rotor

Abstract

To provide a rotor in which a plurality of rotor core block portions can be configured to include three or more rotor core block portions in which positions of magnetic poles of the rotor core block portions are shifted from each other while suppressing an increase in the number of molds for manufacturing the rotor core block portions.SOLUTION: A plurality of rotor core block portions 10a in a rotor 100 includes a first rotor core block portion 11 in which a key 10d engages with a first key groove 23a, a second rotor core block portion 12 in which the key 10d engages with the first key groove 23a and the first rotor core block portion 11 is disposed so as to be turned over in a Z direction, and positions of magnetic poles MP are shifted from that of the first rotor core block portion 11 in a C direction, and a third rotor core block portion 13 in which the key 10d is engaged with a second key groove 23b and the positions of the magnetic poles MP are shifted from those of the first rotor core block portion 11 and the second rotor core block portion 12 in the C direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a rotor. [Background technology]

[0002] BACKGROUND ART Conventionally, a rotor is known that includes a rotor core in which a plurality of rotor core block portions are stacked in the axial direction (see, for example, Patent Document 1).

[0003] Patent Document 1 discloses a rotor including a rotor shaft including an axially extending keyway, and a rotor core in which multiple rotor core block portions are stacked in the axial direction, each rotor core block portion having an axially extending key engaging with the keyway and multiple magnet accommodating holes in which permanent magnets are disposed. In the rotor described in Patent Document 1, the multiple rotor core block portions include a first rotor core block portion and a second rotor core block portion that is arranged upside down in the axial direction relative to the first rotor core block portion and in which the positions of the magnetic poles formed by the permanent magnets of the rotor core block portion are shifted circumferentially from the first rotor core block portion. In other words, the rotor described in Patent Document 1 includes only rotor core block portions of the same shape, and the multiple rotor core block portions include two rotor core block portions in which the positions of the magnetic poles of the rotor core block portions are shifted from each other. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-18339 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the conventional rotor described in Patent Document 1, when the multiple rotor core block portions are configured to include three or more rotor core block portions whose magnetic pole positions are offset from one another, two or more types of rotor core block portions with mutually different shapes are required. In this case, two or more types of molds are required for manufacturing the rotor core block portions. For this reason, there is a demand for a rotor that can be configured to include three or more rotor core block portions whose magnetic pole positions are offset from one another while suppressing an increase in the number of molds for manufacturing the rotor core block portions.

[0006] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide a rotor that can be configured to include three or more rotor core block sections in which the magnetic pole positions of the rotor core block sections are offset from each other, while suppressing an increase in the number of molds required to manufacture the rotor core block sections. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, a rotor in one aspect of the present invention comprises: a rotor shaft including a first key groove extending in the axial direction and a second key groove extending in the axial direction and formed at a position circumferentially offset from the first key groove; and a rotor core in which a plurality of rotor core block portions are stacked in the axial direction, the rotor core block portions having a key extending in the axial direction and engaging with the first key groove or the second key groove, and a plurality of magnet accommodating holes in which permanent magnets are arranged, the plurality of rotor core block portions including a first rotor core block portion whose key engages with the first key groove, a second rotor core block portion whose key engages with the first key groove and is arranged axially upside down from the first rotor core block portion, and in which the positions of the magnetic poles formed by the permanent magnets of the rotor core block portion are offset circumferentially from the first rotor core block portion, and a third rotor core block portion whose key engages with the second key groove and in which the positions of the magnetic poles are offset circumferentially from the first rotor core block portion and the second rotor core block portion.

[0008] In one aspect of the present invention, as described above, the rotor includes a first rotor core block portion having a key that engages with a first key groove, a second rotor core block portion having a key that engages with the first key groove and that is arranged axially upside down relative to the first rotor core block portion, and having magnetic poles formed by the permanent magnets of the rotor core block portion that are shifted in the circumferential direction from those of the first rotor core block portion, and a third rotor core block portion having a key that engages with the second key groove and having magnetic poles that are shifted in the circumferential direction from those of the first rotor core block portion and the second rotor core block portion. This allows the rotor to be configured so that the first, second, and third rotor core block portions have the same shape, thereby including three rotor core block portions whose magnetic poles are shifted from one another. As a result, the rotor core block portions can be configured to include three or more rotor core block portions whose magnetic poles are shifted from one another while suppressing an increase in the number of molds required to manufacture the rotor core block portions.

[0009] In the rotor according to the above aspect, preferably, the first key grooves are formed in a pair on the rotor shaft symmetrically with respect to the rotation axis of the rotor shaft, the second key grooves are formed in a pair on the rotor shaft symmetrically with respect to the rotation axis, and the keys are formed in a pair on the rotor core block portion symmetrically with respect to the rotation axis.

[0010] With this configuration, the first key groove of the rotor shaft and the key of the first rotor core block portion can be engaged at two locations facing each other with respect to the rotation axis, thereby enabling a balanced distribution of loads acting on the first key groove of the rotor shaft and the key of the first rotor core block portion when the rotor shaft and the first rotor core block portion rotate. Furthermore, the first key groove of the rotor shaft and the key of the second rotor core block portion can be engaged at two locations facing each other with respect to the rotation axis, thereby enabling a balanced distribution of loads acting on the first key groove of the rotor shaft and the key of the second rotor core block portion when the rotor shaft and the second rotor core block portion rotate. Furthermore, the second key groove of the rotor shaft and the key of the third rotor core block portion can be engaged at two locations facing each other with respect to the rotation axis, thereby enabling a balanced distribution of loads acting on the second key groove of the rotor shaft and the key of the third rotor core block portion when the rotor shaft and the third rotor core block portion rotate. As a result, when the rotor shaft and rotor core rotate, the load acting on each of the first key groove of the rotor shaft, the second key groove of the rotor shaft, the key of the first rotor core block portion, the key of the second rotor core block portion, and the key of the third rotor core block portion can be reduced.

[0011] In the rotor according to the above aspect, preferably, the plurality of rotor core block portions further include a fourth rotor core block portion whose key engages with the second key groove and is arranged axially upside down relative to the third rotor core block portion, and whose magnetic pole position is shifted circumferentially from the first rotor core block portion, the second rotor core block portion, and the third rotor core block portion.

[0012] By configuring in this manner, the first rotor core block portion, the second rotor core block portion, the third rotor core block portion, and the fourth rotor core block portion can be configured so that multiple rotor core block portions include four rotor core block portions in which the magnetic pole positions of the rotor core block portions are offset from each other, using only rotor core block portions of the same shape.

[0013] In the rotor according to the above aspect, preferably, the first key groove is formed throughout the entire portion of the rotor shaft where the plurality of rotor core block portions are arranged, and the second key groove is not formed in at least the portion of the rotor shaft where the first rotor core block portion or the second rotor core block portion arranged at the end of one or the other of the plurality of rotor core block portions is arranged.

[0014] With this configuration, the first key groove is formed over the entire portion of the rotor shaft where the multiple rotor core block portions are arranged, while the second key groove is not formed in the portion of the rotor shaft where the first rotor core block portion or the second rotor core block portion, which is located at one or the other axial end of the multiple rotor core block portions, is arranged, and is therefore shorter than the first key groove. This makes it easy to distinguish between the first key groove and the second key groove. This makes it possible to prevent the multiple rotor core block portions, each having a key that engages with the first key groove or the second key groove, from being arranged in an incorrect position on the rotor shaft when the multiple rotor core block portions are arranged on the rotor shaft. Furthermore, the processing costs for forming the key grooves on the rotor shaft can be reduced compared to when the second key groove is formed over the entire portion of the rotor shaft where the multiple rotor core block portions are arranged. Furthermore, since the key of the first rotor core block portion and the key of the second rotor core block portion do not engage with the second key groove, the second key groove does not have to be formed in the portion of the rotor shaft where the first rotor core block portion or the second rotor core block portion located at the end on one or the other axial side of the multiple rotor core block portions is located.

[0015] In the present application, the rotor according to the above aspect may also have the following configuration.

[0016] (Additional note 1) In the rotor according to the above aspect, preferably, the second key groove is formed at a position circumferentially shifted from the first key groove by a predetermined first angle, and the positions of the magnetic poles of the multiple rotor core block portions adjacent to each other in the axial direction are shifted by a predetermined second angle, and the first angle is set based on the number of magnetic poles of the rotor core block portion and the second angle.

[0017] With this configuration, the first angle by which the first key groove and the second key groove are shifted in the circumferential direction can be set based on the number of magnetic poles in the rotor core block portion and the second angle by which the positions of the magnetic poles are shifted between adjacent rotor core block portions in the axial direction.

[0018] (Additional note 2) In a configuration in which the first angle is set based on the number of magnetic poles of the rotor core block portion and the second angle, preferably, the multiple rotor core block portions further include a fourth rotor core block portion in which the key engages with the second key groove and the third rotor core block portion is arranged upside down in the axial direction, and the magnetic pole positions are shifted circumferentially from the first rotor core block portion, the second rotor core block portion, and the third rotor core block portion, and the first rotor core block portion, the second rotor core block portion, the third rotor core block portion, and the fourth rotor core block portion are stacked in this order in the axial direction, and the first angle is set to (360 / number of magnetic poles) + 2 × second angle.

[0019] With this configuration, in a configuration in which the first rotor core block portion, the second rotor core block portion, the third rotor core block portion, and the fourth rotor core block portion are stacked in this order in the axial direction, the first angle can be set based on the number of magnetic poles of the rotor core block portions and the second angle.

[0020] (Additional note 3) In a configuration in which the first angle is set based on the number of magnetic poles of the rotor core block portion and the second angle, preferably, the multiple rotor core block portions further include a fourth rotor core block portion in which the key engages with the second key groove and the third rotor core block portion is arranged upside down in the axial direction, and the magnetic pole positions are shifted circumferentially from the first rotor core block portion, the second rotor core block portion, and the third rotor core block portion, and the first rotor core block portion, the third rotor core block portion, the second rotor core block portion, and the fourth rotor core block portion are stacked in the axial direction in this order, and the first angle x 2 = (360 / number of magnetic poles) + second angle is set.

[0021] With this configuration, in a configuration in which the first rotor core block portion, the third rotor core block portion, the second rotor core block portion, and the fourth rotor core block portion are stacked in this order in the axial direction, the first angle can be set based on the number of magnetic poles of the rotor core block portions and the second angle. [Effects of the Invention]

[0022] According to the present invention, as described above, it is possible to provide a rotor that can be configured so that the multiple rotor core block portions include three or more rotor core block portions in which the magnetic pole positions of the rotor core block portions are offset from each other, while suppressing an increase in the number of molds required to manufacture the rotor core block portions. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a view of a rotor according to an embodiment of the present invention as seen from the outside in the radial direction. [Figure 2] 1 is a cross-sectional view of a first rotor core block and a second rotor core block portion in a rotor according to an embodiment of the present invention, viewed from the axial direction. [Figure 3] 3 is a view of a third rotor core block and a fourth rotor core block portion in a rotor according to an embodiment of the present invention, viewed from the axial direction. FIG. [Figure 4]3 is a cross-sectional view of a second rotor core block and a third rotor core block portion in a rotor according to an embodiment of the present invention, as viewed from the axial direction. FIG. [Figure 5] FIG. 10 is a view of a rotor according to a first modified example of the present invention, viewed from the outside in the radial direction. [Figure 6] FIG. 10 is a view of a rotor according to a second modified example of the present invention, viewed from the outside in the radial direction. [Figure 7] FIG. 10 is a view of a rotor according to a third modified example of the present invention, viewed from the outside in the radial direction. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0025] The configuration of a rotor 100 according to one embodiment of the present invention will be described with reference to FIGS.

[0026] (Overall rotor configuration) 1, the rotor 100 includes a rotor core 10 and a rotor shaft 20. The rotor 100 constitutes a part of an inner rotor type rotating electric machine (not shown). The rotating electric machine is, for example, a motor, a generator, or a motor / generator.

[0027] In the following description, the axial, radial, and circumferential directions of the rotor 100 (rotor core 10, rotor shaft 20) are referred to as the Z direction, R direction, and C direction, respectively. One side and the other side in the axial direction (Z direction) are referred to as the Z1 side and the Z2 side, respectively. The inner side and the outer side in the radial direction (R direction) are referred to as the R1 side and the R2 side, respectively. The axial direction of the rotor 100 (rotor core 10, rotor shaft 20) is the direction along the rotation axis A of the rotor 100 (rotor core 10, rotor shaft 20).

[0028] The rotor core 10 is made up of a plurality of (eight) rotor core block portions 10a stacked in the Z direction. Each of the plurality of rotor core block portions 10a is formed by stacking a plurality of electromagnetic steel plates (e.g., silicon steel plates) in the Z direction. Each of the plurality of rotor core block portions 10a has the same shape. When viewed from the Z direction, a through hole 10b is formed in the center of the rotor core 10. The through hole 10b passes through the rotor core 10 in the Z direction.

[0029] As shown in FIG. 2, each of the rotor core block portions 10a has 12 magnet accommodating holes 10c. Each of the magnet accommodating holes 10c penetrates the rotor core block portion 10a in the Z direction. A permanent magnet (not shown) is disposed inside each of the magnet accommodating holes 10c. The permanent magnet forms a magnetic pole. Specifically, in each of the rotor core block portions 10a, one magnetic pole MP is formed by the permanent magnets disposed in the two magnet accommodating holes 10c. That is, six magnetic poles MP are formed in each of the rotor core block portions 10a.

[0030] 1, the rotor shaft 20 includes a main body 21 having a through portion that passes through the through hole 10b of the rotor core 10, and a flange portion 22 that is arranged on the Z2 side of the through portion of the main body 21. The flange portion 22 protrudes from the main body 21 on the R2 side. The flange portion 22 is arranged so as to be adjacent in the Z direction to a rotor core block portion 10a (a first rotor core block portion 11 described later) that is arranged at the end on the Z2 side of the multiple rotor core block portions 10a.

[0031] (Rotor shaft keyway and rotor core block key) 2, the rotor shaft 20 includes a first key groove 23a extending in the Z direction and a second key groove 23b extending in the Z direction and formed at a position shifted in the C direction from the first key groove 23a. The first key grooves 23a are formed as a pair symmetrically with respect to the rotation axis A on the rotor shaft 20. Furthermore, the second key grooves 23b are formed as a pair symmetrically with respect to the rotation axis A on the rotor shaft 20.

[0032] Each of the rotor core block portions 10a has a key 10d that extends in the Z direction and engages with the first key groove 23a or the second key groove 23b. A pair of keys 10d are formed symmetrically with each other with respect to the rotation axis A of the rotor shaft 20 in each of the rotor core block portions 10a.

[0033] (Configuration of multiple rotor core blocks) 1, the multiple rotor core block portions 10a include a first rotor core block portion 11, a second rotor core block portion 12, a third rotor core block portion 13, and a fourth rotor core block portion 14. In the rotor core 10, the first rotor core block portion 11, the second rotor core block portion 12, the third rotor core block portion 13, the fourth rotor core block portion 14, the third rotor core block portion 13, the second rotor core block portion 12, and the first rotor core block portion 11 are stacked in this order from the Z1 side toward the Z2 side. That is, the multiple rotor core block portions 10a include two sets of the first rotor core block portion 11, the second rotor core block portion 12, the third rotor core block portion 13, and the fourth rotor core block portion 14.

[0034] As shown in Fig. 2, the key 10d of the first rotor core block portion 11 engages with the first key groove 23a. The position of the d-axis (not shown) of the first rotor core block portion 11 is shifted toward the C1 side from the position of the key 10d. Note that Fig. 2 shows the first rotor core block portion 11 and the second rotor core block portion 12 on the Z1 side of the two first rotor core block portions 11 and second rotor core block portions 12, as well as the rotor shaft 20.

[0035] In the second rotor core block portion 12, the key 10d engages with the first key groove 23a. The second rotor core block portion 12 is arranged by turning the first rotor core block portion 11 upside down in the Z direction. That is, the d-axis position of the second rotor core block portion 12 is shifted toward the C2 side from the position of the key 10d by the same amount as the shift in the first rotor core block portion 11. As a result, the position of the magnetic pole MP of the rotor core block portion 10a of the second rotor core block portion 12 is shifted in the C direction from that of the first rotor core block portion 11.

[0036] As shown in Fig. 3, the key 10d of the third rotor core block portion 13 engages with the second key groove 23b. The position of the d-axis of the third rotor core block portion 13 is shifted toward the C1 side from the position of the key 10d. Note that Fig. 3 shows the third rotor core block portion 13 and the fourth rotor core block portion 14 on the Z1 side of the two third rotor core block portions 13 and fourth rotor core block portions 14, as well as the rotor shaft 20.

[0037] In the fourth rotor core block portion 14, the key 10d engages with the second key groove 23b. The fourth rotor core block portion 14 is disposed by flipping the third rotor core block portion 13 over in the Z direction. That is, the d-axis position of the fourth rotor core block portion 14 is shifted toward the C2 side from the position of the key 10d by the same amount as the shift in the fourth rotor core block portion 14. As a result, the position of the magnetic pole MP of the fourth rotor core block portion 14 is shifted in the C direction from that of the third rotor core block portion 13.

[0038] (Position and arrangement of the rotor shaft key groove and rotor core block key) As shown in FIG. 2, the second key groove 23b is formed at a position offset by a predetermined first angle α in the C direction from the first key groove 23a.

[0039] As shown in FIGS. 2 to 4, the positions of the magnetic poles MP of the multiple rotor core block portions 10a adjacent to each other in the Z direction are offset by a predetermined second angle β. Specifically, as shown in FIG. 2, the position of the magnetic poles MP of the second rotor core block portion 12 is offset by the second angle β toward the C1 side with respect to the first rotor core block portion 11. As shown in FIG. 4, the position of the magnetic poles MP of the third rotor core block portion 13 is offset by the second angle β toward the C1 side with respect to the second rotor core block portion 12. That is, the position of the magnetic poles MP of the third rotor core block portion 13 is offset in the C direction from the first rotor core block portion 11 and the second rotor core block portion 12. As shown in FIG. 3, the position of the magnetic poles MP of the fourth rotor core block portion 14 is offset by the second angle β toward the C1 side with respect to the third rotor core block portion 13. That is, the position of the magnetic poles MP of the fourth rotor core block portion 14 is shifted in the C direction from the first rotor core block portion 11, the second rotor core block portion 12, and the third rotor core block portion 13. Note that the positions of the magnetic poles MP of adjacent fourth rotor core block portions 14 (see FIG. 1) are not shifted. Note that FIG. 4 shows the second rotor core block portion 12 and the third rotor core block portion 13 on the Z1 side of the two second rotor core block portions 12 and the two third rotor core block portions 13, and the rotor shaft 20.

[0040] The first angle α is set based on the number of magnetic poles MP of the rotor core block portion 10a and the second angle β. Specifically, the first angle α is set to (360 / number of magnetic poles MP) + 2 × second angle β. Note that the figure shows an example where the first angle α is 5 degrees, the number of magnetic poles MP is 6, and the second angle is 70 degrees.

[0041] (Length of the rotor shaft keyway) As shown in FIG. 1, the rotor shaft 20 includes a flange portion 22 arranged adjacent in the Z direction to a first rotor core block portion 11 arranged at the end of the plurality of rotor core block portions 10a on the Z2 side. Therefore, each of the plurality of rotor core block portions 10a is arranged on the rotor shaft 20 from the side opposite in the Z direction (the Z1 side) to the side on which the flange portion 22 is arranged. Also, as described above, in the rotor core 10, the first rotor core block portion 11, the second rotor core block portion 12, the third rotor core block portion 13, the fourth rotor core block portion 14, the fourth rotor core block portion 14, the third rotor core block portion 13, the second rotor core block portion 12, and the first rotor core block portion 11 are stacked in this order from the Z1 side toward the Z2 side. Also, as shown in FIG. 2, the key 10d of the first rotor core block portion 11 and the key 10d of the second rotor core block portion 12 are not engaged with the second key groove 23b.

[0042] 1, the first key groove 23a is formed over the entire portion of the rotor shaft 20 where the plurality of rotor core block portions 10a are arranged. On the other hand, the second key groove 23b is not formed in a portion of the rotor shaft 20 where the first rotor core block portion 11 adjacent to the flange portion 22 in the Z direction and the second rotor core block portion 12 adjacent in the Z direction to the first rotor core block portion 11 adjacent to the flange portion 22 in the Z direction are formed. Furthermore, the second key groove 23b is formed over the entire portion of the rotor shaft 20 where the plurality of rotor core block portions 10a are arranged, except for a portion where the first rotor core block portion 11 adjacent to the flange portion 22 in the Z direction and the second rotor core block portion 12 adjacent in the Z direction to the first rotor core block portion 11 adjacent to the flange portion 22 in the Z direction are formed. That is, the second key groove 23b is not formed in at least the portion of the rotor shaft 20 where the first rotor core block portion 11 arranged at the Z2 end of the multiple rotor core block portions 10a is arranged, and is formed so as to extend from the opposite side (Z1 side) of the first rotor core block portion 11 side (Z2 side) arranged adjacent to the flange portion 22 in the portion where the multiple rotor core block portions 10a are arranged toward the first rotor core block portion 11 side arranged adjacent to the flange portion 22.

[0043] (Effects of this embodiment) In this embodiment, the following effects can be obtained.

[0044] In this embodiment, as described above, the multiple rotor core block portions 10a include a first rotor core block portion 11 in which the key 10d engages with the first key groove 23a, a second rotor core block portion 12 in which the key 10d engages with the first key groove 23a and the first rotor core block portion 11 is arranged upside down in the Z direction, and the position of the magnetic pole MP formed by the permanent magnet of the rotor core block portion 10a is shifted from that of the first rotor core block portion 11 in the C direction, and a third rotor core block portion 13 in which the key 10d engages with the second key groove 23b and the position of the magnetic pole MP is shifted from that of the first rotor core block portion 11 and the second rotor core block portion 12 in the C direction. This allows the multiple rotor core block portions 10a to be configured to include three rotor core block portions 10a in which the positions of the magnetic poles MP of the rotor core block portions 10a are shifted from one another using only rotor core block portions 10a of the same shape, including the first rotor core block portion 11, the second rotor core block portion 12, and the third rotor core block portion 13. As a result, the multiple rotor core block portions 10a can be configured to include three or more rotor core block portions 10a in which the positions of the magnetic poles MP of the rotor core block portions 10a are shifted from one another, while suppressing an increase in the number of molds for manufacturing the rotor core block portions 10a.

[0045] Furthermore, in this embodiment, as described above, the first key grooves 23a are formed in a pair on the rotor shaft 20, symmetrically with respect to each other with respect to the rotation axis A of the rotor shaft 20. Furthermore, the second key grooves 23b are formed in a pair on the rotor shaft 20, symmetrically with respect to each other with respect to the rotation axis A. Furthermore, the keys 10d are formed in a pair on the rotor core block portion 10a, symmetrically with respect to each other with respect to the rotation axis A. This allows the first key grooves 23a of the rotor shaft 20 and the keys 10d of the first rotor core block portion 11 to be engaged with each other at two locations that face each other with respect to the rotation axis A, so that when the rotor shaft 20 and the first rotor core block portion 11 rotate, the load acting on the first key grooves 23a of the rotor shaft 20 and the keys 10d of the first rotor core block portion 11 can be distributed in a balanced manner. Furthermore, since the first key groove 23a of the rotor shaft 20 and the key 10d of the second rotor core block portion 12 can be engaged at two locations that face each other with respect to the rotation axis A, the load acting on the first key groove 23a of the rotor shaft 20 and the key 10d of the second rotor core block portion 12 can be distributed in a balanced manner when the rotor shaft 20 and the second rotor core block portion 12 rotate. Furthermore, since the second key groove 23b of the rotor shaft 20 and the key 10d of the third rotor core block portion 13 can be engaged at two locations that face each other with respect to the rotation axis A, the load acting on the second key groove 23b of the rotor shaft 20 and the key 10d of the third rotor core block portion 13 can be distributed in a balanced manner when the rotor shaft 20 and the third rotor core block portion 13 rotate. As a result, when the rotor shaft 20 and the rotor core 10 rotate, the load acting on each of the first key groove 23a of the rotor shaft 20, the second key groove 23b of the rotor shaft 20, the key 10d of the first rotor core block portion 11, the key 10d of the second rotor core block portion 12, and the key 10d of the third rotor core block portion 13 can be reduced.

[0046] Furthermore, in this embodiment, as described above, the multiple rotor core block portions 10a include a fourth rotor core block portion 14 in which the key 10d engages with the second key groove 23b and the third rotor core block portion 13 is disposed upside down in the Z direction, and in which the positions of the magnetic poles MP are shifted in the C direction from the first rotor core block portion 11, the second rotor core block portion 12, and the third rotor core block portion 13. As a result, the multiple rotor core block portions 10a can be configured to include four rotor core block portions 10a in which the positions of the magnetic poles MP of the rotor core block portions 10a are shifted from one another using only the rotor core block portions 10a of the same shape, using the first rotor core block portion 11, the second rotor core block portion 12, the third rotor core block portion 13, and the fourth rotor core block portion 14.

[0047] Furthermore, in the present embodiment, as described above, the first key groove 23a is formed over the entire portion of the rotor shaft 20 where the plurality of rotor core block portions 10a are arranged. Furthermore, the second key groove 23b is not formed in at least a portion of the rotor shaft 20 where the first rotor core block portion 11 arranged at the end on the Z2 side of the plurality of rotor core block portions 10a is arranged. As a result, while the first key groove 23a is formed over the entire portion of the rotor shaft 20 where the plurality of rotor core block portions 10a are arranged, the second key groove 23b is shorter than the first key groove 23a by an amount that is not formed in the portion of the rotor shaft 20 where the first rotor core block portion 11 arranged at the end on the Z2 side of the plurality of rotor core block portions 10a is arranged. Therefore, it is possible to easily distinguish between the first key groove 23a and the second key groove 23b. This makes it possible to prevent each of the multiple rotor core block portions 10a, each having a key 10d that engages with the first key groove 23a or the second key groove 23b, from being disposed on the rotor shaft 20 in an incorrect position on the rotor shaft 20. Furthermore, compared to when the second key groove 23b is formed over the entire portion of the rotor shaft 20 where the multiple rotor core block portions 10a are disposed, the processing costs for forming the key grooves on the rotor shaft 20 can be reduced. Note that, because the key 10d of the first rotor core block portion 11 does not engage with the second key groove 23b, the second key groove 23b does not need to be formed in the portion of the rotor shaft 20 where the first rotor core block portion 11, which is disposed at the end on the Z2 side of the multiple rotor core block portions 10a, is disposed.

[0048] Furthermore, in this embodiment, as described above, the second key groove 23b is formed at a position offset by a predetermined first angle α in the C direction from the first key groove 23a. Furthermore, the positions of the magnetic poles MP of the rotor core block portions 10a adjacent to each other in the Z direction are offset by a predetermined second angle β. The first angle α is set based on the number of magnetic poles MP of the rotor core block portion 10a and the second angle β. This makes it possible to set the first angle α by which the first key groove 23a and the second key groove 23b are offset in the C direction based on the number of magnetic poles MP of the rotor core block portion 10a and the second angle β by which the positions of the magnetic poles MP of the rotor core block portion 10a adjacent to each other in the Z direction are offset.

[0049] Furthermore, in this embodiment, as described above, the multiple rotor core block portions 10a include a fourth rotor core block portion 14 in which the keys 10d are engaged with the second key grooves 23b and the third rotor core block portion 13 is disposed upside down in the Z direction, and the positions of the magnetic poles MP are shifted in the C direction from the first rotor core block portion 11, the second rotor core block portion 12, and the third rotor core block portion 13. Furthermore, the first rotor core block portion 11, the second rotor core block portion 12, the third rotor core block portion 13, and the fourth rotor core block portion 14 are stacked in this order in the Z direction. The first angle α is set to (360 / number of magnetic poles MP)+2×second angle β. As a result, in a configuration in which the first rotor core block portion 11, the second rotor core block portion 12, the third rotor core block portion 13, and the fourth rotor core block portion 14 are stacked in this order in the Z direction, the first angle α can be set based on the number of magnetic poles MP of the rotor core block portion 10a and the second angle β.

[0050] [Variations] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims rather than the above description of the embodiments, and further includes all modifications (variations) within the meaning and scope of the claims.

[0051] For example, in the above embodiment, an example has been described in which a pair of first key grooves 23a are formed on the rotor shaft 20 symmetrically with respect to the rotation axis A of the rotor shaft 20, a pair of second key grooves 23b are formed on the rotor shaft 20 symmetrically with respect to the rotation axis A, and a pair of keys 10d are formed on the rotor core block portion 10a symmetrically with respect to the rotation axis A. However, the present invention is not limited to this. In the present invention, a pair of first key grooves may be formed on the rotor shaft asymmetrically with respect to the rotation axis of the rotor shaft, a pair of second key grooves may be formed on the rotor shaft asymmetrically with respect to the rotation axis, and a pair of keys may be formed on the rotor core block portion asymmetrically with respect to the rotation axis. Furthermore, one or three or more first key grooves may be formed on the rotor shaft, one or three or more second key grooves may be formed on the rotor shaft, and one or three or more keys may be formed on the rotor core block portion.

[0052] Furthermore, in the above embodiment, an example was shown in which the multiple rotor core block portions 10a include a fourth rotor core block portion 14 in which the key 10d engages with the second key groove 23b and the third rotor core block portion 13 is disposed upside down in the Z direction (axial direction), and the position of the magnetic pole MP is shifted in the C direction (circumferential direction) from the first rotor core block portion 11, the second rotor core block portion 12, and the third rotor core block portion 13, but the present invention is not limited to this. In the present invention, the multiple rotor core block portions do not have to include a fourth rotor core block portion in which the key engages with the second key groove and the third rotor core block portion is disposed upside down in the axial direction, and the position of the magnetic pole is shifted in the circumferential direction from the first rotor core block portion, the second rotor core block portion, and the third rotor core block portion.

[0053] Furthermore, in the above embodiment, an example was shown in which the second key groove 23b is not formed in the portion of the rotor shaft 20 where the first rotor core block portion 11 adjacent to the flange portion 22 in the Z direction (axial direction) and the second rotor core block portion 12 adjacent in the Z direction to the first rotor core block portion 11 adjacent to the flange portion 22 in the Z direction are formed, but the present invention is not limited to this. In the present invention, the second key groove may not be formed in the portion of the rotor shaft where the first rotor core block portion adjacent to the flange portion in the axial direction is formed, but may be formed in the portion where the second rotor core block portion adjacent in the axial direction to the first rotor core block portion adjacent to the flange portion in the axial direction is formed.

[0054] In the above embodiment, the first key groove 23a is formed over the entire portion of the rotor shaft 20 where the plurality of rotor core block portions 10a are arranged, and the second key groove 23b is not formed in at least a portion of the rotor shaft 20 where the first rotor core block portion 11 arranged at the end on the Z2 side (the other side in the axial direction) of the plurality of rotor core block portions 10a is arranged, but the present invention is not limited to this. In the present invention, the first key groove does not have to be formed at least in a portion of the rotor shaft where the second rotor core block portion arranged at the end on the other side in the axial direction of the plurality of rotor core block portions is arranged. Furthermore, the rotor shaft may have the first key groove formed over the entire portion of the rotor shaft where the plurality of rotor core block portions are arranged, and the second key groove formed over the entire portion of the rotor shaft where the plurality of rotor core block portions are arranged.

[0055] In the above embodiment, an example was shown in which the rotor shaft 20 includes the flange portion 22 arranged adjacent in the Z direction (axial direction) to the first rotor core block portion 11 arranged at the end on the Z2 side (the other side in the axial direction) of the multiple rotor core block portions 10a, but the present invention is not limited to this. In the present invention, the rotor shaft does not have to include a flange portion arranged adjacent in the axial direction to the first rotor core block portion or the second rotor core block arranged at the end on one or the other side in the axial direction of the multiple rotor core block portions.

[0056] Furthermore, in the above embodiment, an example has been shown in which the first rotor core block portion 11, the second rotor core block portion 12, the third rotor core block portion 13, and the fourth rotor core block portion 14 are stacked in this order in the Z direction, and the first angle α is set to (360 / number of magnetic poles MP) + 2 × second angle β, but the present invention is not limited to this. In the present invention, the first rotor core block portion 11, the third rotor core block portion 13, the second rotor core block portion 12, and the fourth rotor core block portion 14 may be stacked in this order in the Z direction, as in the rotor core 210 of the rotor 200 according to the first modified example shown in FIG. 5. In this case, the first angle α × 2 is set to (360 / number of magnetic poles MP) + second angle β. This allows the first angle to be set based on the number of magnetic poles of the rotor core block portions and the second angle in a configuration in which the first rotor core block portion, the third rotor core block portion, the second rotor core block portion, and the fourth rotor core block portion are stacked in this order in the axial direction.

[0057] Furthermore, in the above embodiment, an example has been shown in which the multiple rotor core block portions 10a include two sets of the first rotor core block portion 11, the second rotor core block portion 12, the third rotor core block portion 13, and the fourth rotor core block portion 14, but the present invention is not limited to this. In the present invention, the multiple rotor core block portions 10a may include only one set of the first rotor core block portion 11, the second rotor core block portion 12, the third rotor core block portion 13, and the fourth rotor core block portion 14, as in the rotor core 310 of the rotor 300 according to the second modified example shown in FIG. 6 and the rotor core 410 of the rotor 400 according to the third modified example shown in FIG. 7. Furthermore, the multiple rotor core block portions may include three or more sets of the first rotor core block portion, the second rotor core block portion, the third rotor core block portion, and the fourth rotor core block portion. [Explanation of symbols]

[0058] 10, 210, 310, 410... rotor core, 10a... rotor core block portion, 10d... key, 11... first rotor core block portion, 12... second rotor core block portion, 13... third rotor core block portion, 14... fourth rotor core block portion, 20... rotor shaft, 23a... first keyway, 23b... second keyway, 22... flange portion, 100, 200, 300, 400... rotor, A... rotation axis, MP... magnetic pole, α... first angle, β... second angle

Claims

1. a rotor shaft including a first key groove extending in an axial direction and a second key groove extending in the axial direction and formed at a position offset in a circumferential direction from the first key groove; a rotor core in which a plurality of rotor core block portions, each having a key extending in the axial direction and engaging with the first key groove or the second key groove, and a plurality of magnet accommodating holes in which permanent magnets are disposed, are stacked in the axial direction; The plurality of rotor core block portions include a first rotor core block portion in which the key engages with the first key groove, a second rotor core block portion in which the key engages with the first key groove and which is arranged by flipping the first rotor core block portion in the axial direction, and in which the position of the magnetic pole formed by the permanent magnet of the rotor core block portion is shifted in the circumferential direction from that of the first rotor core block portion, and a third rotor core block portion in which the key engages with the second key groove and the position of the magnetic pole is shifted in the circumferential direction from that of the first rotor core block portion and the second rotor core block portion.

2. a pair of the first key grooves are formed on the rotor shaft symmetrically with respect to a rotation axis of the rotor shaft, a pair of the second key grooves are formed on the rotor shaft symmetrically with respect to the rotation axis, The rotor according to claim 1 , wherein a pair of said keys are formed in said rotor core block portion symmetrically with respect to said rotation axis.

3. 2. The rotor according to claim 1, wherein the plurality of rotor core block portions further include a fourth rotor core block portion in which the key engages with the second key groove and the third rotor core block portion is arranged upside down in the axial direction, and the magnetic pole positions are shifted in the circumferential direction from the first rotor core block portion, the second rotor core block portion, and the third rotor core block portion.

4. the first key groove is formed over an entire portion of the rotor shaft where the plurality of rotor core block portions are arranged, 2. The rotor according to claim 1, wherein the second key groove is not formed in at least a portion of the rotor shaft where the first rotor core block portion or the second rotor core block portion, which is located at one end or the other end in the axial direction of the plurality of rotor core block portions, is located.

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