WO2015050010A1

WO2015050010A1 - Rotor core, rotor, and rotary electric machine

Info

Publication number: WO2015050010A1
Application number: PCT/JP2014/074982
Authority: WO
Inventors: 憲生竹田; 良司小林; 博光岡本
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2013-10-03
Filing date: 2014-09-22
Publication date: 2015-04-09
Also published as: JP2015073387A; JP6189699B2

Abstract

Provided are a rotor core that simultaneously achieves high-speed rotation and strength reliability, a rotor that uses the rotor core, and a rotary electric machine that is equipped with the rotor. This rotary electric machine is equipped with a rotor (20) that has a rotor core (2) and a shaft (5) that is press-fitted to the rotor core (2). The rotor core (2) has fitting parts (8) to be brought into contact with the shaft (5), wherein the fitting parts (8) have a curvature radius (rc), at the tip of the fitting parts (8), that is greater than a value (R_s-ΔR) that is obtained by subtracting a press-fitting interference (ΔR) from the radius (Rs) of the shaft (5).

Description

Rotor core, rotor, and rotating electric machine

The present invention relates to a rotor core, a rotor, and a rotating electrical machine.

The rotor of a rotating electrical machine is mainly composed of a rotor core in which electromagnetic steel plates are laminated in the axial direction and a shaft fastened to the rotor core. By increasing the speed of the rotating electrical machine, the size and weight can be reduced. However, since the rotor core is deformed in a direction away from the shaft due to the centrifugal force generated by the high-speed rotation, the fastening portion with the rotor core shaft has a large fastening force and a stable fastening method must be employed.

When the rotor core and the shaft are fastened by shrink fitting, a circular hole is provided in the center of the rotor core, and the shaft of the round bar is inserted into the circular hole so that the outer peripheral surface of the shaft and the rotor core extend over the entire circumference. Fastening in the contacted state is possible. On the other hand, when the shaft is press-fitted into the rotor core and fastened together, a large load is required to press-fit the cylindrical shaft into the center hole of the circular hole formed in the rotor core. As a result, a large-scale press device is required to achieve the fastening with the shaft and the rotor iron core in contact with each other by press-fitting. In order to solve this problem, a fastening method is disclosed in which the center hole of the rotor core and the shaft partially abut.

In Patent Document 1, a plurality of protrusions (press-fit portions 31 in FIG. 6) are formed at predetermined intervals in the circumferential direction of the circumferential surface of the center hole of the rotor core. In Patent Document 2, the cross-sectional shape of the central hole of the rotor core into which the cylindrical shaft is inserted is a square (hole 170 in FIG. 8), a regular triangle (hole 170 in FIG. 19), or the like.

JP 2012-23823 A JP 2004-135463 A

In the method in which the shaft is press-fitted and the shaft and the rotor core are partially brought into contact with each other along the circumferential direction to fasten the two, pressure is generated at the contact portion (contact portion) between the shaft and the rotor core. There is a problem that the pressure defined in each region of the contact part varies, that is, a pressure distribution occurs in the contact part.

(1) A rotor core according to the invention of claim 1 includes a center hole into which a cylindrical shaft is press-fitted, and a plurality of fitting portions formed in the circumferential direction in the center hole. Is brought into contact with the shaft when it is press-fitted into the center hole, and the distal end shape of the fitting portion is characterized in that the circumferential dependency of the pressure due to contact with the shaft is substantially uniform.
(2) A rotor according to an eighth aspect of the present invention includes a rotor iron core and a shaft that is press-fitted into a central hole of the rotor iron core, and is provided rotatably on the inner peripheral side of the stator. 8. A rotating electric machine is configured, and a plurality of fitting portions that are fitted to the peripheral surface of the shaft are formed in the center hole of the rotor core, and the rotor core is defined in any one of claims 1 to 7. It is a rotor core as described.
(3) A rotating electrical machine according to the invention of claim 9 includes a stator having slots and teeth, and windings wound around the teeth, and a rotor core provided rotatably on the inner peripheral side of the stator. A rotor in which a shaft is press-fitted into the center hole of the rotor, and a plurality of fitting portions that fit into the peripheral surface of the shaft are formed in the center hole of the rotor core. It is a rotor as described in above.

By using the rotor core according to the present invention, it is possible to provide a rotor core, a rotor, and a rotating electrical machine that achieve both high speed and strength reliability.

The figure which shows the structure of the rotary electric machine 100 of this invention. The perspective view which shows the rotor 20 of 1st Embodiment. A radial direction sectional view of rotor 20 of a 1st embodiment. A radial direction sectional view of rotor core 2 of a 1st embodiment. Radial direction sectional drawing which shows the part for 45 degrees of circumferential directions among the rotor cores 2 of 1st Embodiment. Radial direction sectional drawing of the fitting part 8 vicinity of the rotor core 2 of 1st Embodiment. The figure which shows the pressure distribution of the front-end | tip 9 of the fitting part 8. FIG. The figure which shows the force which the front-end | tip 9 of the fitting part 8 of the rotor core 2 receives from the shaft 5. FIG. Radial direction sectional drawing of 2 A of rotor cores. Radial direction sectional drawing of the rotor core 2B. The figure which shows the pressure fluctuation of the fitting part 8 by the centrifugal force in 2 A of rotor cores, and the rotor core 2B. Radial direction sectional drawing of the rotor core 2C. The figure which shows the pressure distribution of the fitting part 8 in the rotor core 2A and the rotor core 2C. Radial direction sectional drawing of the rotor core 2 of 2nd Embodiment. It is sectional drawing of the rotor core 2 of 3rd Embodiment.

As an example of the rotating electrical machine according to the present invention, an application example in an 8-pole 12-slot concentrated winding permanent magnet synchronous motor will be described. However, the present invention is not limited to this, and can be applied to other types of motors. The present invention can also be applied to a generator or the like.

-First embodiment-
FIG. 1 is a radial cross-sectional view showing a rotating electrical machine 100 according to the first embodiment. The rotating electrical machine 100 includes a rotor 20 and a stator 30 disposed on the outer peripheral side of the rotor 20. Reference numeral 1 denotes the rotation center of the rotating electrical machine 100, that is, the rotation axis.

The rotor 20 is inserted into the rotor core 2, the columnar shaft 5 that is press-fitted into the center hole 6 of the rotor core 2, and the magnet insertion hole 3 that is formed in the circumferential direction on the outer periphery side of the rotor core 2. The permanent magnet 21 is provided. The fitting portions 8 of the center hole 6 of the rotor core 2 are formed in the center hole 6 at equal intervals in the circumferential direction as well shown in FIGS. 3 to 5 and protrude toward the inner peripheral side. Has a shape. The shaft 5 abuts on the tip 9 of the fitting portion 8, and the rotor core 2 and the shaft 5 are fastened. When the shaft 5 is press-fitted into the center hole 6 of the rotor core 2, the shaft 5 and the fitting portion 8 abut against each other and elastically deform together, but the fitting portion 8 has a greater degree of elastic deformation than the shaft 5. . In order to reduce the weight of the rotor 20, the lightening holes 4 are formed at equal intervals in the circumferential direction in a region where the influence of the magnetic flux of the rotor core 2 does not reach. As the permanent magnet 21, a neodymium magnet, a samarium cobalt magnet, a ferrite magnet, or the like is mainly used, but other than these may be used.

The stator 30 includes a tooth 31 formed in the inner circumferential side circumferential direction, a slot 32 formed between the pair of teeth 31, and a winding 33 inserted into the slot 32 and wound around the tooth 31. Yes. Winding 33 is connected to a power converter (not shown). The rotor 20 of the rotating electrical machine 100 is driven to rotate when a three-phase alternating current is applied to the winding 33 of the stator 30 from a power converter (not shown). The stator 30 is the same in various types of rotating electrical machines to which the present invention is applied. Therefore, hereinafter, the description will be made with the stator 30 omitted.

FIG. 2 is a perspective view showing the rotor 20. FIG. 3 is a radial cross-sectional view of the rotor 20. FIG. 4 is a radial cross-sectional view of the rotor core 2. The fitting portions 8 of the rotor core 2 are formed in the center hole 6 at equal intervals in the circumferential direction and have a shape protruding toward the inner peripheral side (FIGS. 3 and 4). And the cylindrical shaft 5 contact | abuts to the front-end | tip 9 of the fitting part 8, and the rotor core 2 and the shaft 5 are fastened (FIG. 3). Further, the permanent magnet 21 is inserted into the magnet insertion hole 3 to constitute the rotor 20 (FIGS. 2 and 3).

Referring to FIGS. 5 to 7, it will be described that the pressure distribution changes depending on the curvature radius of the tip 9 of the fitting portion 8. Here, “pressure” refers to a radial force per unit area. The “pressure distribution” refers to the circumferential direction dependency of the pressure applied to the tip 9. The same applies to the following. Hereinafter, unless otherwise specified, the radius of curvature of the tip 9 of the fitting portion 8 and the radius of the shaft are expressed by the shape before press-fitting. This is because it is convenient when discussing the radius of curvature of the tip 9 of the fitting portion 8 and the radius of the shaft. In the shape after press-fitting, both the fitting portion 8 and the shaft are elastically deformed, and the above discussion becomes difficult.

FIG. 5 is an enlarged view of a region 11 surrounded by a broken line shown in FIG. 4, that is, a 45 ° circumferential direction of the rotor core 2. Regarding the three points of the tip 9 of the fitting portion 8, the left end in the figure is point A, the right end in the figure is point B, and the middle point thereof is point C. The same definition applies below. In the first embodiment, the shape of the tip 9 of the fitting portion 8 before the shaft 5 is press-fitted is an arc having a curvature radius rc. Here, if the radius of the shaft before press-fitting is Rs and the allowance due to press-fitting is ΔR, the distance from the center C of the arc to the rotation axis 1 is Rs−ΔR in the state before press-fitting. Although only the shaft 5 is elastically deformed as Rs−ΔR, as described above, both the shaft 5 and the fitting portion 8 are elastically deformed. Further, the degree of elastic deformation of the fitting portion 8 is greater than that of the shaft 5.

FIG. 6 is an enlarged view of the vicinity of the fitting portion 8. The fitting portion 8 is formed in the center hole 6 of the rotor core 2 and has a shape protruding toward the inner peripheral side, and has a tip 9 formed on the inner peripheral side and a side surface 15 facing the circumferential direction. . The tip 9 contacts the shaft 5. An arc 10 having a radius Rs−ΔR is indicated by a broken line. The arc 10 is formed around the rotation axis 1. As shown in the drawing, the radius of curvature rc of the tip 9 of the fitting portion 8 of the rotor core 2 of the first embodiment is larger than Rs−ΔR. That is, rc> Rs−ΔR.

FIG. 7 shows the pressure applied to the tip 9 of the fitting portion 8 by the magnitude relationship between the radius of curvature rc of the tip 9 of the fitting portion 8 and the distance Rs−ΔR from the point C of the tip 9 before press-fitting to the rotating shaft 1. It shows how the distribution changes. The vertical axis represents pressure, and the horizontal axis represents the position of the tip 9 of the fitting portion 8. As described above, the rotor core 2 of the first embodiment satisfies rc> Rs−ΔR.

When the radius of curvature rc of the tip 9 is equal to the distance Rs−ΔR, that is, when rc = Rs−ΔR, the pressure distribution at the tip 9 of the fitting portion 8 is at points A and B compared to point C. Pressure is high. In this case, in the vicinity of the points A and B where high pressure is caused by press-fitting, the material is deteriorated due to repeated centrifugal force and torque, so that a stable fastening force cannot be realized for a long time.

On the other hand, in the rotor core 2 of the first embodiment, the curvature radius rc of the tip 9 is larger than Rs−ΔR and set to an appropriate value (rc> Rs−ΔR), so that the point A of the tip 9 and The pressure generated at point B is reduced, and the pressure can be made substantially uniform at points A, B, and C of the tip 9.

However, when the radius of curvature rc is extremely large, for example, when the shape of the tip 9 is a straight line (rc >> Rs−ΔR), the pressure increases near the middle point C. Further, in this case, it becomes difficult to come into contact with the shaft 5 at points A and B at the circumferential end, and the pressure approaches zero. Therefore, it is not preferable to form the tip 9 in a straight line.

By setting rc> Rs−ΔR as in the rotor 20 of the first embodiment, if the pressure distribution at the tip 9 of the fitting portion 8 becomes uniform, the region where material deterioration due to high pressure occurs can be reduced. Therefore, a press-fit fastening structure between the rotor core 2 and the shaft 5 having a stable fastening force for a long period can be realized.

In order to increase the speed of the rotating electrical machine 100, it is necessary to increase the allowable rotational speed of the rotor 20. In order to increase the allowable rotational speed of the rotor, it is necessary to increase the contact pressure between the rotor core 2 and the shaft 5 by press-fitting, for example, by increasing the interference ΔR between the rotor core 2 and the shaft 5. At this time, if the curvature radius rc of the tip 9 is equal to Rs−ΔR, the pressure generated at the circumferential end portions A and B of the tip 9 may exceed the yield stress of the material used for the rotor core 2. Yes, it is not possible to easily increase the tightening allowance during press-fitting. On the other hand, if the radius of curvature rc of the tip 9 is made larger than the radius (Rs−ΔR) and the pressure distribution due to contact is made uniform, the pressure at the points A, B, and C increases as the tightening margin increases. Is uniformly increased, it is possible to easily increase the fastening allowance ΔR aimed at speeding up the rotating electrical machine 100.

The above contents are expressed by the following equations (1) to (3).
T = f r (1)
f <Nμp L ₁ L ₂ (2)
p <σ _y (3)
here,
T is the torque,
f is a frictional force applied to all the fitting portions 8 of the rotor core 2;
r is the radius of the shaft when pressed into the rotor core 2;
N is the number of fitting portions 8 (eight in the rotor core 2 of the first embodiment),
μ is the coefficient of static friction,
p is the radial pressure received from the shaft 5,
L ₁ is the circumferential length of the tip 9 of each fitting portion 8 when elastically deformed by the pressure from the shaft 5;
L ₂ is the thickness of the rotor core 2,
σ _y is the yield stress of the material constituting the rotor core 2,
It is.

FIG. 8 is a diagram showing the force that the tip 9 of the fitting portion 8 of the rotor core 2 receives from the shaft 5 when the shaft 5 (not shown) is press-fitted into the rotor core 2. Of the above parameters, f, r, μ, p, L ₁ and σ _y are shown.

If the frictional force f is within the range of the above equation (2) in the entire region of the fitting portion 8 that contacts the shaft 5 of the rotor core 2, the torque T shown in the above equation (1) The maximum torque of the rotating electrical machine 100 is exceeded and the shaft 5 does not slide relative to the rotor core 2. Further, if the radial pressure p received from the shaft 5 is within the range of the yield stress shown in Formula (3) at each point of the contact surface of the tip 9 of the fitting portion 8, the rotor core 2 is plastically deformed. do not do. That is, making the pressure distribution due to the shaft 5 abutting against the fitting portion 8 lowers the maximum value of the pressure p defined at each point of the abutting surface of the tip 9 of the fitting portion 8. The fact that the maximum value of the pressure p decreases and moves away from the yield stress σ _y means that plastic deformation is difficult. Therefore, the tightening allowance ΔR can be easily increased by that amount.

<Examination on fitting part 8 and lightening hole 4>
In the rotor core 2 of the rotor 20 of the first embodiment, as shown in FIG. 4 and the like, the fitting portion 8 is located on the radially inner side of the lightening hole 4, and the fitting portion 8 and the lightening are removed. The number of holes 4 is equal. Here, with respect to the meaning of “the fitting portion 8 is located on the radially inner side of the lightening hole 4”, the lightening hole 4 a which is one of the lightening holes 4 of the rotor core 2 shown in FIG. The fitting part 8a which is one of the joint parts 8 will be described as an example. “The fitting portion 8a is located on the radially inner side of the lightening hole 4a” is an area indicated by an angle θ1 that is sandwiched between the line segment 41 and the line segment 42 that are in contact with the lightening hole 4a through the rotation axis 1. And it means that the fitting part 8a is located in the area | region of the inner peripheral side from the lightening hole 4a. The same applies to the following. In addition, similarly to the rotor core 2 of the first embodiment shown in FIG. 4, also in the rotor core 2 A shown in FIG. 9, which will be described later, the fitting portion 8 is positioned on the radially inner side of the lightening hole 4. .

Hereinafter, it will be described how “the circumferential position of the fitting portion 8 with respect to the lightening hole 4” and “the number of the fitting portion 8 with respect to the lightening hole 4” influence. In the rotor core 2 of the first embodiment, the radius of curvature rc of the tip 9 is larger than Rs−ΔR, but in the following, instead of the rotor core 2 of the first embodiment, the tip 9 of the fitting portion 8 A rotor core 2A (FIG. 9), which is a rotor core having the same radius of curvature rc and Rs−ΔR, is used as a reference. The only difference between the rotor core 2A and the rotor core 2 of the first embodiment is whether or not the radius of curvature rc of the tip 9 is equal to Rs-ΔR, and the other configurations are the same. As a comparison object of the rotor core 2A, a rotor core 2B (FIG. 10) and a rotor core 2C (FIG. 12) described later are introduced. In the rotor core 2 A, the rotor core 2 B, and the rotor core 2 C, like the rotor core 2, the fitting portions 8 are formed at equal intervals in the circumferential direction. Further, similarly to the fitting portion 8, the lightening holes 4 are also formed at equal intervals in the circumferential direction. In addition, in the rotor core 2A, the rotor core 2B, and the rotor core 2C, the definitions of the points A, B, and C at the tip 9 of the fitting portion 8 are the same as those of the rotor core 2 of the first embodiment. (See FIGS. 5, 9, 10, and 12).

-About the circumferential position of the fitting part 8 with respect to the lightening hole 4-
Here, the effect of the position of the fitting portion 8 relative to the lightening hole 4 on the pressure fluctuation of the fitting portion 8 due to centrifugal force when the number of the lightening holes 4 and the fitting portions 8 is equal will be described. The pressure when the fitting portion 8 and the shaft 5 come into contact with each other varies when the rotor core 2 receives a force on the outer diameter side due to centrifugal force. In order for the portion where the fitting portion 8 and the shaft 5 are in contact with each other (pressure contact portion) to stably exhibit the fastening force even with this pressure fluctuation, the pressure distribution in the contact portion is substantially uniform. It is desirable to be.

FIG. 9 shows the rotor core 2A. FIG. 10 shows the rotor core 2B. In the rotor core 2 A and the rotor core 2 B, the number of the hollow holes 4 and the fitting portions 8 are equal, and each is eight. Needless to say, the specific number of eight is one example in which the number of the lightening holes 4 and the fitting portions 8 are equal. The same applies to the following.

In the rotor core 2 A shown in FIG. 9, the circumferential center 12 of the lightening hole 4 and the circumferential center 13 of the fitting portion are arranged so as to substantially coincide. On the other hand, in the rotor core 2 B shown in FIG. 10, the fitting portion 8 is located between the lightening holes 4. Here, regarding the meaning of “the fitting portion 8 is located between the lightening holes 4”, the lightening holes 4 b and 4 c which are the lightening holes 4 adjacent to each other of the rotor core 2 shown in FIG. A description will be given by taking a fitting portion 8b which is one of the fitting portions 8 as an example. First, “between the lightening holes 4” means between the lightening holes 4 adjacent to each other (here, between the lightening holes 4b and 4c). In addition, “the fitting portion 8b is located between the lightening holes 4” means an angle between the line segment 43 passing through the rotation axis 1 and contacting the lightening hole 4b and the line segment 44 contacting the lightening hole 4c. This means that the fitting portion 8b is located in the region indicated by θ2 and in the region on the inner peripheral side of the lightening holes 4b and 4c. The same applies to the following.

Naturally, in the positional relationship in which the above-described fitting portion 8 is located between the lightening holes 4, the circumferential center 12 of the lightening holes 4 and the circumferential center 13 of the fitting portion do not coincide. Further, in order to examine only the influence of the arrangement of the fitting portion 8, the curvature radius rc and Rs−ΔR of the tip 9 of the fitting portion 8 are set to be equal in the rotor core 2 B as well as the rotor core 2 A.

FIG. 11 is a diagram illustrating the circumferential dependence of pressure fluctuations of the fitting portion 8 due to centrifugal force in each of the rotating electrical machine 100 using the rotor core 2A and the rotating electrical machine 100 using the rotor core 2B. . The vertical axis represents pressure fluctuation due to centrifugal force, and the horizontal axis represents the position of the tip 9 of the fitting portion 8. In the figure, two broken lines are drawn, and the pressure distribution at the tip 9 of the fitting portion 8 of the rotor core 2A (line connecting white circles) and the rotor core 2B (line connecting white squares) is shown. ing. In almost all regions of the tip 9, the broken line indicating the pressure distribution of the rotor core 2B has a higher pressure fluctuation due to centrifugal force than that of the rotor core 2A. From this, it can be seen that by forming the fitting portion 8 on the radially inner side of the lightening hole 4, the pressure fluctuation of the fitting portion 8 due to centrifugal force is reduced. In the rotor core 2 of the first embodiment in which the radius of curvature rc of the tip 9 is larger than Rs−ΔR, the same result is obtained when the above comparison is made.

-About the number of the fitting part 8 for the lightening hole 4-
Here, the effect of the number of the fitting portions 8 with respect to the lightening holes 4 on the pressure distribution at the tip 9 of the fitting portion 8 that abuts the shaft 5 will be described. In the rotor core 2A, the number of the lightening holes 4 and the fitting portions 8 are equal, and both are eight (see FIG. 4). For the description of FIG. 13A to be described later, two of the eight equivalent fitting portions 8 included in the rotor core 2A shown in FIG. 9 are denoted with the

fitting portions

8a and 8b. Reworked.

In the rotor core 2C shown in FIG. 12, the number of the fitting portions 8 and the number of the hollow holes 4 are different. Specifically, ten fitting portions 8 and eight lightening holes 4 are formed. For the description of FIG. 13B described later, three of the ten fitting portions 8 included in the rotor core 2C shown in FIG. 12 include three fitting portions 8c, fitting portions 8d, and fitting portions. The code was re-assigned to 8e. The entire fitting portion 8 c is located on the radially inner side of the lightening hole 4. In the fitting portion 8 d, about half of the point A side is located on the radially inner side of the lightening hole 4, and about half of the point B side is located between the lightening holes 4. The entire fitting portion 8 e is located between the lightening holes 4. The non-equivalence of the fitting portions 8c to 8e as described above affects the pressure distribution at the tip 9 of the fitting portion 8 that contacts the shaft 5. Details will be described later with reference to FIG.

FIG. 13A shows the pressure distribution at the tip 9 of the fitting portion 8 of the rotor core 2 that contacts the shaft 5 and the pressure distribution in the rotating electrical machine 100 using the rotor core 2A shown in FIG. It is the figure which showed the fitting part dependence. The vertical axis represents pressure, and the horizontal axis represents the position of the tip 9 of the fitting portion 8. FIG. 13A shows two broken lines. This shows the pressure distribution at the tip 9 of the fitting part 8a (line connecting white circles) and the fitting part 8b (line connecting black circles) which are the fitting parts 8 of the rotor core 2A shown in FIG. Yes. It can be seen that the above-mentioned two broken lines showing the pressure distribution at the respective tips 9 of the fitting portion 8a and the fitting portion 8b almost overlap and show the same pressure distribution. This is because the fitting portions 8 of the rotor core 2A have the same number as the lightening holes 4 and are formed at equal intervals in the circumferential direction, so that the fitting portions 8a and the fitting portions 8b are the lightening holes. This is because it is equivalent to the position of 4.

FIG. 13B shows a fitting portion 8c, a fitting portion 8d, which is a fitting portion 8 of the rotor core 2 that comes into contact with the shaft 5, in the rotating electrical machine 100 using the rotor core 2C shown in FIG. It is the figure which showed the pressure distribution in each front-end | tip 9 of the fitting part 8e, and the fitting part dependence of the pressure distribution. The vertical axis represents pressure, and the horizontal axis represents the position of the tip 9 of the fitting portion 8. FIG. 13B shows three broken lines. This includes a fitting portion 8c (line connecting white circles), a fitting portion 8d (line connecting black circles), and a fitting portion 8e (white squares) which are the fitting portions 8 of the rotor core 2C shown in FIG. The pressure distribution at the tip 9 of the connected line) is shown. Since the above-mentioned three broken lines indicating the pressure distribution at the respective tips 9 of the fitting portions 8c to 8e do not overlap, it can be seen that the pressure distributions are not equal in the fitting portions 8c to 8e. This is because the number of the fitting portions 8 of the rotor core 2C is different from that of the lightening holes 4 and is formed at equal intervals in the circumferential direction.

Thus, in the rotor core 2A, there is no difference in pressure between each of the fitting portions 8, and the rotor core 2 and the shaft 5 that are highly reliable in the long term are realized. In the rotor core 2 of the first embodiment, which is the rotor core having the radius of curvature rc of the tip 9 larger than Rs−ΔR, similar results are obtained even when the above-described comparison is made.

As described above, “the effect of the circumferential position of the fitting portion 8 with respect to the lightening hole 4 on the pressure fluctuation in the fitting portion 8” and “the number of the fitting portion 8 with respect to the lightening hole 4 abuts on the shaft 5. The “effect on the pressure distribution at the tip 9 of the fitting portion 8 of the rotor core 2” can be similarly achieved in the second and third embodiments described below.

-Second embodiment-
FIG. 14 is a radial cross-sectional view of the vicinity of the fitting portion 8 of the rotor core 2 of the rotor 20 of the rotating electrical machine 100 of the second embodiment. Also in the second embodiment, the tip 9 of the fitting portion 8 is an arc. However, unlike the first embodiment, the radius of curvature rc of the arc is a radius Rs−ΔR (see FIGS. 5 and 6). equal. That is, rc = Rs−ΔR. A notch 14 is formed in the circumferential side surface 15 of the fitting portion 8. As described above, when the radius of curvature rc of the tip 9 is equal to Rs−ΔR, the pressure due to the press-fitting at the end A point and the B point of the tip 9 contacting the shaft 5 becomes higher than the C point at the middle point. Therefore, in the second embodiment, the curvature radius rc and the radius Rs−ΔR of the tip 9 are made equal as described above, and the notch 14 is further provided on the side surface 15. Thereby, since the rigidity of the fitting part 8 in the vicinity of the end A point and the B point is reduced, a pressure increase at the end A point and the B point when the shaft 5 is press-fitted is reduced. As described above, the second embodiment also has the effect of uniformizing the pressure distribution at the tip 9 of the fitting portion 8 of the rotor core 2 in contact with the shaft 5, as in the first embodiment, and is stable over a long period of time. Fastening can be realized.

-Third embodiment-
FIG. 15 is a radial cross-sectional view of the vicinity of the fitting portion 8 of the rotor 20 of the rotating electrical machine 100 of the third embodiment. In 3rd Embodiment, the shape of the front-end | tip 9 of the fitting part 8 is not a circular arc but the spline curve which satisfy | fills the following conditions. For example, as shown in FIG. 15, a point 16 that divides the tip 9 at equal intervals in the circumferential direction is considered, and the point 16 is moved in the radial direction so that the pressure distribution generated at the tip 9 by press fitting becomes uniform. The tip 9 is formed by a spline curve that smoothly connects the points 16 arranged in this manner. As a result, in the third embodiment as well, as in the first and second embodiments, the pressure distribution at the tip 9 of the fitting portion 8 of the rotor core 2 that comes into contact with the shaft 5 is uniformed. A stable fastening can be realized over a long period of time.

In the above embodiment, the fitting portions 8 of the rotor core 2 and the lightening holes 4 are arranged at equal intervals in the circumferential direction, but may be arranged at non-equal intervals as long as they do not contradict the gist of the present invention. Is possible.

Although an example of a motor has been shown as the rotating electrical machine in the above embodiment, the present invention can also be applied to a generator or the like.

The above description is merely an example, and the invention is not limited to the above embodiment.

DESCRIPTION OF SYMBOLS 1 ... Rotating shaft, 2 ... Rotor core, 3 ... Permanent magnet insertion hole, 4 ... Meat removal hole,
5 ... Shaft 6 ... Center hole of rotor core,
8: The fitting portion of the rotor core and the shaft, 9 ... The tip of the fitting portion,
10: Arc of radius Rs-ΔR, 11: Area of 45 ° in the circumferential direction of the rotor core,
12 ... Center in the circumferential direction of the hole, 13 ... Center in the circumferential direction of the fitting portion,
14 ... Notch on the side surface of the fitting part, 15 ... Side surface of the fitting part, 16 ... Division point at the tip of the fitting part,
20 ... Rotor (rotor), 21 ... Permanent magnet, 30 ... Stator (stator),
31 ... Teeth, 32 ... Slot, 33 ... Winding, 100 ... Rotating electric machine,
T: Torque, f: Friction force, r ... Shaft radius when press-fitted,
N: number of fitting portions 8, μ: coefficient of static friction, p: pressure,
L ₁ ... Circumferential length at the tip of the fitting part, L ₂ ... Thickness, σ _y ... Yield stress

Claims

A central hole into which a cylindrical shaft is press-fitted, and
A plurality of fitting portions formed in the circumferential direction in the center hole,
In the rotor core that contacts the shaft when the shaft is press-fitted into the center hole,
The front end shape of the fitting portion is a rotor core having a shape in which the circumferential dependency of pressure due to contact with the shaft is substantially uniform.
The rotor core according to claim 1,
The tip shape of the fitting portion is an arc,
The radius of the circular arc is a rotor core larger than a value obtained by subtracting the press-fit interference from the radius of the shaft.
The rotor core according to claim 1,
The tip shape of the fitting portion is an arc,
The radius of the arc is equal to the value obtained by subtracting the press-fit interference from the radius of the shaft,
The fitting portion is a rotor core having notches on both side surfaces in the circumferential direction.
The rotor core according to claim 1,
The tip shape of the fitting portion is a rotor core defined by a spline curve in which the circumferential dependency of the pressure from the shaft is substantially uniform.
In the rotor core according to any one of claims 1 to 4,
It further comprises a plurality of lightening holes formed in the circumferential direction,
The fitting portion is a rotor core formed on the radially inner side of the lightening hole.
In the rotor core according to claim 5,
The fitting portion and the lightening hole are rotor cores formed so that a center in a circumferential direction of the lightening hole and the fitting portion substantially coincides with each other.
In the rotor core according to any one of claims 1 to 4,
Formed in the circumferential direction, further comprising the same number of lightening holes as the fitting portion,
The fitting portion is a rotor core formed on the radially inner side of the lightening hole.
A rotor iron core and a shaft that is press-fitted into and integrated with a central hole of the rotor iron core, and is rotatably provided on the inner peripheral side of the stator to constitute a rotating electric machine; In the rotor in which a plurality of fitting portions that are fitted to the peripheral surface of the shaft are formed in the center hole of
The rotor according to any one of claims 1 to 7, wherein the rotor core is a rotor core.
A stator having slots and teeth, and windings wound around the teeth;
A rotor provided rotatably on the inner peripheral side of the stator and having a shaft press-fitted into a center hole of the rotor core, and fitted into a peripheral surface of the shaft in the center hole of the rotor core. In a rotating electrical machine in which a plurality of mating portions are formed,
The rotating electric machine according to claim 8, wherein the rotor is a rotor according to claim 8.