JP6435838B2 - Rotating electric machine rotor and rotating electric machine including the same - Google Patents

Description

  The present invention relates to a rotor of a rotating electric machine such as an embedded magnet type motor (so-called IPM motor) and a rotating electric machine including the same.

  Conventionally, a rotor core, a plurality of magnet insertion holes provided at a certain interval in the circumferential direction on the outer periphery of the rotor core, and magnetic pole formation inserted and fixed in these magnet insertion holes, respectively Rotation of rotary electricity provided with a permanent magnet for use, and an outer peripheral hole portion provided on the outer peripheral portion of the rotor core and extending from a predetermined angular position with respect to the center of the magnetic pole to a predetermined angular position on the direction side away from the center A child is known (see, for example, Patent Document 1). The outer peripheral hole portion is formed such that the opening area sequentially increases from the predetermined angular position with respect to the center of the magnetic pole toward the direction away from the center. Thereby, reduction of torque ripple, iron loss, and harmonics is achieved.

JP 2009-77525 A

  However, in a rotor of a conventional rotary electric machine such as Patent Document 1, when the rotational speed of the rotor is increased, a large bending stress is generated in the tip portion (partition wall portion) that partitions the outer peripheral hole portion due to centrifugal force. There is a problem.

  The present invention has been made in view of such a point, and an object of the present invention is to reduce stress generated in the partition between the magnetic poles so that it can withstand high-speed rotation.

  In order to achieve the above object, in the present invention, the shape of the partition wall is an arc shape that can avoid stress concentration.

Specifically, in the first invention, a rotor core (11) having a plurality of magnet insertion holes (12) formed in the circumferential direction;
A permanent magnet (13) embedded in each of the plurality of magnet insertion holes (12) to form a magnetic pole;
A partition wall portion (15) that forms a gap (16) between the adjacent magnet insertion hole portions (12) corresponding to different magnetic poles and the outer edge of the rotor core (11),
The partition wall (15) defines the space between the adjacent magnet insertion holes (12) when viewed from the axial direction of the rotor core (11) and extends in the radial direction of the rotor core (11). A radial partition (15a),
Arc-shaped partition walls that branch from the radial partition wall (15a) so as to form the air gap (16) and extend toward the outer edge of the rotor core (11) so as to swell toward the magnet insertion hole (12). (15b).

  That is, during high-speed rotation, force is applied in the direction of pulling the radial partition wall (15a) by centrifugal force. The radial partition wall (15a) only needs to withstand the tensile force, and it should have sufficient strength to withstand it. However, when the tensile force generated in the radial partition wall (15a) is transmitted to the outer edge side of the rotor core (11). Therefore, it is necessary to avoid stress concentration due to bending stress. According to the above configuration, since the radial partition wall (15a) is connected to the arc-shaped partition wall (15b) where the load is easily transmitted, the tensile force generated in the radial partition wall (15a) is 15b) is transmitted smoothly and stress concentration is unlikely to occur.

In the second invention, in the first invention,
The first arc that forms the surface on the permanent magnet (13) side of the arc-shaped partition wall (15b) and the second arc that forms the surface on the opposite side of the permanent magnet (13) are concentric.

  According to said structure, the tensile force (F) which generate | occur | produced in the radial direction partition (15a) is smoothly transmitted to the circular-arc-shaped partition (15b) with almost no change in thickness.

In the third invention, in the second invention,
The centers of the first arc and the second arc are arranged outside the outer edge of the rotor core (11).

  According to the above configuration, the first arc and the second arc of the arc-shaped partition wall (15b) are increased, so that the tensile force (F) generated in the radial partition wall (15a) is smoother than the arc-shaped partition wall (15b). Is transmitted to.

In the fourth invention, in the first invention,
The arc-shaped partition wall (15b) is configured such that the thickness (t2) on the outer edge side of the rotor core (11) is thicker than the thickness (t1) on the radial partition wall (15a) side.

  According to the above configuration, by increasing the thickness (t2) on the outer edge side of the arc-shaped partition wall (15b), the load transmitted from the radial partition wall (15a) is more smoothly transmitted to the outer edge side, and the stress is increased. Alleviated. Further, by not making the thickness (t1) on the radial partition wall (15a) side unnecessarily thick, it is possible to avoid a decrease in magnetic flux that is effective in the stator (20).

  A rotating electrical machine (1) according to a fifth aspect of the invention includes the rotor (10) according to any one of the first to fourth aspects, and a stator (20) through which the rotor (10) is inserted.

  According to the above configuration, the electric rotating machine (1) does not generate stress concentration due to centrifugal force even when it rotates at high speed.

  As described above, according to the present invention, the load generated by the centrifugal force at the time of high-speed rotation is smoothly transmitted in the partition wall portion (15) and stress concentration is less likely to occur, so it can withstand high-speed rotation. The rotor (10) of the rotating electrical machine (1) is obtained.

  According to the second aspect of the invention, the thickness of the arc-shaped partition wall (15b) is constant and the load is transmitted smoothly, so that stress concentration can be avoided appropriately.

  According to the third aspect of the invention, by increasing the radius of the arc-shaped partition wall (15b), the load can be transmitted more smoothly and stress concentration can be avoided.

  According to the fourth aspect of the present invention, not only can the load from the radial partition wall (15a) be smoothly transmitted to the outer edge side to relieve the stress, but also effective magnetic flux reduction to the stator (20) can be effectively reduced. Can be avoided.

  According to the fifth aspect of the present invention, since stress concentration does not occur even when high-speed rotation is performed, a rotating electric machine (1) that is hard to break and has high durability and high-speed operation can be obtained.

It is a cross-sectional view showing an IPM motor according to an embodiment of the present invention. It is a cross-sectional view showing a rotor. It is a cross-sectional view which expands and shows a partition part and its periphery. FIG. 4 (A) is a diagram showing the high stress portion generated in the partition wall portion according to the embodiment of the present invention by hatching, and FIG. 4 (B) shows the high stress portion generated in the partition wall portion of the rotor according to the comparative example. It is a figure shown by hatching. FIG. 5A is a cross-sectional view when the center position of the concentric circles of the first arc and the second arc is at the outer edge of the rotor core, and FIG. 5B is a diagram of the concentric circles of the first arc and the second arc. The cross-sectional view when the center position is outside the outer edge of the rotor core is shown. It is a graph which shows the relationship between the center position of a concentric circle, and Mises stress. FIG. 6 is a view corresponding to FIG. 3 showing a rotor according to a modification of the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

  A motor (1) will be described as an example of the rotating electrical machine of the present invention. FIG. 1 is a cross-sectional view of a motor (1) according to Embodiment 1 of the present invention. This motor (1) is used, for example, in an electric compressor of an air conditioner (not shown).

<overall structure>
The motor (1) is a motor (a so-called IPM motor) in which a permanent magnet (13) is embedded in a rotor (10). In this example, the motor (1) is a rotor (10 ), A stator (20), and a drive shaft (40), which are accommodated in a casing (50) of the electric compressor, and in the following, the axial direction means the rotational axis direction of the motor (1). In this case, the direction of the axis (O) of the drive shaft (40) means the radial direction means the direction perpendicular to the axis (O), and the outer peripheral side means from the axis (O). The farther side is referred to, and the inner peripheral side is closer to the axis (O).

<Structure of stator>
As shown in FIG. 1, the stator (20) includes a cylindrical stator core (21) and a coil (26). The stator core (21) is a laminated core in which, for example, an electromagnetic steel plate is punched out by pressing to produce the planar laminated plate of FIG. 1, and a large number of laminated plates are laminated in the axial direction. The stator core (21) may be formed of a dust core. The stator core (21) includes one back yoke portion (22), a plurality (six in this example) of teeth portions (23), and a flange portion (24).

  The back yoke portion (22) is an annular portion formed on the outer peripheral portion of the stator core (21). The outer periphery of the back yoke portion (22) is fixed to the inner surface of the casing (50). The teeth part (23) is a part formed in a rectangular parallelepiped shape extending in the radial direction from the inner peripheral surface of the back yoke part (22). Between each teeth part (23), the slot (25) for coils in which a coil (26) is accommodated is formed. A coil (26) is wound around each tooth portion (23) by a so-called concentrated winding method. The wound coil (26) is accommodated in the coil slot (25). Thereby, an electromagnet is formed in each teeth part (23). The brim portion (24) is continuously formed on the inner peripheral side of each tooth portion (23). The brim portion (24) has a larger width (length in the circumferential direction) than the tooth portion (23), and the inner circumferential surface is formed into a cylindrical surface. The cylindrical surface of the collar portion (24) faces the outer peripheral surface (cylindrical surface) of the rotor (10) with a predetermined distance, that is, an air gap (G).

<Rotor structure>
As shown in FIG. 2, the rotor (10) has a shaft insertion hole (14) in which the drive shaft (40) is inserted and fixed at the center, and a plurality of magnet insertion holes ( 12) has a cylindrical rotor core (11) formed. The rotor core (11) is a laminated core in which, for example, an electromagnetic steel plate is punched out by pressing to create the planar laminated plate of FIG. 2, and a large number of laminated plates are laminated in the axial direction. The rotor core (11) may be formed of a dust core. Further, for example, permanent magnets (13) forming four magnetic poles are embedded in each magnet insertion hole (12). Magnet torque is generated by the permanent magnet (13), and reluctance torque is also generated by the rotor core (11).

  The rotor core (11) has a partition wall portion (15) that forms a gap (16) between the adjacent magnet insertion hole portions (12) corresponding to different magnetic poles and the outer edge of the rotor core (11). Is provided. Specifically, since the rotor (10) of this embodiment has four poles, it has four partition walls (15). The other four magnet insertion holes (12) are provided with only linear partitions, and no gap (16) is formed. By forming a moderately sized gap (16), magnetic flux short circuit is prevented.

  As shown in an enlarged view in FIG. 3, each partition wall portion (15) defines a space between adjacent magnet insertion holes (12) when viewed from the axial direction of the rotor core (11) and the rotor core ( 11) A radial partition wall (15a) extending in the radial direction is provided. A space | gap (16) consists of a fan-shaped space penetrated up and down. The reason why the outer edge of the gap (16) is covered with the thin portion (16a) is to prevent air resistance during rotation. The partition wall (15) branches from the radial partition wall (15a) so as to form a gap (16) and swells toward the outer edge of the rotor core (11) toward the magnet insertion hole (12). An arc-shaped partition wall (15b) is provided. In the present embodiment, the radial partition wall (15a) extends linearly, but may gradually become thicker toward the radially outer side, for example.

  As shown in FIG. 3, when viewed from the axial direction, the first circular arc that forms the surface on the permanent magnet (13) side of the arc-shaped partition wall (15b), and the first arc that forms the surface opposite to the permanent magnet (13). The two arcs are assumed to be concentric. The radius (R1) of the first arc is larger than the radius (R2) of the second arc (R1> R2) and is concentric. Therefore, the arc-shaped partition wall (15b) having substantially the same thickness by the difference in radius. Is formed.

  Next, the operation of the rotor (10) of the rotary electric machine according to the present embodiment will be described. During high-speed rotation, as shown in FIG. 4A, a load is applied in the direction of pulling the radial partition wall (15a) by centrifugal force. At this time, the radial partition wall (15a) only needs to withstand the pulling force (F), so long as it has enough strength. Since the pulling force (F) generated in the radial partition wall (15a) is transmitted to the outer edge side of the rotor core (11), the arc-shaped partition wall (15b) needs to withstand the load.

  FIG. 4B shows an example of the stress distribution by analysis in the rotor core (111) according to the comparative example having no gap (16). In this comparative example, the centrifugal force (F) generated during high-speed operation pulls the radial partition wall (115a) in the radial direction, and the load is transmitted to the outer edge portion (115b) of the rotor core (111). Since the outer edge portion (115b) intersects the radial partition wall (115a) substantially perpendicularly, stress is generated in a direction in which the outer edge portion (115b) is bent. For this reason, a high stress region (S) occurs in a wide range.

  On the other hand, as shown in FIG. 4A, in the rotor core (11) according to the embodiment of the present invention, the radial partition wall (15a) is connected to the arc-shaped partition wall (15b) that smoothly transmits the load. The tensile force (F) generated in the radial partition wall (15a) is smoothly transmitted to the arc-shaped partition wall (15b), and stress concentration hardly occurs. That is, the generation of bending stress is prevented as much as possible. High-stress regions (S) are slightly generated at the corners at both ends of the arc-shaped partition wall (15b), but this portion can be easily relieved by increasing the radius R of the corners. .

  Further, as shown in FIG. 5A, in the present embodiment, the first arc and the second arc are concentric, so that the thickness of the arc-shaped partition wall (15b) is constant, and stress concentration is appropriately performed. Can be avoided. On the other hand, as shown in FIG. 5B, the center C of the first arc and the second arc may be arranged outside the outer edge of the rotor core (11) (R1 ′> R1, R2 ′> R2). . If it does so, the 1st circular arc and 2nd circular arc of an arc-shaped partition (15b) will become large.

  Next, FIG. 6 shows an outline of the analysis result of Mises stress generated in the partition wall portion (15) when the center position x (see FIG. 5B) of the concentric circle is moved. As can be seen from this, it is understood that the stress is relaxed as the value of x is increased. Thus, by making the value of x as large as possible, the tensile force generated in the radial partition wall (15a) is smoothly transmitted to the arc-shaped partition wall (15b).

  Therefore, according to the rotor (10) of the rotating electrical machine according to the present embodiment, the load generated by the centrifugal force at the time of high-speed rotation is smoothly transmitted in the partition wall (15), and stress concentration is less likely to occur. A rotor (10) of a rotating electrical machine that can withstand high-speed rotation is obtained.

-Modification-
FIG. 7 shows a modification of the embodiment of the present invention, which differs from the above embodiment in that the shape of the arc-shaped partition wall (15b) is different. In the following modifications, the same portions as those in FIGS. 1 to 6 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this modification, the thickness of the arc-shaped partition wall (15b) is changed. Specifically, the thickness (t2) is increased by increasing the thickness of the thin wall portion (16a) rather than the thickness (t1) on the radial partition wall (15a) side (t2> t1). In this modification, the gap (16) side is thickened, but the magnet insertion hole (12) side may be thickened.

  In this way, by increasing the thickness (t2) on the thin-walled portion (16a) side, the high stress region (S) appearing in FIG. Further, by not increasing the thickness (t1) on the radial partition wall (15a) side more than necessary, it is possible to avoid a decrease in magnetic flux that is effective in the stator (20) while reducing stress.

(Other embodiments)
The present invention may be configured as follows with respect to the above embodiment.

  That is, in the above-described embodiment, the case where the magnetic pole has four poles has been described, but there is no particular limitation such as six poles or eight poles. In that case, the gap (16) and the partition wall (15) may be formed according to the number of magnetic poles.

  In the above embodiment, the rotary electric machine is the motor (1) used for the electric compressor of the air conditioner. However, the use thereof is not particularly limited, and may be a generator.

  As described above, the present invention is useful for rotors of rotating electrical machines such as motors and generators that can rotate at high speed.

1 Motor (rotary electric machine)
DESCRIPTION OF SYMBOLS 10 Rotor 11 Rotor core 12 Magnet insertion hole 13 Permanent magnet 15 Partition 15a Radial partition 15b Arc-shaped partition 16 Gap 20 Stator

Claims (4)

A rotor core (11) having a plurality of magnet insertion holes (12) formed in the circumferential direction;
A permanent magnet (13) embedded in each of the plurality of magnet insertion holes (12) to form a magnetic pole;
A partition wall portion (15) that forms a gap (16) between the adjacent magnet insertion hole portions (12) corresponding to different magnetic poles and the outer edge of the rotor core (11),
The partition wall (15) is viewed from the axial direction of the rotor core (11).
A radial partition (15a) that partitions between the adjacent magnet insertion holes (12) and extends in the radial direction of the rotor core (11),
Arc-shaped partition walls that branch from the radial partition wall (15a) so as to form the air gap (16) and extend toward the outer edge of the rotor core (11) so as to swell toward the magnet insertion hole (12). (15b) and
The first arc that forms the surface of the arc-shaped partition wall (15b) on the permanent magnet (13) side and the second arc that forms the surface opposite to the permanent magnet (13) are concentric. Rotor of rotating electrical machine (10). The rotor (10) of a rotating electrical machine according to claim 1 ,
The rotor (10) of the rotating electrical machine, wherein the center of the first arc and the second arc is arranged outside the outer edge of the rotor core (11). A rotor core (11) having a plurality of magnet insertion holes (12) formed in the circumferential direction;
A permanent magnet (13) embedded in each of the plurality of magnet insertion holes (12) to form a magnetic pole;
A partition wall portion (15) that forms a gap (16) between the adjacent magnet insertion hole portions (12) corresponding to different magnetic poles and the outer edge of the rotor core (11),
The partition wall (15) is viewed from the axial direction of the rotor core (11).
A radial partition (15a) that partitions between the adjacent magnet insertion holes (12) and extends in the radial direction of the rotor core (11),
Arc-shaped partition walls that branch from the radial partition wall (15a) so as to form the air gap (16) and extend toward the outer edge of the rotor core (11) so as to swell toward the magnet insertion hole (12). (15b) and
The arc-shaped partition wall (15b) has a thickness (t2) on the outer edge side of the rotor core (11) larger than a thickness (t1) on the radial partition wall (15a) side. Rotor (10). A rotor (10) of a rotating electrical machine according to any one of claims 1 to 3 ;
A rotating electric machine comprising: a stator (20) through which the rotor (10) is inserted.

Images