JP6139473B2 - Rotating electrical machine rotor - Google Patents

Description

  The present invention relates to a rotor of a rotating electrical machine.

  For example, Patent Document 1 discloses a rotating shaft, a holding member (rotor holding member) that is fixed to the rotating shaft and rotates integrally with the rotating shaft, and a rotor core that is fitted around the outer peripheral surface of the holding member. There is disclosed a rotating electrical machine comprising:

  The holding member is formed in a cup shape having a cylindrical portion that holds the rotor core, a disk-shaped outer diameter side connected to the cylindrical portion, and a disk-shaped inner diameter side fixed to the rotating shaft. Yes.

JP 2010-252522 A

  By the way, when an annular rotor core is press-fitted and assembled to the outer peripheral surface of the holding member disclosed in Patent Literature 1, the holding portion is held at a portion connected to the disk portion on one side along the axial direction of the cylindrical portion. The rigidity of the member increases, and the stress generated in the rotor core during press-fitting into the holding member increases. For this reason, there exists a possibility that the intensity | strength of a rotor core may fall in the part with a large stress of a rotor core.

  In other words, the stress of the rotor core generated during press-fitting into the holding member increases on one side along the axial direction of the cylindrical portion and decreases on the other side along the axial direction, thereby reducing the stress in the axial direction of the rotor core. There is a risk of variation and non-uniformity. Accordingly, it is necessary to set (design) the rotor core so that a predetermined strength can be ensured on one side of the cylindrical portion where the stress generated in the rotor core is high. As a result, the degree of freedom in designing the rotor core may be reduced.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a rotor of a rotating electrical machine capable of improving the degree of freedom in designing a rotor core.

In order to achieve the above object, the present invention provides a rotating electrical machine comprising: a rotating shaft; and a holding member that is formed separately from the rotating shaft and is fixed to the rotating shaft and holds a rotor core on the outer periphery. In this rotor, the holding member includes a fitting portion fitted to the rotation shaft, a tubular portion formed in a tubular shape and fitted on the rotor core, and one axial end of the tubular portion. A disk-shaped disk part connected to the cylindrical part to connect the cylindrical part and the fitting part, and the outer diameter of one axial side of the outer peripheral surface of the cylindrical part is the cylindrical part The outer diameter of the outer circumferential surface of the cylindrical portion is set smaller than the outer diameter of the outer circumferential surface of the cylindrical portion, and one axial side of the outer circumferential surface of the cylindrical portion extends over a predetermined distance in the axial direction of the cylindrical portion. A small diameter portion formed smaller than the outer diameter of the large diameter portion on the other side of the cylindrical portion, A thickened portion formed by bulging an inner peripheral surface of the cylindrical portion is formed at a corner portion to which the disk portion is connected, and the small diameter portion is formed of the cylindrical portion having the corner portion. from one end along the axial direction, and wherein the extension Mashimasu Rukoto to the other side in the axial direction of the cylindrical portion beyond the end face of the thickening portion along the axial direction.

  According to the present invention, the outer diameter on one side in the axial direction on the outer peripheral surface of the cylindrical portion is set smaller than the outer diameter on the other side in the axial direction, and the outer diameter on one side in the axial direction of the cylindrical portion is The inner surface of the rotor core is in a non-contact state in the radial direction orthogonal to the axial direction. The inner diameter of the rotor core that is the press-fitting surface is formed constant in the axial direction of the rotor core. Therefore, for example, when the rotor core is press-fitted and assembled to the outer peripheral surface of the cylindrical portion of the holding member, the outer diameter on one side in the axial direction of the cylindrical portion and the inner peripheral surface of the rotor core are in a non-contact state. It is possible to avoid the press-fitting stress being transmitted to the rotor core.

  Therefore, according to the present invention, in the axial direction of the rotor core, the press-fitting stress generated in the rotor core on one side where the disk portion is provided can be suppressed, and the stress distribution in the axial direction of the rotor core can be made substantially uniform. As a result, according to the present invention, the degree of freedom in designing the rotor core can be improved.

  According to the present invention, in the cylindrical portion, the large-diameter portion on the other side in the axial direction functions as a holding surface of the rotor core, and “relief” is provided between the small-diameter portion on the one side in the axial direction and the inner peripheral surface of the rotor core. Can be provided as a clearance. Therefore, in the present invention, in the axial direction of the rotor core, the press-fitting stress generated in the rotor core on the small diameter portion side through the clearance can be suppressed, and the stress distribution in the axial direction of the rotor core can be made substantially uniform. As a result, according to the present invention, the degree of freedom in designing the rotor core can be improved.

  Moreover, according to this invention, the small diameter part extended predetermined distance over the axial direction of a cylindrical part can be easily manufactured, for example by giving a cutting process with respect to the one side of a rotating shaft.

  According to the present invention, by providing the thickened portion, it is possible to improve the rigidity and strength of the cylindrical portion of the holding member that externally fits the rotor core. Thereby, the deformation | transformation and vibration to the outer radial direction of a holding member at the time of rotation of a rotor core can be suppressed.

  Further, according to the present invention, even if the rigidity and strength of the holding member is increased by forming the thickened portion, the cylindrical shape in which the small diameter portion exceeds the end face of the thickened portion along the axial direction. By extending to the other side in the axial direction of the portion, the press-fitting stress generated in the rotor core is further effectively suppressed as compared with the case where the small diameter portion does not exceed the end face of the thickened portion along the axial direction. be able to.

Furthermore, the present invention provides a rotor of a rotating electrical machine having a rotating shaft and a holding member that is formed separately from the rotating shaft and is fixed to the rotating shaft, and that holds a rotor core on the outer periphery. The member is connected to a fitting portion fitted to the rotating shaft, a tubular portion formed in a tubular shape and externally fitted to the rotor core, and connected to one end portion in the axial direction of the tubular portion. A disc-shaped disc portion that connects the tubular portion and the fitting portion, and the outer diameter on one side in the axial direction on the outer peripheral surface of the cylindrical portion is the axial direction on the outer peripheral surface of the cylindrical portion Is set to be smaller than the outer diameter of the other side of the cylindrical portion, and one axial side of the outer peripheral surface of the cylindrical portion extends over a predetermined distance in the axial direction of the cylindrical portion, and has a larger diameter on the other side in the axial direction. It has a small diameter portion which is smaller than the outer diameter of the section, between the large diameter portion and the small diameter portion The field, characterized by Rukoto annular step portion is formed.

  According to the present invention, by forming the annular step portion, it is possible to easily manufacture a rotating shaft having a large diameter portion and a small diameter portion, and to reduce the manufacturing cost.

  According to the present invention, it is possible to obtain a rotor of a rotating electrical machine that can improve the degree of freedom in designing the rotor core.

It is a longitudinal cross-sectional view along the axial direction of the electric motor with which the rotor which concerns on embodiment of this invention was integrated. It is an arrow view of the rotor seen from the arrow X direction of FIG. It is an expanded vertical sectional view of the rotor and holding member which comprise an electric motor. It is a perspective sectional view showing clearance between a small diameter part of a cylindrical part, and a rotor core. It is a characteristic view which shows the relationship between the press-fitting stress which generate | occur | produces in the one side of the rotor core along an axial direction, and the length dimension of the small diameter part along an axial direction.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. FIG. 1 is a longitudinal sectional view along the axial direction of an electric motor incorporating a rotor according to an embodiment of the present invention, and FIG. 2 is an arrow view of the rotor as viewed from the direction of arrow X in FIG. In the present embodiment, the “axial direction” refers to the direction of the center line A of the shaft 12 or the direction along the center line A. “One side” and “the other side” refer to the directions shown in FIG.

  The rotating electrical machine is an electric motor 10 that is used as a rotational drive source of, for example, a hybrid vehicle or an electric vehicle. The electric motor 10 is composed of, for example, a three-phase brushless DC motor.

  As shown in FIG. 1, the electric motor 10 is rotatably held via a bearing (not shown), and faces a shaft 12 that functions as a rotating shaft, a stator 14 that includes a plurality of armatures, and the stator 14. And the holding member 18 which is fixed to the shaft 12 and holds the rotor 16 on the outer periphery. In FIG. 1, illustration of a casing or the like that holds the stator 14 from the outer diameter side is omitted. In FIG. 2, illustration of the stator 14 in FIG. 1 is omitted.

  In FIG. 1, the shaft 12 exemplifies a hollow shaft having a through-hole 12 a penetrating along the direction of the center line A. However, the shaft 12 is not limited to this and may be a solid shaft. .

  The stator 14 is constituted by an iron core 14a and a coil 14b wound around the iron core 14a, and is arranged at substantially equal intervals in the circumferential direction around the center line A of the shaft 12. The coil 14b is configured by a U-phase, V-phase, and W-phase three-phase coil.

  FIG. 3 is an enlarged longitudinal sectional view of a rotor and a holding member constituting the electric motor, and FIG. 4 is a perspective sectional view showing a clearance between a small diameter portion of the cylindrical portion and the rotor core.

  As shown in FIG. 3, the holding member 18 is fitted to the shaft 12 and fixed to the outer peripheral surface of the shaft 12. The holding member 18 is formed in a cylindrical shape and the rotor core 22 is externally fitted to the outer peripheral surface. A cylindrical portion 24, and a disk-shaped disc portion 26 that is connected to one end 24 a in the axial direction of the cylindrical portion 24 and connects the cylindrical portion 24 and the fitting portion 20.

  The fitting portion 20 is formed in a substantially cylindrical shape that extends along the center line A of the shaft 12 and surrounds the outer peripheral surface of the shaft 12. The fitting portion 20 is fitted to the outer peripheral surface of the shaft 12 and is fixed via a fixing member 21.

  The cylindrical portion 24 has a substantially cylindrical shape larger in diameter than the fitting portion 20, and the rotor core 22 is fitted on the outer peripheral surface thereof. A small diameter portion 28 is formed on one side of the outer peripheral surface of the cylindrical portion 24 along the axial direction. On the other side of the outer peripheral surface of the cylindrical portion 24 along the axial direction, a large-diameter portion 30 having an outer diameter set larger than that of the small-diameter portion 28 is formed. The outer diameter of the small diameter portion 28 located on one side in the axial direction on the outer peripheral surface of the cylindrical portion 24 is set smaller than the outer diameter of the large diameter portion 30 located on the other side in the axial direction.

  The small-diameter portion 28 is formed smaller than the outer diameter of the large-diameter portion 30 on the other side in the axial direction, and extends from the one-side end portion 24a along the axial direction of the cylindrical portion 24 over a predetermined distance in the axial direction. Yes. At the boundary between the small diameter portion 28 and the large diameter portion 30 of the cylindrical portion 24, an annular step portion 32 that makes one round of the outer peripheral surface of the shaft 12 is formed.

  As shown in FIG. 4, between the outer peripheral surface of the small diameter portion 28 and the inner peripheral surface of the rotor core 22, it extends substantially parallel to the center line A of the shaft 12 (the axis of the cylindrical portion 24), and A clearance 34 is formed that is spaced apart by a predetermined interval ΔS in the radial direction. By forming a clearance 34 between the cylindrical portion 24 and the rotor core 22, the small diameter portion 28 is set in a non-contact state with the inner peripheral surface of the rotor core 22.

  In other words, the small-diameter portion 28 facing the inner peripheral surface of the rotor core 22 functions as “escape” that does not contact the inner peripheral surface of the rotor core 22 via the clearance 34. By providing this “relief”, for example, when the rotor core 22 is press-fitted into the holding member 18, transmission of press-fitting stress from the holding member 18 side to the rotor core 22 side is avoided. For this reason, it suppresses that the press-fitting stress which generate | occur | produces in the one side (small diameter part 28 side) in the axial direction of the rotor core 22 becomes high compared with the other side (large diameter part 30 side) of the axial direction of the rotor core 22. Can do.

  A thickened portion 36 formed by bulging the inner peripheral surface of the cylindrical portion 24 is formed at a corner portion 35 where the cylindrical portion 24 and the disk portion 26 are connected. The length of the small-diameter portion 28 along the axial direction is such that the axial direction of the tubular portion 24 extends from the end 24a along the axial direction of the tubular portion 24 to the end surface 36a of the thickened portion 36 along the axial direction. The dimension T is set to extend to the other side portion 37. Note that, in the length dimension T of the small diameter portion 28 shown in FIG. 4, the range of the length dimension T1 substantially functions as a relief.

  The thickened portion 36 has an inclined portion 38 that suspends between the cylindrical portion 24 and the disk portion 26. The inclined portion 38 is formed so that the cross-sectional width dimension of the thickened portion 36 gradually decreases from the cylindrical portion 24 side toward the disk portion 26 side.

  The holding member 18 is formed separately from the shaft 12. Moreover, in this embodiment, although the holding member 18 which integrally formed the fitting part 20, the cylindrical part 24, and the disk part 26 is illustrated, it is not limited to this, and each is separate. For example, it may be integrally coupled with a fastening member such as a screw.

  Returning to FIG. 3, the rotor 16 includes, for example, a rotor core 22 formed by laminating a plurality of ring-shaped magnetic thin plates, and a plurality of rotors arranged along the circumferential direction at substantially equal intervals around the axis of the shaft 12. And a permanent magnet 40 (see FIG. 2). The plurality of permanent magnets 40 are set so that the polarities of the adjacent permanent magnets 40 are different from each other. The inner diameter of the inner peripheral surface of the rotor core 22 that is press-fitted into the cylindrical portion 24 of the holding member 18 is set to be constant along the axial direction of the rotor core 22.

  The electric motor 10 in which the rotor 16 according to the present embodiment is incorporated is basically configured as described above. Next, the function and effect will be described.

  FIG. 5 is a characteristic diagram showing the relationship between the press-fitting stress generated on one side of the rotor core along the axial direction and the length dimension of the small diameter portion along the axial direction. In the characteristic diagram shown in FIG. 5, the starting point of the length dimension of the small-diameter portion 28 is not the one end 24 a of the cylindrical portion 24, but the end face on one side of the rotor core 22 that substantially functions as “escape”. Is set to 0.

  As can be understood from FIG. 5, the radial clearance 34 formed between the small-diameter portion 28 of the cylindrical portion 24 and the inner peripheral surface of the rotor core 22 functions as a “relief”, so that it is imparted to the rotor core 22. The press-fit stress that is applied can be reduced up to the dimension T1. As a result, in the present embodiment, fatigue failure of the rotor core 22 can be suppressed, and the degree of freedom in designing the rotor core 22 can be improved.

  In the present embodiment, the outer diameter of the small diameter portion 28 located on one side in the axial direction on the outer peripheral surface of the cylindrical portion 24 is set smaller than the outer diameter of the large diameter portion 30 located on the other side in the axial direction, The outer diameter of the small diameter portion 28 and the inner peripheral surface of the rotor core 22 are in a non-contact state in the radial direction orthogonal to the axial direction via the clearance 34.

  Therefore, when the rotor core 22 is press-fitted into the outer peripheral surface of the cylindrical portion 24 of the holding member 18 and assembled, the outer diameter of the small diameter portion 28 of the cylindrical portion 24 and the inner peripheral surface of the rotor core 22 are in a non-contact state. It is possible to avoid the press-fitting stress being transmitted to the rotor core 22.

  In the present embodiment, after the rotor core 22 is assembled to the holding member 18 and the electric motor 10 is completed, when the electric motor 10 is operated to rotate the rotor core 22 and the holding member 18 integrally, The centrifugal stress (centrifugal force) generated in the small-diameter portion 28 is the centrifugal stress applied to the rotor core 22 because the outer diameter of the small-diameter portion 28 of the cylindrical portion 24 and the inner peripheral surface of the rotor core 22 are not in contact with each other by the clearance 34. Can be prevented from being transmitted.

  Therefore, in this embodiment, in the axial direction of the rotor core 22, stress (pressing stress and centrifugal stress) generated in the rotor core 22 on one side where the disk portion 26 is provided is suppressed, and stress in the axial direction of the rotor core 22 is suppressed. The distribution can be made substantially uniform. As a result, in the present embodiment, the degree of freedom in designing the rotor core 22 can be improved. For example, it is not necessary to set the strength of the rotor core 22 corresponding to the peak point of the non-uniform stress distribution, and the degree of freedom in setting increases.

  In addition, in this embodiment, the design flexibility of the rotor core 22 is improved to suppress a decrease in rigidity and strength of the rotor core 22 caused by an increase in stress (press-fit stress and centrifugal stress) generated in the rotor core 22. can do.

  In other words, in this embodiment, after the rotor core 22 is assembled to the holding member 18 and the electric motor 10 is completed, when the rotor core 22 and the holding member 18 rotate integrally, in addition to the press-fit stress applied to the rotor core 22. Thus, centrifugal stress (centrifugal force) is generated. Therefore, in order to maintain the strength of the rotor core 22, it is necessary to consider a stress that is a sum of both the press-fitting stress and the centrifugal stress, but in this embodiment, the pressure stress can be reduced (homogenized in the axial direction). Further, there is an advantage that the stress obtained by adding both the press-fitting stress and the centrifugal stress can be reduced.

  Furthermore, in this embodiment, the small diameter part 28 extended for a predetermined distance over the axial direction of the cylindrical part 24 can be easily manufactured by performing a cutting process with respect to the one side of the shaft 12, for example.

  Furthermore, in the present embodiment, by providing the thickened portion 36, the rigidity and strength of the cylindrical portion 24 of the holding member 18 to which the rotor core 22 is fitted can be improved. Thereby, the deformation | transformation and vibration to the outer radial direction of the holding member 18 at the time of rotation of the rotor core 22 can be suppressed.

  Furthermore, in this embodiment, even if the rigidity and strength at the corner portion 35 of the holding member 18 and the vicinity of the corner portion 35 are increased by forming the thickened portion 36, the small-diameter portion 28 is the shaft. The small-diameter portion 28 does not exceed the end surface 36a of the thickening portion 36 along the axial direction by extending to the other side in the axial direction of the cylindrical portion 24 beyond the end surface 36a of the thickening portion 36 along the direction. Compared to the case, the press-fitting stress generated in the rotor core 22 can be more effectively suppressed.

  Furthermore, in the present embodiment, by forming the annular step portion 32, the shaft 12 having the large diameter portion 30 and the small diameter portion 28 can be easily manufactured, and the manufacturing cost can be reduced.

10 Electric motor (rotary electric machine)
12 Shaft (Rotating shaft)
16 rotor 18 holding member 20 fitting part 22 rotor core 24 cylindrical part 24a one side end part 26 disk part 28 small diameter part 30 large diameter part 32 annular step part 34 clearance 35 corner part 36 thickening part 36a (in the thickening part) End face T, T1 Length dimension of the small diameter part along the axial direction

Claims (2)

A rotation axis;
A holding member that is formed separately from the rotating shaft and is fixed to the rotating shaft, and holds the rotor core on the outer periphery;
In a rotor of a rotating electric machine having
The holding member is
A fitting portion fitted to the rotating shaft;
A cylindrical part that is formed in a cylindrical shape and on which the rotor core is fitted; and
A disk-shaped disk part connected to one end part in the axial direction of the cylindrical part and connecting the cylindrical part and the fitting part;
With
The outer diameter on one side in the axial direction on the outer peripheral surface of the cylindrical part is set smaller than the outer diameter on the other side in the axial direction on the outer peripheral surface of the cylindrical part ,
One side in the axial direction on the outer peripheral surface of the cylindrical part extends over a predetermined distance in the axial direction of the cylindrical part, and is a small diameter part formed smaller than the outer diameter of the large diameter part on the other side in the axial direction Have
In the corner portion where the tubular portion and the disc portion are connected, a thickened portion is formed, which is formed by bulging the inner peripheral surface of the tubular portion,
The small diameter portion extends from one end along the axial direction of the cylindrical portion having the corner portion to the other side in the axial direction of the cylindrical portion beyond the end surface of the thickened portion along the axial direction. the rotor of a rotary electric machine characterized by be Rukoto. A rotation axis;
A holding member that is formed separately from the rotating shaft and is fixed to the rotating shaft, and holds the rotor core on the outer periphery;
In a rotor of a rotating electric machine having
The holding member is
A fitting portion fitted to the rotating shaft;
A cylindrical part that is formed in a cylindrical shape and on which the rotor core is fitted; and
A disk-shaped disk part connected to one end part in the axial direction of the cylindrical part and connecting the cylindrical part and the fitting part;
With
The outer diameter on one side in the axial direction on the outer peripheral surface of the cylindrical part is set smaller than the outer diameter on the other side in the axial direction on the outer peripheral surface of the cylindrical part,
One side in the axial direction on the outer peripheral surface of the cylindrical part extends over a predetermined distance in the axial direction of the cylindrical part, and is a small diameter part formed smaller than the outer diameter of the large diameter part on the other side in the axial direction I have a,
Wherein the boundary between the large diameter portion and the small diameter portion, the rotor of the rotary electric machine characterized by Rukoto annular step portion is formed.

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