JP2009254005A - Motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor which outputs a large torque in the case of being set to a somewhat stronger field phase in a low-speed range, and outputs its induced voltage sufficiently in the case of being set to a weaker field phase in a high-speed range. <P>SOLUTION: The motor is equipped with: an outer rotor 5 which has a plurality of peripheral permanent magnets 9A that are arranged at specified intervals in its circumferential direction so that the direction of magnetization faces in the circumferential direction; an inner rotor 6 which has a plurality of inner permanent magnets 9B that are provided concentrically with the outer rotor and are arranged at specified intervals in its circumferential direction so that the direction of magnetization faces in its radial direction; and a means which changes the relative phase between the outer rotor and the inner rotor. Herein, the length Win in the direction of magnetization of the inner permanent magnet and the length Wout in the direction of magnetization of the peripheral permanent magnet are the same, and the area of magnetic flux generating face of the inner permanent magnet is double the area of the magnetic flux generating face of the outer permanent magnet. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electric motor capable of changing the field characteristics of a permanent magnet provided in a rotor.

For example, as a conventional electric motor, provided with an inner peripheral side rotor having an inner peripheral side permanent magnet and an outer peripheral side rotor having an outer peripheral side permanent magnet provided concentrically with each other around a rotation shaft, There has been proposed a technique in which the field characteristics of a permanent magnet are controlled by changing the phase between the side rotor and the outer rotor (see, for example, Patent Document 1). In the electric motor described in Patent Document 1, a member that is displaced in the radial direction by the action of a centrifugal force is used, or each rotor rotates to a stator winding while maintaining a rotation speed due to inertia. The phase of each rotor is changed by generating a magnetic field.
JP 2002-204541 A

  By the way, in the electric motor, the torque can be increased by controlling the field strongly in the low speed region, and the induced voltage generated in the stator winding is controlled by weakly controlling the field in the high speed region. It is desirable that the number of rotations can be increased by reducing the speed.

  In the electric motor described in Patent Document 1, it is described that the field weakening phase is set in a high speed region, but the magnetic flux generated by the permanent magnet of the outer rotor is more than the magnetic flux generated by the permanent magnet of the inner rotor. In the case where is stronger, there is a problem that the magnetic flux exerted on the stator cannot be weakened, and as a result, the induced voltage cannot be reduced sufficiently.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to set a strong field phase in the low speed range and to set a weak field phase in the high speed range. It is an object of the present invention to provide an electric motor that can sufficiently reduce the induced voltage.

  In order to achieve the above-described object, the invention according to claim 1 is directed to a plurality of outer peripheral side permanent magnets (for example, outer periphery in the embodiment) arranged at predetermined intervals in the circumferential direction so that the magnetization direction thereof is in the circumferential direction. The outer circumferential rotor (for example, the outer circumferential rotor 5 in the embodiment) provided with the side permanent magnet 9A) is provided concentrically with the outer circumferential rotor, and the circumferential direction is such that the magnetization direction is in the radial direction. An inner circumferential rotor (for example, the inner circumferential rotor 6 in the embodiment) having a plurality of inner circumferential permanent magnets (for example, the inner circumferential permanent magnet 9B in the embodiment) arranged at predetermined intervals in Phase changing means capable of changing a relative phase between the outer circumferential rotor and the inner circumferential rotor by rotating at least one of the outer circumferential rotor and the inner circumferential rotor. For example, the phase changing means 12) in the embodiment and The magnetization direction length of the inner peripheral permanent magnet (for example, the magnetization direction length Win in the embodiment) is the magnetization direction length of the outer peripheral permanent magnet (for example, the embodiment). Is the same as the magnetization direction length Wout), and the area of the magnetic flux generating surface of the inner peripheral permanent magnet (for example, the area Lin in the embodiment) is the area of the magnetic flux generating surface of the outer peripheral permanent magnet (for example, The area is twice the area Wout) in the embodiment.

  According to a second aspect of the present invention, in the electric motor according to the first aspect, each inner peripheral permanent magnet is constituted by a pair of permanent magnets having the same dimensions.

  According to a third aspect of the present invention, there is provided an outer peripheral rotor including a plurality of outer peripheral permanent magnets arranged at predetermined intervals in the circumferential direction so that the magnetization direction thereof is in the circumferential direction, and concentric with the outer rotor. An inner peripheral rotor having a plurality of inner peripheral permanent magnets arranged at predetermined intervals in the circumferential direction so that the magnetization direction thereof is in the radial direction, the outer peripheral rotor, and the inner periphery A phase changing means capable of changing a relative phase between the outer peripheral rotor and the inner peripheral rotor by rotating at least one of the side rotors, The magnetizing direction length of the inner peripheral side permanent magnet is the same as the magnetizing direction length of the outer peripheral side permanent magnet, and the area of the magnetic flux generating surface of the inner peripheral side permanent magnet is the same as that of the outer peripheral side permanent magnet. It is characterized by being 1.6 to 2 times the surface area.

  According to the electric motor of the first aspect, a large torque can be produced when the strong field phase is set, and the induced voltage when the weak field phase is controlled can be made substantially zero, Iron loss can be reduced sufficiently.

  According to the electric motor of the second aspect, the same permanent magnet can be used for the outer peripheral side rotor and the inner peripheral side rotor, and productivity can be improved.

  According to the electric motor of the third aspect, when a strong field phase is set, a large torque can be output, and an induced voltage when controlling to the weak field phase is controlled to the strong field phase. It can be suppressed to 10% or less of the induced voltage, and the motor iron loss can be sufficiently reduced.

(First embodiment)
Hereinafter, the electric motor which concerns on 1st Embodiment of this invention is demonstrated in detail based on drawing. As shown in FIGS. 1 and 2, the electric motor 1 of the present embodiment is an inner rotor type brushless DC motor in which a rotor unit 3 is arranged on the inner peripheral side of an annular stator 2, for example, a hybrid vehicle And used as a driving source for electric vehicles and the like. The stator 2 has a multi-phase stator winding 2a, and the rotor unit 3 has a rotating shaft 4 at the shaft core. When the electric motor 1 is used as a vehicle driving source, the rotational force of the electric motor 1 is transmitted to a wheel drive shaft (not shown) via a transmission (not shown). In this case, if the electric motor 1 is caused to function as a generator when the vehicle is decelerated, the generated power can be recovered as regenerative energy in the battery. In the hybrid vehicle, the rotating shaft 4 of the electric motor 1 can be further connected to a crankshaft (not shown) of the internal combustion engine so that it can be used for power generation by the internal combustion engine.

  The rotor unit 3 includes an annular outer circumferential rotor 5 and an annular inner circumferential rotor 6 disposed concentrically inside the outer circumferential rotor 5. The circumferential rotor 6 is rotatable relative to a set angle range.

  In the outer peripheral side rotor 5 and the inner peripheral side rotor 6, the annular rotor cores 7 and 8 which are rotor main bodies are made of, for example, a laminated steel plate in which a plurality of electromagnetic steel plates are laminated in a direction along the rotation axis 4. A plurality of magnet mounting slots 7a, 8a extending in the axial direction are provided in the rotor cores 7, 8 along the circumferential direction.

  Each of the magnet mounting slots 7a and 8a is mounted with a flat plate-like outer peripheral permanent magnet 9A and inner peripheral permanent magnet 9B magnetized in the thickness direction. In this case, as shown in FIGS. 3A and 3B, the plurality of outer peripheral side permanent magnets 9A have a predetermined interval in the circumferential direction (this embodiment) so that the magnetization direction (thickness direction) faces the circumferential direction. The inner permanent magnets 9B are arranged at a predetermined interval in the circumferential direction (22.5 ° in this embodiment) so that the magnetization direction (thickness direction) faces the radial direction. ).

  The same number of outer peripheral side permanent magnets 9A and inner peripheral side permanent magnets 9B (8 pole pairs in this embodiment) are provided, and the direction of the magnetic poles of the outer peripheral side permanent magnets 9A adjacent in the circumferential direction on the outer peripheral side rotor 5 Are set in reverse, and the direction of the magnetic pole of the inner peripheral side permanent magnet 9B adjacent in the circumferential direction on the inner peripheral side rotor 6 is also set in reverse.

  As shown in FIG. 2, the magnetization direction length Win of the inner peripheral permanent magnet 9B is set to be the same as the magnetization direction length Wout of the outer peripheral permanent magnet 9A. Moreover, the length Lin in the circumferential direction of the inner peripheral side permanent magnet 9B is set to be twice the length Lout in the radial direction of the outer peripheral side permanent magnet 9A. For this reason, since the length in the axial direction of the outer peripheral side permanent magnet 9A and the inner peripheral side permanent magnet 9B is substantially the same, the area of the magnetic flux generating surface of the inner peripheral side permanent magnet 9B is the magnetic flux of the outer peripheral side permanent magnet 9A. It is set to twice the area of the generation surface.

  As shown in FIG. 3A, the same polarity of the inner peripheral permanent magnet 9B, that is, the N pole (or S pole) is opposed to the opposite N pole (or S pole) of the adjacent outer peripheral permanent magnet 9A. As described above, when the relative rotation angle between the outer rotor 5 and the inner rotor 6 is adjusted, a strong field phase state in which the field of the entire rotor unit 3 is most enhanced can be obtained. On the other hand, as shown in FIG. 3B, the opposite pole of the inner peripheral side permanent magnet 9B, that is, the S pole (or N pole) is opposed to the opposite N pole (or S pole) of the adjacent outer peripheral permanent magnet 9A. As described above, when the relative rotation angle between the outer circumferential rotor 5 and the inner circumferential rotor 6 is adjusted, the field weakening phase where the field of the entire rotor unit 3 is weakened most can be obtained.

  The rotor unit 3 includes a rotation mechanism 11 for relatively rotating the outer peripheral rotor 5 and the inner peripheral rotor 6. This rotating mechanism 11 constitutes a phase changing means 12 for arbitrarily changing the relative phase of both the rotors 5 and 6, and is operated by the pressure of the working fluid which is an incompressible working fluid. It is like that. The phase changing means 12 includes the above-described rotation mechanism 11 and a hydraulic pressure control device (not shown) that controls supply and discharge of hydraulic fluid to and from the rotation mechanism 11 as main elements.

  The rotating mechanism 11 includes a vane rotor 14 that is spline-fitted to the outer periphery of the rotating shaft 4 so as to be integrally rotatable, and an annular housing 15 that is disposed to be relatively rotatable on the outer peripheral side of the vane rotor 14. Are integrally fitted and fixed to the inner peripheral surface of the inner rotor 6, and the vane rotor 14 is a pair of disk-like members straddling the end faces of both sides of the annular housing 15 and the inner rotor 6 in the axial direction. It is integrally coupled to the outer peripheral rotor 5 via drive plates 16A and 16B (end plates). Therefore, the vane rotor 14 is integrated with the rotary shaft 4 and the outer peripheral rotor 5, and the annular housing 15 is integrated with the inner peripheral rotor 6. In the figure, reference numeral 22 denotes a bolt for connecting the drive plates 16A, 16B and the vane rotor 14, and reference numeral 23 denotes a bolt for connecting the drive plates 16A, 16B to the outer peripheral rotor 5.

  In the vane rotor 14, a plurality of vanes 18 protruding radially outward are provided at equal intervals in the circumferential direction on the outer periphery of a cylindrical boss portion 17 that is spline-fitted to the rotary shaft 4. On the other hand, the annular housing 15 is provided with a plurality of concave portions 19 on the inner peripheral surface at equal intervals in the circumferential direction, and the corresponding vanes 18 of the vane rotor 14 are accommodated in these concave portions 19. Each recess 19 includes a bottom wall 20 having an arcuate surface that substantially matches the rotational trajectory of the tip of the vane 18, and a partition wall 21 that defines the adjacent recesses 19, and the relative relationship between the vane rotor 14 and the annular housing 15. At the time of rotation, the vane 18 moves between the one partition wall 21 and the other partition wall 21. The tip of each vane 18 is provided with a seal member 31 including a seal 31a that is slidably contacted with the bottom wall 20 along the axial direction, and a spring 31b that presses the seal 31a toward the bottom wall 20. The space between the vane 18 and the bottom wall 20 is liquid-tightly sealed. Further, a seal 32 a which is slidably contacted with the outer peripheral surface of the boss portion 17 along the axial direction at the distal end portion of each partition wall 21 and a spring 32 b which presses the seal 32 a toward the outer peripheral surface of the boss portion 17. The member 32 is provided and seals between the partition wall 21 and the outer peripheral surface of the boss portion 17 in a liquid-tight manner.

  The drive plates 16A and 16B on both sides connecting the outer rotor 5 and the vane rotor 14 are slidably in close contact with both side surfaces (axial end surfaces) of the annular housing 15, and the side of each recess 19 of the annular housing 15 Respectively. Accordingly, each concave portion 19 of the annular housing 15 forms an independent space together with the boss portion 17 of the vane rotor 14 and the drive plates 16A and 16B on both sides, and this space is an introduction space into which hydraulic fluid is introduced. . Each introduction space is divided into two chambers by corresponding vanes 18 of the vane rotor 14, one chamber being an advance side working chamber 24 and the other chamber being a retard side working chamber 25. .

  The advance side working chamber 24 rotates the inner circumferential side rotor 6 relative to the outer circumferential side rotor 5 in the advance direction by the pressure of the working fluid introduced inside, and the retard side working chamber 25 is The inner rotor 6 is rotated relative to the outer rotor 5 in the retard direction by the pressure of the working fluid introduced therein. In this case, the “advance angle” means that the inner rotor 6 is advanced in the main rotation direction of the electric motor 1 indicated by the arrow R in FIG. 2 with respect to the outer rotor 5. Means that the inner rotor 6 is moved in the direction opposite to the main rotation direction R of the electric motor 1 with respect to the outer rotor 5.

  Further, the supply and discharge of the hydraulic fluid to and from each of the advance side working chambers 24 and the retard side working chambers 25 is performed through the rotating shaft 4. Specifically, the advance side working chamber 24 is substantially formed in a passage hole 26 a formed in the rotating shaft 4, an annular groove 26 b formed in the outer peripheral surface connected to the passage hole 26 a, and the boss portion 17 of the vane rotor 14. The hydraulic pressure control device is connected through a plurality of conduction holes 26c formed in the radial direction. Further, the retard side working chamber 25 is formed in a substantially radial direction in the passage hole 27a formed in the rotating shaft 4, the annular groove 27b formed in the outer peripheral surface connected to the passage hole 27a, and the boss portion 17 of the vane rotor 14. The hydraulic pressure control device is connected through a plurality of conduction holes 27c formed in the.

  In the above configuration, when the field characteristics of the electric motor 1 are changed, the hydraulic fluid is supplied to one of the advance side working chamber 24 and the retard side working chamber 25 by supplying and discharging the hydraulic fluid by the hydraulic pressure control device. At the same time, the hydraulic fluid is discharged from the other side. When the supply and discharge of the hydraulic fluid is controlled in this way, the vane rotor 14 and the annular housing 15 are relatively rotated, and the relative phases of the outer peripheral rotor 5 and the inner peripheral rotor 6 are operated accordingly. .

  When the relative phase of the outer circumferential rotor 5 and the inner circumferential rotor 6 is manipulated, between the strong field state shown in FIG. 3A and the weak field state shown in FIG. The strength of the magnetic field exerted on the stator 2 changes. When the strength of the magnetic field changes, the induced voltage constant changes accordingly, and as a result, the characteristics of the electric motor 1 are changed. That is, when the induced voltage constant increases due to the strong field, the allowable rotational speed at which the motor 1 can be operated decreases, but the maximum torque that can be output increases. Conversely, when the induced voltage constant decreases due to the weak field, Although the maximum torque that can be output from the electric motor 1 decreases, the allowable rotational speed at which the motor 1 can operate increases.

  In particular, in the present electric motor 1, the outer peripheral side permanent magnet 9A of the outer peripheral side rotor 5 is arranged so that the magnetization direction faces the circumferential direction, and the inner peripheral side permanent magnet 9B of the inner peripheral side rotor 6 is set to have a magnetization direction. Further, the inner circumferential side permanent magnet 9B is set to have the same magnetization direction length Win and the outer circumferential side permanent magnet 9A. The area of the magnetic flux generation surface of 9B is set to twice the area of the magnetic flux generation surface of the outer peripheral side permanent magnet 9A (that is, Lin: Lout = 2: 1). Therefore, when the strong field phase is set as shown in FIG. 3A, a strong field can be exerted on the stator 2, and as shown in FIG. When the phase is set, the influence of the field can be hardly exerted on the stator 2. That is, when the strong field phase is set in the low speed range, a large torque can be taken out, and when the weak field phase is set in the high speed range, the induced voltage can be made almost zero. Therefore, the motor iron loss can be sufficiently reduced.

  For example, as in the comparative example shown in FIG. 4, when the area of the magnetic flux generation surface of the outer peripheral permanent magnet 9B is increased in order to obtain a strong torque (ie, the axial length is constant, the radial length is If it is increased), even in the state of field weakening as shown in the figure, the influence of the magnetic field is greatly exerted on the stator 2 side, so that the induced voltage becomes large.

  FIG. 5 shows a case where the ratio of the area of the magnetic flux generation surface of the inner peripheral side permanent magnet 9B and the area of the magnetic flux generation surface of the outer peripheral side permanent magnet 9A, that is, the ratio of the mutual circumferential length Lin: Lout is changed. The change of the magnitude | size of the induced voltage with respect to the relative angle change of an inner peripheral side rotor and an outer peripheral side rotor is shown. In this case, the rotation speed is 1000 rpm. From this graph, it can be seen that when Lin: Lout = 1: 2, Lin: Lout = 1: 1, the effect of reducing the induced voltage is small when the field weakening phase, that is, the electrical angle is 180 °. On the other hand, when Lin: Lout = 3: 1 or Lin: Lout = 4: 1, the induced voltage is inverted beyond zero in the field weakening phase. In contrast, when Lin: Lout = 2: 1, the induced voltage can be made zero in the field-weakening phase. It can also be seen that when Lin: Lout = 1.6: 1, the induced voltage is strengthened and can be suppressed to 10% or less of the induced voltage of the field phase.

  Therefore, according to the electric motor 1 of the present embodiment, the magnetization direction length Win of the inner peripheral permanent magnet 9B is the same as the magnetization direction length Wout of the outer peripheral permanent magnet 9A, and the inner peripheral permanent magnet 9B By setting the area of the magnetic flux generation surface to 1.6 to 2 times the area of the magnetic flux generation surface of the outer peripheral permanent magnet 9A, a large torque can be generated when the strong field phase is set, and the weak field The induced voltage when the phase is controlled can be strengthened and suppressed to 10% or less of the induced voltage of the field phase, and the motor iron loss can be sufficiently reduced. In particular, by setting the area of the magnetic flux generating surface of the inner peripheral side permanent magnet 9B to twice the area of the magnetic flux generating surface of the outer peripheral side permanent magnet 9A, the induced voltage when controlled to the field weakening phase is made zero. Can do. Moreover, when the electric motor 1 of this embodiment is applied to a series hybrid vehicle having a lockup mechanism, the drag loss of each rotor at the time of lockup can be made close to zero.

(Second Embodiment)
FIG. 6 is a cross-sectional view of the electric motor 1A according to the second embodiment as viewed from the axial direction. In this electric motor 1A, the inner peripheral side permanent magnet 9B is constituted by a pair of permanent magnets 9B1 and 9B2 having the same dimensions. By doing in this way, the permanent magnet 9B1 of the inner peripheral side permanent magnet 9B and the permanent magnet 9B1 of the inner peripheral side permanent magnet 9B can use the same permanent magnet, and the productivity of a magnet can be improved. Other configurations and operations are the same as those in the first embodiment.

In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.
Further, in the present embodiment, the phase changing means 12 rotates the inner circumferential rotor 6 so that the relative phase between the outer circumferential rotor 5 and the inner circumferential rotor 6 can be changed. However, the relative phase between the rotors 5 and 6 may be changed by rotating the outer peripheral rotor 5.

It is sectional drawing of the electric motor of 1st Embodiment of this invention, and is a figure equivalent to the II sectional view taken on the line of FIG. It is sectional drawing seen from the axial direction of the same electric motor. (A) is a figure which shows the state of the magnetic flux in the case of a strong field phase, (b) is a figure which shows the state of the magnetic flux in the case of a field weakening phase. It is a figure which shows the state of the magnetic flux in the case of a field weakening phase in a comparative example. The magnitude of the induced voltage for the change in the relative angle between the inner and outer rotors when the ratio of the area of the magnetic flux generation surface of the inner peripheral side permanent magnet to the area of the magnetic flux generation surface of the outer peripheral side permanent magnet is changed It is a graph which shows the change of. It is sectional drawing seen from the axial direction of the electric motor of 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric motor 5 Outer peripheral side rotor 6 Inner peripheral side rotor 9A Outer peripheral side permanent magnet 9B Inner peripheral side permanent magnet 12 Phase change means Win Inner peripheral side permanent magnet magnetization direction length Wout Outer peripheral side permanent magnet magnetization direction length Lin The circumferential length of the inner peripheral permanent magnet Lout The radial length of the outer permanent magnet

Claims (3)

An outer peripheral rotor comprising a plurality of outer peripheral permanent magnets arranged at predetermined intervals in the circumferential direction so that the magnetization direction thereof is in the circumferential direction;
An inner circumferential rotor that is provided concentrically with the outer circumferential rotor and has a plurality of inner circumferential permanent magnets arranged at predetermined intervals in the circumferential direction so that the magnetization direction thereof is in the radial direction;
Phase changing means capable of changing a relative phase between the outer circumferential rotor and the inner circumferential rotor by rotating at least one of the outer circumferential rotor and the inner circumferential rotor; ,
An electric motor comprising:
The magnetization direction length of the inner peripheral side permanent magnet is the same as the magnetization direction length of the outer peripheral side permanent magnet,
The area of the magnetic flux generation surface of the inner peripheral permanent magnet is twice the area of the magnetic flux generation surface of the outer peripheral permanent magnet.   2. The electric motor according to claim 1, wherein each of the inner peripheral side permanent magnets is constituted by a pair of permanent magnets having the same dimensions. An outer peripheral rotor comprising a plurality of outer peripheral permanent magnets arranged at predetermined intervals in the circumferential direction so that the magnetization direction thereof is in the circumferential direction;
An inner circumferential rotor that is provided concentrically with the outer circumferential rotor and has a plurality of inner circumferential permanent magnets arranged at predetermined intervals in the circumferential direction so that the magnetization direction thereof is in the radial direction;
Phase changing means capable of changing a relative phase between the outer circumferential rotor and the inner circumferential rotor by rotating at least one of the outer circumferential rotor and the inner circumferential rotor; ,
An electric motor comprising:
The magnetization direction length of the inner peripheral side permanent magnet is the same as the magnetization direction length of the outer peripheral side permanent magnet,
The area of the magnetic flux generating surface of the inner peripheral side permanent magnet is 1.6 to 2 times the area of the magnetic flux generating surface of the outer peripheral side permanent magnet.

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