaft 151, and a ring-shaped rotor magnet 153 fixed to the outer circumferential surface of the rotor yoke 152. A boss portion 152a is formed in the center of the rotor yoke 152, which is made of a magnetic metallic material, for example, by burring, and the shaft 151 and the rotor yoke 152 are coupled to each other by pressing the shaft 151 into the boss portion 152a.

[0024] A boss portion 131a is formed in the center of the housing 131, and a metal (e.g., brass) bearing holder 132 is press-fitted into the boss portion 131a. A pair of ball bearings 133 are attached to the bearing holder 132, and the shaft 151 is rotatably supported by the pair of ball bearings 133. A compression coil spring 134 is interposed between the pair of ball bearings 133, and applies a preload to the ball bearings 133 by biasing them against the outer rings of the ball bearings 133.

[0025] 4, a plurality of flanges 131b extending radially outward are formed at equal intervals in the circumferential direction on the periphery of the opening of the housing 131. A long through hole 131c is formed in each flange 131b along the circumferential direction. The through hole 131c is used for joining to the lower casing 112 described later.

[0026] 3, a circuit board 144 mounting a circuit for controlling the driving of the motor 130 is disposed axially above the stator core 141. Terminals of the coils of the U-phase, V-phase, and W-phase wound around the stator core 141 are inserted into through holes (not shown) that are connected to wiring patterns formed on the mounting surface of the circuit board 144 and connected by solder 145 (see FIG. 5).

[0027] 5 is the mounting surface of the circuit board 144. The other terminals of the U-phase, V-phase, and W-phase coils 143 are bundled, twisted, and soldered together to form a common line coupling portion 143a (see FIG. 7).

[0028] 3. End cap configuration A resin end cap 160 is attached to the axially upper side of the housing 131. Figures 7 and 8 are views showing the end cap 160. The end cap 160 includes an outer annular portion 161 and an inner annular portion 162 disposed inside the outer annular portion 161 with a gap 161a therebetween. A pocket portion 163 that protrudes radially inward is formed on the inner circumferential surface of the inner annular portion 162.

[0029] As shown in Fig. 7 and Fig. 9, the pocket portion 163 is a cylinder with both ends open and a cross-sectional shape of a substantially semicircular arc. Fig. 9 is a rear view of the end cap 160. As shown in Fig. 7(B), a substantially semicircular notch 144a is formed in the outer periphery of the circuit board 144 to match the shape of the pocket portion 163, and the lower end of the pocket portion 163 is accommodated in the notch 144a. The common coupling portion 143a of the coil of each phase protrudes in the axial direction from the notch 144a of the circuit board 144 and is inserted into the pocket portion 163. The tips of the coil terminals are soldered to each other at the common coupling portion 143a.

[0030] As shown in Fig. 8, a plurality of (four in this example) flanges 164 protruding radially outward are formed at equal intervals in the circumferential direction on the outer peripheral surface of the outer annular portion 161 of the end cap 160, and a long through hole 164a is formed in the flanges 164 along the circumferential direction. In addition, a plurality of (five in this example) frames 165 protruding radially outward are formed on the outer peripheral surface of the outer annular portion 161 of the end cap 160. The frames 165 are rectangular in plan view and penetrate in the axial direction. The frames 165 are used to attach a cover 170, which will be described later.

[0031] A connector housing 166 is formed integrally with the end cap 160. A connector pin 167 is formed integrally with the connector housing 166 by insert molding. The connector pin 167 is crank-shaped, and one end of the connector pin 167 is passed through a through hole (not shown) formed in the circuit board 144 and solder-joined on the opposite mounting surface (the back surface of the circuit board 144 in FIG. 7(A)). The other end of the connector pin 167 protrudes into the internal space of the connector housing 166 and is connected to a socket inserted into the connector housing 166.

[0032] A plurality of connection terminals 168 (two in this example) are formed integrally with end cap 160 at the position of flange portion 164 by insert molding. Connection terminal 168 is L-shaped, and one end (see FIG. 8) having an angular cross section is passed through a through hole (not shown) formed in circuit board 144 and solder-joined on the opposite mounting surface. The through hole is connected to a GND pattern (solid pattern) formed on circuit board 144.

[0033] 4, the other end of connection terminal 168 is exposed on the lower surface of flange portion 164 of end cap 160, and is sandwiched between the lower surface of flange portion 164 and the upper surface of flange portion 131b of housing 131. As a result, the GND pattern of circuit board 144 is set to the reference potential (for example, zero volts).

[0034] Here, the mounting structure of the end cap 160 will be described with reference to Fig. 4. As shown in Fig. 4, the lower casing 112 is formed with a boss portion 112b that protrudes upward in the figure. The boss portion 112b penetrates through a through hole 131c formed in the flange portion 131b of the housing 131 and through a through hole 164a formed in the flange portion 164 of the end cap 160 and protrudes upward, and has an upper end portion that is thermally caulked to form a head portion 112c that presses against the flange portion 164. With this configuration, the end cap 160 is joined to the lower casing 112.

[0035] A resin cover 170 is attached to the end cap 160 to prevent dust, foreign matter, etc. from entering the inside of the motor 130. The cover 170 is substantially circular and cup-shaped, and its peripheral portion 171 extends in the axial direction. The end of the peripheral portion 171 is a tapered portion 171a whose thickness gradually decreases downward.

[0036] The cover 170 is detachably attached to the end cap 160 by pushing the tapered portion 171a into the gap 161a between the outer annular portions 161 of the end cap 160. In addition, a plurality of (five in this example) protrusions 172 protruding radially outward are formed on the outer circumferential surface of the peripheral portion 171 of the cover 170 (see FIG. 1). The protrusions 172 fit into a frame 165 formed on the end cap 160 to prevent the cover 170 from rotating.

[0037] 4.How to assemble a centrifugal blower i) Bonding the circuit board and end cap 8 are inserted into through holes from the mounting surface side of circuit board 144, and the tips of each connector pin 167 protruding from the opposite mounting surface of circuit board 144 are connected with solder. Also, the angular lower end of connection terminal 168 is inserted into a through hole formed in circuit board 144 and connected to the GND pattern, and the tip of the connection terminal protruding from the opposite mounting surface of circuit board 144 is connected with solder. This joins end cap 160 and circuit board 144.

[0038] ii) Connection between the motor and the circuit board The terminals of the U-phase, V-phase, and W-phase of the three-phase coil wound around the stator 140 of the motor 130 are bundled and twisted together to form the common line coupling portion 143a. These common line coupling portions 143a are soldered together and cut to a predetermined length. The soldered common line coupling portions 143a are bent so as to be parallel to the axial direction and made to stand upright. The terminals of the coils of each phase are also bent so as to be parallel to the axial direction and made to stand upright.

[0039] The terminals of the U-phase, V-phase, and W-phase are inserted into the predetermined through holes from the opposite mounting surface of the circuit board 144, and the common line coupling portion 143a is accommodated in a pocket portion 163 formed on the inner peripheral surface of the end cap 160 by protruding from a notch 144a formed on the outer peripheral edge of the circuit board 144 to the mounting surface side. The above operation is performed by bringing the end cap 160 to which the circuit board 144 is coupled and the housing 131 of the motor 130 close to each other. Then, the tips of the terminals of the U-phase, V-phase, and W-phase protruding to the mounting surface side are connected with solder 145 (see FIGS. 5 and 7). As a result, the connection terminal 168 insert-formed in the end cap 160 abuts against the flange portion 131b of the housing 131 of the motor 130.

[0040] iii) Connection between the motor and the lower casing The motor 130 to which the end cap 160 and the circuit board 144 are coupled is inserted from above into the upper opening of the lower casing 112. At this time, the boss portion 112b formed around the opening of the lower casing 112 is inserted into the through hole 131c formed in the flange portion 131b of the housing 131 of the motor 130 and the through hole 164a formed in the flange portion 164 of the end cap 160.

[0041] Then, the tip of boss portion 112b protruding from through hole 164a of flange portion 164 of end cap 160 is heated and expanded to plastically deform, thereby forming head portion 112c. By forming head portion 112c in this manner, connection terminal 168 is sandwiched between end cap 160 and flange portion 131b of housing 131 of motor 130, and abuts against flange portion 131b of housing 131 of motor 130 for close contact.

[0042] iv) Impeller to motor coupling The impeller 120 is inserted into the lower opening of the lower casing 112 , and the lower end of the shaft 151 is press-fitted into the block 125 of the impeller 120 .

[0043] V) Other The tapered portion 171a of the peripheral portion 171 of the cover 170 is press-fitted into the gap 161a between the outer annular portion 161 and the inner annular portion 162 of the end cap 160, and the cover 170 is attached to the end cap 160. Also, the claw portions 112a of the lower casing 112 are inserted into and engaged with the engaging portions 111a of the upper casing 111, and the upper casing 111 and the lower casing 112 are joined together.

[0044] 5.Effects According to the centrifugal blower 100 having the above-mentioned configuration, the common line coupling portion 143a protrudes axially upward from the circuit board 144 and is housed in the pocket portion 163 of the end cap 160. This not only eliminates the need to cover the common line coupling portion 143a with a tube, but also makes it possible to insulate the common line coupling portion 143a from other members simply by inserting the common line coupling portion 143a into the pocket portion 163, thereby improving workability. This makes it possible to easily insulate the common line coupling portion 143a from other members. Furthermore, since the periphery of the common line coupling portion 143a is surrounded by the pocket portion 163, the insulated state can be reliably maintained.

[0045] In particular, in the above embodiment, since the pocket portion 163 extends in the axial direction, the common line coupling portion 143a can be extended in the axial direction without being bent, and the common line coupling portion 143a can be moved in the axial direction relative to the pocket portion 163 and inserted into the pocket portion 163, thereby further improving workability.

[0046] 6.Example of changes The present invention is not limited to the above-described embodiment, and various modifications are possible as follows. i) A boss portion protruding downward is formed on the flange portion 164 of the end cap 160, and the boss portion is inserted into a through hole 131c formed in the flange portion 131b of the housing 131 of the motor 130. The tip of the boss portion protruding from the through hole 131c is heated and plastically deformed, thereby allowing the boss portion to be crimped and fixed. ii) The flange portion 131b of the housing 131 can be press-fitted into the inner circumferential surface of the end cap 160. iii) The pocket portion 163 may be inclined or perpendicular to the axial direction. iv) The upper opening of the pocket portion 163 can be closed with a lid. [Industrial Applicability]

[0047] INDUSTRIAL APPLICABILITY The present invention can be used in centrifugal fans used for blowing, ventilating, cooling, etc. in home electric appliances, office automation equipment, and industrial and vehicle air conditioners. [Explanation of symbols]

[0048] 100... centrifugal blower, 110... casing, 111... upper casing, 111a... engagement portion, 112... lower casing, 112a... claw portion, 112b... boss portion, 112c... head portion, 113... flow path, 114... suction port, 115... discharge port, 116... fixed leg, 116a... collar, 120... impeller, 121... blade, 122... hub, 123... connecting ring, 124... boss portion, 124a... through hole, 125... bush, 130... motor, 131... housing, 131a... boss portion, 131b... flange portion, 131c... through hole, 132... bearing holder, 133... ball bearing, 134... compression coil spring, 140... stator, 141...stator core, 142...insulator, 143...coil, 143a...common line coupling portion, 144...circuit board, 144a...notch, 145...solder, 150...rotor, 152...rotor yoke, 152a...boss portion, 153...rotor magnet, 151...shaft, 160...end cap, 161...outer annular portion, 161a...gap, 162...inner annular portion, 163...pocket portion (cylindrical portion), 164...flange portion, 164a...through hole, 165...frame, 166...connector housing, 167...connector pin, 168...connection terminal, 170...cover, 171...periphery, 171a...tapered portion, 172...protrusion.

Claims

1. A centrifugal blower that houses an impeller inside a casing, a motor for rotating the impeller, and a circuit board having a circuit mounted thereon for controlling and driving the motor, The motor is disposed on one axial end side of the circuit board, and an end cap is provided on the other axial end side of the circuit board, The end cap includes an annular portion extending in an axial direction and a cylindrical portion protruding radially inward from an inner circumferential surface of the annular portion, The motor is a three-phase brushless motor having a stator, and the stator has three-phase coils wound in a star connection and a common line coupling portion; The common line coupling portion penetrates the circuit board, protrudes toward the other axial end, and is accommodated in the cylindrical portion of the end cap.

2. 2. The centrifugal blower according to claim 1, wherein the cylindrical portion extends in an axial direction, and the common line coupling portion is housed in the cylindrical portion so as to extend in the axial direction.

3. The casing has an upper casing and a lower casing, 3. The centrifugal blower according to claim 1, wherein the end cap is attached to the lower casing.

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