JP7351123B2 - rotating electric machine - Google Patents

Description

The present invention relates to a rotating electric machine.

Conventionally, rotating electric machines have, for example, a fixed member having a cylindrical portion, a stator in which windings are wound around a stator core fixed to the inside of the fixed member, and a stator core fixed to the inside of the fixed member in the radial direction. Some devices include a rotor that is rotatably supported (for example, see Patent Document 1). The stator core of such a rotating electrical machine is generally held in pressure contact with the inner circumferential surface of a fixing member by shrink fitting or press fitting.

Japanese Patent Application Publication No. 2015-186322

By the way, in recent years, the permanent magnets of the rotor are made of strong neodymium magnets, and the material of the stator core is made of permendur, which has a higher saturation magnetic flux density than the general silicon steel plate. It is being considered to improve the efficiency of electrical machinery and, by extension, increase its output.

However, it is known that plate materials made of permendur, which has a high saturation magnetic flux density, have their magnetic properties such as magnetic permeability significantly reduced when a large compressive force is applied. If it is pressed into place and fixed, a large compressive force is applied and the magnetic properties are significantly degraded, making it impossible to obtain a highly efficient rotating electric machine.

The present invention has been made to solve the above problems, and its purpose is to provide a rotating electrical machine that can achieve high efficiency.

A rotating electric machine (11) that solves the above problems includes a stator (14, 65) in which a winding (17) is wound around a stator core (16, 51, 61), and a stator core (14, 65) in which the stator core is fixed. A rotating electrical machine (11, 64) comprising a fixing member (12, 13, 63) and a rotor (15, 67) arranged opposite to the stator core and rotatably supported, The stator core includes soft magnetic plates (41, 54, 62) having a saturation magnetic flux density of 2.0 Tesla or more, and is provided so that a tensile force is applied to the soft magnetic plates.

According to the same configuration, the stator core includes a soft magnetic plate material with a saturation magnetic flux density of 2.0 Tesla or more, so for example, a general soft magnetic plate material such as a silicon steel plate with a saturation magnetic flux density of less than 2.0 Tesla. It is possible to obtain a highly efficient rotating electrical machine compared to a machine constructed solely of the following. A soft magnetic plate material with a saturation magnetic flux density of 2.0 Tesla or more is provided in such a way that a tensile force is applied to the soft magnetic plate material, since the magnetic properties such as magnetic permeability are significantly improved when a tensile force is applied to the soft magnetic plate material. Therefore, it is possible to improve the magnetic properties of the stator core. Therefore, it becomes possible to obtain a highly efficient rotating electric machine.

FIG. 1 is a cross-sectional view of a rotating electrical machine in one embodiment. FIG. 2 is a partial plan view of a stator in one embodiment. FIG. 3 is a partial plan view of a rotor in one embodiment. FIG. 2 is a circuit diagram showing a circuit configuration in one embodiment. FIG. 1 is a partial cross-sectional view of a rotating electrical machine in one embodiment. FIG. 2 is a plan view of a stator in one embodiment. FIG. 2 is a top view of the housing in one embodiment. Magnetic field strength-magnetic flux density characteristic diagram of soft magnetic plate material obtained from experimental results. FIG. 7 is a plan view of a stator in another example. FIG. 7 is a partial plan view of a stator in another example. The partial sectional view of the rotating electric machine in another example. FIG. 7 is a partial cross-sectional view of a stator in another example.

Hereinafter, one embodiment of a rotating electrical machine will be described according to FIGS. 1 to 8.
As shown in FIG. 1, the rotating electric machine 11 includes a pair of housings 12 and 13 as fixed members in the axial direction, a substantially cylindrical stator 14 fixed to the housings 12 and 13, and a radial direction of the stator 14. The rotor 15 is rotatably supported inside.

The housings 12, 13 have substantially disk-shaped disk portions 12a, 13a, and cylindrical portions 12b, 13b extending in the axial direction from the outer edges of the disk portions 12a, 13a. The stator 14 is fixed while sandwiching the stator 14.

As shown in FIGS. 1 and 2, the stator 14 includes a stator core 16 and a winding 17 wound thereon. Specifically, as shown in FIG. 2, the stator core 16 includes an annular yoke portion 16a and a plurality of circumferential teeth portions 16b extending radially inward from the yoke portion 16a. The winding 17 is formed by applying an enamel coating 17b to a conductor 17a made of copper, aluminum, or the like. The windings 17 are arranged in parallel in the radial direction between the teeth portions 16b and are held in such a manner that they are covered with the insulating paper 18.

As shown in FIG. 1, the rotor 15 includes a rotating shaft 20 rotatably supported by a pair of bearings 19 fixed at the axial centers of a pair of housings 12 and 13, and a rotating shaft 20 fixed to the rotating shaft 20. It includes a child core 21 and a permanent magnet 22 fixed to the outer surface of the rotor core 21, and the permanent magnet 22 is arranged to face the stator core 16 in the radial direction.

As shown in FIG. 3, the permanent magnet 22 of this embodiment is a neodymium magnet and has a Halbach arrangement. The arrows illustrated in FIG. 3 indicate the magnetization direction of the permanent magnet 22, with the base point of the arrow corresponding to the south pole and the end point of the arrow corresponding to the north pole.

As shown in FIG. 4, the windings 17 of the U-phase, V-phase, and W-phase are Y-connected, and a control device 31 is connected to the terminals of the windings 17 of each phase. There is.
The control device 31 includes a three-phase inverter circuit 32 for generating three-phase driving power having a phase difference of 120 degrees from the DC power of the DC power source E. The three-phase inverter circuit 32 is a bridge circuit having three pairs of MOSFETs 33a, 33b, 33c, 33d, 33e, and 33f connected in series between a high-potential side power line L1 connected to a DC power source E and a ground line GND. It consists of Note that free wheel diodes D1 to D6 are connected to each MOSFET 33a, 33b, 33c, 33d, 33e, and 33f, respectively.

The output terminal Su between the U-phase MOSFETs 33a and 33b is connected to the terminal of the U-phase winding 17, and the output terminal Sv between the V-phase MOSFETs 33c and 33d is connected to the terminal of the V-phase winding 17. The output terminal Sw between the W-phase MOSFETs 33e and 33f is connected to the terminal of the W-phase winding 17.

Further, the control device 31 includes a current command unit 34, and the current command unit 34 controls each MOSFET 33a, 33b, A control signal is output to the gates Ga to Gf of 33c, 33d, 33e, and 33f to perform PWM control.

Here, as shown in FIGS. 1 and 5, the stator core 16 of the present embodiment is made up of laminated soft magnetic plates 41 with a saturation magnetic flux density of 2.0 Tesla or more, and the soft magnetic plates 41 have a tensile force. It is set up so that force is applied.

To explain in detail, first, the soft magnetic plate material 41 constituting the stator core 16 is a plate material made of permendur having a saturation magnetic flux density of about 2.3 Tesla. An insulating member made of polyamide film, polymer paper, or the like is sandwiched between the soft magnetic plates 41.

As shown in FIG. 5, the stator core 16 has a plurality of core holes 16c in the circumferential direction that penetrate in the axial direction. The core hole 16c is formed in a bulged portion 16d that bulges outward in the radial direction from the yoke portion 16a of the stator core 16. Eight bulges 16d and iron core holes 16c of this embodiment are formed at equal angular intervals in the circumferential direction.

Moreover, as shown in FIG. 6, the housings 12 and 13 have a plurality of fixing holes 12c and 13c in the circumferential direction that penetrate in the axial direction. Eight fixing holes 12c, 13c are formed in the disk portions 12a, 13a of the housings 12, 13 at equal angular intervals in the circumferential direction.

As shown in FIG. 1, the stator core 16 is fixed to the housings 12, 13 by through bolts 42 inserted into the fixing holes 12c, 13c and the core hole 16c. The through bolts 42 of this embodiment pass through one of the fixing holes 12c and the core hole 16c, and are screwed into the female threads formed on the inner surface of the other fixing hole 13c, thereby fixing the stator core 16. It is fixed to the housings 12 and 13. The through bolt 42 of this embodiment is made of a material containing a metal with an elastic modulus higher than that of steel, which has an elastic modulus of approximately 200 GPa, and specifically, is made of molybdenum, which has an elastic modulus of approximately 320 GPa.

As shown in FIGS. 5 to 7, when the stator core 16 and the housings 12, 13 are not fixed, the core hole radius R1, which is the distance from the shaft center Z where the core hole 16c is provided, is: The fixed hole radius R2 is set smaller than the fixed hole radius R2, which is the distance from the shaft center Z where the fixed holes 12c and 13c are provided. When the stator core 16 is fixed to the housings 12 and 13 by the through bolts 42 inserted through the fixing holes 12c and 13c and the core hole 16c, the core hole 16c of the stator core 16 is pulled radially outward. As a result, a tensile force is applied to the stator core 16 and, by extension, to the soft magnetic plate material 41. In this embodiment, the through bolts 42 are inserted into the fixing holes 12c, 13c and the iron core hole 16c while the housings 12, 13 made of aluminum material are cooled and shrunk, and when the housings 12, 13 return to room temperature, By making the fixing hole radius R2 larger than the core hole radius R1, a tensile force is applied to the soft magnetic plate material 41.

Next, the operation of the rotating electric machine 11 configured as described above will be explained.
When a three-phase drive current is supplied from the control device 31 to the windings 17 of the stator 14, a rotating magnetic field is generated in the stator 14, and the rotor 15 is rotationally driven. A strong neodymium magnet is used as the permanent magnet 22, but a soft magnetic plate 41, which is a plate made of permendur having a saturation magnetic flux density of 2.0 Tesla or more, is used as the material for the stator core 16. Therefore, magnetic saturation can be avoided, an uninterrupted flow of magnetic flux can be ensured, and the rotor 15 can be rotationally driven with high efficiency.

Next, the effects of the above embodiment will be described below.
(1) Since the stator core 16 includes the soft magnetic plate material 41 with a saturation magnetic flux density of 2.0 Tesla or more, for example, only general soft magnetic plate materials such as silicon steel plates with a saturation magnetic flux density of less than 2.0 Tesla are used. It is possible to obtain a rotating electrical machine 11 with higher efficiency than that configured with the following. The soft magnetic plate material 41 having a saturation magnetic flux density of 2.0 Tesla or more has magnetic properties such as magnetic permeability significantly improved when a tensile force is applied. Note that FIG. 8 is a magnetic field strength-magnetic flux density characteristic diagram obtained from the experimental results, and the characteristic X1 of the soft magnetic plate 41 to which compressive force is applied is greater than the characteristic X2 of the soft magnetic plate 41 to which no compressive force is applied. Characteristic X3 of the soft magnetic plate material 41 to which the magnetic flux density is significantly reduced and tensile force is applied shows that the magnetic flux density is significantly improved compared to the characteristic X2. Therefore, by providing the soft magnetic plate material 41 so as to apply a tensile force, it is possible to improve the magnetic properties of the stator core 16. Therefore, it becomes possible to obtain a highly efficient rotating electric machine 11.

(2) When the housings 12, 13 and the stator core 16 are not fixed, the core hole radius R1, which is the distance from the shaft center Z where the core holes 16c are provided, is the axis where the fixing holes 12c, 13c are provided. It is set smaller than the fixed hole radius R2, which is the distance from the center Z. Therefore, when the stator core 16 is fixed to the housings 12, 13 by the through bolts 42 inserted through the fixing holes 12c, 13c and the core hole 16c, the stator core 16 is pulled radially outward in the core hole 16c. Therefore, a tensile force is applied to the stator core 16 and, by extension, the soft magnetic plate material 41. With this configuration, it is possible to easily and reliably maintain a state in which a tensile force is applied to the soft magnetic plate material 41.

(3) The through bolt 42 contains a metal with an elastic modulus higher than that of steel with an elastic modulus of about 200 GPa, and in this embodiment is made of molybdenum, so the soft magnetic plate 41 has a higher elasticity than steel. It is possible to apply a strong tensile force and maintain the strong tensile force.

The above embodiment can be modified and implemented as follows. Further, this embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
- In the above embodiment, the stator core 16 is provided so that a tensile force is applied to the soft magnetic plate material 41 by the through bolts 42 while being fixed to the housings 12 and 13, but the stator core 16 is not limited to this, Other configurations may be used as long as the soft magnetic plate material having a saturation magnetic flux density of 2.0 Tesla or more that constitutes the child core is provided so that a tensile force is applied thereto.

For example, changes may be made as shown in FIGS. 9 and 10. That is, in this example, the stator core 51 includes an annular yoke member 52 and teeth members 53. The teeth member 53 includes a plurality of teeth portions 53a in the circumferential direction that are engaged with the yoke member 52 and extend radially inward from the yoke member 52, and a connecting portion that connects the radially inner ends of the teeth portions 53a in the circumferential direction. 53b. The yoke member 52 and the tooth member 53 are engaged so that a tensile force is applied to the soft magnetic plate 54. Specifically, first, in this example, the tooth member 53 is formed by laminating soft magnetic plates 54 such as permendur having a saturation magnetic flux density of 2.0 Tesla or more. The yoke member 52 in this example is made of laminated general soft magnetic plates such as silicon steel plates. Tab tail recesses 52a are formed on the radially inner side of the yoke member 52 at equal angular intervals in the circumferential direction, and on the radially outer side of each tooth portion 53a, when fitted into the tab tail recesses 52a, tab tail recesses 52a are formed radially inward. A tab tail protrusion 53c is formed that engages to restrict movement. Note that the tab tail concave portion 52a and the tab tail convex portion 53c have a substantially trapezoidal shape when viewed from the axial direction, and the tab tail convex portion 53c is removed from the tab tail concave portion 52a by engaging each other's inclined surfaces inclined with respect to the radial direction. radially inward movement of is restricted. The dimensions of the yoke member 52 and the teeth member 53 are set so that a tensile force is applied to the soft magnetic plate material 54 constituting the teeth member 53 when the tab tail recess 52a and the tab tail protrusion 53c are engaged. has been done. That is, in this example, by fitting the tab tail convex portion 53c into the tab tail concave portion 52a while pulling each tooth portion 53a including the tab tail convex portion 53c radially outward, the soft magnetic plate material 54 constituting the tooth member 53 in the assembled state Each dimension is set so that a tensile force is applied to the

Even in this case, the state in which a tensile force is applied to the soft magnetic plate material 54 is maintained, the magnetic properties of the stator core 51 can be improved, and a highly efficient rotating electric machine can be obtained. Further, in this example, the teeth member 53 is made of a soft magnetic plate material 54 such as permendur having a saturation magnetic flux density of 2.0 Tesla or more, and the yoke member 52 is made of a general soft magnetic plate material such as a silicon steel plate. Therefore, the high efficiency of the rotating electric machine can be achieved by efficiently using the soft magnetic plate material 54, which is likely to be expensive and has a saturation magnetic flux density of 2.0 Tesla or more, for the teeth portions 53a. Of course, the yoke member 52 may be made of a soft magnetic plate material other than a general soft magnetic plate material such as a silicon steel plate, or may be formed by laminating soft magnetic plate materials such as permendur.

Further, for example, changes may be made as shown in FIG. 11. That is, in this example, the stator core 61 has a cylindrical portion 61a and a plurality of teeth portions 61b in the circumferential direction extending radially outward from the cylindrical portion 61a, and has a permeable portion with a saturation magnetic flux density of 2.0 Tesla or more. Soft magnetic plate materials 62 such as Mendur are laminated. The cylindrical portion 61a of the stator core 61 is press-fitted onto the outer periphery of a center piece 63 serving as a fixing member so that a tensile force is applied to the soft magnetic plate 62. Note that the rotating electric machine 64 in this example is of an outer rotor type, and a rotor 67 having a rotor yoke 66 and a permanent magnet 22 is rotatable on the radially outer side of a stator 65 having the stator core 61 and the winding 17. It is set in.

Even in this case, a state in which a tensile force is applied to the soft magnetic plate material 62 is maintained, the magnetic characteristics of the stator core 61 can be improved, and a highly efficient rotating electric machine 64 can be obtained.

- Although not specifically mentioned in the above embodiment, the laminated soft magnetic plates 41 may be fixed in any manner in the axial direction of the stator core 16.
For example, as shown in FIG. 12, the stator core 16 may have a through hole 71 that penetrates in the axial direction, and magnetic powder 72 may be fixed in a compressed state within the through hole 71. . In addition, it is preferable that the magnetic powder 72 has an insulating film for each powder. By doing so, it is possible to reduce eddy current loss and improve magnetic properties, compared to, for example, fixing in the axial direction by caulking or welding. That is, when the soft magnetic plates 41 are fixed together in the axial direction by caulking or welding, for example, there is a risk that an eddy current path may be formed or the magnetic properties may be deteriorated due to the application of compressive force. These can be avoided. Further, for example, especially when the soft magnetic plate material 41 is a pressed product, unevenness may occur on the inner surface of the through hole 71 due to burrs or sagging, but the magnetic powder 72 also enters into those gaps, so the soft The magnetic plate material 41 is firmly fixed in the axial direction. Further, since the magnetic powder 72 enters into the gaps between the unevenness, the gaps become less likely to become magnetic resistance, and the magnetic properties of the stator core 16 are improved.

- In the above embodiment, the through bolt 42 is inserted into the fixing holes 12c, 13c and the iron core hole 16c while the housings 12, 13 are cooled and contracted, and when the housings 12, 13 return to room temperature, the fixing hole radius R2 changes to the iron core. Although a tensile force is applied to the soft magnetic plate material 41 by making the hole radius larger than R1, the through bolt 42 may be inserted therethrough by other methods.

- In the above embodiment, the through bolts 42 pass through one of the fixing holes 12c and the core hole 16c, and are screwed into the female threads formed on the inner surface of the other fixing hole 13c, thereby fixing the stator core 16. Although fixed to the housings 12 and 13, the fixing hole 13c is not limited to this, for example, a female thread may not be formed on the inner surface of the fixing hole 13c, and the fixing hole 13c may be fastened and fixed using a nut.

- In the above embodiment, the through bolt is made of molybdenum, but is not limited to this, and may be made of tungsten with an elastic modulus of about 340 GPa, for example. Even in this case, the same effect as effect (3) of the above embodiment can be obtained. Also, of course, the through bolt may be made of general steel.

- In the above embodiment, the soft magnetic plate 41 is made of permendur with a saturation magnetic flux density of about 2.3 Tesla, but is not limited to this, and any material with a saturation magnetic flux density of 2.0 Tesla or more is used. It is also possible to change the plate material to another material.

- In the above embodiment, the permanent magnet 22 is a neodymium magnet, but the present invention is not limited to this, and for example, other rare earth magnets or ferrite magnets may be used. Further, in the above embodiment, the permanent magnets 22 are arranged in a Halbach arrangement, but the permanent magnets 22 are not limited to this arrangement, and may be arranged in other arrangements. Further, the permanent magnet 22 may be embedded in the rotor core 21. That is, the rotor 15 may be of a surface magnet type or an embedded magnet type.

- The control device 31 of the above embodiment may be changed to another configuration, for example, it may be a control device using IGBTs instead of MOSFETs 33a, 33b, 33c, 33d, 33e, and 33f.

11,64...Rotating electric machine, 12,13...Housing (fixing member), 12c, 13c...Fixing hole, 14,65...Stator, 15,67...Rotor, 16,51,61...Stator core, 16c... Iron core hole, 17... Winding wire, 41, 54, 62... Soft magnetic plate material, 42... Through bolt, 52... Yoke member, 53... Teeth member, 53a, 61b... Teeth part, 53b... Connection part, 61a... Cylindrical part, 63... Center piece (fixing member), 71... Through hole, 72... Magnetic powder, R1... Iron core hole radius, R2... Fixed hole radius.

Claims (3)

a stator (14, 65) in which a winding (17) is wound around a stator core (16, 51, 61);
a fixing member (12, 13, 63) to which the stator core is fixed;
A rotating electric machine (11, 64) comprising a rotor (15, 67) arranged opposite to the stator core and rotatably supported,
The stator core includes soft magnetic plates (41, 54, 62) with a saturation magnetic flux density of 2.0 Tesla or more, and is provided so that a tensile force is applied to the soft magnetic plates,
The fixing member (12, 13) has a plurality of fixing holes (12c, 13c) in the circumferential direction that penetrate in the axial direction,
The stator core (16) has a plurality of core holes (16c) in the circumferential direction passing through the stator core (16), and is fixed to the fixing member by a through bolt (42) inserted through the fixing hole and the core hole. shall be done;
When the stator core and the fixing member are not fixed, the core hole radius (R1), which is the distance from the shaft center where the core hole is provided, is the distance from the shaft center where the fixing hole is provided. A rotating electric machine that is set smaller than a certain fixed hole radius (R2). The rotating electric machine according to claim 1, wherein the through bolt includes a metal having a higher elastic modulus than steel. The stator core has a through hole (71) passing through in the axial direction, and magnetic powder (72) having an insulating film for each powder is fixed in a compressed state in the through hole. The rotating electric machine according to claim 1 or claim 2 .