JP5274539B2 - Electric motor and blower - Google Patents

Description

  The present invention relates to an electric motor using an inverter and a blower that blows air.

  Many blower motors have built-in inverters from the viewpoint of structural convenience. When a motor is driven by an inverter, it is known that a voltage is induced between the shaft ends of the motor or between the winding and the stator core as the inverter is switched. When the bearing structure is a ball bearing, the voltage is applied between the inner and outer rings of the bearing, causing electric discharge inside, which may cause a problem called electrolytic corrosion. For this reason, various structural measures for preventing this electric corrosion have been proposed for inverter-driven motors.

  Conventionally, an outer ring of two ball bearings mounted on a motor is electrically connected so that a voltage generated between a winding of a shaft and a stator core is not transmitted to the ball bearing (for example, a patent) Reference 1).

  In addition, an insulating sleeve is interposed between an outer ring and a shaft of a ball bearing mounted on a motor, thereby reducing the induced voltage between the inner and outer rings of the ball bearing and suppressing electrolytic corrosion (for example, patents). Reference 2).

  Furthermore, the thing which suppresses generation | occurrence | production of electrolytic corrosion by comprising the ball | bowl (rolling element) of the ball bearing with which a motor is mounted | worn with a ceramic is proposed (for example, refer patent document 3).

JP 2001-158152 A Japanese Patent No. 3612879 JP 2009-190959 A

  However, in the technique described in Patent Document 1, it is necessary to change the structure of the bracket and the frame, and there is a problem that it is difficult to share the conventional motor and the manufacturing equipment and the cost is increased.

  Moreover, in the technique described in Patent Document 2, it is necessary to change the outer dimensions of the shaft or the bearing, and there is a problem that it is difficult to share the conventional motor and manufacturing equipment, and the cost increases.

  Furthermore, in the technique described in Patent Document 3, there is a problem that the ceramic, which is the material of the ball (rolling element) of the ball bearing, is extremely expensive and the cost of the motor increases.

  In addition, as a general technique, a method such as changing the bearing from a ball bearing to a plain bearing is also conceivable, but the structure is different, such as no bearing shape or thrust in the thrust direction. There was a problem that it was necessary.

  The present invention has been made in order to solve the above-described problems. It is possible to reduce the power consumption without changing the external dimensions of the brackets, frames, and shafts of conventional motors and without using expensive materials such as ceramics. Provided are an electric motor capable of taking measures against food and a blower using the electric motor.

The electric motor according to the present invention is an electric motor comprising a mold stator, a rotor, and a bracket attached to one axial end of the mold stator,
A mold stator is a stator in which a coil is wound around a stator iron core via an insulating part, and is molded with a mold resin.
The rotor is arranged inside the mold stator, and the rotor magnet and shaft are integrated by a resin part,
A first slide bearing provided on the bracket for supporting the shaft and having a rotating body and a housing constituting a hydrodynamic bearing;
And a cylindrical second slide bearing which is provided on a bearing support portion of the mold stator and forms a sliding portion with the shaft.

  The electric motor according to the present invention can improve the resistance to electric corrosion without modifying the structure other than the bearing portion, and can be configured at low cost because it does not use expensive parts such as ceramics.

FIG. 3 shows the first embodiment and is a cross-sectional view of the electric motor 100. FIG. 3 shows the first embodiment, and is an exploded sectional view of the electric motor 100. FIG. 5 shows the first embodiment, and shows an assembly procedure (part 1) of the electric motor 100; FIG. 5 shows the first embodiment, and shows an assembly procedure (part 2) of the electric motor 100. FIG. 3 shows the first embodiment and is a cross-sectional view of the mold stator 10. FIG. 5 shows the first embodiment, and is a perspective view of a stator 40. Fig. 5 shows the first embodiment, and is a cross-sectional view of a second plain bearing 21a. Fig. 5 shows the first embodiment, and is a cross-sectional view of a first plain bearing 21b. FIG. 5 shows the first embodiment, and is a cross-sectional view of the bracket 30. FIG. 3 shows the first embodiment and is a cross-sectional view of a rotor 20. FIG. 5 shows the first embodiment, and is a side view of the rotor 20 as viewed from the load side. FIG. 3 is a diagram illustrating the first embodiment and is a diagram illustrating a resin magnet 22 of a rotor ((a) is a left side view, (b) is a CC cross-sectional view of (a), and (c) is a right side view). FIG. 5 is a diagram illustrating the first embodiment and is a diagram illustrating a position detection resin magnet 25 ((a) is a left side view, (b) is a front view, and (c) is an enlarged view of a portion D in (b)). FIG. 3 shows the first embodiment, and is a circuit diagram of an electric motor built-in drive circuit 1 incorporated in the electric motor 100. FIG. 5 shows the first embodiment, and shows a manufacturing process of the rotor 20. FIG. 5 shows the first embodiment, and shows a manufacturing process of the electric motor 100. FIG. 5 shows the first embodiment, and is a front view of the cross flow fan 200. FIG. 3 is a diagram showing the first embodiment, and is a longitudinal sectional view of an air conditioner 300 using a cross flow fan 200.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 shows the first embodiment and is a cross-sectional view of an electric motor 100. An electric motor 100 shown in FIG. 1 includes a mold stator 10, a rotor 20 (defined as a rotor of the electric motor), and a metal bracket 30 attached to one axial end of the mold stator 10. The electric motor 100 is, for example, a brushless DC motor having a permanent magnet in the rotor 20 and driven by an inverter. In FIG. 1, the elements constituting the mold stator 10 and the rotor 20 are denoted by reference numerals, but are not described here. Those codes will be described later.

FIG. 2 is a diagram showing the first embodiment, and is an exploded sectional view of the electric motor 100. As shown in FIG. 2, the electric motor 100 includes the following elements.
(1) Mold stator 10;
(2) second sliding bearing 21a;
(3) Rotor 20;
(4) first slide bearing 21b;
(5) Bracket 30.
The present embodiment is characterized in that the second sliding bearing 21a and the first sliding bearing 21b are used as bearings. By using a plain bearing instead of a rolling bearing as the bearing, the occurrence of electrolytic corrosion due to the shaft current is suppressed.

  Before describing each element constituting the electric motor 100, the assembly procedure of the electric motor 100 will be roughly described, although details will be described later.

  FIGS. 3 and 4 are diagrams showing the first embodiment, FIG. 3 is a diagram showing an assembly procedure (part 1) of the electric motor 100, and FIG. 4 is a diagram showing an assembly procedure (part 2) of the electric motor 100.

  As shown in FIG. 3, first, the second slide bearing 21 a is press-fitted into the bearing support portion 11 of the mold stator 10. Further, the first plain bearing 21 b is press-fitted into the bearing support portion 30 a of the bracket 30.

  Next, as shown in FIG. 4, the rotor 20 is press-fitted into the first plain bearing 21 b that is press-fitted into the bearing support portion 30 a of the bracket 30.

  Furthermore, the shaft 23 of the rotor 20 is inserted into the hole 11a of the mold stator 10, and the press-fitting portion 30b of the bracket 30 is press-fitted into the inner peripheral portion 10a of the mold stator 10, whereby the electric motor 100 is completed.

  FIG. 5 shows the first embodiment and is a cross-sectional view of the mold stator 10. The mold stator 10 has one axial end (the right side in FIG. 5) opened, and an opening 10b is formed here. The rotor 20 is inserted from this opening 10b. A hole 11 a that is slightly larger than the diameter of the shaft 23 of the rotor 20 is formed in the other axial end portion (left side in FIG. 4) of the mold stator 10.

  A mold stator 10 shown in FIG. 5 includes a stator 40 and a mold resin 50 for molding. For the mold resin 50, for example, a thermosetting resin such as an unsaturated polyester resin is used. Since the stator 40 is attached with a substrate and the like which will be described later and has a weak structure, low pressure molding is desirable. Therefore, thermosetting resins such as unsaturated polyester resins are used.

FIG. 6 is a diagram showing the first embodiment, and is a perspective view of the stator 40. The stator 40 shown in FIG. 6 has the following configuration.
(1) An electromagnetic steel sheet having a thickness of about 0.1 to 0.7 mm is punched into a strip shape, and a strip-shaped stator core 41 is manufactured by laminating by caulking, welding, bonding, or the like. The strip-shaped stator core 41 includes a plurality of teeth (not shown). The inside of which concentrated coil 42 described later is applied is a tooth. In FIG. 6, the teeth are not visible.
(2) The insulating portion 43 is applied to the teeth. The insulating portion 43 is formed integrally with or separately from the stator core 41 using, for example, a thermoplastic resin such as PBT (polybutylene terephthalate).
(3) Concentrated winding coil 42 is wound around the teeth provided with insulating portion 43. A plurality of concentrated winding coils 42 are connected to form, for example, a three-phase single Y-connection winding. However, distributed winding may be used.
(4) Since it is a three-phase single-Y connection (star connection), a terminal 44 (power supply is connected) to each phase (U-phase, V-phase, W-phase) coil 42 is connected to the connection side of the insulating portion 43. The supplied power supply terminal 44a and neutral point terminal 44b) are assembled. There are three power terminals 44a and three neutral point terminals 44b.
(5) The board | substrate 45 is attached to the insulation part 43 (side in which the terminal 44 is assembled | attached) on the connection side. A substrate 45 on which a lead wire lead-out component 46 that leads out the lead wire 47 is assembled is assembled to the insulating portion 43 to form the stator 40. A chamfered prism 48 (not shown in FIG. 5 but the main body is a prism) of the insulating part 43 formed in the stator core 41 is inserted into a prism insertion hole (not shown) provided in the substrate 45. Thus, positioning in the rotational direction is performed, and the position in the axial direction is determined by installing the substrate 45 on the substrate installation surface (not shown) of the insulating portion 43. Further, by thermally welding the prisms 48 protruding from the substrate 45, the substrate 45 and the insulating portion 43 are fixed, and the portions protruding from the substrate 45 of the terminals 44 of the stator 40 are electrically soldered. Are also joined. An IC 49a (driving element) for driving the electric motor 100 (for example, a brushless DC motor), a Hall IC 49b (position detecting element: see FIGS. 1 and 5) for detecting the position of the rotor 20 and the like are mounted on the substrate 45. Yes. IC 49a, Hall IC 49b, etc. are defined as electronic components.

  FIG. 7 shows the first embodiment and is a cross-sectional view of the second plain bearing 21a. As shown in FIG. 7, the second plain bearing 21 a has a donut shape (cylindrical shape) as a whole and includes an outer peripheral portion 21 a-1 and an inner peripheral portion 21 a-2. The outer peripheral portion 21 a-1 of the second plain bearing 21 a is fixed to the bearing support portion 11 of the mold stator 10. A predetermined gap is formed between the inner peripheral portion 21 a-2 of the second sliding bearing 21 a and the shaft 23 of the rotor 20. The second plain bearing 21a is made of a sintered metal impregnated with oil or the like. The second plain bearing 21a is fixed to the bearing support portion 11 of the mold stator 10, and the shaft 23 of the rotor 20 rotates. The inner peripheral portion 21a-2 of the second plain bearing 21a and the outer peripheral portion of the shaft 23 slide.

  The inner and outer diameters of the second slide bearing 21a are the dimensions indicated by the ball bearing identification number (for example, 6201), and have a shape compatible with the ball bearing.

FIG. 8 shows the first embodiment and is a cross-sectional view of the first plain bearing 21b. As shown in FIG. 8, the first plain bearing 21b is configured by the following elements.
(1) Rotating body 21b-1;
(2) outer housing 21b-2;
(3) inner housing 21b-3;
(4) Thrust dynamic pressure bearing portion 21b-4 (dynamic pressure bearing portion);
(5) Radial dynamic pressure bearing portion 21b-5 (dynamic pressure bearing portion);
(6) Inner peripheral part 21b-6.

  The inner and outer diameters of the first plain bearing 21b are the dimensions indicated by the ball bearing identification number (for example, 608), and have a shape compatible with the ball bearing.

  The rotating body 21b-1 has a substantially donut shape and is made of sintered metal or the like. The inner peripheral portion 21b-6 of the rotating body 21b-1 is press-fitted into the shaft 23, and the rotating body 21b-1 is integrated with the shaft 23 and rotates.

  The outer housing 21b-2 is press-fitted into the bearing support portion 30a of the bracket 30. The outer housing 21b-2 constitutes one thrust dynamic pressure bearing portion 21b-4.

  The inner housing 21b-3 is provided inside the outer housing 21b-2, and constitutes the other thrust dynamic pressure bearing portion 21b-4 and radial dynamic pressure bearing portion 21b-5.

  FIG. 9 shows the first embodiment and is a cross-sectional view of the bracket 30. The bracket 30 supports the first plain bearing 21b with a bearing support portion 30a. The bracket 30 is press-fitted into the mold stator 10 by using a press-fit portion 30b having a substantially ring shape of the bracket 30 and a U-shaped cross section as an opening 10b in the inner peripheral portion 10a (mold resin portion) of the mold stator 10. This is done by press-fitting to the side. The outer diameter of the press-fit portion 30b of the bracket 30 is larger than the inner diameter of the inner peripheral portion 10a of the mold stator 10 by the press-fit allowance. The material of the bracket 30 is made of metal, for example, a galvanized steel plate. However, it is not limited to galvanized steel sheet.

  10 and 11 show the first embodiment, FIG. 10 is a cross-sectional view of the rotor 20, and FIG. 11 is a side view of the rotor 20 viewed from the load side.

  As shown in FIG. 10, the rotor 20 includes a shaft 23 provided with a knurled portion 23a, a ring-shaped rotor resin magnet 22 (an example of a rotor magnet), and a ring-shaped position detection resin magnet 25 ( An example of a position detecting magnet), and a resin portion 24 for integrally molding them.

  A resin magnet 22 of a ring-shaped rotor, a shaft 23, and a position detection resin magnet 25 are integrated by a resin portion 24 injected by a vertical molding machine. At this time, the resin part 24 connects the central cylinder part 24g (formed inside the rotor resin magnet 22) formed on the outer periphery of the shaft 23 and the rotor resin magnet 22 to the central cylinder part 24g. A plurality of axial ribs 24j (see FIG. 11) formed radially in the radial direction about the shaft 23. A cavity 24k (see FIG. 11) penetrating in the axial direction is formed between the ribs 24j.

  A thermoplastic resin such as PBT (polybutylene terephthalate) or PPS (polyphenylene sulfide) is used for the resin used for the resin portion 24. Those in which a glass filler is blended with these resins are also suitable.

  As shown in FIG. 10, in the resin portion 24, a mold inner diameter pressing portion 24a for holding the inner diameter of the position detection resin magnet 25 and the position detection resin magnet 25 are set in a mold (lower mold). A taper part 24b for facilitating and a resin injection part 24c at the time of resin molding are formed after resin molding.

  FIGS. 12A and 12B are diagrams showing the first embodiment, and are views showing a resin magnet 22 of a rotor ((a) is a left side view, (b) is a cross-sectional view taken along the line CC in (a), and (c) is a right side view). Figure).

  The configuration of the resin magnet 22 of the ring-shaped rotor will be described with reference to FIG. The rotor resin magnet 22 is formed by mixing a thermoplastic material with a magnetic material. The rotor resin magnet 22 has an axial end of the inner diameter (on the right side in FIG. 12B) in order to ensure the coaxiality of the shaft 23 and the rotor resin magnet 22 during mold clamping during resin molding. The notch 22a is formed. In the example of FIG. 12, the notches 22a are formed at eight locations at substantially equal intervals in the circumferential direction (FIG. 12C).

  Further, on the resin magnet 22 of the rotor, pedestals 22b on which the position detection resin magnet 25 is placed are formed at substantially equal intervals in the circumferential direction on the end surface of the other axial end portion (left side in FIG. 12B). ing.

  The pedestal 22b is formed from the vicinity of the inner diameter of the resin magnet 22 of the rotor toward the outer diameter, and the positioning projection 22c is radially directed from the tip of the pedestal 22b toward the outer periphery of the resin magnet 22 of the rotor. It extends to. The positioning projection 22c is used for positioning the rotor resin magnet 22 in the circumferential direction (rotation direction) when the resin magnet 22 of the rotor, the resin magnet 25 for position detection, and the shaft 23 are integrally formed by the resin portion 24. .

  FIG. 13 is a diagram showing the first embodiment, and is a diagram showing the position detection resin magnet 25 ((a) is a left side view, (b) is a front view, and (c) is an enlarged view of a portion D in (b)). It is. The configuration of the ring-shaped position detection resin magnet 25 will be described with reference to FIG.

  The position detecting resin magnet 25 includes steps 25b at both axial end portions on the inner diameter side. The step 25b is necessary to prevent the position detecting resin magnet 25 from coming off in the axial direction by filling the step 25b on the axial end portion side of the rotor 20 with a part of the resin portion 24.

  In FIG. 13, the one provided with the step 25 b at both ends is shown. However, the step 25 b may be provided at one of the ends, and it should be positioned on the axial end of the rotor 20. However, when both ends are provided with a step 25b, the position detection resin magnet 25 is set without worrying about the front and back when the resin magnet 24 for position detection is set on the mold (lower mold) when the resin portion 24 of the rotor 20 is integrally formed. Excellent workability because it can.

  Further, the position detecting resin magnet 25 includes eight ribs 25a (substantially triangular in cross section) that are circumferentially detented when embedded in the resin portion 24 in the step 25b at substantially equal intervals in the circumferential direction. However, the number, shape, and arrangement interval of the ribs 25a may be arbitrary.

  The pedestal 22b of the rotor resin magnet 22 formed integrally with the shaft 23 enables the position detection resin magnet 25 to be separated from the end surface of the rotor resin magnet 22. As a result, the thickness of the position detecting resin magnet 25 can be minimized and disposed at an arbitrary position, and the cost can be reduced by filling a cheaper thermoplastic resin than the resin magnet 22 of the rotor. It becomes.

  As shown in FIG. 13, the position detecting resin magnet 25 has steps 25 b on both sides in the thickness direction, and ribs 25 a that prevent rotation when embedded in resin. Further, the coaxiality between the inner diameter of the position detecting resin magnet 25 and the outer diameter of the position detecting resin magnet 25 is made with high accuracy.

  When molded integrally with the shaft 23, the outer periphery of the position detection resin magnet 25 is filled with a taper-shaped resin (resin portion 24). Correspondingly, the resin to be filled is blocked by the axial end face (outer side) on one side of the position detection resin magnet 25 and the axial end faces of the rotor resin magnet 22, so that the outer diameter of the rotor resin magnet 22 is variable. It is possible to suppress the occurrence of the problem, and the quality is improved.

  Further, by arranging the gate port at the time of integral molding with the shaft 23 further inside than the inner diameter of the resin magnet 22 of the rotor and arranging the resin injection portion 24c in a convex shape, the concentration of pressure is alleviated, and the resin Can be easily filled, and the convex portion of the resin injection portion 24c can be used for positioning.

  Further, the rotor 20 shown in FIG. 10 uses a rotor resin magnet 22 formed by mixing a magnetic material with a thermoplastic resin in a permanent magnet, but other permanent magnets (rare earth magnets (neodymium, samarium) are used. Iron), sintered ferrite, etc.) may be used.

  Similarly, other permanent magnets (rare earth magnets (neodymium, samarium iron), sintered ferrite, etc.) may be used for the position detecting resin magnet 25.

  As already mentioned, when the electric motor is operated using an inverter, the carrier frequency of the inverter should be set high for the purpose of reducing the noise of the electric motor generated due to the switching of the transistors in the power circuit. Yes. As the carrier frequency is set higher, the shaft voltage generated on the motor shaft based on the high frequency induction increases, and the shaft current easily flows. When the bearing is a rolling bearing consisting of both inner and outer races and rolling elements, the shaft current causes corrosion called electro-corrosion on the rolling surface of the rolling element (balls and rollers rolling between the inner and outer rings). Deteriorating the durability of rolling bearings. However, in the present embodiment, instead of rolling bearings, sliding bearings (first sliding bearing 21b and second sliding bearing 21a) are used, so that even if axial current flows, electrolytic corrosion of the bearings occurs. do not do.

  The shaft current that is the cause of electric corrosion appears more prominently as the power supply voltage of the inverter is higher, the PWM (Pulse Width Modulation) frequency is higher, and the impedance of the path through which the shaft current flows is lower. The path through which the axial current flows is a path through the stator core 41, the winding (coil 42), the bearings (first sliding bearing 21b, second sliding bearing 21a), and the shaft 23. Further, although each member is normally insulated in terms of direct current, it is known that it can be expressed as a stray capacitance (capacitor) and is in a conductive state in terms of high frequency. The winding (coil 42) and the bearings (first sliding bearing 21b, second sliding bearing 21a) are usually separated by the diameter of the rotor 20, so the stray capacitance is very small. Since there is a case where the capacity increases, it will be described below.

  As one type of blower motor, there is a DC brushless motor that incorporates an inverter circuit. The electric motor 100 of the present embodiment is also included in them. In this case, since the method of detecting the magnetic flux of the rotor 20 (the magnetic flux of the position detection resin magnet 25) and energizing is used, the substrate 45 is often installed on the side surface of the rotor 20. At this time, since the substrate 45 has a copper foil pattern, it acts to increase the stray capacitance of the portion where the substrate 45 is interposed. The electric motor having such a structure is particularly effective in the structure shown in the present embodiment because the improvement in the resistance to electrolytic corrosion is deteriorated.

  Therefore, the rotor 20 of the present embodiment is particularly effective for reducing the shaft current when the electric motor 100 is operated by an inverter.

  FIG. 14 is a diagram showing the first embodiment, and is a circuit diagram of the motor built-in drive circuit 1 of the motor 100. The motor built-in drive circuit 1 will be described with reference to FIG. As shown in FIG. 14, AC power is supplied to a drive circuit 1 with a built-in motor from a commercial AC power supply 2 provided outside the motor 100. The AC voltage supplied from the commercial AC power supply 2 is converted into a DC voltage by the rectifier circuit 3. The DC voltage converted by the rectifier circuit 3 is converted to an AC voltage having a variable frequency by the inverter main circuit 4 and applied to the electric motor 100. The electric motor 100 is driven by variable frequency AC power supplied from the inverter main circuit 4. The rectifier circuit 3 includes a chopper circuit that boosts the voltage applied from the commercial AC power supply 2 and a smoothing capacitor that smoothes the rectified DC voltage.

  The inverter main circuit 4 is a three-phase bridge inverter circuit, and the switching section of the inverter main circuit 4 has six IGBTs 6a to 6f (insulated gate bipolar transistors, simply defined as transistors) and six flywheel diodes serving as inverter main elements. SiC-SBDs 7a-7f (Schottky barrier diodes, simply defined as diodes) using silicon carbide (SiC) as (FRD) are provided. The SiC-SBDs 7a to 7f, which are FRDs, are reverse current prevention means for suppressing the counter electromotive force generated when the IGBTs 6a to 6f turn the current from ON to OFF.

  In the first embodiment, the IGBTs 6a to 6f and the SiC-SBDs 7a to 7f are IC modules in which each chip is mounted on the same lead frame and molded with epoxy resin and packaged. The IGBTs 6a to 6f may be IGBTs using SiC or GaN instead of IGBTs using silicon (Si-IGBT), and MOSFETs (Metal-Oxide-Semiconductor Field-) using Si, SiC, or GaN instead of IGBTs. Other switching elements such as Effect Transistor may be used.

  Two voltage-dividing resistors 8a and 8b connected in series are provided between the rectifier circuit 3 and the inverter main circuit 4, and the high-voltage DC voltage is reduced by the voltage-dividing circuit using the voltage-dividing resistors 8a and 8b. A DC voltage detector 8 is provided for sampling and holding the electrical signal.

  In addition, the electric motor 100 includes a rotor 20 (FIG. 10) and a mold stator 10 (FIG. 5), and the rotor 20 is rotated by AC power supplied from the inverter main circuit 4. A Hall IC 49b for detecting the position detecting resin magnet 25 is provided in the vicinity of the rotor 20 of the mold stator 10, and an electric signal from the Hall IC 49b is processed and converted into position information of the rotor 20. A rotor position detection unit 110 is provided.

  The position information of the rotor 20 detected by the rotor position detection unit 110 is output to the output voltage calculation unit 120. The output voltage calculation unit 120 is an optimum inverter main unit to be applied to the electric motor 100 based on the command of the target rotational speed N given from the outside of the electric motor built-in drive circuit 1 or information on the operating condition of the apparatus and the positional information of the rotor 20. The output voltage of the circuit 4 is calculated. The output voltage calculation unit 120 outputs the calculated output voltage to the PWM signal generation unit 130. PWM is an abbreviation for Pulse Width Modulation.

  The PWM signal generation unit 130 outputs a PWM signal that becomes the output voltage given from the output voltage calculation unit 120 to the main element drive circuit 4a that drives each of the IGBTs 6a to 6f of the inverter main circuit 4, and the inverter main circuit 4 Each of the IGBTs 6a to 6f is switched by the main element drive circuit 4a.

  In the first embodiment, the inverter main circuit 4 is a three-phase bridge, but another inverter circuit such as a single phase may be used.

  Here, the wide band gap semiconductor will be described. A wide band gap semiconductor is a generic term for semiconductors having a larger band gap than Si, and SiC used in the SiC-SBDs 7a to 7f is one of the wide band gap semiconductors, in addition to gallium nitride (GaN), There are diamonds. Furthermore, wide band gap semiconductors, particularly SiC, have higher heat resistance temperature, dielectric breakdown strength, and thermal conductivity than Si. In the first embodiment, SiC is used for the FRD of the inverter circuit, but other wide band gap semiconductors may be used instead of SiC.

FIG. 15 is a diagram illustrating the first embodiment, and is a diagram illustrating a manufacturing process of the rotor 20. The manufacturing process of the rotor 20 will be described with reference to FIG.
(1) Forming and demagnetizing the resin magnet 25 for position detection and the resin magnet 22 of the rotor. The shaft 23 is processed (step 1).
(2) The position detection resin magnet 25 is set in the lower mold with the end portion having the step 25b facing downward, and the inner diameter pressing portion provided in the lower mold holds the inner diameter of the position detection resin magnet 25 (step 2). ).
(3) The positioning projection 22c of the resin magnet 22 of the rotor is fitted into the positioning projection insertion portion provided in the lower mold and set in the lower mold (step 3).
(4) The inserted shaft 23 is set in the lower mold, and the mold is clamped so that the notch 22a of the resin magnet 22 of the rotor is pressed by the notch pressing portion of the upper mold (step 4).
(5) Resin (resin portion 24) is molded (step 5). The resin magnet 22 of the rotor, the resin magnet 25 for position detection, and the shaft 23 are integrally formed by the resin portion 24.
(6) The position detecting resin magnet 25 and the rotor resin magnet 22 are magnetized (step 6).

  According to the manufacturing process described above, when the resin magnet 22 of the rotor, the shaft 23, and the position detection resin magnet 25 are integrated with the resin (resin portion 24), all the parts are set in the mold and the resin. Since the molding is performed, the cost of the rotor 20 can be reduced by reducing the work process.

FIG. 16 is a diagram illustrating the first embodiment, and is a diagram illustrating a manufacturing process of the electric motor 100. The manufacturing process of the electric motor 100 will be described with reference to FIG.
(1) The mold stator 10 is manufactured. In addition, the first sliding bearing 21b and the second sliding bearing 21a are manufactured. In addition, the bracket 30 is manufactured. In addition, the rotor 20 is manufactured (step 10).
(2) The first plain bearing 21b is press-fitted into the mold stator 10. At the same time, the second plain bearing 21a is press-fitted into the bracket 30 (step 11).
(3) The bracket 30 is press-fitted into the rotor 20 (step 12).
(4) Insert the rotor 20 into the mold stator 10 and press-fit the bracket 30 (step 12).

  In the manufacturing process of the electric motor 100 as described above, the first sliding bearing 21b is not subjected to a large thrust load due to press-fitting, so that it is possible to improve the manufacturing yield.

  FIG. 17 shows the first embodiment and is a front view of the cross flow fan 200. FIG. In the cross-flow fan 200 in which the shaft shown in FIG. 17 is installed in the horizontal direction and the blade load (cross-flow fan 201) is connected, the bearing on the non-load side of the shaft 23 is loaded against the load-side bearing. small. For this reason, the first slide bearing 21b having a relatively low load resistance and a relatively low load resistance is provided on the non-load side and the second load having a relatively high load resistance due to the dimensional restrictions on the bearing width due to the housing (outer housing 21b-2, inner housing 21b-3). By making the plain bearing 21a on the load side, a highly durable bearing structure can be obtained.

  The blade shape of the target blower includes a propeller fan and the like in addition to the cross-flow fan 201, but the first slide bearing 21b also has a sliding surface (thrust dynamic pressure bearing portion) on the side surface side (doughnut-shaped portion). 21b-4), and a blade having a high thrust load is unsuitable because the loss torque increases. Therefore, the shaft 23 is in the horizontal direction, the blade shape of the blower is the cross flow fan 200, or two or more sirocco fans (not shown) whose fluid inlet faces are in the axial direction and face each other, etc. Even if the structure of the present application is applied, the loss torque is small and it is convenient if the blade has a small thrust load accompanying the blowing operation.

  FIG. 18 shows the first embodiment, and is a longitudinal sectional view of an air conditioner 300 using a cross flow fan 200. As an example of equipment using the cross flow fan 200, there is an air conditioner 300, for example. As the air conditioner 300, a separate type having an indoor unit and an outdoor unit is widely used. Air conditioner 300 shown in FIG. 18 is a longitudinal sectional view of an indoor unit.

  As shown in FIG. 18, a suction port 348 for sucking room air is formed on the upper surface of the air conditioner 300 (indoor unit). A filter (not shown) of an automatic filter cleaning mechanism is disposed near the suction port 348 to remove dust from indoor air.

  A substantially inverted V-shaped indoor heat exchanger 305 is disposed so as to face the suction port 348.

  An indoor blower (cross flow fan 200) is disposed inside the substantially inverted V-shaped indoor heat exchanger 305 (on the side opposite to the suction port 348).

  An air outlet 349 that opens into the room is formed in the lower part of the air conditioner 300 (indoor unit), and a wind direction controller 350 that controls the air direction of the conditioned air is provided in the air outlet 349. The wind direction control unit 350 illustrated in FIG. 18 controls the wind direction in the vertical direction. Although not shown, a device that controls the wind direction in the left-right direction is also used.

  A drain pan 343 is provided below the indoor heat exchanger 305. The drain pan 343 receives the defrost water generated in the indoor heat exchanger 305, and the defrost water temporarily stored in the drain pan 343 is discharged from the drain hose connected to the drain pan 343 to the outside. In addition, although the drain pan is provided also in the back surface, description is abbreviate | omitted.

  The electric motor 100 uses the first sliding bearing 21b that fixes the axial position of the rotor 20 and the second sliding bearing 21a that allows the axial position to be free, so that problems due to high-frequency electrolytic corrosion do not occur.

  Since the electric motor 100 has substantially the same shape as the size specified by the ball bearing identification number, there is almost no change in the structure of the motor members other than the bearings, and an inexpensive electric motor 100 that does not require manufacturing equipment can be provided.

  In the case where the shaft 23 is installed in the horizontal direction and the blade load is connected, the electric motor 100 can have a highly durable bearing structure by setting the first sliding bearing 21b on the non-load side.

  DESCRIPTION OF SYMBOLS 1 Motor built-in drive circuit, 2 Commercial AC power supply, 3 Rectifier circuit, 4 Inverter main circuit, 4a Main element drive circuit, 6a-6f IGBT, 7a-7f SiC-SBD, 8 DC voltage detection part, 8a Voltage dividing resistor, 8b Voltage divider resistor, 10 Mold stator, 10a Inner peripheral part, 10b Opening part, 11 Bearing support part, 11a Hole, 20 Rotor, 21a 2nd slide bearing, 21b 1st slide bearing, 21b-1 Rotating body, 21b-2 outer housing, 21b-3 inner housing, 21b-4 thrust dynamic pressure bearing portion, 21b-5 radial dynamic pressure bearing portion, 21b-6 inner peripheral portion, 22 rotor resin magnet, 22a notch, 22b pedestal , 22c positioning protrusion, 23 shaft, 23a knurled, 24 resin part, 24a inner diameter pressing part, 24b taper part, 4c Resin injection part, 24g Center tube part, 24h Anti-load side end face, 24j Rib, 24k Cavity, 25 Position detection resin magnet, 25a Rib, 25b Step, 30 Bracket, 30a Bearing support part, 30b Press fit part, 40 Stator , 41 Stator core, 42 Coil, 43 Insulating part, 44 terminal, 44a Power supply terminal, 44b Neutral point terminal, 45 Substrate, 46 Lead wire lead-out part, 47 Lead wire, 48 Rectangular column, 49a IC, 49b Hall IC, 50 Mold resin, 100 motor, 110 rotor position detector, 120 output voltage calculator, 130 PWM signal generator, 200 crossflow fan, 201 once-through fan, 300 air conditioner, 305 indoor heat exchanger, 343 drain pan, 348 suction Mouth, 349 Air outlet, 350 Air direction control unit.

Claims (7)

The mold stator stator coil is wound is molded with a molding resin into the stator iron core via an insulating section,
Is disposed inside the front Symbol mold stator, a rotor Ma Gunetto and shaft are integrated by the resin portion,
A bracket attached to one end of the mold stator in the axial direction;
A first fixing unit fixed to the bracket and having a rotating body integrated with the shaft and rotating to support an axial position of the rotor, and a housing constituting a hydrodynamic bearing portion that supports the rotating body . Plain bearings,
An inner peripheral portion that is fixed to the other axial end portion of the mold stator and has a predetermined gap between the shaft and the shaft so that the rotor can be freely positioned in the axial direction. a second sliding bearing of the cylindrical shape have a
Motor characterized by comprising a. 2. The electric motor according to claim 1 , wherein an inner diameter and an outer diameter dimension of the first sliding bearing and the second sliding bearing substantially coincide with values defined by a bearing number of the ball bearing. The said shaft protrudes outside only from the said other end part of an axial direction among the axial direction both ends of the said mold stator, A load is connected to this protruded part of Claim 1 or 2 characterized by the above-mentioned. Electric motor. The electric motor according to any one of claims 1 to 3, wherein the electric motor is driven by a PWM (Pulse Width Modulation) inverter that switches at a carrier frequency higher than a commercial frequency. The PWM inverter motor according to claim 4, characterized in that it is built into the motor. The PWM inverter motor according to claim 5, characterized in that it is arranged at a position Ru increases the stray capacitance between said shaft and said coil. A blower comprising the electric motor according to claim 3 , wherein a cross- flow fan is provided as the load .

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