JP2004242461A - Rotor of variable magnetic flux magnet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotor of variable magnetic flux magnet type, excellent in reliability and simpler and more compact than a conventional one. <P>SOLUTION: Fixed rotors 3 and 4 of magnet type fixed to a rotating shaft 2 are provided with a relative rotation mechanism relatively rotating a movable rotor 5 by centrifugal force which is the magnet type rotor engaged rotatably with the rotating shaft 2. The relative rotation mechanism comprises a guide groove having a spiral groove, and a guide member that moves in it under a centrifugal force. The guide member is energized inward in radial direction by a spring. Thus, the relative angle between the fixed rotors 3 and 4 and the movable rotor 5 is changed according to changes in rotational speed during electric operation, so that a synthesized magnetic flux amount is changed. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a magnetic flux variable magnet type rotor.
[0002]
Problems to be solved by the prior art and the invention
Permanent magnet type synchronous machines are more suitable for rotary electric machines for vehicles that require higher reliability and smaller and lighter weight because they can realize higher output, more compact and simpler configuration than other types of synchronous machines. Since the rotating electrical machine for vehicles has a wide rotation speed range, if a sufficiently large magnet magnetic field is secured to secure low-speed torque, an excessive armature winding induced voltage is generated during high-speed rotation, so the magnet magnetic field during high-speed rotation is reduced. It has been proposed to provide a demagnetizing mechanism for performing the operation.
[0003]
Patent Document 1 discloses that a magnetic short-circuit member that magnetically short-circuits these permanent magnets is axially inserted into a magnet-type rotor core, a stationary yoke is further provided inside the rotor core, and a field coil is wound therearound. By controlling the amount of short-circuit magnetic flux flowing through the magnetic short-circuit member by energizing the field coil, it is possible to control the amount of effective field magnetic flux that effectively interlinks with the armature winding to adjust the voltage generated by the armature winding. We have proposed a synchronous machine with a static field coil magnet.
[0004]
However, the variable magnetic flux amount method has a problem that the structure is complicated and a static yoke is used, so that the magnetic resistance of the field coil circuit is large and a field current loss occurs.
[0005]
Patent Document 2 discloses that a permanent magnet of a magnet type rotor core is housed together with a spring in a sliding hole formed in a radial direction in the rotor core, and when a centrifugal force acting on the permanent magnet increases, the permanent magnet resists the elastic urging force of the spring. A structure has been proposed in which a magnet comes out of the sliding hole, thereby reducing the amount of magnetic flux applied to the rotor core by the permanent magnet. However, this technique is difficult to apply to a magnet-type rotor core using a thin plate magnet extending in a substantially circumferential direction, which is currently mainstream, and has a major problem that the amount of magnetic flux is small structurally. there were.
[0006]
Patent Document 3 discloses that a magnet type rotor is divided into two parts in the axial direction, one rotor (fixed rotor) is fixed to a rotating shaft, and the other rotor (movable rotor) is rotatable around the rotating shaft. Utilizing the fact that the direction of the torque acting on the rotor during power generation and rotation is reversed, it has been proposed to rotate the free-rotating rotor relative to the fixed rotor. In addition, a structure is employed in which the movable rotor is coupled to the rotating shaft using a bolt fastening mechanism so that the movable rotor is separated from the fixed rotor simultaneously with the rotation of the rotor. However, since this technique does not reduce the rotor magnetic flux during high-speed rotation, it does not help to reduce the amount of magnet magnetic flux during high-speed rotation. Patent Document 3 also proposes a technique in which the number of rotations is detected, and an actuator separates a movable rotor from a fixed rotor in an axial direction. However, in this method, it is necessary to provide an actuator having a rotation speed detecting device and a servo mechanism, and the loss due to the structural complexity greatly exceeds the technical benefit.
[0007]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a magnetic flux variable magnet type rotor that is much simpler, more compact, and more reliable than conventional ones.
[0008]
[Patent Document 1] JP-A-10-304633 [Patent Document 2] JP-A-7-288940 [Patent Document 3] JP-A-2002-262534 [0009]
[Means for Solving the Problems]
A magnetic flux variable magnet type rotor according to the present invention includes a fixed rotor having a permanent magnet type field pole and fixed to a rotating shaft, and a fixed rotor having a permanent magnet type field pole and being axially adjacent to the fixed rotor. A movable rotor attached to the rotating shaft so as to be relatively rotatable with respect to the rotor,
A pair of guide grooves individually provided on the fixed rotor side and the movable rotor side, and both rotors are relatively rotated within a predetermined angle range as they are guided in the pair of guide grooves and move in the radial direction. A relative rotation mechanism having a guide, a weight fixed to the guide, and both ends individually locked to both rotors, or separately locked to the movable rotor and the rotating shaft. A spring for transmitting the torque of the movable rotor to the fixed rotor by the relative rotation of the two rotors during the electric operation.
[0010]
That is, according to the present invention, by changing the relative rotation angle (with respect to the stator coil) of the two magnet rotors in the same rotation direction in accordance with the rotation speed, the two magnet rotors linked to the stator coil are changed. The composite magnet flux is reduced during high-speed rotation compared to low-speed rotation. In order to change the relative rotation angle of both rotors between high-speed rotation and low-speed rotation, a guide that moves radially outward in the spiral mechanism by centrifugal force acting on the weight during high-speed rotation is used. The guide is urged by a spring during low-speed rotation and returns radially inward in the spiral mechanism.
[0011]
With this configuration, the relative rotation angles of the at least two magnet rotors can be changed according to the speed in the same rotation direction, so that the electromotive force generated in the stator coil during the high-speed electric operation is reduced to that during the low-speed electric operation. The power generation voltage generated in the stator coil during the high-speed power generation operation can be reduced as compared with that during the low-speed power generation operation, and favorable electric characteristics can be obtained in terms of circuit operation.
[0012]
In a preferred aspect, the guide grooves are axially recessed or penetrated in the rotors, and one end of the guide is provided in one of the guide grooves, and the other end of the guide is provided in the guide grooves. The other is movably inserted into the other, so that the relative rotation mechanism, that is, the guide mechanism can be simplified.
[0013]
In a preferred aspect, since the guide is formed integrally with the weight, the structure can be simplified.
[0014]
In a preferred embodiment, the spring comprises a coil spring or a spiral or bow spring. Thereby, the spring can be simplified.
[0015]
In a preferred aspect, a helical linear mechanism that displaces the movable rotor mounted on the rotating shaft so as to be axially displaceable with respect to the rotating shaft in the axial direction with respect to the rotating shaft as the movable rotor relatively rotates. Having. Thereby, in addition to the change in the magnetic flux amount of the stator coil linkage magnet due to the relative rotation of the two rotors, the change can be performed by the direct movement of the movable rotor, and the control of the magnetic flux amount can be further improved. it can.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that these examples show embodiments, and it is naturally possible to replace constituent elements with known alternative elements.
(Example 1)
The variable magnetic flux type magnet rotor according to the first embodiment will be described below. This magnetic flux variable magnet type rotor is arranged, for example, radially inside a stator (not shown) of the synchronous machine. In the following embodiments, the magnet magnetic flux amount control during the electric operation will be described, but the magnet magnetic flux amount control during the power generation operation is also essentially possible by reversing the circumferential movement direction of the weight.
[0017]
FIG. 1 shows a magnetic flux variable magnet type rotor (rotor) 1 of this embodiment. A magnetic flux amount variable magnet type rotor core (hereinafter, also simply referred to as a rotor) 1 includes a rotating shaft 2, a pair of fixed rotors (hereinafter, also referred to as fixed rotors) 3, 4, and both fixed rotors 3, 4 in an axial direction. And a movable rotor (hereinafter, also referred to as a movable rotor) 5 interposed therebetween.
[0018]
The fixed rotors 3 and 4 are so-called SPM rotors in which a total of four magnets 7 are fixed on the surface of the rotor core 6 at a constant pitch in the circumferential direction and alternately in polarity. The fixed rotors 3 and 4 have a rotor core (rotor core) 6 made of laminated electromagnetic steel sheets or soft iron fitted and fixed to the rotating shaft 2 and a magnet 7 fixed to the surface thereof.
[0019]
The movable rotor 5 is rotatably held on the rotating shaft 2 by, for example, fitting a sleeve inserted into a shaft hole of a rotor core (rotor core) 8 (see FIG. 3) made of laminated electromagnetic steel sheets or soft iron to the rotating shaft 2. Have been. The movable rotor 5 is a so-called SPM rotor in which a total of four magnets 9 are fixed on the surface of the rotor core 8 at a constant pitch in the circumferential direction and alternately in polarity. The number of magnets of the rotors 3 to 5 is equal.
[0020]
In this embodiment, a pair of fixed rotors 3, 4 and one movable rotor 5 are used, but one fixed rotor 3, 4 and one movable rotor 5 are axially adjacent to each other. Alternatively, more or more fixed rotors 3 and 4 and movable rotors 5 may be used as appropriate.
[0021]
FIG. 1 shows a case where the relative angle between the permanent magnet 9 of the movable rotor 5 and the permanent magnets 7 of the fixed rotors 3 and 4 is very small, and FIG. 2 shows a case where the relative angle is an electrical angle π. FIG. 3 shows a relative rotation mechanism of the movable rotor 5.
[0022]
FIG. 3 is a schematic cross-sectional view of the boundary between the movable rotor 5 and the fixed rotor 4 in FIG. For simplification, hatching of the cross section is omitted. Therefore, FIG. 3 shows the movable rotor 5 side. In FIG. 3, the rotor core 8 of the movable rotor 5 is rotatably fitted to the rotating shaft 2 for simplicity of illustration, but is fitted via a sleeve or the like as described above. Is also good.
[0023]
In FIG. 3, 10 is a weight, 11 is a weight pole, 12 is a pole guide groove, 13 is a rotation guide groove, 14 is a helical spring (coil spring), and 15 is a key groove.
[0024]
As shown in FIG. 3, a pair of spiral guide grooves 13 are formed in the axial direction on both ends of the rotor core 8 of the movable rotor 5. Note that the groove 13 may be formed so as to penetrate the rotor core 8 in the axial direction instead of the recess. As shown in FIG. 3, the grooves 13 are arranged 180 degrees symmetrically, and in FIG. 3, are bent in a counterclockwise direction toward the outside in the radial direction. Each of the grooves 13 has a weight 10 inserted in the axial direction. The width of the groove 13 is set so that the weight 10 can slide or rotate freely therein.
[0025]
The weight 10 is a cylindrical pin, and a weight pole 11 having a coaxial center protrudes from both end surfaces thereof. These weight poles 11 are also cylindrical pins, but are smaller in diameter than the weights 10. The reason why the diameter is small is that the weight 10 and the pair of weight poles 11 constitute a guide in the present invention, and the groove 13 and a pole guide groove 12 described later constitute a guide groove in the present invention.
[0026]
In this embodiment, in order to simplify the structure, the guide also serves as a weight for generating centrifugal force.However, a guide that moves while being guided by the guide groove and a weight that biases the guide are used. They may be formed separately and mechanically connected.
[0027]
FIG. 4 is an enlarged view of FIG. 3, but the illustration of broken lines of the weight pole 11 and the pole guide groove 12 on the fixed rotor 4 side shown in FIG. 3 is omitted.
[0028]
The helical spring (coil spring) 14 is wound around the rotating shaft 2, one end of which is locked to the rotating shaft 2 so as to fall into the key groove 15, and the other end faces the outer peripheral surface of the rotating shaft 2. The groove 13 is locked at the corner of the opening facing inward in the radial direction. FIG. 7 schematically illustrates a state in which the helix spring 14 is housed. The helical spring 14 is accommodated in a spring accommodating hole in which the diameter of the through groove of the rotating shaft 2 is increased by a predetermined depth from the end face of the rotor core 8.
[0029]
Thus, in a state where no external force is applied, the movable rotor 5 having the rotor core 8 is in a state schematically illustrated in FIG. 1, that is, a state where the relative rotation angle with respect to the fixed rotor 3 is substantially zero. Here, the relative rotation angle 0 means a state where the magnet arrangement of the rotors 3 to 5 is aligned in the circumferential direction including the magnetic pole direction. FIG. 6 shows an enlarged view of the arrangement of the helix spring 14.
[0030]
FIG. 5 is a schematic cross-sectional view taken along line AA of FIG. 2 at the boundary between the movable rotor 5 and the fixed rotor 4. For simplification, hatching of the cross section is omitted. Therefore, FIG. 5 shows the fixed rotor 4 side. The rotor cores 6 of the fixed rotors 3 and 4 are pressed into the rotating shaft 2, and are fixed by pressing a key 16 (see FIG. 7) into a key groove 15 of the rotating shaft 2.
[0031]
As shown in FIG. 5, a pair of linear pole guide grooves 12 are formed in the end faces of the fixed rotors 3 and 4 facing the movable rotor 5 in the axial direction (the pole guide grooves 12 may be recessed (or penetrated)). The pole guide groove 12 extends in the radial direction. The pair of grooves 12 are arranged symmetrically by 180 degrees, and the weight poles 11 are inserted in the respective grooves 12 in the axial direction. The width of the groove 12 is set to a size that allows the weight pole 11 to slide or rotate freely therein.
[0032]
As described above, the weight poles 11 protrude from both end faces of the weight 10 in the axial direction. The two weight poles 11 integrated with one weight 10 are formed by the groove 12 of the stationary rotor 3 and the stationary rotor 3. 4 are individually fitted in the grooves 12. The diameter of the weight 10 and the diameter of the weight pole 11 may be reversed or equal.
[0033]
In this embodiment, the groove 12 extends linearly in the radial direction, but may be a spiral groove. However, in this case, the spiral direction is preferably on the opposite side of the groove 13, that is, clockwise.
[0034]
Thus, in a state where no external force is applied, the movable rotor 5 having the rotor core 8 is in a state schematically illustrated in FIG. 1, that is, a state where the relative rotation angle with respect to the fixed rotor 3 is substantially zero. Here, the relative rotation angle 0 means a state where the magnet arrangement of the rotors 3 to 5 is aligned in the circumferential direction including the magnetic pole direction.
[0035]
As described above, when no external force acts on the rotor 1, the movable rotor 5 is brought into a relative rotation state shown in FIG. 1 with respect to the fixed rotors 3 and 4 by the urging force of the helical spring 14. In this state, the weight 10 and the weight pole 11 are pressed to the radially innermost positions of the grooves 13 and 12.
[0036]
When the rotor 1 is started by energizing a stator coil (not shown), the rotor 1 rotates and moves radially outward in the grooves 12 and 13 by centrifugal force acting on the weights 10 and the weight poles 11. The movable rotor 5 rotates relatively to the fixed rotors 3 and 4. The electromagnetic torque acting on the movable rotor 5 is transmitted to the rotating shaft 2 through the helical spring 14, and at this time, the electromagnetic torque is urged in a direction to compress (or extend) the helical spring 14. And transmitted to the rotating shaft 2.
[0037]
As a result, the radial positions of the weight 10 and the weight pole 11 are determined by the circumferential component force applied to the surface of the groove 13, the elastic biasing force of the helical spring 14, and the movable rotor 5. At the position where the electromagnetic force acting on the rotor is balanced, and at this position, a relative angle is formed between the two rotors in which the groove 13 and the groove 12 coincide with each other in the axial direction.
[0038]
When the rotor 1 rotates at high speed, the centrifugal force acting on the weights 10 and the weight poles 11 becomes strong, whereby the weight poles 11 and the weight poles 11 largely rotate the movable rotor 5 while compressing the helical spring 14. As a result, the magnet electromotive force generated in the stator coil by all the magnets 7, 9 of the fixed rotors 3, 4 and the movable rotor 5 is reduced. Thereby, demagnetization at the time of high-speed rotation, which has been a problem in the conventional magnet type synchronous machine, can be realized.
[0039]
FIG. 8 shows the relationship between the rotor speed and the back electromotive voltage (magnet electromotive force) of the stator coil according to this embodiment. In this embodiment, the counter-electromotive voltage can be substantially saturated during high-speed rotation by the relative rotation.
[0040]
(Modification)
In the above-described embodiment, the demagnetization in the high-speed electric operation is performed with respect to the low-speed electric operation in the magnet-type synchronous motor. Good.
[0041]
(Modification)
In the above embodiment, the helix spring 14 is used as the spring, but it is obvious that a spiral spring or a leaf spring (bow spring) may be used. When a leaf spring is used, it is preferable to dispose it in an axial gap between the movable rotor 5 and the fixed rotor 3 (or 4). In these cases as well, one end of the spring should be individually fixed to the movable rotor 5 and the other end to the fixed rotor 3 (or 4) or the rotating shaft 2.
(Example 2)
A variable magnetic flux type magnet rotor according to another embodiment of the present invention will be described below with reference to FIG. In order to simplify the description, the description of the configuration functionally common to the first embodiment will be omitted or simplified.
[0042]
In this embodiment, instead of a guide comprising a weight 10 and two weight poles 11, a guide comprising one weight 10 and a weight pole 11 is used. However, in FIG. 9, the weight 10 at the time of high-speed rotation is illustrated as a weight 10a, and the weight 10 at the time of low-speed rotation is illustrated as a weight 10b. Similarly, the weight pole 11 during high-speed rotation is illustrated as a weight pole 11a, and the weight pole 11 during low-speed rotation is illustrated as a weight pole 11b.
[0043]
In this embodiment, in particular, the rotation guide groove 13 (see FIG. 6) is formed to penetrate the rotor core 8 (see FIG. 6) of the movable rotor 5 in the axial direction, and the pole guide groove 12 (see FIG. 5). Is formed so as to penetrate through the rotor core 6 (see FIG. 5) of the fixed rotor 3 in the axial direction. The shapes of these grooves 12, 13 when viewed in the radial direction may be the same as in the first embodiment.
[0044]
In this embodiment, the weight 10 penetrates the groove 13 of the rotor core 8 in the axial direction, and the weight pole 11 penetrates the groove 12 of the rotor core 6 in the axial direction.
[0045]
Both ends of the rod-shaped guide comprising the weight 10 and the weight pole 11 are urged radially inward by a coil spring 20 on both axial sides of the fixed rotor 3 and the movable rotor 5. However, in FIG. 9, the coil spring 20 during high-speed rotation is illustrated as a coil spring 20b, and the coil spring 20 during low-speed rotation is illustrated as a coil spring 20a. One end of the coil spring 20 is locked to the rotating shaft 2 and the other end is locked to the guide, that is, the weight 10 and the weight pole 11, and the coil spring 20 urges the guide radially inward. Of course, it is clear that additional weights may be added to the guide if needed. It is more preferable that the end of the coil spring 20 on the rotation shaft locking side be locked to a sleeve rotatably fitted to the rotation shaft 2.
[0046]
Further, in this embodiment, a sleeve is press-fitted into a shaft hole of the rotor core 8 of the movable rotor 5 through which the rotating shaft 2 passes, and a spiral groove is formed on the inner peripheral surface of the sleeve. Further, a spiral groove 22 is also formed on the outer peripheral surface of the rotating shaft 2, and these two spiral grooves are fitted to each other so as to be relatively rotatable.
[0047]
By doing so, similarly to the first embodiment, the demagnetization due to the relative rotation of the movable rotor 5 during high-speed rotation and the relative rotation of the movable rotor 5 cause the movable rotor 5 to rotate the spiral of the rotating shaft 2. It rotates along the groove 22 in a direction away from the fixed rotor 3, whereby a further demagnetizing effect can be obtained. The combination of the helical groove of the sleeve and the helical groove of the rotary shaft 2 constitutes a helical linear mechanism according to the present invention.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a magnetic flux amount variable magnet type rotor according to a first embodiment.
FIG. 2 is a perspective view showing a variable magnetic flux type magnet rotor according to the first embodiment.
FIG. 3 is a schematic view taken along line AA of Example 1;
FIG. 4 is an enlarged view of FIG. 3;
FIG. 5 is a schematic diagram of Example 1 taken along line AA.
FIG. 6 is an enlarged side view around the relative rotation mechanism of FIG. 1;
FIG. 7 is an enlarged sectional view in the axial direction around the helical spring of the variable magnetic flux amount type magnet rotor according to the first embodiment.
FIG. 8 is a characteristic diagram showing a back electromotive force characteristic when the magnetic flux variable magnet type rotor according to the first embodiment is used.
FIG. 9 is a schematic axial cross-sectional view (hatching omitted) showing the variable magnetic flux amount type magnet rotor of the second embodiment.
[Explanation of symbols]
1 rotor (magnetic flux variable magnet type rotor)
2 rotating shaft 3 fixed rotor (fixed rotor)
4 Fixed rotor 5 Movable rotor (movable rotor)
6 Rotor core of fixed rotor 7 Permanent magnet 8 Rotor core of movable rotor 9 Permanent magnet 10 Weight (weight, guide)
11 Weight poles (weights, guides)
12 Pole guide groove (guide groove)
13 Guide groove for rotation (guide groove)
14. Tsurumaki spring (spring)

Claims (5)

A fixed rotor having a permanent magnet type field pole and fixed to a rotating shaft,
A movable rotor having a permanent magnet type field pole and attached to the rotating shaft so as to be rotatable relative to the fixed rotor adjacent to the fixed rotor in the axial direction;
With
A pair of guide grooves provided separately on the fixed rotor side and the movable rotor side, and the two rotors are relatively rotated within a predetermined angle range as they are guided in the pair of guide grooves and move in the radial direction. A relative rotation mechanism having a guide,
A weight fixed to the guide,
Both ends are individually locked to the two rotors, or individually locked to the movable rotor and the rotating shaft, and the relative rotation of the two rotors during electric operation reduces the torque of the movable rotor. A spring transmitting to the fixed rotor,
A variable magnetic flux type magnet rotor comprising: The variable magnetic flux type magnet rotor according to claim 1,
The guide groove is recessed or penetrated in the both rotors in the axial direction,
A variable magnetic flux amount magnet rotor, wherein one end of the guide is movably inserted into one of the two guide grooves, and the other end of the guide is movably inserted into the other of the two guide grooves. The variable magnetic flux type magnet rotor according to claim 1,
The guide element is formed integrally with the weight, wherein the magnetic flux amount is variable. The variable magnetic flux type magnet rotor according to claim 1,
The variable magnetic flux type rotor according to claim 1, wherein the spring comprises a coil spring, a spiral or a bow spring. The variable magnetic flux type magnet rotor according to claim 1,
The movable rotor mounted on the rotating shaft so as to be axially displaceable with respect to the rotating shaft, having a helical linear mechanism that is displaced in the axial direction with respect to the rotating shaft as the relative rotation of the movable rotor is performed. Characteristic variable magnetic flux rotor.

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