JP2017147778A - Switched reluctance motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the space factor of coils.SOLUTION: Teeth 441 are arranged at a predetermined pitch angle α in a circumferential direction of a stator 44 to a center C1 of a rotor 42. Each of the teeth 441 has a pair of planar side walls 441a and 441b inclined so as to become narrower as they go to the front end, at a taper angle θ1 of 1/2 of the pitch angle α. Adjacent coils L are configured to be close to each other from the base to the front end.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a switched reluctance motor.

  In recent years, a switched reluctance motor, which is a motor that does not require a permanent magnet, has attracted attention from the viewpoint of easy availability of materials and low cost. The switched reluctance motor includes a stator and a rotor provided with salient poles called teeth, and a coil wound around each tooth of the stator. The switched reluctance motor rotates the rotor by supplying a current based on the rotor position information to the coil and generating a continuous magnetic attraction force.

  In the switched reluctance motor, a magnetic attractive force is generated at a position where the stator teeth and the rotor teeth are displaced, and torque is generated. However, if the positions of both teeth are shifted, there is a problem that the rise of torque becomes dull due to the magnetic saturation of the teeth.

  Therefore, Patent Document 1 discloses a switched reluctance motor in which a teeth portion on the stator side is formed in a tapered shape that narrows toward the rotor side, and magnetic flux is concentrated on the tip end side of the teeth.

JP-A-10-322992

  However, in patent document 1, although the angle range of 1 degree-60 degree | times is employ | adopted as a taper angle of a teeth part, the grounds for taking this angle range are not shown clearly. Moreover, in patent document 1, improving the space factor of the coil wound around a teeth part is not considered at all. Therefore, in patent document 1, there exists room for the further improvement regarding what kind of shape the taper shape of a teeth part should be made when improving the space factor of a coil.

  The objective of this invention is providing the switched reluctance motor which can improve the space factor of a coil.

A switched reluctance motor according to an aspect of the present invention is a switched reluctance motor including a rotor and a stator,
The stator includes a plurality of teeth disposed at a predetermined pitch angle in a circumferential direction of the stator with respect to a rotation axis of the rotor, and a plurality of coils wound around each of the plurality of teeth.
Each of the plurality of teeth has a pair of flat side walls inclined so as to be narrowed toward the tip at a taper angle of ½ of the pitch angle.
Each of the plurality of coils is configured to be close to a coil adjacent from the tip to the base.

  According to this aspect, each of the plurality of teeth has a pair of planar side walls inclined so as to be narrowed toward the tip at a taper angle of ½ of the pitch angle of the teeth. In adjacent teeth, opposing side walls are parallel to each other. Therefore, in this aspect, each coil can be wound so that it may adjoin with the coil which adjoins from a front-end | tip to a root, the space factor of a coil can be improved, and the efficiency of a motor can be improved.

  In the above aspect, the coil may be a flat wire.

  According to this aspect, since the coil is composed of a rectangular wire, the space factor can be improved as compared with the case where the coil is composed of a round wire.

  In the above aspect, the coil may be a rectangular wire having a rectangular cross section.

  According to this aspect, since the coil is configured by a rectangular wire having a rectangular cross section, the number of turns can be reduced as compared with a case where the coil is configured by a square wire.

  In the above aspect, the coil may be an edgewise rectangular wire.

  According to this aspect, since the coil is composed of edge-wise wound rectangular wires, the coil can be wound with a small number of layers, the number of air layers interposed between the coils can be reduced, and the coil to the teeth. The heat conductivity of the coil can be increased, and the cooling performance of the coil can be improved.

  In the above aspect, the coil may be a single layer winding.

  According to this aspect, since it is comprised by the coil of single layer winding, an air layer does not interpose between coils, the heat conductivity from a coil to teeth is improved, and the cooling property of a coil can further be improved.

  In the above aspect, the coil may be a flat-wise wound rectangular wire.

  According to this aspect, since the coil is composed of flat-wise wound rectangular wires, the coil can be easily formed.

  The said aspect WHEREIN: You may further provide the insulating sheet provided with the surface interposed between the said stator and the said coil, and the surface interposed between adjacent coils.

  According to this aspect, since the insulating sheet having the surface interposed between the stator and the coil and the surface interposed between the adjacent coils is provided, the stator and the coil are insulated and the adjacent coil is provided. We can insulate each other.

  According to the present invention, each coil can be wound so as to be close to the adjacent coil from the tip to the base, the space factor of the coil can be improved, and the efficiency of the motor can be improved.

1 is a schematic configuration diagram of a hybrid vehicle to which an SR motor according to an embodiment of the present invention is applied. It is the schematic which showed the internal structure of SR motor when it sees from the main surface. FIG. 3 is a perspective view of the SR motor shown in FIG. 2. It is the figure which expanded and showed the teeth provided in the stator in SR motor concerning this embodiment. It is the figure which expanded and showed the slot. FIG. 5 is a schematic diagram showing the internal structure of the SR motor when viewed from the main surface when a flat-wise coil is employed.

  An embodiment of a switched reluctance motor (hereinafter referred to as “SR motor”) according to the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a hybrid vehicle 100 to which an SR motor according to an embodiment of the present invention is applied.

  The hybrid vehicle 100 includes wheels 10, 10, an axle 12, an engine 20, a transmission 30, an SR motor 40, an inverter 50, a battery 60, a controller 70, and various sensors (a crank angle sensor 81, an accelerator opening). A degree sensor 83, a vehicle speed sensor 84), and a silent switch 90.

  The hybrid vehicle 100 is a so-called parallel hybrid vehicle. The engine 20 and the SR motor 40 function as a driving source that outputs the driving force of the vehicle. In the hybrid vehicle 100, traveling by only the engine 20, traveling by both the engine 20 and the SR motor 40, according to driving conditions, Alternatively, traveling using only the SR motor 40 is realized.

  The engine 20 is connected to the axle 12 via a transmission 30. The engine 20 is a gasoline engine, for example.

  The SR motor 40 is connected to the axle 12 and is connected to the battery 60 via the inverter 50. The SR motor 40 is supplied after the power of the battery 60 is converted into AC power by the inverter 50. The SR motor 40 receives power supply and functions as an electric motor to rotate the axle 12. In the present embodiment, the SR motor 40 also functions as a generator. Specifically, the SR motor 40 performs a regenerative operation during deceleration and supplies power to the battery 60 via the inverter 50. The detailed structure of the SR motor 40 will be described later.

  The silent switch 90 is a switch that switches the control mode of the SR motor 40 between a normal mode and a silent mode. The silent switch 90 is a switch operated by a user (passenger), and the mode is switched by the user operating the silent switch 90 on / off. Specifically, when the silent switch 90 is turned on, the control mode of the SR motor 40 is in the silent mode, and when the silent switch 90 is turned off, the control mode of the SR motor 40 is in the normal mode. In the present embodiment, the silent switch 90 is provided on the handle. Note that the silent switch 90 may be attached to any position as long as the driver can operate it while driving, and may be attached to an instrument panel, for example.

  The controller 70 includes a main controller 71, an engine controller 72 that controls the engine 20, and a motor controller 73 that controls the SR motor 40. The controller 70 is a controller based on a well-known microcomputer, and includes a central processing unit (CPU) that executes a program, a memory that is configured by, for example, a RAM or a ROM and stores a program and data, and an electrical signal And an input / output (I / O) bus for performing input / output. In addition, each controller 71, 72, 73 may be comprised as a mutually separate controller, and may be comprised as one controller.

  At least the detection signals detected by the crank angle sensor 81, the accelerator opening sensor 83, and the vehicle speed sensor 84 and the operation signal of the silent switch 90 are input to the controller 70.

  The controller 70, in particular, the main controller 71 calculates current operating conditions based on the detection signals of the sensors, and determines driving / stopping of the engine 20 and the SR motor 40 based on the calculated operating conditions. In the present embodiment, in the low load region where the load is low, the engine 20 is stopped and only the SR motor 40 drives the wheels 10 and 10. In the high load region where the load is higher than the low load region, the SR motor 40 basically drives the wheels 10 and 10, but when the output of the SR motor 40 alone is not sufficient, such as during rapid acceleration, the engine 20 is driven, and the SR motor 40 and the engine 20 drive the wheels 10 and 10. The main controller 71 outputs a drive command signal for the engine 20 to the engine controller 72 when the engine 20 is driven, and controls the drive command signal for the SR motor 40 when the SR motor 40 is driven. Output to the device 73.

  The engine controller 72 calculates the throttle opening, fuel injection pulse, and the like based on the operating conditions, and outputs a signal to the throttle, injector, and the like.

  The motor controller 73 determines the control mode of the SR motor 40 based on the operation state of the silent switch 90 at least in the operation region where the SR motor 40 is driven as an electric motor, and determines the determined control mode and the drive state of the engine 20. Based on the above, the rate of change of magnetic energy generated in the SR motor 40 is determined. The motor controller 73 determines a current waveform to be supplied to the SR motor 40 based on the determined rate of change of magnetic energy, and outputs a signal corresponding to this current to the inverter 50.

  Next, the details of the structure of the SR motor 40 will be described. FIG. 2 is a schematic diagram showing the internal structure of the SR motor 40 when viewed from the main surface. FIG. 3 is a perspective view of the SR motor 40 shown in FIG.

  The SR motor 40 includes a rotating shaft 46, a rotor 42 that surrounds the rotating shaft 46, a stator 44 that surrounds the rotor 42, and a case 45 that houses the rotor 42 and the stator 44.

  The rotor 42 is generally composed of a disk-shaped member having a predetermined thickness, and includes a plurality of teeth 421 that project radially outward in the radial direction. In the present embodiment, the rotor 42 is made of a magnetic material such as an iron core and has twelve teeth 421, but this is an example.

  The rotating shaft 46 is formed of a rod-like member having a longitudinal direction in a direction orthogonal to the paper surface, and is fixed to the inner periphery of the rotor 42. Thereby, when the rotor 42 rotates, the rotating shaft 46 rotates and the wheel 10 is driven.

  The stator 44 is made of a magnetic material such as an iron core. The stator 44 includes an annular back yoke 447 that surrounds the outside of the rotor 42, and a plurality of teeth 441 that project radially from the back yoke 447 toward the rotor 42 side (inside). Coils L are wound around the teeth 441. 2 and the subsequent drawings, the coil L is shown in cross section, and the illustration of the coil L located on the front side of the tooth 441 is omitted.

  In the present embodiment, the stator 44 has 18 teeth 441 around which three-phase coils Lu, Lv, and Lw of U, V, and W phases are wound. In the present embodiment, the back yoke 447 and the teeth 441 may be configured integrally or may be configured to be assembled.

  In the SR motor 40, the coil L is energized in order, and the tooth 441 of the rotor 42 is magnetically attracted to the teeth 441 of the stator 44, thereby generating rotational torque in the rotor 42. In the present embodiment, current is sequentially supplied from the inverter 50 to the coils Lu, Lv, and Lw.

  A plurality of (six in FIG. 2) bolts 44a are provided on the outer edge side of the back yoke 447 at regular intervals, and the stator 44 is attached to the case 45 by the bolts 44a.

  In the SR motor 40 configured as described above, it is not necessary to use permanent magnets for the rotor 42 and the stator 44. Therefore, the use of this SR motor 40 is advantageous in terms of cost compared to the case of using a motor using a permanent magnet. Further, since no permanent magnet is used, no back electromotive force is generated in the SR motor 40. Therefore, in this SR motor 40, high motor efficiency can be maintained up to a higher rotational speed region.

  FIG. 4 is an enlarged view of the teeth 441 provided on the stator 44 in the SR motor 40 according to the present embodiment.

  The teeth 441 are arranged at a predetermined pitch angle α in the circumferential direction of the stator 44 with respect to the center C1 of the rotor 42 (see FIG. 2). Here, the pitch angle α is an angle formed between adjacent teeth 441. Specifically, when attention is paid to one tooth 441, a radial line D41 passing through the center in the width direction of the one tooth 441 and a radial line D41 of the tooth 441 adjacent to the one tooth 441 are formed. Is an angle. Here, the radial direction line D41 is a line in the radial direction passing through the center point in the width direction of the tooth 441 and the center C1.

  Each of the teeth 441 includes a pair of side walls 441a and 441b configured by opposing planes. The side walls 441a and 441b have a tapered shape that narrows toward the tip. Further, the side walls 441a and 441b are inclined in line symmetry with respect to the radial line D41. Further, the taper angle θ1 of the side walls 441a and 441b is set to ½ of the pitch angle α.

  Here, the taper angle θ <b> 1 is an angle formed by the side walls 441 a and 441 b of the tooth 441 with respect to the radial line D <b> 41 of the tooth 441 when attention is paid to a certain tooth 441.

  In the present embodiment, since the taper angle θ1 is set to ½ of the pitch angle α, the adjacent side walls (side walls 441b and 441a) are parallel between adjacent teeth 441. Therefore, the slot 442, which is a space formed between the side walls 441b and 441a, generally has a rectangular parallelepiped shape (or a cubic shape). The shape of the tip portion 441d of the tooth 441 is a quadrangle when viewed from the radial direction. Therefore, the teeth 441 generally have a truncated pyramid shape with a square cross section.

  The coil L is, for example, a rectangular wire whose surface is made of copper wire and whose cross section is rectangular. In addition, the coil L is configured by a concentrated winding coil wound around one tooth 441. Moreover, the coil L is comprised by the coil of the edgewise winding by which the short side of the cross section was bent. Further, the long side of the cross section of the coil L has a length approximately half of the width W of the slot 442. In addition, the coil L is wound on the tooth 441 in a single layer. Therefore, adjacent coils L are close to each other from the tip to the root. Here, the tip of the coil L refers to a position on the center C1 side (inside) of the coil L wound around the tooth 441, and the root of the coil L refers to the back yoke 447 side of the coil L wound around the tooth 441. Points to

  In addition, the phrase “close” means that the adjacent coils L are arranged at an interval so as not to be in electrical contact. Specifically, the proximity means at least an interval that allows the insulating sheet 446 (see FIG. 5) to be interposed between the adjacent coils L.

  FIG. 5 is an enlarged view of the slot 442. As shown in FIG. 5, the coil L is wound around the tooth 441 in a spiral manner along the shape of the tooth 441. Therefore, the long side t1 of the cross section of the coil L is inclined by the angle θ2 with respect to the direction of the width W of the slot 442. Therefore, strictly speaking, a value (t1 · cos θ2) obtained by multiplying the long side t1 by cos θ2 has a value substantially equal to W / 2.

  However, when t1 · cos θ2 = W / 2 is set, the insulating sheet 446 cannot be interposed between the adjacent coils L and between the coil L and the side walls 441a and 441b. Therefore, more strictly, in consideration of the insertion space of the insulating sheet 446, t1 · cos θ2 has a value smaller than W / 2 by a certain gap length. As the gap length, a length slightly larger than twice the thickness of the insulating sheet 446 can be adopted.

  In the example of FIG. 5, the coil L is wound with an inclination of the angle θ2, and accordingly, the bottom surface 442a of the slot 442 is inclined. Specifically, the bottom surface 442a includes a bottom surface 442a1 corresponding to the left coil L and a bottom surface 442a2 corresponding to the right coil L in FIG. The bottom surfaces 442a1 and 442a2 are planes that are inclined symmetrically with respect to the center line D42 of the slot 442 at an angle θ2 with respect to the width W direction. In the example of FIG. 5, the angle θ2 is the same as the taper angle θ1, but this is an example, and an angle different from the taper angle θ1 may be employed.

  The insulating sheet 446 is made of, for example, an insulator, and is interposed between adjacent coils L, between the side walls 441a and 441b and the coil L, and between the bottom surface 442a and the coil L. Specifically, the insulating sheet 446 includes surfaces 446a, 446b, 446c, 446d, 446e, 446f, and 446g connected in a counterclockwise direction. The surface 446 a includes the tip of the insulating sheet 446, has a length shorter than half of the width W, and covers a part of the opening side of the slot 442. The surface 446b is interposed between the right coil L and the side wall 441b, and insulates the right coil L from the right tooth 441. The surface 446c is interposed between the bottom surface 442a and the left and right coils L, and insulates the left and right coils L from the back yoke 447. The surface 446d is interposed between the left coil L and the side wall 441a and insulates the left coil L from the left tooth 441. The surface 446 e has a length approximately half of the width W and covers a part of the slot 442 on the opening side. The surface 446f is interposed between the left and right coils L and insulates the left coil L from the right coil L. The surface 446g includes the rear end of the insulating sheet 446, and is interposed between the surface 446c and the right coil L to insulate the right coil L from the back yoke 447.

  A pair of protrusions 441 c facing the opening side of the slot 442 are provided at the tip of the tooth 441. A pair of protrusions 441 c exist for each slot 442. The lid 445 is formed of a flexible member having substantially the same length as the width W of the slot 442, and is attached to the distal end side of the slot 442 by a pair of protrusions 441c, and closes the opening of the slot 442.

  The insulating sheet 446 is attached to the slot 442 as follows. First, before the left coil L and the right coil L are assembled, the insulating sheet 446 is inserted into the slot 442 along the side wall 441b, the bottom surface 442a, and the side wall 441a. At this time, the surface 446a and the surfaces 446e to 446g are not bent and protrude from the opening of the slot 442. Next, the left and right coils L are assembled to the teeth 441.

  Next, the insulating sheet 446 is pushed in between the left and right coils L until the bending disappears, and finally the rear end reaches a predetermined position on the bottom surface 442a2. Thereby, the surfaces 446e to 446g are formed. Next, the front end side of the insulating sheet 446 is bent to form a surface 446a. As described above, the insulating sheet 446 is attached to the slot 442. When the mounting of the insulating sheet 446 is completed, the lid 445 is screwed into the pair of protrusions 441c and attached.

  As described above, according to the SR motor 40 according to the present embodiment, the teeth 441 have a pair of planar shapes inclined such that the taper angle θ1 is ½ of the pitch angle α and narrow toward the tip. Side walls 441a and 441b. Therefore, in the adjacent teeth 441, the opposing side walls 441a and 441b are parallel to each other. As a result, adjacent coils L can be wound so as to be close to each other from the tip to the base, the space factor of the coil L can be improved, and the efficiency of the motor can be improved.

  In addition, since the coil L is formed of a rectangular wire with edgewise winding, the slot 442 can occupy almost the entire space even if it is a single layer winding. As a result, compared to the case where a multi-layer coil L is employed, no air layer is interposed between the coils L, the heat transfer from the coil L to the teeth 441 is enhanced, and the cooling performance of the coil L is enhanced. it can.

(Modification 1)
In the above embodiment, the coil L is edgewise wound, but the present invention is not limited to this, and the coil L may be flatwise wound. FIG. 6 is a schematic diagram showing the internal structure of the SR motor 40 when viewed from the main surface when the flat-wise coil L is employed.

  In FIG. 6, the difference from FIG. That is, in FIG. 6, since the coil L of flatwise winding is adopted, the cross section SD of the coil L has a rectangular shape that is long in the radial direction. Flatwise winding refers to a winding method in which the long side of the cross section SD is bent. Even when flatwise winding is employed, the coil L is concentrated winding.

  In the example of FIG. 6, the coil L has three layers. Therefore, when the short side of the cross section SD of the coil L is t2, 3 · t2 is set to be approximately half the width W. When this is generalized to n (n is an integer of 1 or more) layer winding, n · t2 is set to be approximately half the width W.

  However, considering that the coil L is spirally wound at an angle θ2 and the insulating sheet 446 is interposed as described in FIG. 5, 3 · t2 · cos θ2 is half of the width W. Less than a certain gap length. When this is generalized to n-layer winding, n · t 2 · cos θ 2 has a value smaller than half of the width W by a certain gap length.

  As described above, according to the SR motor 40 of the modified example, the coil L is easily formed because it is configured by the flat-wise coil L.

(Modification 2)
Although the cross section of the coil L has been described as a rectangle, the present invention is not limited to this and may be a square. However, from the viewpoint of reducing the number of turns, the cross section of the coil L is preferably rectangular rather than square.

C1 center D41 radial direction line D42 center line L coil α pitch angle θ1 taper angle 40 SR motor 42 rotor 421 teeth 44 stator 441 teeth 441a, 441b side wall 441c protrusion 441d tip 442 slot 445 cover 446 insulating sheet 446 insulating sheet 446 446d, 446e, 446f, 446g Surface 447 Back yoke 45 Case 46 Rotating shaft

Claims (7)

A switched reluctance motor comprising a rotor and a stator,
The stator includes a plurality of teeth disposed at a predetermined pitch angle in a circumferential direction of the stator with respect to a rotation axis of the rotor, and a plurality of coils wound around each of the plurality of teeth.
Each of the plurality of teeth has a pair of flat side walls inclined so as to be narrowed toward the tip at a taper angle of ½ of the pitch angle.
Each of the plurality of coils is a switched reluctance motor configured to be close to an adjacent coil from the tip to the base. The switched reluctance motor according to claim 1,
The coil is a switched reluctance motor that is a flat wire. The switched reluctance motor according to claim 2,
The coil is a switched reluctance motor having a rectangular wire with a rectangular cross section. In the switched reluctance motor according to claim 2 or 3,
The coil is a switched reluctance motor that is a rectangular wire with edgewise winding. The switched reluctance motor according to claim 4,
The coil is a switched reluctance motor having a single layer winding. In the switched reluctance motor according to claim 2 or 3,
The coil is a switched reluctance motor that is a flat-wire wound rectangular wire. In the switched reluctance motor according to any one of claims 1 to 6,
A switched reluctance motor further comprising an insulating sheet having a surface interposed between the stator and the coil and a surface interposed between adjacent coils.

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