JP6870989B2 - Rotor and electric motor - Google Patents

Description

The present invention relates to a rotor and an electric motor.

Conventionally, as an electric motor, a stator having a tooth around which a coil is wound and a rotor rotatably provided inside the stator in the radial direction are provided, and the rotor is rotationally driven by controlling energization of the coil. Brushless motors are known.

A rotor of this type of brushless motor has a rotating shaft, a substantially cylindrical rotor core that is externally fitted and fixed to the rotating shaft, and a magnet provided on the rotor core.
As a method of arranging a magnet in a rotor, a permanent magnet embedding method (IPM: Interior Permanent Magnet) in which a plurality of slits are formed in a rotor core made of a magnetic material and a permanent magnet is arranged in the slits is known.

Further, in recent years, among IPM motors, permanent magnets are arranged (radially) in the rotor core along the radial direction, and the permanent magnets are given a shape having strong magnetic anisotropy to generate a large reluctance torque. PMR (Permanent Magnetic Reluctance) motors are known.

Japanese Unexamined Patent Publication No. 2015-21163 Japanese Unexamined Patent Publication No. 2016-67192

By the way, in the PMR motor, it is desirable to reduce the location where the magnetic flux leaks as much as possible because the magnetic circuit of the rotor core concentrates the magnetic flux. For example, if the distance between the permanent magnets adjacent to each other in the circumferential direction is as narrow as possible at the inner end in the radial direction of each permanent magnet, the wall thickness of the rotor core at this portion becomes thin and magnetic saturation occurs. As a result, the leakage flux inside the permanent magnet in the radial direction can be reduced, and the magnetic characteristics of the rotor can be improved.
However, if the rotor core has a thin portion, the rigidity of the thin portion becomes low. Therefore, there is a possibility that the rotor core will be deformed by the centrifugal force when the rotor rotates.

Therefore, the present invention has been made in view of the above circumstances, and provides a rotor and an electric motor capable of ensuring rigidity while suppressing deterioration of magnetic characteristics due to leakage flux.

In order to solve the above problem, the rotor according to the present invention includes a rotating shaft, fitted fixed cylindrical inner circumferential core to the rotating shaft, and is located radially outwardly of the inner circumferential core, Further, the rotor core having a plurality of magnetic pole cores arranged at predetermined intervals in the circumferential direction and the magnetic poles adjacent to each other in the circumferential direction so that one end in the radial direction abuts on the outer peripheral surface of the inner peripheral core. The rotor core includes a plurality of permanent magnets provided so as to fill the space between the portion cores, and the rotor core has a plurality of intermediate cores and a plurality of end cores composed of a plurality of electromagnetic steel plates laminated in the axial direction. The core comprises the inner peripheral core and the plurality of magnetic pole cores separate from the inner peripheral core, and the end core includes the inner peripheral core, the plurality of magnetic pole cores, and the inner peripheral core. The rotor core comprises an inner connecting portion that connects the plurality of magnetic pole portions cores along the radial direction, and the rotor core includes an outer peripheral surface of the inner peripheral core in the intermediate core and the magnetic pole portion core in the intermediate core. It is characterized by having an opening formed by an inner peripheral surface and the inner connecting portion of the end core.

Thus, the inner connecting portion that causes the leakage flux without forming over the entire axial direction, by forming a part, it is possible to reduce the magnetic path in the inner connecting portion. Therefore, it is possible to suppress the deterioration of the magnetic characteristics of the rotor due to the leakage flux while ensuring the required wall thickness as the wall thickness in the circumferential direction of the inner connecting portion.
With such a configuration, the rotor can be formed only by laminating the intermediate core and the end core, so that the manufacturing cost of the rotor can be reduced.
Further, since the intermediate core without the inner connecting portion and the outer peripheral connecting portion is arranged in most of the central part in the axial direction having a relatively high magnetic flux density, the magnetic flux leakage can be effectively reduced and it is effective on the outer peripheral surface of the rotor. Permanent magnets can be exposed to. Therefore, the magnetic characteristics of the rotor can be maximized while ensuring the rigidity of the rotor.

A rotor according to the present invention, the Endokoa is characterized in that a part of each other the plurality of magnetic pole portions adjacent cores further comprising an outer connecting portion connecting radially outer side of the permanent magnet in the circumferential direction.

In this way, the magnetic path of the inner connecting portion and the outer peripheral connecting portion as a whole can be reduced by forming the outer peripheral connecting portion, which causes the leakage flux, not in the entire axial direction but in a part thereof. Can be done. Therefore, it is possible to suppress the deterioration of the magnetic characteristics of the rotor due to the leakage flux while ensuring the required wall thickness as the wall thickness in the circumferential direction of the outer peripheral connecting portion.

The rotor according to the present invention is characterized in that the ratio of the intermediate core to the end core is set to 8: 2.

With this configuration, the magnetic characteristics of the rotor can be reliably enhanced while ensuring the rigidity of the rotor.

The rotor according to the present invention is characterized in that the end cores are arranged on both sides in the axial direction of the intermediate core.

With this configuration, magnetic flux leakage to the inner peripheral core side can be reduced.
Further, since the rotor can be formed only by laminating the intermediate core and the end core, the manufacturing cost of the rotor can be reduced.

In the rotor according to the present invention, the recesses are formed on both sides in the circumferential direction at the radial inner ends of the permanent magnets, and the inner connecting portions are formed between the permanent magnets adjacent to each other in the circumferential direction. It is characterized in that it is arranged between the recesses adjacent to each other in the circumferential direction.

With such a configuration, the number of formed portions of the inner connecting portion can be reduced as much as possible, and the magnetic flux leakage to the inner peripheral core side can be surely reduced.

The rotor according to the present invention is characterized in that each of the internal connecting portions is formed in a region of 1/4 with respect to the entire axial direction.

With this configuration, it is possible to minimize magnetic flux leakage due to the internal connecting portion while ensuring the rigidity of the rotor.

The rotor according to the present invention is characterized in that at least one of the circumferential width of the inner connecting portion and the radial width of the outer peripheral connecting portion is set to a width capable of magnetic saturation.

With such a configuration, magnetic flux leakage due to the internal connecting portion can be reliably suppressed.

In the electric motor according to the present invention, the rotor described above, the annular stator core formed so as to surround the rotor, and the inner peripheral surface of the stator core project radially inward, and the coil is wound. It is characterized by comprising a stator having a plurality of teeth to be formed.

With such a configuration, it is possible to provide an electric motor capable of ensuring rigidity while suppressing deterioration of magnetic characteristics due to leakage flux.

According to the present invention, the inner connecting portion and the outer peripheral connecting portion that cause the leakage flux are formed in a part of the inner connecting portion and the outer peripheral connecting portion without forming in the entire axial direction, so that the inner connecting portion and the outer peripheral connecting portion as a whole can be formed. The magnetic path can be reduced. Therefore, it is possible to suppress the deterioration of the magnetic characteristics of the rotor due to the leakage flux while ensuring the required wall thickness as the wall thickness of the inner connecting portion and the outer peripheral connecting portion in the circumferential direction.

It is a perspective view of the motor with a reduction gear in embodiment of this invention. It is sectional drawing which follows the AA line of FIG. FIG. 5 is a cross-sectional view orthogonal to the axial direction of the stator and rotor according to the first embodiment of the present invention. It is a perspective view of the rotor in 1st Embodiment of this invention. It is a perspective view of the rotor core in 1st Embodiment of this invention. It is a perspective view of the end electromagnetic steel sheet in 1st Embodiment of this invention. It is a perspective view of the intermediate electromagnetic steel sheet in 1st Embodiment of this invention. It is a graph which compared the effective magnetic flux amount of the rotor core in 1st Embodiment of this invention. It is a figure which shows the analysis result of the stress of the rotor core in 1st Embodiment of this invention. It is a perspective view of the rotor in the 2nd Embodiment of this invention. It is a perspective view of the rotor core in the 2nd Embodiment of this invention. It is a perspective view of the rotor core in 3rd Embodiment of this invention. It is a perspective view of the rotor core in 4th Embodiment of this invention.

Next, an embodiment of the present invention will be described with reference to the drawings.

(Motor with reducer)
FIG. 1 is a perspective view of the motor 1 with a speed reducer, and FIG. 2 is a cross-sectional view taken along the line AA of FIG.
As shown in FIGS. 1 and 2, the motor 1 with a speed reducer is, for example, a drive source for electrical components (for example, wipers, power windows, sunroofs, electric seats, etc.) mounted on a vehicle. The motor 1 with a speed reducer includes a motor unit 2, a speed reduction unit 3 that decelerates and outputs the rotation of the motor unit 2, and a controller unit 4 that controls the drive of the motor unit 2.
In the following description, the term "axial direction" refers to the axial direction of the rotating shaft 31 of the motor unit 2, the term "circumferential direction" refers to the circumferential direction of the rotating shaft 31, and the term simply "radial direction" refers to the axial direction. It refers to the radial direction of the rotating shaft 31.

(Motor part)
The motor unit 2 is provided with a motor case 5, a substantially cylindrical stator 8 housed in the motor case 5, and a rotor 9 provided inside the stator 8 in the radial direction and rotatably provided with respect to the stator 8. And have.

(Motor case)
The motor case 5 is made of a material having excellent heat dissipation, such as aluminum die-cast or an iron plate. The motor case 5 includes a first motor case 6 and a second motor case 7 which are configured to be rotatable in the axial direction. The first motor case 6 and the second motor case 7 are each formed in a bottomed tubular shape, and the motor cases 5 having an internal space are formed by fitting the openings 6a and 7a, respectively.

More specifically, the first motor case 6 is integrally molded with the gear case 40 so that the bottom portion 10 is joined to the gear case 40 of the speed reduction portion 3. A through hole 10a through which the rotating shaft 31 of the rotor 9 can be inserted is formed at substantially the center of the bottom portion 10 in the radial direction.
Further, the peripheral wall portion 11 of the first motor case 6 is formed so as to have a substantially regular hexagon when viewed from the axial direction. On the inner peripheral surface of the peripheral wall portion 11, a stator inner fitting portion 18 having an enlarged diameter formed by a step is formed on the opening 6a side. The outer peripheral surface of the stator 8 is fitted to the stator inner fitting portion 18. Further, on the outer peripheral surface of the peripheral wall portion 11 of the first motor case 6, a fitting portion 12 having a reduced diameter formed via a step portion 12a is formed on the opening 6a side. The fitting portion 12 is for fitting the opening 7a of the second motor case 7.

The peripheral wall portion 14 of the second motor case 7 is also formed so as to have a substantially regular hexagon when viewed from the axial direction so as to correspond to the shape of the peripheral wall portion 11 of the first motor case 6. On the outer peripheral surface of the peripheral wall portion 14, a ridge portion 16 is formed over the entire circumference on the opening 7a side. Further, in the opening 7a of the second motor case 7, a fitting portion 17 having an enlarged diameter formed by a step is formed. The fitting portion 17 and the fitting portion 12 of the first motor case 6 are fitted. Further, the stepped portion 12a of the first motor case 6 and the convex portion 16 of the second motor case 7 come into contact with each other to determine the relative positions of the first motor case 6 and the second motor case 7 in the axial direction. To.

(Stator)
FIG. 3 is a cross-sectional view of the stator 8 and the rotor 9 orthogonal to the axial direction.
As shown in FIGS. 2 and 3, the stator 8 includes a tubular core portion 21 and a plurality of teeth 22 (for example, six in the present embodiment) protruding inward in the radial direction from the core portion 21. Has an integrally molded stator core 20. The stator core 20 is formed by laminating a plurality of metal plates in the axial direction. The stator core 20 is not limited to the case where a plurality of metal plates are laminated in the axial direction, and may be formed by, for example, pressure molding soft magnetic powder.

The core portion 21 forms a magnetic path and constitutes an outer shell of the stator 8. The core portion 21 has a substantially regular hexagonal cross-sectional shape orthogonal to the axial direction so as to correspond to the shapes of the peripheral wall portions 11 and 14 of the two motor cases 6 and 7. The outer peripheral surface of the core portion 21 is internally fitted into the stator inner fitting portion 18 of the first motor case 6.

The tooth 22 is integrally formed with a tooth body 101 protruding in the radial direction from the inner peripheral surface of the core portion 21 and a flange portion 102 extending in the circumferential direction from the radial inner end of the tooth body 101. Is. The flange portion 102 is formed so as to extend from the tooth body 101 on both sides in the circumferential direction. Further, the inner peripheral surface 102a of the flange portion 102 is formed in an arc shape centered on the center C1 of the rotation axis. Then, a slot 19 is formed between the flange portions 102 adjacent to each other in the circumferential direction.

The inner peripheral surface of the core portion 21 and the teeth 22 are covered with a resin insulator 23. A coil 24 is wound around each tooth 22 from above the insulator 23. Each coil 24 generates a magnetic field for rotating the rotor 9 by supplying power from the controller unit 4.

(First Embodiment)
(Rotor)
FIG. 4 is a perspective view of the rotor 9.
As shown in FIGS. 2 to 4, the rotor 9 includes a rotating shaft 31, a columnar rotor core 32 outerly fitted and fixed to the rotating shaft 31, and a plurality of rotors 9 embedded in the rotor core 32 at equal intervals in the circumferential direction. (For example, in the first embodiment, four) permanent magnets 33 are provided. The rotating shaft 31 is integrally molded with the worm shaft 44 that constitutes the deceleration unit 3.

FIG. 5 is a perspective view of the rotor core 32.
As shown in the figure, the rotor core 32 is an intermediate core 111 formed by laminating a plurality of intermediate electromagnetic steel sheets 111a, and an end core 112 formed by laminating a plurality of end electromagnetic steel sheets 112a arranged on both sides in the axial direction of the intermediate core 111. It is composed of and.

FIG. 6 is a perspective view of the end electromagnetic steel sheet 112a.
As shown in the figure, the end electromagnetic steel sheets 112a are arranged at equal intervals in the circumferential direction so as to surround the inner peripheral portion 113 having a substantially annular shape that is externally fitted and fixed to the rotating shaft 31 and the inner peripheral portion 113. An inner connecting portion 117 that connects the four substantially fan-shaped magnetic pole portions 114, an inner peripheral portion 113 and the four magnetic pole portions 114, and an outer peripheral connection that connects the arcuate surfaces 114a of the magnetic pole portions 114 adjacent in the circumferential direction. The part 118 and the part 118 are integrated.

The inner diameter of the inner peripheral portion 113 is set so that the rotating shaft 31 can be press-fitted or inserted. Further, on the outer peripheral surface of the inner peripheral portion 113, four convex strip portions 115 are arranged at equal intervals in the circumferential direction. The ridge portion 115 is formed in a substantially rectangular shape that is long in the circumferential direction, and the lower bottom 33a of the permanent magnet 33, which will be described later, is brought into contact with the radial outer end 115a thereof.

The magnetic pole portion 114 is formed so as to be substantially fan-shaped in the axial plan view so as to fill the space between the permanent magnets 33 adjacent to each other in the circumferential direction. The magnetic pole portion 114 is arranged so that its arcuate surface 114a faces outward in the radial direction. Further, the magnetic pole portion 114 is arranged so that the tip portion 114b on the side opposite to the arc surface 114a faces the position substantially in the circumferential direction of the concave portion 119 formed in the inner peripheral portion 113 in the radial direction. ..

The arcuate surface 114a of the magnetic pole portion 114 constitutes the outer peripheral surface of the intermediate electromagnetic steel plate 111a (rotor core 32). Further, groove portions 116 are formed slightly before both ends of the arcuate surface 114a in the circumferential direction. The groove portion 116 is formed in a substantially triangular shape so as to taper inward in the radial direction.

An outer peripheral connecting portion 118 is formed on the circumferential end side of the arcuate surface 114a formed in this way with respect to the groove portion 116. By connecting the arcuate surfaces 114a of the magnetic pole portions 114 adjacent to each other in the circumferential direction by the outer peripheral connecting portion 118, the magnet accommodating portion 120 surrounded by these magnetic pole portions 114 and the outer peripheral connecting portion 118 is formed.
Since the magnetic pole portion 114 is formed in a substantially fan shape, the magnet accommodating portion 120 has an isosceles trapezoidal shape so that the width in the circumferential direction gradually increases as the shape in the axial plan view becomes inward in the radial direction. There is. Further, the magnet accommodating portion 120 formed in this way and the recess 119 formed in the inner peripheral portion 113 are communicated with each other.

Further, an inner connecting portion 117 is integrally formed at the center between the convex portions 115 adjacent to each other in the circumferential direction of the inner peripheral portion 113. The inner connecting portion 117 extends along the radial direction, and connects the inner peripheral portion 113 and the tip portion 114b of each magnetic pole portion 114. As a result, the inner peripheral portion 113 and the four magnetic pole portions 114 are integrated via the inner connecting portion 117. The inner connecting portion 117 has a rod shape extending along the radial direction, and the cross-sectional shape along the axial direction is substantially square. By forming the inner connecting portion 117, a concave portion 119 is formed between the inner connecting portion 117 and the convex portion 115, respectively.

Then, in this way, a plurality of end electromagnetic steel plates 112a in which the inner peripheral portion 113, the four magnetic pole portions 114, the four inner connecting portions 117, and the four outer peripheral connecting portions 118 are integrated (for example, the first one). In the embodiment, 4 sheets) are laminated. Further, the end core 112 is formed by integrating each end electromagnetic steel sheet 112a by, for example, caulking and fixing.

FIG. 7 is a perspective view of the intermediate electromagnetic steel sheet 111a.
As shown in the figure, the intermediate electromagnetic steel sheets 111a are arranged at equal intervals in the circumferential direction so as to surround the inner peripheral portion 113 which is substantially annular and fixed to the rotating shaft 31 and the inner peripheral portion 113. The four substantially fan-shaped magnetic pole portions 114 and the four magnetic pole portions 114 are divided and configured. That is, the intermediate electromagnetic steel sheet 111a is obtained by removing the inner connecting portion 117 and the outer peripheral connecting portion 118 from the end electromagnetic steel sheet 112a. Since the inner peripheral portion 113 and the magnetic pole portion 114 of the intermediate electromagnetic steel sheet 111a have the same configuration as the inner peripheral portion 113 and the magnetic pole portion 114 of the end electromagnetic steel sheet 112a, the same reference numerals are given and the description thereof will be omitted. ..

In this way, a plurality of (for example, 32 in this embodiment) intermediate electromagnetic steel sheets 111a in which the inner peripheral portion 113 and the four magnetic pole portions 114 are separately configured are laminated and caulked to be fixed, thereby fixing the intermediate core 111. Is formed.
Here, the intermediate core 111 itself remains divided into the laminated inner peripheral portion 113 and each magnetic pole portion 114. However, the end cores 112 are arranged at both ends in the axial direction of the intermediate core 111, and the intermediate core 111 and the end core 112 are integrated by, for example, caulking. Therefore, as shown in FIG. 5, the inner peripheral portion 113 of the intermediate core 111 and each magnetic pole portion 114 are integrated via the end core 112, and the rotor core 32 is further configured.

Then, as shown in FIG. 5, the rotor core 32 has a substantially cylindrical inner peripheral core 121 formed by laminating inner peripheral portions 113 and four magnetic pole portions extending in the axial direction formed by laminating magnetic pole portions 114. The core 122 is provided with an inner connecting portion 117 for connecting the inner peripheral core 121 and the magnetic pole portion core 122, and an outer peripheral connecting portion 118 for connecting the magnetic pole portion cores 122 adjacent to each other in the circumferential direction.
By fitting and fixing the inner peripheral core 121 to the rotating shaft 31, the entire rotor core 32 is fixed to the rotating shaft 31. The magnetic pole portion core 122 serves as a path for the magnetic flux formed by the permanent magnet 33 and the magnetic flux formed by the stator 8.

Further, openings 117a and 118a are formed in the inner connecting portion 117 and the outer peripheral connecting portion 118 of the rotor core 32 at positions corresponding to the intermediate core 111, respectively. Further, on the outer peripheral surface 32a of the rotor core 32, groove portions 116 are formed on both sides of each magnet accommodating portion 120 in the circumferential direction so as to extend in the entire axial direction.
Here, as shown in detail in FIG. 3, the two groove portions 116 located on both sides in the circumferential direction with the magnet accommodating portion 120 sandwiched have a circumferential length L1 between the centers in the circumferential direction in the flange portion 102 of the teeth 22. The circumference length of the inner peripheral surface is set to be longer than L2.

The permanent magnet 33 is fitted in the magnet storage portion 120 of the rotor core 32 configured in this way. The permanent magnet 33 is formed to have an isobaric shape so that the cross-sectional shape orthogonal to the axial direction gradually increases in the circumferential direction toward the inside in the radial direction so as to correspond to the shape of the magnet housing portion 120. Has been done. That is, the permanent magnet 33 is located between the lower base 33a located on the inner side in the radial direction, the upper base 33b located on the outer side in the radial direction, and the lower base 33a and the upper base 33b in the cross-sectional shape orthogonal to the axial direction. It has a pair of legs 33c and the like.

Further, since the permanent magnet 33 is magnetized in parallel orientation or polar anisotropic orientation and is formed so as to have an isosceles trapezoidal shape, the orientation for converging the magnetic flux is determined. It is on the outer peripheral side of the rotor core 32 (the teeth 22 side of the stator 8). As a result, the direction of the magnetic flux in the magnetic pole portion core 122 can be easily converged toward the teeth 22 side. Further, the magnetic flux can be concentrated in the magnetic pole core 122 without bringing the permanent magnets 33 adjacent to each other in the circumferential direction close to each other. Then, the q-axis magnetic path can be set large, and a high reluctance torque can be generated. Therefore, the effective magnetic flux of the rotor core 32 can be increased.

Further, in the state where the permanent magnet 33 is stored in the magnet storage portion 120, the upper bottom 33b is exposed to the outside in the radial direction through the opening 118a of the outer peripheral surface 32a of the rotor core 32.
On the other hand, the lower bottom 33a of the permanent magnet 33 is in contact with the radial outer end 115a of the convex portion 115 of the rotor core 32. Therefore, recesses 119 are interposed between the lower base 33a of the permanent magnet 33 and the inner peripheral core 121 of the rotor core 32 on both sides of the lower base 33a in the circumferential direction. That is, the recess 119 functions as a flux barrier (cavity) 119a that makes it difficult for the magnetic flux to pass through.

Further, the inner connecting portion 117 is arranged between the permanent magnets 33 adjacent to each other in the circumferential direction and between the recesses 119 adjacent to each other in the circumferential direction. Here, it is desirable that the width H1 of the inner connecting portion 117 in the circumferential direction is as narrow as possible within a range in which the rigidity of the rotor core 32 can be secured. Further, it is desirable that the width H1 of the inner connecting portion 117 is set to a width in which the magnetic flux of the permanent magnet 33 can be saturated.

(Deceleration part)
Returning to FIGS. 1 and 2, the speed reduction unit 3 includes a gear case 40 to which the motor case 5 is attached, and a worm speed reduction mechanism 41 housed in the gear case 40. The gear case 40 is made of a material having excellent heat dissipation such as aluminum die casting. The gear case 40 is formed in a box shape having an opening 40a on one surface, and has a gear accommodating portion 42 for accommodating the worm reduction mechanism 41 inside. Further, on the side wall 40b of the gear case 40, an opening 43 for communicating the through hole 10a of the first motor case 6 and the gear accommodating portion 42 is formed at a portion where the first motor case 6 is integrally molded. There is.

Further, three fixing brackets 54a, 54b, 54c are integrally molded on the side wall 40b of the gear case 40. These fixing brackets 54a, 54b, 54c are for fixing the motor 1 with a speed reducer to a vehicle body or the like (not shown). The three fixing brackets 54a, 54b, 54c are arranged at substantially equal intervals in the circumferential direction so as to avoid the motor portion 2. Anti-vibration rubber 55 is attached to each of the fixing brackets 54a, 54b, 54c. The anti-vibration rubber 55 is for preventing vibration when driving the motor 1 with a speed reducer from being transmitted to a vehicle body (not shown).

Further, a substantially cylindrical bearing boss 49 is projected from the bottom wall 40c of the gear case 40.
The bearing boss 49 is for rotatably supporting the output shaft 48 of the worm reduction mechanism 41, and is provided with a slide bearing (not shown) on the inner peripheral surface. Further, an O-ring (not shown) is attached to the inner peripheral edge of the tip of the bearing boss 49. As a result, dust and water are prevented from entering from the outside to the inside through the bearing boss 49. Further, a plurality of ribs 52 are provided on the outer peripheral surface of the bearing boss 49. As a result, the rigidity of the bearing boss 49 is ensured.

The worm reduction mechanism 41 housed in the gear accommodating portion 42 is composed of a worm shaft 44 and a worm wheel 45 meshed with the worm shaft 44. The worm shaft 44 is arranged coaxially with the rotating shaft 31 of the motor unit 2. The worm shaft 44 is rotatably supported at both ends by bearings 46 and 47 provided on the gear case 40. The end of the worm shaft 44 on the motor portion 2 side projects through the bearing 46 to the opening 43 of the gear case 40. The end of the protruding worm shaft 44 and the end of the rotating shaft 31 of the motor unit 2 are joined, and the worm shaft 44 and the rotating shaft 31 are integrated. The worm shaft 44 and the rotating shaft 31 may be integrally formed by forming the worm shaft portion and the rotating shaft portion from one base material.

The worm wheel 45 meshed with the worm shaft 44 is provided with an output shaft 48 at the center of the worm wheel 45 in the radial direction. The output shaft 48 is arranged coaxially with the rotation axis direction of the worm wheel 45, and projects to the outside of the gear case 40 via the bearing boss 49 of the gear case 40. A spline 48a that can be connected to an electrical component (not shown) is formed at the protruding tip of the output shaft 48.

Further, at the center of the worm wheel 45 in the radial direction, a sensor magnet (not shown) is provided on the side opposite to the side on which the output shaft 48 is projected. This sensor magnet constitutes one of the rotation position detection units 60 that detects the rotation position of the worm wheel 45. The magnetic detection element 61 that constitutes the other side of the rotation position detection unit 60 is provided on the controller unit 4 that is arranged to face the worm wheel 45 on the sensor magnet side of the worm wheel 45 (the opening 40a side of the gear case 40). There is.

(Controller part)
The controller unit 4 that controls the drive of the motor unit 2 has a controller board 62 on which the magnetic detection element 61 is mounted, and a cover 63 provided so as to close the opening 40a of the gear case 40. The controller board 62 is arranged to face the sensor magnet side of the worm wheel 45 (the opening 40a side of the gear case 40).

The controller substrate 62 is a so-called epoxy substrate in which a plurality of conductive patterns (not shown) are formed. The terminal portion of the coil 24 drawn from the stator core 20 of the motor portion 2 is connected to the controller board 62, and the terminals of the connector provided on the cover 63 (both not shown) are electrically connected to the controller board 62. There is. Further, in addition to the magnetic detection element 61, the controller board 62 is applied to a power module or a controller board including switching elements such as FETs (Field Effect Transistors) that control the current supplied to the coil 24. A capacitor (not shown) that smoothes the voltage is mounted.

The cover 63 that covers the controller substrate 62 configured in this way is made of resin and is formed so as to bulge slightly outward. The inner surface side of the cover 63 is a controller accommodating portion 56 for accommodating the controller board 62 and the like.
Further, a connector (not shown) is integrally molded on the outer peripheral portion of the cover 63. This connector is formed so as to be fitted with a connector extending from an external power supply (not shown). The controller board 62 is electrically connected to the terminals of a connector (not shown). As a result, the electric power of the external power source is supplied to the controller board 62.

Further, a fitting portion 81 that is fitted with the end portion of the side wall 40b of the gear case 40 is formed so as to project from the opening edge of the cover 63. The fitting portion 81 is composed of two walls 81a and 81b along the opening edge of the cover 63. Then, the end of the side wall 40b of the gear case 40 is inserted (fitted) between these two walls 81a and 81b. As a result, the labyrinth portion 83 is formed between the gear case 40 and the cover 63. The labyrinth portion 83 prevents dust and water from entering between the gear case 40 and the cover 63. The gear case 40 and the cover 63 are fixed by fastening bolts (not shown).

(Operation of motor with reducer)
Next, the operation of the motor 1 with a speed reducer will be described.
In the motor 1 with a speed reducer, the electric power supplied to the controller board 62 via a connector (not shown) is selectively supplied to each coil 24 of the motor unit 2 via a power module (not shown). Then, a predetermined magnetic field is formed in the stator 8 (teeth 22), and a magnetic attractive force or a repulsive force is generated between the magnetic field and the permanent magnet 33 of the rotor 9. As a result, the rotor 9 continuously rotates.

When the rotor 9 rotates, the worm shaft 44 integrated with the rotating shaft 31 rotates, and the worm wheel 45 meshed with the worm shaft 44 rotates. Then, the output shaft 48 connected to the worm wheel 45 rotates, and the desired electrical component is driven.

Further, the rotation position detection result of the worm wheel 45 detected by the magnetic detection element 61 mounted on the controller board 62 is output as a signal to an external device (not shown).
In the external device (not shown), the switching timing of the switching element of the power module (not shown) is controlled based on the rotation position detection signal of the worm wheel 45, and the drive control of the motor unit 2 is performed. The output of the drive signal of the power module and the drive control of the motor unit 2 may be performed by the controller unit 4.

(Rotor action and effect)
Next, the action and effect of the rotor 9 will be described.
The rotor core 32 of the rotor 9 includes an inner peripheral core 121 that is externally fitted and fixed to the rotating shaft 31, a magnetic pole core 122 that constitutes a magnetic pole, and an inner connecting portion 117 that connects the inner peripheral core 121 and the magnetic pole core 122. It is composed of an outer peripheral connecting portion 118 for connecting the magnetic pole portion cores 122 adjacent to each other in the circumferential direction. Of these, openings 117a and 118a are formed in the inner connecting portion 117 and the outer peripheral connecting portion 118. That is, the inner connecting portion 117 connects a part of the inner peripheral core 121 and the magnetic pole portion core 122. Further, the outer peripheral connecting portion 118 connects a part of the magnetic pole portion cores 122 to each other.

In this way, the inner connecting portion 117 and the outer peripheral connecting portion 118, which cause the leakage flux, are formed in a part of the inner connecting portion 117 and the outer peripheral connecting portion 118 without being formed over the entire axial direction. The magnetic path as can be reduced. Therefore, it is possible to suppress the deterioration of the magnetic characteristics of the rotor 9 due to the leakage flux while ensuring the required wall thickness as the wall thickness of the inner connecting portion 117 and the outer peripheral connecting portion 118 in the circumferential direction.

Further, in forming the openings 117a and 118a in the inner connecting portion 117 and the outer peripheral connecting portion 118, the rotor core 32 is divided into the inner peripheral portion 113 and the magnetic pole portion 114, and the intermediate core 111 and the inner peripheral portion thereof. It is composed of an inner connecting portion 117 for connecting 113 and a magnetic pole portion 114, and an end core 112 having an outer peripheral connecting portion 118. Therefore, the rotor core 32 having the openings 117a and 118a can be formed only by laminating the intermediate core 111 and the end core 112. Therefore, the manufacturing cost of the rotor 9 can be reduced.

Here, in the permanent magnet 33, the magnetic flux densities at both ends in the axial direction are more likely to decrease than most of the magnetic flux densities in the center in the axial direction. Therefore, by arranging the intermediate core 111 without the inner connecting portion 117 and the outer peripheral connecting portion 118 at a position corresponding to most of the axial center of the permanent magnet 33 having a relatively high magnetic flux density, the magnetic flux leakage of the rotor core 32 Can be effectively reduced. Further, the permanent magnet 33 can be effectively exposed on the outer peripheral surface 32a of the rotor core 32. Therefore, the magnetic characteristics of the rotor 9 can be maximized while ensuring the rigidity of the rotor 9.

Further, in the first embodiment, the intermediate core 111 is composed of 32 intermediate electromagnetic steel sheets 111a, and the end core 112 is composed of four end electromagnetic steel sheets 112a. In other words, the ratio of the intermediate core 111 and the end core 112 constituting the rotor core 32 is set to 8: 2. If this is referred to only as the inner connecting portion 117, the inner connecting portion 117 is formed in a region 1/4 of the entire axial direction of the portion where the inner connecting portion 117 is formed. Further, in terms of only the outer peripheral connecting portion 118, the outer peripheral connecting portion 118 is formed in a region 1/4 of the entire axial direction of the portion where the outer peripheral connecting portion 118 is formed.
With this configuration, the rigidity of the rotor core 32 can be reliably ensured, and the magnetic characteristics of the rotor core 32 can be reliably enhanced. This will be described in more detail below.

FIG. 8 is a graph comparing the effective magnetic flux amounts of the rotor core 32 according to the ratio of the intermediate core 111 and the end core 112 (0:10, 5: 5, 8: 2).
As shown in the figure, it can be confirmed that an excellent effective magnetic flux amount can be obtained when the ratio of the intermediate core 111 to the end core 112 is 8: 2.

FIG. 9 is a diagram showing an analysis result of stress applied when the rotor core 32 is rotated when the ratio of the intermediate core 111 to the end core 112 is 8: 2.
As shown in the figure, it can be confirmed that the inner connecting portion 117 and the outer peripheral connecting portion 118 of the end core 112 allow the rotor core 32 to have sufficient strength without scattering the magnetic pole portion core 122 and the permanent magnet 33. ..

Further, by forming the recess 119 in the inner peripheral core 121 (inner peripheral portion 113) of the rotor core 32, the flux barrier 119a is formed between the lower bottom 33a of the permanent magnet 33 and the inner peripheral core 121 of the rotor core 32. The magnet. Therefore, the magnetic flux leakage to the inner peripheral core 121 side of the permanent magnet 33 can be reduced more reliably.

In this way, the recesses 119 are formed on both sides of the lower bottom 33a of each permanent magnet 33 in the circumferential direction. Further, the inner connecting portion 117 is arranged between the permanent magnets 33 adjacent to each other in the circumferential direction and between the recesses 119 adjacent to each other in the circumferential direction. Therefore, the inner peripheral core 121 and the magnetic pole core 122 can be integrated while minimizing the arrangement location of the inner connecting portion 117. Therefore, the magnetic flux leakage of the permanent magnet 33 can be reduced as much as possible while the rotor core 32 is integrated while ensuring sufficient strength.
Further, by setting the width H1 of the inner connecting portion 117 in the circumferential direction to a width in which the magnetic flux of the permanent magnet 33 can be saturated, the magnetic flux leakage of the permanent magnet 33 to the inner peripheral core 121 side can be surely reduced.

Further, on the outer peripheral surface 32a of the rotor core 32, groove portions 116 are formed on both sides of each magnet accommodating portion 120 in the circumferential direction so as to extend in the entire axial direction. Further, in the two groove portions 116 located on both sides in the circumferential direction with the magnet accommodating portion 120 in between, the circumferential length L1 between the centers in the circumferential direction is larger than the circumferential length L2 of the inner peripheral surface of the flange portion 102 of the teeth 22. Is also set long. At the location where the groove 116 is formed, the gap between the rotor core 32 and the teeth 22 of the stator 8 becomes large. Therefore, in the groove 116, the influence of the magnetic flux of the rotor core 32 on the teeth 22 is reduced. That is, by forming the groove portion 116 on the outer peripheral surface 32a of the rotor core 32, it is possible to suppress a sudden change in the magnetic flux due to the location where the permanent magnet 33 is arranged and the location other than the permanent magnet 33, and the cogging of the rotor 9 can be suppressed. Can be suppressed.

(Second Embodiment)
(Rotor)
Next, the second embodiment will be described with reference to FIGS. 10 and 11.
FIG. 10 is a perspective view of the rotor 209 according to the second embodiment, and corresponds to FIG. 4 described above. FIG. 11 is a perspective view of the rotor core 232 according to the second embodiment, and corresponds to FIG. 5 described above.

As shown in FIGS. 10 and 11, the difference between the first embodiment and the second embodiment is that the rotor core 32 of the first embodiment has an intermediate core 111 and both sides of the intermediate core 111 in the axial direction. In contrast to the rotor core 232 of the second embodiment, the intermediate electromagnetic steel plates 111a constituting the intermediate core 111 and the end electromagnetic steel plates 112a constituting the end core 112 are alternately arranged. It is in the point of being stacked. End electromagnetic steel sheets 112a are arranged at both ends of the rotor core 232 in the axial direction.
Even with such a configuration, the volumes of the inner connecting portion 117 and the outer peripheral connecting portion 118, which cause magnetic flux leakage of the permanent magnet 33, can be reduced, so that the same effect as that of the first embodiment described above can be reduced. Play.

(Third Embodiment)
(Rotor core)
Next, a third embodiment will be described with reference to FIG.
FIG. 12 is a perspective view of the rotor core 332 according to the third embodiment, and corresponds to FIG. 5 described above.
As shown in the figure, the rotor core 332 of the third embodiment is not formed with the outer peripheral connecting portion 118, and the inner peripheral core 121 and the magnetic pole portion core 122 are integrated only by the inner connecting portion 117. .. This point is different from the above-described first embodiment.

Here, by forming the opening 117a in the inner connecting portion 117, the inner connecting portion 117 is formed in a region 1/4 of the entire axial direction of the portion where the inner connecting portion 117 is formed. It becomes a shape.
Further, instead of forming the outer peripheral connecting portion 118 (see FIG. 5) on the rotor core 332, the rotor core 332 projects toward the outer peripheral portion of the magnetic pole portion core 122 toward the magnet accommodating portion 120 and along the circumferential direction. The claw portion 131 is formed. The claw portion 131 can prevent the permanent magnet 33 (not shown in FIG. 12) from coming out from the rotor core 332 toward the outer side in the radial direction.

As described above, in the above-described third embodiment, the area of the permanent magnet 33 exposed on the outer peripheral surface 332a of the rotor core 332 is increased by the amount that the outer peripheral connecting portion 118 is not formed. Therefore, in addition to the same effect as that of the first embodiment described above, the magnetic characteristics of the rotor 309 can be improved.

(Fourth Embodiment)
(Rotor core)
Next, a fourth embodiment will be described with reference to FIG.
FIG. 13 is a perspective view of the rotor core 432 according to the fourth embodiment, and corresponds to FIG. 5 described above.
Since the comparison with the above-mentioned second embodiment is easy to understand, the present fourth embodiment is compared with the second embodiment. That is, as shown in FIGS. 11 and 13, the difference between the above-mentioned second embodiment and the present fourth embodiment is that in the above-mentioned second embodiment, the outer peripheral connecting portion 118 is formed. In the fourth embodiment, the outer peripheral connecting portion 118 is not formed, and the inner peripheral core 121 and the magnetic pole portion core 122 are integrated only by the inner connecting portion 117.

The rotor core 432 is not formed with the outer peripheral connecting portion 118 (see FIG. 11), but instead protrudes toward the outer peripheral portion of the magnetic pole portion core 122 toward the magnet accommodating portion 120 and along the circumferential direction. The claw portion 131 is formed. The claw portion 131 can prevent the permanent magnet 33 (not shown in FIG. 13) from coming out from the rotor core 332 toward the outer side in the radial direction.
Even in the case of such a configuration, the same effect as that of the above-described third embodiment is obtained.

The present invention is not limited to the above-described embodiment, and includes various modifications to the above-described embodiment without departing from the spirit of the present invention.
For example, in the above-described embodiment, the case where the motor 1 with a speed reducer is a drive source for electrical components (for example, a power window, a sunroof, an electric seat, etc.) mounted on a vehicle has been described. However, the present invention is not limited to this, and the motor 1 with a speed reducer can be used for various purposes.
It is also possible to use the motor unit 2 alone in various devices without providing the speed reduction unit 3.

Further, in the above-described embodiment, a case where four magnet housing portions 120 are formed in the rotor cores 32, 232, 332, 432 and four permanent magnets 33 are provided in the rotor cores 32, 232, 332, 432 has been described. However, the number is not limited to this, and the number of magnet housing portions 120 of the rotor cores 32, 232, 332, 432 and the number of permanent magnets 33 can be arbitrarily set.

Further, in the above-described embodiment, a case where a recess 119 is formed in the inner peripheral core 121 of the rotor cores 32, 232, 332, 432 and the recess 119 functions as a flux barrier 119a that makes it difficult for magnetic flux to pass through has been described. However, the present invention is not limited to this, and the recess 119 may be filled with an insulating material such as resin. With this configuration, the rigidity of the rotor cores 32, 232, 332, and 432 can be increased while suppressing the magnetic flux leakage of the permanent magnet 33 inward in the radial direction (inner peripheral core 121 side).

Further, in the above-described embodiment, the case where a plurality of electrical steel sheets (intermediate electrical steel sheet 111a, end electrical steel sheet 112a) are laminated to form the rotor cores 32, 232, 332, 432 has been described. However, the present invention is not limited to this, and it is sufficient that a shape such as the rotor cores 32, 232, 332, 432 can be finally formed. That is, for example, the rotor cores 32, 232, 332, 432 can be formed into a so-called powder core structure in which soft magnetic powder is pressure-molded.

1 ... Motor with speed reducer, 2 ... Motor unit (electric motor), 8 ... Stator, 9,209,309 ... Rotor, 20 ... Stator core, 22 ... Teeth, 24 ... Coil, 31 ... Rotating shaft, 32,332,432 ... Rotor core, 33 ... Permanent magnet, 111 ... Intermediate core, 111a ... Intermediate electromagnetic steel sheet (Electromagnetic steel sheet), 112 ... End core, 112a ... End electromagnetic steel sheet (Electromagnetic steel sheet), 113 ... Inner circumference, 114 ... Magnetic steel sheet 117 ... Inner connecting part, 118 ... Outer connecting part, 119 ... Recessed part, 119a ... Flux barrier (cavity part), 121 ... Inner peripheral core, 122 ... Magnetic pole core, H1 ... Width

Claims (8)

Rotation axis and
Having said fitted to the rotary shaft fixed cylindrical inner circumferential core, and is located radially outwardly of the inner circumferential core and circumferentially arranged at predetermined intervals a plurality of magnetic pole portions core With the rotor core
A plurality of permanent magnets provided so as to abut one end in the radial direction on the outer peripheral surface of the inner peripheral core and to fill the space between the magnetic pole cores adjacent in the circumferential direction.
Equipped with a,
The rotor core has a plurality of intermediate cores and a plurality of end cores composed of a plurality of electrical steel sheets laminated in the axial direction.
The intermediate core
With the inner core
The plurality of magnetic pole cores that are separate from the inner core,
Consists of
The end core
With the inner core
With the plurality of magnetic pole cores
An inner connecting portion that connects the inner peripheral core and the plurality of magnetic pole portion cores along the radial direction, and an inner connecting portion.
Consists of
The rotor core has an opening formed by an outer peripheral surface of the inner peripheral core of the intermediate core, an inner peripheral surface of the magnetic pole core of the intermediate core, and an inner connecting portion of the end core. /> A rotor characterized by that. The end core according to claim 1, further comprising an outer peripheral connecting portion for connecting a part of the plurality of magnetic pole portion cores adjacent to each other in the circumferential direction on the radial outer side of the permanent magnet. Rotor. The rotor according to claim 1 or 2, wherein the ratio of the intermediate core to the end core is set to 8: 2. The end cores are arranged on both sides of the intermediate core in the axial direction.
The rotor according to claim 3. Claims 1 to 4 are characterized in that a plurality of recesses are formed in the inner peripheral core so that a plurality of cavities are formed between the inner peripheral core and the permanent magnet. The rotor according to any one of the above. The recesses are formed on both sides in the circumferential direction at the radial inner end of each permanent magnet.
The rotor according to claim 5 , wherein the inner connecting portion is arranged between the permanent magnets adjacent to each other in the circumferential direction and between the recesses adjacent to each other in the circumferential direction. Wherein the connecting portion of the circumferential width, and wherein the at least one of the radial width of the outer peripheral coupling portion, of the claims 2 to 6, characterized in that it is set to a magnetic saturable width The rotor according to any one item. The rotor according to any one of claims 1 to 7.
An annular stator core formed so as to surround the rotor, and a stator having a plurality of teeth protruding inward in the radial direction from the inner peripheral surface of the stator core and winding a coil.
An electric motor characterized by being equipped with.

Images