JP4082182B2 - Rotating electric machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotating electrical machine that functions as an electric motor, a generator, or both. In particular, it relates to a rotating electrical machine having a permanent magnet in the rotor.
[0002]
[Prior art]
Many electric motors in which a permanent magnet is embedded in a rotor are used for reasons such as low loss, high efficiency, and high output. Since this electric motor has a constant magnetic flux from the rotor, the induced voltage becomes excessive during high-speed rotation, and is operated by weakening it and allowing a field current to flow. However, the efficiency at the time of high-speed rotation deteriorates by passing a field weakening current. Therefore, in Japanese Patent Laid-Open No. 7-107718, a part of the stator yoke portion is moved in the axial direction to reduce the magnetic flux during high-speed rotation and suppress the induced power. By suppressing the induced voltage during high-speed rotation, it is possible to reduce the current flowing through the coil, thus improving the efficiency.
[0003]
[Patent Document 1]
JP-A-7-107718
[0004]
[Problems to be solved by the invention]
However, by moving the stator yoke portion in the axial direction, the magnetic flux concentrates on the remaining stator core, resulting in a large iron loss. In addition, in order to increase the effect, a very large moving distance is required.
[0005]
An object of this invention is to provide the electric motor which can suppress an induced voltage at the time of high speed rotation more simply.
[0006]
[Means for Solving the Problems]
In a rotating electrical machine comprising a stator core and a substantially cylindrical stator having coils wound around respective teeth of the stator core, and a rotor having a plurality of permanent magnets supported rotatably with respect to the stator, the stator core comprises: A moving part that is movable relative to the coil along a substantially radial direction of the stator, and a moving mechanism that moves the moving part along the substantially radial direction based on the number of rotations of the rotor. . When the rotational speed of the rotor is zero, at least a part of the moving part is located inside the coil and the moving part moves to the outside of the stator due to an increase in the rotational speed of the rotor.
[0007]
[Action / Effect]
By moving a part of the stator core in the radial direction using the moving part as a moving part, it is possible to change the flux linkage with respect to the stator and to adjust the induced voltage to the coil of the stator. For example, when torque is required (low rotation), move it closer to the rotor, and move it away from the rotor to improve efficiency at high rotations, greatly improving the motor characteristics. Is possible.
[0008]
Further, since the air gap is generated in the coil due to the movement of the moving part in the coil, the linkage flux can be adjusted with a small amount of movement.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In addition, although embodiment is demonstrated with respect to the electric motor 100, it is applicable similarly with respect to a generator.
[0010]
FIG. 1 is a sectional side view in the axial direction of an electric motor 100 according to a first embodiment of the present invention. Referring to FIG. 1, an electric motor 100 includes a rotating shaft 1, a rotor 3 that is arranged around the rotating shaft 1 and fixed to the rotating shaft 1, a stator 5 that is arranged around the rotor 3, and a case that houses the stator 5. 7 is provided. The rotor 3 and the stator 5 each have a substantially cylindrical shape extending in the axial direction, and a gap corresponding to an air gap exists between the rotor 3 and the stator 5 so that they do not contact each other. The rotor 3 includes a cylindrical outer peripheral surface 20, and the stator 5 includes a cylindrical outer peripheral surface 40. The stator core 6 of the stator 5 is provided with a winding 11 composed of a plurality of coils 19. A rotating magnetic field generated by an alternating current flowing through the winding 11 exerts a force on the permanent magnet 9, and the rotor 3 rotates together with the rotating shaft 1. To do.
[0011]
The case 7 includes a cylindrical plate 7a that contacts the stator 5 and side plates 7b and 7c that block openings at both axial ends of the cylindrical plate 7a. However, the cylindrical plate 7a has an opening through which the stator core moving portion 6b moves. Both ends of the rotating shaft 1 are supported by side plates 7 b and 7 c of the case 7 via bearings 16 and can rotate with respect to the stator 5 and the case 7. On the outer surface of one side plate of the case 7, a rotation sensor 12 (rotation speed detecting means) for detecting the rotation speed (the number of rotations per unit time) of the rotary shaft 1 is attached.
[0012]
The stator core 6 includes a stator core fixing portion 6a fixed to the case 7 and the coil 19, and one or more stator core moving portions 6b that can move in the radial direction with respect to the stator core fixing portion 6a. The electric motor 100 includes a stator core moving mechanism 10 for applying a radial force to the stator core moving part 6b to move the stator core moving part 6b in the radial direction. Here, the radial direction is defined as a direction along the radius of the substantially cylindrical rotor 3 or the substantially cylindrical stator 5. The central axis 8 of the rotating shaft 1 coincides with the central axis of the substantially cylindrical rotor 3 or the substantially cylindrical stator 5.
[0013]
In the present embodiment, the stator core fixing portion 6a has an integral structure, but may have a divided structure that is divided into a plurality of divided cores in the circumferential direction. In the case of a split structure, each split core has a tooth, and a coil is wound around each split core.
[0014]
FIG. 2 shows a cross section perpendicular to the axial direction of the rotor according to the first embodiment of the present invention, which is a cross section taken along the line II-II in FIG. In the vicinity of the outer peripheral surface 20 of the rotor 3, a plurality of plate-like permanent magnets 9 are embedded at substantially the same distance from the central axis 8 of the rotating shaft 1 with the longitudinal direction being substantially parallel to the rotating shaft 1. Here, the shape of the permanent magnet 9 is not limited to a plate shape, and may take various shapes such as a V shape. The permanent magnets 9 are arranged at predetermined intervals (for example, 45 °) in the circumferential direction of the rotor 3 so that adjacent magnetic poles are different from each other. Here, the circumferential direction is a direction along the circumference of a cylinder having the central axis 8 as an axis.
[0015]
The stator core 6 includes a stator core fixing portion 6a fixed to a coil 19 wound around a tooth portion 6c, and a stator core moving portion 6b movable relative to the stator core fixing portion 6a and the coil 19 of the stator 5. Yes. Here, the teeth portion refers to a portion of the stator core 6 protruding in the radial direction. The stator core moving part 6b has a substantially rectangular parallelepiped shape. In addition, both the stator core fixing | fixed part 6a and the stator core moving part 6b are comprised with the electromagnetic steel plate (for example, silicon steel plate) laminated | stacked on the axial direction. By configuring the stator core with laminated magnetic steel sheets, material costs can be reduced.
[0016]
The stator core fixing portion 6a has a sliding groove 17 that guides the stator core moving portion 6b. The sliding groove 17 has a substantially rectangular parallelepiped shape that fits the stator core moving portion 6b. The sliding groove 17 does not penetrate the stator core fixing portion 6a and has a bottom surface 31. The sliding groove 17 is disposed so as to pass through the coil 19 wound around the tooth portion 6 c of the stator core 6. The stator core moving part 6b greatly increases or decreases the flux linkage with respect to the coil 19 by moving in the coil 19 wound around the tooth part 6c. When the rotational speed of the rotor 3 is close to zero, at least a part of the stator core moving part 6b is inside the coil 19, and the stator core moving part 6b moves outside the stator 5 (with the rotor 3 and the rotor 3 as the rotational speed of the rotor 3 increases). Move along the radial direction to the opposite side. The stator core fixing portion 6a has an opening on the stator outer peripheral surface 40 through which the stator core moving portion 6b passes.
[0017]
In the present embodiment, one stator core moving portion 6 b is provided for each tooth portion 6 c and passes through each tooth portion 6 c of the stator core 6. However, the stator core moving part 6b may be provided only in a part of the tooth parts 6c. The number of teeth portions 6 c is twelve, and a total of twelve stator core moving portions 6 b are provided in the stator core 6. A coil 19 is wound around each tooth portion 6 c, and thus the winding 11 includes twelve coils 19. An insulator frame 18 formed of resin or the like is disposed between each coil 19 and the stator core fixing portion 6a so that the coils 19 do not come into contact with the stator core 6. Each coil 19 is wound around the insulator frame 18 in contact with the insulator frame 18. Thus, by dividing the stator core into the moving part and the fixed part, the electric motor 100 can be manufactured more easily, and the cost of the electric motor can be reduced.
[0018]
The stator core moving part 6b has a substantially rectangular parallelepiped shape extending in parallel with the rotary shaft 1, and the longitudinal direction thereof coincides with the axial direction. The cross-sectional shape perpendicular to the rotation axis direction of the stator core moving portion 6b is substantially rectangular, and the long axis 15 of this rectangle is in the radial direction. The stator core moving part 6b has a front surface 71 facing the rotor 3 and a back surface 73 at the end opposite to the front surface 71 in the radial direction. The stator core moving portion 6b slides in a substantially radial direction along a sliding groove 17 extending in a substantially radial direction from the vicinity of the tip surface 14 facing the rotor 3 of the tooth portion 6c. The stator core moving portion 6b moves through the opening of the sliding groove 17 on the stator outer circumferential surface 40. When the rotor 3 is rotating at a low speed so as to reduce the interlinkage magnetic flux with respect to the coil 19 and suppress the induced power, the stator core moving part 6b is in the vicinity of the reference position, and when the rotational speed of the rotor 3 is zero, the stator core moving part The front surface 71 of 6 b is in contact with the bottom surface 31 of the sliding groove 17.
[0019]
On the other hand, when the rotor 3 rotates at high speed, the stator core moving portion 6b is moved along the radial direction through the opening of the sliding groove 17 by the stator core moving mechanism 10 in order to reduce the interlinkage magnetic flux with respect to the winding 11 and suppress the induced power. It is pulled out of the stator. That is, the stator core moving part 6b moves along the radial direction in the direction opposite to the direction toward the central axis 8 as the rotational speed of the rotor 3 increases.
[0020]
The stator core moving mechanism 10 for moving the stator core moving portion 6b in the radial direction will be described in detail with reference to FIGS.
[0021]
The stator core moving mechanism 10 includes a driving motor 21 as a driving force source for supplying a driving force for moving the stator core moving portion 6b, a driving gear 22 attached to the rotating shaft 24 of the driving motor 21, a driving gear 22 and teeth. A ring-shaped internal gear 23 having teeth on the inside, a plurality of long-axis gears 25 meshed with the ring-shaped internal gear 23, a pinion 27 meshed with each long-axis gear 25, and each pinion 27 and teeth A rack 28 to be combined, and a support column 29 which is coupled and fixed to the rack 28 and embedded and fixed in the stator core moving portion 6b. The number of the long shaft gears 25, the pinions 27, and the racks 28 is the same as that of the stator core moving part 6b (12 in this embodiment). The long shaft gear 25 and the pinion 27 are rotatably supported by a fixing member (not shown), and the driving motor 21 is also fixed to a fixing member (not shown). As the drive motor 21, a stepping motor capable of accurately determining the rotation angle is suitable. A plurality of drive motors 21 may be provided.
[0022]
On the other hand, if a plurality of drive motors 21 are installed so that the drive gear 22 of each drive motor 21 is directly engaged with each rack 28, the position of each stator core moving portion 6 b is individually controlled by each drive motor 21. it can. In this case, the internal gear 23, the long shaft gear 25, and the pinion 27 can be omitted. Alternatively, the drive motor 21 may be installed only with respect to a part of the stator core moving part 6b so that only this part of the stator core moving part 6b can be moved.
[0023]
The drive motor 21 rotates the annular internal gear 23 via the drive gear 22, and the plurality of long shaft gears 25 are simultaneously rotated by the rotation of the annular internal gear 23. The annular internal gear 23 functions to transmit the rotation of the driving motor 21 to the plurality of long shaft gears 25. The drive gear 22, the internal gear 23, and the long shaft gear 25 all rotate in the same direction. The rotation of the long shaft gear 25 rotates the pinion 27 engaged therewith in a direction opposite to that of the long shaft gear 25, and the rack 28 converts the rotation of the pinion 27 into a linear motion. As the rack 28 moves in the linear direction, the stator core moving portion 6b also moves in the linear direction. In this case, the linear movement of the rack 28 is the radial movement of the stator and the rotor. In addition, the movement distance of each stator core moving part 6b can also be varied by varying the number of teeth among the plurality of long shaft gears 25.
[0024]
4A to 4C show how the stator core moving part 6b moves in the radial direction.
[0025]
Referring to FIG. 4A, when the rotational speed of the rotor 3 is zero, the stator core moving portion 6b is at the innermost position, and the front surface 71 of the stator core moving portion 6b is in contact with the bottom surface 31 of the sliding groove 17. Touching. In the present specification, this innermost position is simply referred to as a reference position. At this time, the rotating shaft 24 of the driving motor 21 is at the first rotating position corresponding to the reference position of the stator core moving portion 6b.
[0026]
Referring to FIG. 4B, when it is necessary to reduce the flux linkage of the electric motor 100, the stator core moving portion 6b is moved radially outward from the reference position by the rotation of the driving motor 21. Here, the amount of movement of the stator core moving part 6b from the reference position is defined as the displacement X in the radial direction. The displacement X of the stator core moving part 6b is proportional to the rotation angle θ of the rotation shaft 24 of the drive motor 21 with respect to the first rotation position. Until the displacement X reaches the maximum displacement Xmax, the stator core moving part 6b moves radially outward.
[0027]
Referring to FIG. 4 (c), when the displacement X becomes the maximum displacement Xmax, the stator core moving portion 6b is located at the outermost position (maximum displacement position) with respect to the stator. At this time, the rotation shaft 24 of the drive motor 21 is at the second rotation position corresponding to the maximum displacement position of the stator core moving portion 6b. For example, the maximum displacement Xmax of the stator core moving part 6b is set according to the degree to which the flux linkage is reduced. In this case, the maximum displacement Xmax depends on the maximum rotational speed of the rotor 3 and the like.
[0028]
Next, with reference to FIG. 5, the control device of the electric motor 100 will be described.
[0029]
The control device of the electric motor 100 includes an inverter 45 that supplies a current to the electric motor 50, a current sensor 47 that detects the current, a voltage sensor 49 that detects a voltage applied to the electric motor 50 from the inverter 45, and the rotation sensor 12 described above. The controller 45 controls the drive motor 21 provided in the inverter 45 and the stator core moving mechanism 10. In the present embodiment, the inverter 45 supplies an alternating current to the electric motor in a three-phase three-wire system, the current sensor 47 detects a line current, and the voltage sensor 49 detects a line voltage. In the case of this embodiment, the winding 11 is composed of 12 coils 19.
[0030]
The controller 60 is composed of a microcomputer having a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface) which are coupled to each other via a bus. ing. Signals from the rotation sensor 12, the current sensor 47, and the voltage sensor 49 are input to the controller 60 via an input / output interface.
[0031]
The controller 60 sets a three-phase alternating current to be supplied from the inverter 45 and outputs a current command value corresponding to this current to the inverter 45. The inverter 45 supplies current to the electric motor 100 based on the current command value. Further, the controller 60 determines the rotation angle θ of the rotation shaft 24 of the drive motor 21 based on the target displacement X of the stator core moving part 6b, and sends a command signal corresponding to the rotation angle θ to the drive motor 21. Output. When the drive motor 21 is a stepping motor, the controller 60 sends a number of pulses proportional to the rotation angle θ to the drive motor 21. The inverter 45 and the drive motor 21 are electrically coupled to the controller 60 and have an interface for receiving commands from the controller 60.
[0032]
The controller 60 detects the target displacement X of the stator core moving portion 6b according to at least one of the rotational speed of the rotor 3 detected by the rotation sensor 12, the current value detected by the current sensor 47, and the voltage value detected by the voltage sensor 49. And a target rotation angle θ corresponding to the target displacement X is set.
[0033]
Generally, an increase in the rotational speed of the rotor 3 causes an increase in current and voltage supplied from the inverter 45, and therefore the controller 60 can use a current value or a voltage value as an index of the rotational speed. For this reason, it is possible to reduce the induced voltage in the high rotation region by detecting the current value or the voltage value and setting the rotation angle θ according to the current value or the voltage value without detecting the rotation speed. That is, a combination of the current sensor 47 and the controller 60, or a combination of the voltage sensor 49 and the controller 60 can be used as a rotation speed detection unit that detects the rotation speed of the rotor.
[0034]
A control routine for position control of the stator core moving unit executed by the controller 60 will be described with reference to the flowchart of FIG. The controller 60 repeatedly executes a control routine every predetermined time during operation of the electric motor.
[0035]
In step S1, one of the rotational speed of the rotor, the current supplied to the electric motor, or the voltage supplied to the electric motor is read.
[0036]
In step S2, the map is referred to. When the rotational speed is detected, the map of FIG. 7A showing the relationship between the displacement X of the stator core moving portion 6b and the rotational speed is referred to, and when the current is detected, the relationship between the displacement X and the current is shown in FIG. When the map of (b) is referred and a voltage is detected, the map of FIG.7 (c) which shows the relationship between the displacement X and a voltage is referred. In these maps, the displacement X increases with increasing rotational speed, current or voltage. In other words, the relationship between the displacement X and the rotation speed, current or voltage is set such that the induced voltage generated in the stator winding 11 in the high rotation region decreases due to the reduction of the linkage flux. The map of FIG. 7A, the map of FIG. 7B, and the map of FIG. 7C are stored in the memory of the microcomputer. These maps are shown as examples, and various changes can be made depending on the characteristics of the motor. For example, the target displacement X is maintained at zero in a low rotation region where the rotation speed, current, or voltage is less than the respective threshold values, and the target displacement X is increased only above the threshold values. Also good.
[0037]
7A to 7C determine the target displacement X of the stator core moving portion 6b. Since the displacement X and the rotation angle θ are in a proportional relationship, the target rotation angle θ is determined. The target rotation angle θ may be set directly using a map that defines the relationship between the rotation speed, current, or voltage.
[0038]
In step S3, the target value of the displacement X is calculated using the above-mentioned map according to the read rotation speed, current or voltage. When a map for determining the rotation angle θ is provided, the target value of the rotation angle θ may be directly determined from the map.
[0039]
In step S4, the target rotation angle θ of the rotary shaft 24 of the drive motor 21 is calculated from the target value of the displacement X.
[0040]
In step S5, the drive motor 21 is controlled to achieve the target value of the rotation angle θ. Thus, the stator core moving part 6b moves by the target displacement X.
[0041]
With reference to FIG. 8, the effect with respect to the efficiency of the electric motor 100 by said embodiment is demonstrated. As shown in FIG. 8A, when the stator core moving part 6b is always at the innermost position (regular motor) regardless of the rotational speed of the rotor 3, that is, when the displacement X is zero. The region of high efficiency of 95% or more indicated by hatching is on the high torque low rotation side. On the other hand, when the stator core moving part 6b is at the outermost peripheral position, that is, when the displacement X is the maximum value Xmax, as shown in FIG. It is located on the high rotation side compared to zero.
[0042]
Thus, when moving the stator core moving part 6b to the stator outer peripheral side, the efficiency in the high rotation area | region of the rotor 3 rises. This occurs because the amount of magnetic flux linked to the coil 19 changes as the stator core moving part 6b moves.
[0043]
Next, a second embodiment of the stator core moving part 6b will be described. The configuration other than the stator core moving portion 6b is the same as that of the first embodiment, and a description thereof will be omitted.
[0044]
Referring to FIG. 9, unlike the first embodiment, the stator core moving part 6b is configured by laminating electromagnetic steel plates in the circumferential direction of the stator perpendicular to the axial direction. In this case, the number of laminated electromagnetic steel sheets is reduced as compared with the case where the electromagnetic steel sheets are laminated in the axial direction, thereby reducing the cost. Moreover, since the eddy current loss which is a part of iron loss becomes difficult to generate | occur | produce, efficiency also improves.
[0045]
Next, with reference to FIG. 10, 3rd embodiment about the stator core moving part 6b and the sliding groove | channel 17 is described. The configuration other than the stator core moving part 6b and the sliding groove 17 is the same as that of the first embodiment, and a description thereof will be omitted.
[0046]
In the first embodiment, the stator core moving part 6b has a substantially rectangular parallelepiped shape, and both side faces 75 of the stator core moving part 6b are substantially perpendicular to the front face 71. However, in the third embodiment, the angle between the side surface 75 and the front surface 71 of the stator core moving part 6b is an obtuse angle larger than 90 degrees, and the stator core moving part 6b is tapered. Therefore, as shown in the drawing, the cross-sectional shape of the stator core moving portion 6b perpendicular to the axial direction is a substantially trapezoidal shape in which the width between both side surfaces increases as it goes outward in the radial direction. Further, the sliding groove 17 of the stator core moving part 6b has a shape that fits into the stator core moving part 6b when the displacement X is zero, and the width between both side surfaces increases in the same manner as it goes radially outward. It becomes a substantially trapezoidal shape. Therefore, when the displacement X of the stator core moving part 6b is zero, the stator core moving part 6b can be brought into close contact with the inner periphery of the sliding groove 17, thereby the magnetic resistance between the stator core fixing part 6a and the stator core moving part 6b. It is possible to improve the characteristics of the electric motor.
[0047]
In addition, if the stator core fixing | fixed part 6a is formed with a dust core as mentioned later, the shape of the stator core moving part 6b can be set variously. For example, the angle between the side surface 75 of the stator core moving portion 6b and the front surface 71 is maintained at a substantially right angle, and between the axial end surface 77 and the circumferential side surface 75 of the stator core moving portion 6b as described above. The angle can be larger than 90 degrees.
[0048]
Next, the sliding groove 17 of the stator core moving part 6b Reference example Will be described. Since the configuration other than the sliding groove 17 is the same as that of the first embodiment, the description thereof is omitted.
[0049]
Referring to FIG. 11, unlike the first embodiment, the sliding groove 17 does not have the bottom surface 31 through the stator core fixing portion 6a. Therefore, the sliding groove 17 has an opening at the tip surface 14 of the tooth portion 6 c and the stator outer peripheral surface 40. The structure of the sliding groove 17 is not preferable when the stator core fixing portion 6a is formed by laminating electromagnetic steel plates as in the first embodiment because the electromagnetic steel plates are divided. For this reason, the stator core fixing part 6a has the shape shown in FIG. 12, and is a powder core produced by compression firing or compression molding a mixture of a ferromagnetic powder such as iron alloy powder or ferrite powder and an insulating binder. It consists of Thus, the sliding groove 17 indicated by the dotted line can penetrate the stator core fixing portion 6a, the stator core moving portion 6b can be brought closer to the rotor 3 side, and the torque during low-speed rotation is improved. Furthermore, by configuring the stator core fixing portion 6a with a dust core, the degree of freedom regarding the shapes of the stator core fixing portion and the moving portion is increased.
[0050]
Next, the stator core moving part 6b Reference example Will be described.
[0051]
In the first embodiment, the stator core 6 is divided into a stator core fixing portion 6a and a stator core moving portion 6b, and the stator core moving portion 6b moves with respect to the stator core fixing portion 6a to adjust the interlinkage magnetic flux to the coil 19. It was conducted. However, in the present embodiment, as shown in FIG. 13, the stator core 6 does not have a stator core fixing part and is configured only from a stator core moving part. The stator core 6 is divided into the same split cores 51 each including one tooth portion 51a, and each split core 51 corresponds to a stator core moving portion. A plurality of split cores 51 are connected and integrated so as to form a cylindrical shape as a whole, thereby forming a stator core 6. Each split core 51 is moved in the radial direction by the stator core moving mechanism 10.
[0052]
Referring to FIG. 14, the insulator frame 18 has a rectangular parallelepiped sliding groove 55 (shown by a dotted line) that fits into the substantially rectangular parallelepiped tooth portion 51 a of the split core 51. Each coil 19 is wound in close contact with an insulator frame 18. The teeth 51a of the split core 51 slides in the radial direction in the sliding groove 55, that is, in the coil 19. As described above, by configuring the entire stator core 6 with a movable member, it is possible to significantly improve the characteristics of the electric motor as compared with the first embodiment even if the movement amount is the same.
[0053]
In each of the above embodiments, the stator core moving mechanism 10 is configured to move all of the plurality of stator core moving parts 6b, but may be configured to move some of the stator core moving parts 6b as necessary. Although the stator winding is not defined, the stator winding may be concentrated winding or distributed winding. The stator 5 has 12 poles and the rotor 3 has 8 poles, but the present invention can be applied to stators and rotors having other poles. The driving motor 21 is used as a driving force source for supplying a driving force for moving the stator core moving unit 6b. However, the present invention is not limited to this, and the stator core moving unit 6b using another driving force source such as a hydraulic pump. Can also be moved. Furthermore, the present invention can be applied to a rotating electrical machine that operates as an electric motor, a generator, or both, regardless of whether it is AC or DC.
[0054]
The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.
[Brief description of the drawings]
FIG. 1 is a sectional side view in an axial direction of an electric motor according to a first embodiment of the present invention.
2 is a cross-sectional view perpendicular to the axial direction of the electric motor according to the first embodiment, showing a cross section taken along line II-II in FIG. 1;
FIG. 3 is a perspective view showing a stator core moving mechanism of the electric motor according to the first embodiment.
FIG. 4 is a schematic partial cross-sectional view perpendicular to the axial direction of the electric motor, showing how the stator core moving portion moves in the radial direction. (A) is when the stator core moving part is on the innermost side (X = 0), (b) is when the stator core moving part is moved radially outward by the displacement X from the innermost side (c) ) Shows the case where the stator core moving part is on the outermost peripheral side (X = Xmax). As the rotational speed of the rotor increases, the displacement X of the stator core moving part increases.
FIG. 5 is a schematic view showing a control device for an electric motor.
FIG. 6 is a flowchart showing a control routine for position control of a stator core moving unit.
FIG. 7A is a map showing the relationship between the displacement X of the stator core moving part and the rotational speed of the rotor. (B) It is a map which shows the relationship between the displacement X of a stator core moving part, and the electric current of an electric motor. (C) It is a map which shows the relationship between the displacement X of a stator core moving part, and the voltage of an electric motor.
FIG. 8 (a) When the stator core moving part is always at the innermost position regardless of the rotational speed of the rotor, that is, when the displacement X is zero, the region of efficiency of 95% or more is set to the rotational speed-torque. It is an efficiency map of the electric motor shown on a plane. (B) shows a region with an efficiency of 95% or more when the stator core moving part is always at the outermost position regardless of the rotational speed of the rotor, that is, when the displacement X is the maximum value Xmax. It is an efficiency map of the electric motor shown above. Areas of efficiency greater than 95 percent are indicated by hatched areas.
FIG. 9 is a schematic partial cross-sectional view perpendicular to the axial direction of the electric motor according to the second embodiment. (A) is when the stator core moving part is on the innermost side (X = 0), (b) is when the stator core moving part is moved radially outward by the displacement X from the innermost side (c) ) Shows the case where the stator core moving part is on the outermost peripheral side (X = Xmax).
FIG. 10 is a schematic partial sectional view perpendicular to the axial direction of an electric motor according to a third embodiment. (A) is when the stator core moving part is on the innermost side (X = 0), (b) is when the stator core moving part is moved radially outward by the displacement X from the innermost side (c) ) Shows the case where the stator core moving part is on the outermost peripheral side (X = Xmax).
FIG. 11 Reference example It is a general | schematic fragmentary sectional view perpendicular | vertical to the axial direction of the electric motor which concerns on. (A) is when the stator core moving part is on the innermost side (X = 0), (b) is when the stator core moving part is moved radially outward by the displacement X from the innermost side (c) ) Shows the case where the stator core moving part is on the outermost peripheral side (X = Xmax).
FIG. Reference example It is a perspective view which shows the shape of the stator core fixing | fixed part which concerns on this.
FIG. 13 Reference example It is a general | schematic fragmentary sectional view perpendicular | vertical to the axial direction of the electric motor which concerns on. (A) is when the stator core moving part is on the innermost side (X = 0), (b) is when the stator core moving part is moved radially outward by the displacement X from the innermost side (c) ) Shows the case where the stator core moving part is on the outermost peripheral side (X = Xmax).
FIG. 14 Reference example It is a perspective view which shows the frame of the insulator of the electric motor which concerns on.
[Explanation of symbols]
1 Rotating shaft
3 Rotor
5 Stator
6 Stator core
6a stator core fixing part
6b stator core moving part
8 Central axis
9 Rotor permanent magnet
10 stator core moving mechanism
12 rotation sensor
17 sliding groove
18 insulator frame
19 coils
21 drive motor
23 internal gear
23 pinion
24 motor rotation shaft
40 Stator outer peripheral surface
45 inverter
47 current sensor
49 voltage sensor
50 electric motor
60 controllers
71 front
73 back
75 sides
77 end face

Claims (8)

A substantially cylindrical stator having a plurality of stator cores and a coil wound around each of the plurality of stator cores;
In a rotating electrical machine comprising a rotor rotatably supported with respect to the stator and having a plurality of permanent magnets,
The stator core includes a moving part that is movable relative to the coil along a substantially radial direction of the stator, and a fixed part that does not move relative to the coil. The part has a sliding groove that guides the moving part to move, and the sliding groove does not penetrate the fixed part and has a bottom surface on the rotor side,
The rotating electrical machine includes a moving mechanism that moves the moving unit along a substantially radial direction based on the rotational speed of the rotor,
When the rotational speed of the rotor is zero, at least a part of the moving part is located inside the coil, and the moving part moves to the outside of the stator due to an increase in the rotational speed of the rotor. Rotating electric machine.   The rotating electrical machine according to claim 1, wherein the stator core is formed of laminated electromagnetic steel sheets.   The electric motor according to claim 1, wherein the moving part is formed of electromagnetic steel plates stacked in a circumferential direction of the stator.   2. The electric motor according to claim 1, wherein the moving unit includes a front surface facing the rotor and two side surfaces facing each other in a circumferential direction of the stator, and an angle between the front surface and the side surface is an obtuse angle. .   The electric motor according to claim 1, wherein the fixing portion is configured by a dust core.   The moving mechanism includes a driving force source that supplies a driving force for moving the moving unit;
Rotation speed detection means for detecting the rotation speed of the rotor;
The rotating electrical machine according to claim 1, further comprising a control unit electrically coupled to the driving force source.   The rotating electrical machine according to claim 6, wherein the rotational speed detecting unit includes a voltage sensor that detects a voltage of the rotating electrical machine and outputs the voltage, and estimates the rotational speed of the rotor.   The rotating electrical machine according to claim 6, wherein the rotational speed detection unit includes a current sensor that detects a current of the rotating electrical machine and outputs the current, and estimates the rotational speed of the rotor.

Images