JP5518253B2 - Electric motor - Google Patents

Description

  The present invention relates to an electric motor having a stator in which a permanent magnet is sandwiched between two stator cores.

  FIG. 10 shows a cross-sectional structure of a conventional electric motor (for example, see Patent Document 1). The electric motor 100 includes a saliency stator 104 in which stator steel cores 102 and 103 are formed by laminating electromagnetic steel plates on both sides of an axially magnetized permanent magnet 101, and an electromagnetically installed in a central portion of the stator 104. And a saliency rotor 105 in which steel plates are laminated. The rotor 105 has a structure in which the salient pole direction is twisted by 90 degrees in electrical angle, and is integrated with the shaft 107. When the stator 104 is assembled, the permanent magnet 101 for magnetizing the rotor is bonded to the inner peripheral surface of the housing 106, and the stator cores 102 and 103 are press-fitted from both sides of the permanent magnet 101 to fix the permanent magnet 101.

  Further, when the stator cores 102 and 103 are press-fitted, it is necessary to position the teeth between the stator cores 102 and 103. Therefore, as shown in FIGS. 11A and 11B, positioning pins 111 are provided between the housing 106 and the stator 104, and the teeth 108 are positioned at the time of assembly.

  In addition to the above assembly method, for example, as shown in FIG. 12, there is a method in which the stator cores 102 and 103 are respectively press-fitted into the housing 106 from one direction. In this case, the outer diameter of the stator core 102 is increased and the outer diameter of the other stator core 103 is decreased so that the two stator cores 102 and 103 sandwich the permanent magnet 101 after being press-fitted and fixed to the housing 106. In addition, a press-fit portion 112 having a large inner diameter and a press-fit portion 113 having a small inner diameter are also formed on the inner peripheral surface of the housing 106.

JP-A-8-214519

  When the stator cores 102 and 103 are press-fitted from both sides of the permanent magnet 101, clearances 109 and 110 (shown in FIG. 10) are generated between the stator cores 102 and 103 and the permanent magnet 101, and demagnetization occurs during rotor magnetization. This causes a problem that the motor characteristics (torque) are reduced. Further, if the clearances 109 and 110 are to be eliminated, it is necessary to bring the permanent magnet 101 and the stator cores 102 and 103 into contact with each other, and there is a possibility that the permanent magnet 101 may be damaged due to the load of press-fitting the stator core.

  Further, when positioning the teeth 108 of the stator cores 102 and 103 using the positioning pins 111 or the like during the assembly, there is a problem that the cost required for the assembly increases. Specifically, there are an increase in the number of parts of the positioning pin 111, addition of a recess processing for press-fitting the positioning pin 111 into the stator cores 102 and 103, addition of a press-fitting work process of the positioning pin 111, and the like.

Furthermore, since the stator cores 102 and 103 having the same outer diameter are press-fitted into the housing 106 from two directions, there is a problem that workability is deteriorated.
On the other hand, when the stator cores 102 and 103 having different outer diameters are press-fitted into the housing 106 from one direction, two types of stator cores are required. Therefore, the number of parts is increased, and the press-fitting portions 112 and 113 having different inner diameters are added to the housing 106. Therefore, there is a problem that the housing cutting cost also increases.

  The present invention has been made to solve the above-described problems, and aims to eliminate the clearance between the permanent magnet and the stator core and reduce the cost required for assembling the permanent magnet and the stator core to the housing. And

The electric motor of the present invention includes a cylindrical housing, a rotor portion that is rotatably held in a central portion of the housing, and a stator portion that is press-fitted and fixed at a position surrounding the outer periphery of the rotor portion of the housing, A stator core formed with an annular body and a plurality of teeth protruding toward the center from the inner peripheral portion of the annular body, an annular magnet portion that magnetizes the rotor portion in the direction of the rotation axis, and magnet portions are provided on both sides made of a resin member integrally molded through insertion at the stator core, possess a mold portion for holding a magnet part and at least the inner peripheral side stator core, mold section, a shape which closes the gap of the teeth between the stator core, the teeth It is flush with the tip surface .

  According to the present invention, the magnet part and the stator cores on both sides thereof are integrally formed to form the stator part, thereby eliminating the clearance between the magnet part and the stator core and improving the motor characteristics. Further, since the integrally molded stator portion can be press-fitted into the housing from one direction and assembled, the cost required for the assembly can be reduced.

It is sectional drawing which shows the structure of the electric motor which concerns on Embodiment 1 of this invention. 1 is an exploded perspective view showing a configuration of an electric motor according to Embodiment 1. FIG. The structure of the stator ASSY of the electric motor which concerns on Embodiment 1 is shown, Fig.3 (a) is an external appearance perspective view, FIG.3 (b) is a side view. It is sectional drawing which cut | disconnected the stator ASSY of the electric motor which concerns on Embodiment 1 along the AA line of FIG.3 (b). 3 is a plan view showing a configuration of a stator core of the electric motor according to Embodiment 1. FIG. It is the figure which expanded the stator ASSY press-fit part of the electric motor shown in FIG. It is a figure explaining rotation operation of the electric motor concerning Embodiment 1. FIG. It is sectional drawing of the metal mold | die which integrally molds the stator ASSY of the electric motor which concerns on Embodiment 1. FIG. It is the figure which expanded the stator core of the electric motor which concerns on Embodiment 1, and the positioning part of a permanent magnet. It is sectional drawing which shows the structural example of the conventional electric motor. It is a figure which shows another structural example of the conventional electric motor, Fig.11 (a) is sectional drawing, FIG.11 (b) is a top view. It is sectional drawing which shows another structural example of the conventional electric motor.

Hereinafter, in order to explain the present invention in more detail, modes for carrying out the present invention will be described with reference to the accompanying drawings.
Embodiment 1 FIG.
An electric motor 1 shown in FIGS. 1 and 2 constitutes a three-phase AC synchronous motor, and mainly includes a cylindrical housing 2, a stator ASSY (stator portion) 3 press-fitted and fixed to the housing 2, and a shaft (not shown). And a rotor (rotor part) 9 to be rotated. The rotor 9 has two protrusions protruding radially outward at intervals of 180 degrees, and the protrusions are shifted by 90 degrees in the middle of the rotation axis direction X (protrusions 9a and 9b). The rotor 9 may be composed of a permanent magnet. However, when the electric motor 1 is exposed to a high temperature, the magnetic characteristics are deteriorated. preferable. Even when the rotor 9 is formed of laminated steel plates, the protrusions are shifted by 90 degrees in the middle of the rotation axis direction X (protrusions 9a and 9b).
By fixing the shaft to the rotor 9 and rotating the shaft integrally with the rotor 9, the rotational force generated in the rotor 9 is output to the outside. When the electric motor 1 is applied to an automobile turbocharger, an electric compressor, or the like, a shaft fixed to the rotor 9 is connected to a rotating shaft of a turbine (so-called impeller), and the electric motor 1 rotates the turbine.

  FIG. 3A is an external perspective view showing the configuration of the stator ASSY 3, and FIG. 3B shows a side view. FIG. 4 is a cross-sectional view of the stator ASSY 3 in FIG. 3B cut along the line AA. The stator ASSY 3 includes two stator cores 4 and 5, a magnet portion 6 disposed between the stator cores 4 and 5, and a mold portion 7 that integrates them.

FIG. 5 shows a plan view of the stator core 4. The stator core 4 is formed by stacking electromagnetic steel plates in the rotation axis direction X of the rotor 9. The stator core 4 includes an annular body and six projecting portions (hereinafter referred to as teeth 4a) projecting from the inner peripheral portion of the annular body toward the center. A U-shaped coil 8 is attached to each of the teeth 4a.
In the illustrated example, electromagnetic steel sheets are punched out to provide six protruding teeth 4a in the circumferential direction at intervals of 60 degrees, and further, caulking protrusions 4b are formed at 60 degrees in each of six recesses formed alternately with the teeth 4a. Provide at intervals. A plurality of positioning recesses 4c are provided on the outer periphery of the electromagnetic steel sheet. A plurality of the electromagnetic steel sheets are laminated, and the protrusions 4b are caulked and bound to form the stator core 4. Similarly, the stator core 5 is also formed.

  The magnet unit 6 is annular and is configured by combining a plurality of permanent magnets. In the example of FIG. 4, six fan-shaped permanent magnets having a central angle of 60 degrees are used, which is the same number as the teeth 4a. As an example of the arrangement of the permanent magnets, as shown in FIG. 5, the outer peripheral portion 6b of one permanent magnet 6a is arranged so as to cover the outer side in the radial direction corresponding to the teeth 4a forming portion of the stator core 4 (the same applies to the stator core 5). In the state shown in FIG. 4, each of the six permanent magnets is arranged in the same manner as the permanent magnet 6a shown in FIG. Each permanent magnet is positioned such that both end portions on the inner peripheral side are in contact with the projections 4 a of the stator cores 4, 5. In the case of this arrangement example, since the divided portions of the permanent magnets do not overlap the teeth 4a when viewed from the rotation axis direction X, the magnetic characteristics can be improved.

The mold part 7 is composed of a resin member that integrally molds the stator cores 4, 5 and the magnet part 6. The procedure of integral molding will be described later. As shown in FIG. 3A and FIG. 4, a total of 12 coil insertion holes 7 a for inserting the U-shaped coil 8 are formed in the mold portion 7, two for each U-shaped coil 8. .
The U-shaped coil 8 is a one-turn coil obtained by bending a copper plate into a U-shape, and penetrates the coil insertion hole 7a in the rotation axis direction X as shown in FIGS. 1 and 2, and the bent portion is on the stator core 4 side. Further, the tip portion protrudes toward the stator core 5 side.

As shown in FIG. 1, one end of the U-shaped coil 8 inserted into the coil insertion hole 7a of the mold part 7 penetrates the connection plate ASSY 10 and protrudes toward the control circuit board 12 side. It is connected to a copper plate coil 11 (U phase, V phase, W phase) which is a molded energization member. The copper plate coil 11 is connected to the control circuit board 12.
The control circuit board 12 has an inverter, converts an external power source (not shown) input from the connector unit 14 into an alternating current, and based on the position signal input from the position detection sensor 15, the U phase of the copper plate coil 11, A current is passed through the U-shaped coil 8 by sequentially switching the three phases of the V phase and the W phase. The U-shaped coil 8 and the stator cores 4 and 5 are insulated from each other by the mold portion 7.

The position detection sensor 15 includes a Hall element IC (Integrated Circuit) that detects the position of a sensor target 16 (for example, a magnet) that rotates integrally with the rotor 9. The position detection sensor 15 detects the rotational position of the rotor 9 by detecting the position of the sensor target 16 and outputs a position signal to the control circuit board 12.
The opening surface of the housing 2 on the control circuit board 12 side is covered with a cover 13 to protect the control circuit board 12 and the position detection sensor 15 and the like. Further, an O-ring 17 is provided and sealed in the press-fitting portion of the housing 2 and the stator ASSY 3.

Here, an outline of the operation of the electric motor 1 will be described.
FIG. 6 is an enlarged view of the stator ASSY3 press-fitting portion of the electric motor 1 shown in FIG. Magnetic flux (magnet magnetic flux) generated by the magnet portion 6 magnetized in the rotation axis direction X flows out of the teeth 4a of the stator core 4 arranged on the N pole side of the magnet portion 6 to the protrusion of the rotor 9, and the rotation of the rotor 9 The magnetic field magnetic flux flows in the axial direction X, exits from the protrusion on the S pole side of the magnet portion 6, and flows into the teeth 4 a of the stator core 5 disposed on the S pole side of the magnet portion 6. Thus, the magnetic field force of the magnet unit 6 acts on the rotor 9, so that the protrusion of the rotor 9 facing the N pole side of the magnet unit 6 is magnetized to the N pole, and the S pole of the magnet unit 6 The protrusion of the rotor 9 facing the side is magnetized to the S pole.
FIG. 7 is a plan view of the electric motor 1 shown in FIG. 1 as viewed from the left side of the drawing. However, illustration of the housing 2 and the U-shaped coil 8 is omitted. When a current flows through the U-shaped coil 8 via the copper plate coil 11, each tooth of the stator ASSY 3 is magnetized according to the direction of the flowing current, and a rotating magnetic field is generated to generate torque. By sequentially switching the direction of the current flowing through the U-shaped coil 8, the NS polarities of the teeth are rotated and moved as shown in FIGS. 7A to 7C, and the rotor 9 is rotated by the magnetic action. .

Next, the assembly procedure of the stator ASSY 3 will be described.
FIG. 8 is a cross-sectional view of a mold for molding the stator ASSY 3. The mold is composed of a combination of an upper mold 20, a lower mold 21, and a middle shaft 22, and a gap 23 in which the stator cores 4, 5 and the magnet part 6 are installed, and a gap in which a mold 7 is formed by injecting resin. 24 are provided concentrically. The partition of the upper mold 20 and the lower mold 21 may be arbitrary. The middle shaft 22 is a mold that forms a space for disposing the rotor 9, and has a shape in which the outer peripheral surface of the middle shaft 22 is in contact with the tips of the teeth 4 a of the stator cores 4, 5. The cross section of the stator ASSY 3 shown in FIG. 8 corresponds to the cross section cut along the line BB in FIG.

A plurality of positioning protrusions (not shown) in the same direction as the axial direction of the middle shaft 22 are formed on the wall surface of the gap 23 of the lower mold 21 so that the positioning protrusions engage with the positioning recesses 4 c of the stator core 5. In addition, the stator core 5 is installed in the gap 23. Subsequently, the magnet portion 6 is disposed on the upper side of the stator core 5. As described above, the six permanent magnets are arranged in an annular shape, but since the caulking projections 4b protrude from the stator core 5 every 60 degrees, the respective projections 4b are arranged as a guide. FIG. 9A shows an enlarged side view of a divided portion of the projection 4b and the permanent magnet 6a provided on the inner peripheral portion of the stator core 5, and FIG. 9B shows a plan view thereof. As shown in the figure, each permanent magnet 6a is positioned in contact with the caulking projection 4b.
Subsequently, the stator core 4 is installed on the upper side of the magnet portion 6 so that the positioning concave portion 4 c of the stator core 4 engages with the positioning convex portion of the gap 23. Thereby, the phase alignment of each tooth 4a of the stator cores 4 and 5 can be easily performed.

After the stator cores 4 and 5 and the magnet part 6 are installed, the upper mold 20, the lower mold 21 and the middle shaft 22 are fitted, resin is injected from the resin injection port 25 into the gap 24, and the stator ASSY 3 is integrally molded, and the mold Part 7 is formed. When the electric motor 1 is exposed to a high temperature, for example, when applied to a turbocharger for automobiles, the resin member forming the mold part 7 preferably has at least thermosetting properties, for example, polyphenylene sulfide resin (PPS) is used. .
In addition, since a clearance is secured between the permanent magnets of the magnet part 6 by design, it is possible to extend the mold part 7 by flowing resin also on the outer peripheral side of the magnet part 6 of the stator ASSY 3. Moreover, since the inner peripheral surface of the mold part 7 is flush with the tip surface of the teeth 4a (that is, the inner peripheral diameter of the mold part 7 and the diameter of the shape connecting the tip parts of the teeth 4a are the same), Resin sinking and sagging can be prevented.

  When the integrally molded stator ASSY 3 is installed in the housing 2, it is press-fitted from one end side of the housing 2 and fixed as shown in FIG. 6. The housing 2 is provided with a press-fit portion 2a having a slightly smaller inner diameter, and the press-fit portion 2a holds the press-fitted stator core 5. Thereafter, the U-shaped coil 8 is inserted into the coil insertion hole 7a of the mold part 7, and the connection plate ASSY 10 is installed to connect the coils. Further, the rotor 9 fixed to the shaft (not shown) is inserted into the central opening portion of the stator ASSY 3. Since the inner peripheral surface of the mold portion 7 and the tip end surface of the teeth are flush with each other, the central opening portion of the stator ASSY 3 is not uneven and the rotor 9 can be easily inserted.

In FIG. 10 described above, the stator cores 102 and 103 are press-fitted in two directions, so that the clearances 109 and 110 are necessary between the permanent magnets 101. However, in the first embodiment, the stator assembly 3 is integrally formed, so that the stator cores are integrally formed. Clearance between 4, 5 and the magnet portion 6 can be eliminated. In addition, since press-fitting is performed from one direction, workability can be improved as compared with the case of press-fitting from two directions.
In addition, in FIG. 12 described above, it is necessary to press-fit the stator cores 102 and 103 having different outer diameters into the press-fit portions 112 and 113 having different inner diameters, but in the first embodiment, one stator core 4 is held. Since it is held by the other stator core 5 that is integrally formed, the press-fitting portion does not increase, and the housing cutting cost can be reduced. In addition, the cost of preparing stator cores having different outer diameters can be reduced.
Further, in FIG. 11 described above, it is necessary to install the positioning pin 111 on the housing 106 in order to position the teeth of the stator cores 102 and 103. In the first embodiment, a mold is used at the time of integral molding. Since the teeth of the stator cores 4 and 5 are positioned, the cost for using the positioning pins can be reduced. Further, the phase alignment of the teeth 4a of the stator cores 4 and 5 can be performed simultaneously with the integral molding.

  As described above, according to the first embodiment, the stator ASSY 3 of the electric motor 1 includes the stator cores 4 and 5 in which the annular body and the six teeth 4a protruding from the inner peripheral portion of the annular body toward the center are formed. An annular magnet portion 6 that magnetizes the rotor 9 in the rotation axis direction X, and a resin member that is integrally formed by sandwiching the magnet portion 6 between stator cores 4 and 5 provided on both sides. The magnet portion 6 and the stator cores 4 and 5 are The mold portion 7 is held at least on the inner peripheral side, and is press-fitted and fixed at a position surrounding the outer periphery of the rotor 9 of the cylindrical housing 2. For this reason, the clearance between the magnet portion 6 and the stator cores 4 and 5 can be eliminated, the influence of demagnetization due to the clearance is eliminated, and the motor characteristics (torque) are improved. Further, since it is not necessary to press the magnet portion 6 with the stator cores 4 and 5 so as to eliminate the clearance when the stator ASSY 3 is press-fitted into the housing 2, the magnet portion 6 is not damaged. In addition, the assembly to the housing 2 only needs to press-fit the stator ASSY 3 from one direction, and the phase alignment of the teeth 4a is unnecessary, so that the cost required for the assembly can be reduced.

  Moreover, according to Embodiment 1, since the resin member of the mold part 7 has thermosetting property, the heat resistance of the stator ASSY 3 is improved and thermal deformation can be suppressed. For this reason, the electric motor 1 can be used at high temperatures by using it for automobile parts and the like. In particular, PPS excellent in heat resistance and water resistance is suitable as the resin member.

  Further, according to the first embodiment, the mold portion 7 has a shape that closes the gap between the teeth 4a of the stator cores 4 and 5 and is flush with the tip surface of the teeth 4a. Sinking and sagging of members can be prevented.

  Further, according to the first embodiment, the magnet portion 6 has the same number of fan-shaped permanent magnets as the teeth 4 a of the stator cores 4, 5 arranged in an annular shape, and the outer peripheral portion of the permanent magnets is the teeth 4 a of the stator cores 4, 5. Since the radially outer portion corresponding to the formation portion is covered, the magnetic characteristics can be improved.

  Further, according to the first embodiment, a plurality of steel plates are laminated in the rotation axis direction X of the rotor 9 and are caulked together to form the stator cores 4, 5. Since positioning is performed by the crimped protrusion 4b, the number of parts does not increase for positioning the magnet portion 6. Further, since the permanent magnet is not displaced, good magnetic characteristics can be maintained.

In the illustrated example, the coil wound around each tooth of the stator core is a one-turn U-shaped coil. However, the present invention is not limited to this. In addition, although a total of six teeth for the stator core, two each for the U phase, the V phase, and the W phase, are provided, the present invention is not limited to this.
In addition to this, the present invention can be modified in any component of the embodiment or omitted in any component within the scope of the invention.

  As described above, since the permanent magnet and the stator core are integrally formed of the thermosetting resin member, the electric motor according to the present invention is used for an electric motor that rotationally drives an automobile turbocharger and an electric compressor that are exposed to high temperatures. Suitable for

  DESCRIPTION OF SYMBOLS 1 Electric motor, 2 Housing, 2a Press-fit part, 3 Stator, 4,5 Stator core, 4a Teeth, 4b Protrusion, 4c Positioning recessed part, 6 Magnet part, 7 Mold part, 7a Coil insertion hole, 8 U-shaped coil, 9 Rotor, 9a , 9b Projection, 10 Connection plate ASSY, 11 Copper plate coil, 12 Control circuit board, 13 Cover, 14 Connector part, 15 Position detection sensor, 16 Sensor target, 17 O-ring, 20 Upper mold, 21 Lower mold, 22 Central shaft, 23, 24 Air gap, 25 Resin inlet, 100 Electric motor, 101 Permanent magnet, 102, 103 Stator core, 104 Stator, 105 Rotor, 106 Housing, 107 Shaft, 108 Teeth, 109, 110 Clearance, 111 Positioning pin, 112, 113 Press fit part.

Claims (2)

A cylindrical housing;
A rotor part rotatably held in a central part of the housing;
A stator portion press-fitted and fixed at a position surrounding the outer periphery of the rotor portion of the housing,
The stator portion is
A stator core formed with a plurality of teeth projecting toward the center from the inner periphery of the annular body and the annular body;
An annular magnet portion for magnetizing the rotor portion in the rotation axis direction;
The sandwiches the magnet portion in the stator core which is provided on both sides made of integrally molded resin member, possess a mold portion for holding the magnet portion and the stator core at least the inner peripheral side,
The electric motor according to claim 1, wherein the mold portion has a shape that closes a gap between the teeth of the stator core and is flush with a front end surface of the teeth . A cylindrical housing;
A rotor part rotatably held in a central part of the housing;
A stator portion press-fitted and fixed at a position surrounding the outer periphery of the rotor portion of the housing,
The stator portion is
A stator core formed with a plurality of teeth projecting toward the center from the inner periphery of the annular body and the annular body;
An annular magnet portion for magnetizing the rotor portion in the rotation axis direction;
It is composed of a resin member integrally formed by sandwiching the magnet part between the stator cores provided on both sides, and has a mold part for holding the magnet part and the stator core at least on the inner peripheral side,
The magnet portion is formed by annularly arranging the same number of fan-shaped permanent magnets as the teeth of the stator core, and the outer peripheral portion of each permanent magnet covers a radially outer portion corresponding to the teeth forming portion of the stator core,
The stator core is formed by laminating a plurality of steel plates in the direction of the rotation axis of the rotor portion and caulking each other,
Each permanent magnet of the magnet unit, to that electric motive, characterized in that it is positioned in the projection crimped of the stator core.

Images