Electric blower and method for constructing the same

Abstract

An electric blower includes a fan section having a fan, a motor section, mechanically connected to the fan to generate airflow, which includes a stator that a plurality of windings are respectively wound, a flame section, configured to support the fan section and the motor section, which has a plurality of airflow opening portions constituting part of an airflow pass from the fan section to the motor section and a drive-control circuit board, located between the fan section and the motor section, which has a drive-control circuit for controlling current supplied to the plurality of windings and further has a plurality of connection terminals each of which has a through hole. To easily connect the end portions of the plurality of windings with the connection terminals of the circuit board respectively, each end portion of the plurality of windings is projected through each through hole of the plurality of connection terminals respectively and the plurality of connection terminals are exposed to the plurality of airflow opening portions of the flame section.

Description

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates, in general, to an electric blower and, in particular, to an electric blower in which a drive-control circuit board is included.

(2) Description of the Related Art

In an electric blower in which a drive-control circuit board is included, it is necessary to keep a space at which a winding treatment of stator windings is carried out when assembling the blower. In particular, if a diameter of the windings is relatively large, connection of the windings to the circuit board may be troublesome. However, such circumstances have not been considered in the past.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to realize a structure of an electric blower which enables to easily carry out connection between the stator windings and the circuit board when assembling the blower.

To accomplish the above-described object, an electric blower of the present invention comprises a fan section having a fan, a motor section, configured to drive the fan to generate airflow, which includes a stator that a plurality of windings are respectively wound, a flame section, configured to support the fan section and the motor section, which has a plurality of airflow opening portions constituting airflow pass from the fan section to the motor section and a drive-control circuit board, located between the fan section and the motor section, which has a drive-control circuit for controlling current supplied to the plurality of windings and further has a plurality of connection terminals each of which has a through hole, wherein end portions of the plurality of windings are electrically connected with the corresponding connection terminals respectively in a state that each end portion of the plurality of windings is projected through each through hole of the plurality of connection terminals respectively and, the drive-control circuit board is supported by the flame section in a state that the plurality of connection terminals are exposed to the plurality of airflow opening portions of the flame section.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and advantages of this invention will become apparent and more readily appreciated from the following detailed description of the presently preferred exemplary embodiments of the invention taken in conjunction with the accompanying drawings wherein:

FIG. 1 is an exploded perspective view illustrating an electric blower according to a first embodiment of the present invention;

FIG. 2 is a side view illustrating the electric blower, in partly broken, shown in FIG. 1;

FIG. 3a is a plan view illustrating a flame used in the first embodiment;

FIG. 3b is a side view illustrating the flame, in partly broken, shown in FIG. 3a;

FIG. 4 is a plan view illustrating a drive-control circuit board used in the first embodiment;

FIG. 5 is a circuit diagram illustrating a drive-control circuit used in the first embodiment;

FIG. 6a is a plan view illustrating the flame with the drive-control circuit board shown in FIGS. 3a and 4;

FIG. 6b is a plan view illustrating the other side of the flame shown in FIG. 6a;

FIG. 7 is a perspective view illustrating a fixing metal plate used in the first embodiment;

FIG. 8 is a side view illustrating the electric blower, in partly broken, according to a second embodiment; and

FIG. 9 is a plan view illustrating a flame with a drive-control circuit board used in the second embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described in more detail with reference to the accompanying drawings. However, the same numerals are applied to the similar elements in the drawings, and therefore, the detailed descriptions thereof are not repeated.

One embodiment of the present invention will be described with reference to FIGS. 1 through 6.

As shown in FIGS. 1 and 2, an electric blower 1 of one embodiment includes a fan section 3, a motor section 5, and a flame section 7. The fan section 3 includes a fan 311 for generating airflow and a fan cover 312 that the fan 311 is housed. The motor section 5 includes a motor 511, a motor support 512 for supporting the motor 511. The fan section 3 and the motor section 5 both are assembled to the flame section 7. The flame section 7 includes a flame 711. As shown in FIG. 3a, the flame 711 includes a circular flame portion 712 and a crisscross-shaped rib portion 713 extending to the circular flame portion 712 to create a plurality of airflow opening portions 714. A drive-control circuit board 9 for driving the motor 511 is also assembled to the flame section 7.

In this embodiment, a three-phase blushless DC motor that is driven by an inverter circuit is used, as the motor 511. As is well known, a position detection unit for detecting the position of a rotor of the motor is provided. The position detection unit includes a sensor magnet mounted on the rotor and a position detection element, e.g., a hall element, for electro-magnetically detecting the sensor magnet. A detail construction of the position detection unit will be described later.

As shown in FIG. 2, a stator 513 and a rotor 514 fixed to a rotational shaft 516 of the motor 511 are housed in the motor support 512 such that the rotor 514 is located inside the stator 513. The rotor 514 is formed with a plurality of Si-metal plates (rotor core) which are piled up one another and a plurality of permanent magnets which are separately buried in the rotor. As being similar to the rotor 514, the stator 513 is formed with a plurality of Si-metal plates. The stator 513 includes windings 515 wound around a bobbin (not shown). As shown in FIG. 5, a plurality of windings 515a, 515b and 515c form a U-phase, a V-phase and a W-phase with a Y connection. Respective one ends of windings 515 are commonly connected to make a neutral point 517 and the other ends 518 (shown in FIG. 1) are treated to extend upwardly (toward the fan section 3) in the inside of the motor support 512.

The motor support 512 has a cylindrical wall and a bottom wall connected to the cylindrical wall so that air from the fan section 3 is taken into the inside of the motor 511 through an upper opening of the support 512. An upper bearing 11 is provided at the flame 711 and a lower bearing 13 is provided at the motor support 512 respectively and each end portion of the rotational shaft 516 of the rotor 514 is rotatably supported by upper and lower bearings 11 and 13. In the center portion of the bottom wall, there is a first cylinder portion 519 that a lower bearing housing 13a is formed to house the lower bearing 13.

In the motor 511, a plurality of sensor magnets 520 which are used to indicate the location of the magnetic pole of the rotor 514 are provided at regular intervals equal to that of magnetic poles of the rotor 514. Thus, on the rotational shaft 516 of the rotor 514, there are the plurality of permanent magnets which are buried in the rotor 514 and the plurality of sensor magnets 520 which are located at intervals equal to pitches of magnetic poles of the plurality of permanent magnets. A hall element 521 is used to detect the location of the magnetic pole of the sensor magnets 520. A sensor circuit board 522 is provided on a sensor circuit board support 523 fixed at the rear plate portion 524 of the motor support 512.

As shown in FIGS. 3a and 3b, the circular flame portion 712 of the flame 711 is formed in a column shape and has a diameter larger than the external diameter of the motor support 512. In addition, the internal diameter of the circular flame portion 712 is slightly larger than the external diameter of the motor support 512 so that the external wall surface of the motor support 512 is fitted into the internal wall surface of the circular flame portion 712. As described above, the flame 711 has a plurality of airflow opening portions 714 (four in FIG. 3a). The circular flame portion 712 has a rear plane surface 715 shown in FIG. 3b on which three step portions 716 are formed at an equally distance in the circular direction. At the center of the flame 711, there is a second cylinder portion 717 which an upper bearing housing 11a and a hole 718 are formed. The upper bearing housing 11a houses the upper bearing 11.

At the upper side of the flame 711, a rectifying plate 313 is fixed to the second cylinder portion 717 of the flame 711, as shown in FIG. 2. The fan 311 is also fixed to the rotational shaft 516. The fan cover 312 is firmly fixed to the outer surface of the circular flame portion 712 of the flame 711 to cover the rectifying plate 313 and the fan 311.

The fan cover 312 is provided with an intake opening 314 facing a fan opening 315 which is formed at the center portion of the fan 311 to take air into the fan 311. In this embodiment, since the external diameter of the fan cover 312 is larger than the external diameter of the motor support 512, a step is created by the fan cover 312 and the motor support 512. This step is connected by the circular flame portion 712 to provide an airflow path.

As shown in FIG. 4, the drive-control circuit board 9 has a plurality of ear portions 911 (three in FIG. 4) each corresponding to the step portion 716 of circular flame portion 712 so that ear portions 911 are housed in the step portions 716 respectively. The board 9 includes a circular base portion 912 which is located in an inner space 719 of the circular flame portion 712 when the ear portions 911 are housed at the step portions 716. The circular base portion 912 forms a center airflow opening 913. Three screw holes 914 are formed in the circular base portion 912 in the circular direction and the drive-control circuit board 9 is fixed to the flame 711 by screws through a spacer 915 shown in FIG. 2 to form a predetermined gap between the flame 711 and the board 9.

The drive-control circuit formed on the drive-control circuit board 9 of the electric blower 1 will be described with reference to FIG. 5.

The blushless DC motor of the electric blower 1 is driven with AC current produced by the inverter circuit 15. The inverter circuit 15 generates AC current from the power source supplied by a DC power source unit 17. Main part of the drive-control circuit includes an electric blower control unit 19 which controls the operation of the blower 1, drive circuits 21a to 21f for controlling the inverter circuit 15 and power devices 23a to 23f, e.g., MOS FET, constituting the inverter circuit 15. The drive-control circuit includes high-voltage side drive circuits 21a to 21c and low-voltage side drive circuits 21d to 21f.

The DC power source unit 17 is constituted with a secondary cell, such as, e.g., nickel-cadmium (NiCd) cell, nickel-hydrogen cell or lithium ion cell, and supplies DC voltage to the inverter circuit 15. The inverter circuit 15 is constituted with six power devices 23a to 23f each connected in a three-phase bridge connection, as shown in FIG. 5. Power devices 23a to 23f are operated by pulse signals output from the electric blower control unit 19 mainly constituted with a micro-computer, and thus, the drive circuits 21a to 21f are driven by the pulse signals to supply AC current to the windings 515a to 515c of the electric blower 1. The DC power source unit 17 may be constructed by a rectifying commercial power source, instead of a secondary cell.

As shown in FIG. 5, the electric blower control unit 19 is connected with an operation unit 25, a current detection element 27 and an input voltage detection element 29. An operator can select a desired operation (start, stop or power control, e.g., strong or weak) of the electric blower 1 by selecting one of the switches in the operation unit 25. The current detection element 27 detects current flowing into the inverter circuit 15 and the input voltage detection element 29 detects the input voltage from the DC power source unit 17. The electric blower control unit 19 is also connected with the hall element 521 to receive magnetic pole location information of the sensor magnet 520. In this embodiment, an optical pulse encoder or other method that voltages induced among the windings 515a, 515b and 515c are detected by a voltage-phase detection means may be utilized as a method for detecting the magnetic pole location, instead of the hall element 521, although such substituting methods are not shown in the drawings. Windings 515a, 515b and 515c form U-phase, V-phase and W-phase and respective one ends, e.g., start side end, of windings 515a, 515b and 515c are commonly connected as neutral point 517 and the other ends, finish side end, are connected to power devices 23a to 23f which are connected in three-phase bridge, as shown in FIG. 5.

An airflow path of the electric blower 1 will be described in more detail with reference to FIG. 2.

When a rotation shaft 516 of the motor 511 rotates, the fan 311 is integrally rotated with the rotation of the shaft 516 to take air from the outside to the inside of blower 1 through the intake opening 314. Air taken into the blower 1 flows through the fan 311 in a centrifugal direction and blows off from a plurality of exhaust openings 316 of the fan 311. The air from the exhaust openings 316 further flows through an opening 317 of a disk shaped rectifying plate 313 and reaches the rear side of the plate 313. The rear side of the plate 313 is provided with a plurality of arc-shaped blades (not shown) extending to the center of the plate 313. The air from the opening 317 spirally flows along the plurality of blades towards the center of the plate 313 so that the air blown off from the exhaust openings 316 uniformly flows along the plate 313. The air rectified by the plate 313 passes a plurality of airflow opening portions 714 provided at the flame section 7 (shown in FIG. 3a) and reaches the motor section 5 through the center airflow opening 913 provided at the center portion of a drive-control circuit board 9 as shown in FIG. 4. The air guided to the motor section 5 cools the motor 511 and then blows off to the outside of the blower 1 through a plurality of openings 526 provided at a lower portion of the motor support 512.

An assembling process of the electric blower 1 will be described with reference to FIG. 1.

The assembling method of the electric blower 1 of the one embodiment includes four major assembling processes. A first assembling process is a construction of the motor section 5 that the stator 513 is fixed inside the motor support 512. A second assembling process is a construction of a rotational part 525 that a rotational element, e.g., rotor 514, etc. is fixed on the rotational shaft 516. A third assembling process is a construction of the flame section 7 that the drive-control circuit board 9 is mounted on the flame 711. A fourth assembling process is a construction of the fan section 3 that the fan 311 and the rectifying plate 313 are assembled. The first to fourth assembling processes will be described in more detail hereinafter.

The first assembling process will be described. As shown in FIG. 2, the sensor circuit board 522 is firstly mounted on the sensor circuit board support 523 and thereafter, the stator 513 on which windings 515a, 515b and 515c are wound is fixed to the inside of the motor support 512 by screws. At this moment, each length of the other ends 518 of the windings 515a, 515b and 515c shown in FIG. 1 is adjusted such that the length of the end is relatively longer than that required in upward direction to enable the assembling operation to be carried out easily.

Next, the rotational part 525 will be assembled. The rotor 514, the sensor magnets 520, a pair of bearings 11 and 13 are assembled to the rotational shaft 516 of the motor 511. The rotor 514 and a yoke (not shown) for housing the sensor magnets 520 are respectively fixed to the rotational shaft 516 and thereafter the sensor magnets 520 are mounted on the yoke. Further, bearings 11 and 13 are respectively inserted to the rotational shaft 516.

The third assembling process will be described. As shown in FIG. 6a, the drive-control circuit board 9 is located in the inner space 719 of the circular flame portion 712 of the flame 711 and ear portions 911 of the board 9 are housed in the step portions 716 respectively. After that, the drive-control circuit board 9 is fixed to the flame 711 through spacers 915 by inserting screws into spacers 915 through screw holes 914 respectively. Spacers 915 keep an airflow pass within the inner space 719 between the circular flame portion 712 and the drive-control circuit board 9. Connection terminals 916a, 916b and 916c are respectively formed between power devices 23 whose pairs are located on the board 9 at 120 degrees. The other ends 518 of windings 515 are respectively connected to corresponding connection terminals 916a, 916b and 916c. FIG. 6b shows the fixed state of the drive-control circuit board 9 to the flame 711 as being indicated from the fan section 3. Connection terminals 916a, 916b and 916c on the board 9 are exposed from airflow opening portions 714 of the flame 711, respectively. Therefore, a person who assembles the blower 1 can see connection terminals 916 through airflow opening portions 714.

After fixing the drive-control circuit board 9 on the flame 711, power devices 23 are assembled to one surface of the board 9 which does not face airflow opening portions 714 of the flame 711 as shown in FIG. 6a.

Next, the motor section 5, the rotational part 525 and the flame section 7 are assembled. Firstly, the upper bearing 11 of the rotational part 525 is housed in the upper bearing housing 11a of the flame 711. At this moment, in the motor section 5, the other end 518 of each windings 515 extends through a through-hole (not shown) provided on the connection terminal 916 and projects from the flame 711 through airflow opening portion 714 of the flame 711. After that, the lower bearing 13 is housed in the lower bearing housing 13a of the motor support 512. Then, the motor section 5 and the flame section 7 are firmly fixed as a one piece by screws.

41 Furthermore, the other ends 518 of the windings 515a, 515b and 515c respectively projecting from the through-holes of connection terminals 916a, 916b and 916c are electrically connected to corresponding terminals 916a, 916b and 916c. The other ends 518 (three in FIG. 1) is adjusted such that its length and tension are controlled as the operator observes his or her operation from airflow opening portions 714 of the flame 711 and then the other ends 518 are electrically and mechanically connected to connection terminals 916a, 916b and 916c with a solder, respectively. After that, a protruding portion of each end 518 is cut to complete the connection.

As described above, after the drive-control circuit board 9 is fixed on the flame 711, the other end 518 of each winding 515 is projected through the corresponding through-hole of the connection terminal 916 and is electrically connected to the terminal 916. If a specification in which a large current flows through the windings 515 of the stator 513 is applied, windings whose diameter is relatively large are necessitated and thus assemble of above-described sections and connection of such windings with terminals are rather troublesome. However, in this embodiment described above, it is easy to carry out the connection between the other end 518 of winding 515 and the corresponding connection terminal 916 such that the connection process is carried out after the drive-control circuit board 9 is fixed on the flame 711 and then the other end 518 is inserted into the through hole of the connection terminal 916. In addition, the connection process is also carried out easily. This is because that connection terminals 916a, 916b and 916c on the board 9 are exposed from airflow opening portions 714 of the flame 711, respectively and thus, he or she who carries out the connection operation can observe the connection work through the airflow opening portions 714.

At last, the fan section 3 is assembled after the motor section 5, the rotational part 525 and the flame section 7 are integrally assembled, as described above.

The rectifying plate 313 is fixed on the flame 711 of the flame section 7 by screws. The fan 311 is firmly attached to the rotational shaft 516 of the motor 511. After that, the fan cover 312 is firmly fixed to the outer side surface of the rectifying plate 313 to complete assembling processes of the electric blower 1 such that the rectifying plate 313 and the fan 311 are covered by the fan cover 312, as shown in FIG. 2.

According to the above-described assembling processes, since the through holes that the other ends 518 of windings 515 are respectively inserted are provided on the drive-control circuit board 9, each connection path of the other end of winding between the motor 511 and the drive-control circuit board 9 can be shortened.

In the above-described embodiment, the electrical connection between the other ends 518 of windings 515 and the connection terminals 916 of the circuit board 9 is carried out with a solder. However, other method can be used. As shown in FIG. 7, a fixing metal plate 917 that has a notched portion 917a at its one side is used. The fixing metal plate 917 is provided on the connection terminal 916 beforehand. The other end 518 of the winding 515 is projected through the hole 918 on the drive-control circuit board 9 and then is fixed at the notched portion 917a of the plate 917.

A second embodiment of the present invention will be described below. In FIGS. 8 and 9, the same numerals are applied to elements in the second embodiment similar to elements in the first embodiment, and therefore, the detailed descriptions thereof are not repeated.

FIG. 8 is a side view in partially broken of an electric blower of the second embodiment. FIG. 9 is a plan view illustrating an example of internal construction of a part of the electric blower.

In this embodiment, power devices 23′a, 23′b, 23′c, 23′d, 23′e and 23′f each having a main body and three terminals are used instead of power devices 23a, 23b, 23c 23d, 23e and 23f shown in FIG. 6a. When such power device 23′ is assembled, the main body of the power device 23′ is fixed on the surface of the circular flame portion 712 of the flame 711 by screws. After the ear portions 911 of the drive-control circuit board 9 are housed in the step portions 716 of the circular flame portion 712, respectively, power devices 23′ are fixed on the circular flame portion 712 so as to position terminals of each power device 23′ at respective connection terminals (not shown) provided on the board 9. Then each terminals of the power device is electrically and mechanically connected to respective connection terminals with a solder.

In the above-described second embodiment, each terminal of power devices 23′ is connected to the drive-control circuit board 9 with a solder after power devices 23′ are mechanically fixed on the flame 711. Therefore, a mechanical stress is not applied to terminals of power devices 23′. In addition, since each power device 23′ is directly fixed on the flame 711, a heat radiation from power devices 23′ can be increased and since each power device 23′ does not adversely affect airflow within the blower 1, it can minimize a loss of airflow pass.

The present invention has been described with respect to specific embodiments. However, other embodiments based on the principles of the present invention should be obvious to those skill in the art. Such embodiments are intended to be covered by the claims.

Claims

1. An electric blower comprising:

a fan section having a fan;

a motor section configured to drive the fan to generate airflow, the motor section including a stator that a plurality of windings are respectively wound;

a flame section configured to support the fan section and the motor section, the flame section having a plurality of airflow opening portions which constitute an airflow pass from the fan section to the motor section; and

a drive-control circuit board located between the fan section and the motor section, the circuit board having a drive-control circuit for controlling current supplied to the plurality of windings, the circuit board further having a plurality of connection terminals each of which has a through hole;

wherein end portions of the plurality of windings are electrically connected with the corresponding connection terminals respectively in a state that each end portion of the plurality of windings is projected through each through hole of the plurality of connection terminals respectively and, the drive-control circuit board is supported by the flame section in a state that the plurality of connection terminals are exposed to the plurality of airflow opening portions of the flame section.

2. A blower according to claim 1, wherein the flame section has a circular flame portion and the drive-control circuit of the drive-control circuit board includes a plurality of power devices each having a main body and a terminal for switching the current supplied to the plurality of windings, the main body of each power device being fixed on the circular flame portion and the terminals of the plurality of power devices being electrically connected to the corresponding connection terminals of the drive-control circuit board.

3. A method for assembling an electric blower which comprises a fan section, a motor section having a stator that a plurality of windings are respectively wound and a flame section having a flame and a drive-control circuit board, including the steps of

supporting the drive-control circuit board by the flame in a state that a plurality of connection terminals provided on the drive-control circuit board are exposed to a plurality of airflow opening portions of the flame section;

projecting each end portion of the plurality of windings through each through hole which is formed on each connection terminal of the circuit board;

fixing the motor section on the flame section; and

electrically connecting each end portion of the plurality of windings with each connection terminal of the circuit board, respectively.

4. A method according to claim 3, wherein the drive-control circuit board includes a plurality of power devices each having a main body and an electrical terminal, the method further including the steps of:

fixing the main body of each power device on the flame of the flame section; and

electrically connecting each electrical terminal of power devices with each connection terminal of the drive-control circuit board after each main body of power devices is fixed on the flame.