Rotor of a rotating electrical machine and method for manufacturing the same

Abstract

The rotor of a rotating electric machine includes: a rotor core; end plates provided at the ends of the rotor core in the axial direction of the rotor core; and a shaft passing through each of the rotor core and the end plates in the axial direction. The end plate has: an annular flat plate portion in contact with the rotor core; and a warped portion provided on the inner circumferential side of the flat plate portion and in contact with the shaft. In the radial cross-section of the end plate, the warped portion warps in such a manner that it moves away from the rotor core as it moves away from the flat plate portion.

Description

Technical Field

[0001] The present invention relates to a rotor of a rotating electric machine including a rotor core and end plates, and a method for manufacturing the same. Background Art

[0002] Patent Document 1 describes a method for manufacturing a motor rotor having a laminated core and a pair of end plates disposed on both axial sides of the laminated core. The manufacturing method includes: a step of inserting a rotating shaft into a through-hole of an end plate formed in a disk shape so as to be elastic in the plate thickness direction; and a step of bringing the end plate into contact with an end portion of the laminated core in a state where the end plate is elastically deformed. Patent Document 1 describes that according to this manufacturing method, the state where the end portion of the laminated core is in contact with the end plate can be maintained by the elastic restoring force of the end plate.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2008-178253 Summary of the Invention

[0006] Technical Problem to be Solved by the Invention

[0007] In the above manufacturing method, the end plate is pre-formed in a disk shape. Therefore, for example, in each of the above steps, if the end plate is deformed such as warped or skewed, the desired elastic force in the end plate cannot be obtained. Therefore, there is the following technical problem: The end plate and the laminated core do not necessarily adhere closely, and a gap may be generated between the end plate and the end portion of the laminated core.

[0008] The present invention is made to solve the above technical problem, and an object thereof is to provide a rotor of a rotating electric machine and a method for manufacturing the same that can make the end plate adhere more reliably to the rotor core.

[0009] Technical Solution for Solving the Technical Problem

[0010] The rotor of the rotating electric machine of the present invention includes: a rotor core; an end plate disposed at an end portion of the rotor core in the axial direction of the rotor core; and a shaft passing through each of the rotor core and the end plate in the axial direction. The end plate has: a ring-shaped flat plate portion in contact with the rotor core; and a warped portion disposed on the inner peripheral side of the flat plate portion and in contact with the shaft. In a radial cross section of the end plate, the warped portion warps in such a manner that it moves away from the rotor core as it moves away from the flat plate portion.

[0011] The manufacturing method of the rotor of the rotating electric machine of the present invention has a step of press-fitting a first press-fitting portion, which is located on one end side of the rotor core in the shaft on which the rotor core is mounted, into a first through-hole of a flat first end plate supported by a jig. The jig has: a flat surface portion that supports the first end plate; a hole portion that is formed at a position surrounded by the flat surface portion, has a diameter larger than either the diameter of the first through-hole or the diameter of the first press-fitting portion, and extends in a direction perpendicular to the flat surface portion; and a tapered surface that is formed between the inner peripheral surface of the hole portion and the flat surface portion.

[0012] Advantages of the Invention

[0013] According to the present invention, the end plate and the rotor core can be made to adhere more reliably. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a cross-sectional view showing the structure of the rotor of the rotating electric machine according to Embodiment 1 of the present invention.

[0015] Figure 2 It is Figure 1 a cross-sectional view showing an enlarged II portion.

[0016] Figure 3 It is a cross-sectional view showing the structure of the rotor of the rotating electric machine according to the comparative example of Embodiment 1 of the present invention.

[0017] Figure 4 It is a top view showing the structure of the first end plate used in the manufacturing method of the rotor of the rotating electric machine according to Embodiment 1 of the present invention.

[0018] Figure 5 It is a cross-sectional view showing the structure of the first press-fitting portion of the shaft used in the manufacturing method of the rotor of the rotating electric machine according to Embodiment 1 of the present invention.

[0019] Figure 6 It is Figure 5 a cross-sectional view showing an enlarged VI portion.

[0020] Figure 7 It is a top view showing the structure of the second end plate used in the manufacturing method of the rotor of the rotating electric machine according to Embodiment 1 of the present invention.

[0021] Figure 8 It is Figure 7 a top view showing an enlarged VIII portion.

[0022] Figure 9 It is a cross-sectional view showing the structure of the second press-fitting portion of the shaft used in the manufacturing method of the rotor of the rotating electric machine according to Embodiment 1 of the present invention.

[0023] Figure 10 This is a cross-sectional view showing the manufacturing process of the rotor of the rotating electric machine according to Embodiment 1 of the present invention.

[0024] Figure 11 This is a cross-sectional view showing the manufacturing process of the rotor of the rotating electric machine according to Embodiment 1 of the present invention.

[0025] Figure 12 This is a Figure 11 cross-sectional view showing an enlarged view of part XII.

[0026] Figure 13 This is a cross-sectional view showing the manufacturing process of the rotor of the rotating electric machine according to Embodiment 1 of the present invention. Detailed Embodiment

[0027] Embodiment 1

[0028] The rotor of the rotating electric machine according to Embodiment 1 of the present invention and its manufacturing method will be described. First, Figure 1 and Figure 2 will be used to describe the structure of the rotor of the rotating electric machine according to the present embodiment. Figure 1 This is a cross-sectional view showing the structure of the rotor 100 of the rotating electric machine according to the present embodiment. Figure 2 This is a Figure 1 cross-sectional view showing an enlarged view of part II. In Figure 1 and Figure 2 a radial cross-section of the rotor core 10, the first end plate 20, and the second end plate 30 is shown. In the present embodiment, an IPM (Interior Permanent Magnet) type rotor 100 in which permanent magnets 14 are buried inside is shown.

[0029] Figure 1 and Figure 2 The rotor 100 shown constitutes part of an inner rotor type rotating electric machine. The inner rotor type rotating electric machine includes the rotor 100 and a stator (not shown) disposed on the outer peripheral side of the rotor 100. The rotor 100 is rotatably supported relative to the stator by bearings (not shown). The rotor 100 includes a rotor core 10, a first end plate 20, a second end plate 30, and a shaft 40. The first end plate 20 is disposed at one end portion of the rotor core 10 in the axial direction of the rotor core 10. The second end plate 30 is disposed at the other end portion of the rotor core 10 in the above-mentioned axial direction. The shaft 40 penetrates each of the rotor core 10, the first end plate 20, and the second end plate 30 along the above-mentioned axial direction.

[0030] A part of the shaft 40 in the axial direction has a large-diameter portion 41. The large-diameter portion 41 has a larger diameter than other parts of the shaft 40. The rotor core 10, the first end plate 20, and the second end plate 30 are fixed to the large-diameter portion 41. The large-diameter portion 41 has a first press-fitting portion 41a press-fitted into the first end plate 20 and a second press-fitting portion 41b press-fitted into the second end plate 30. Each of the first press-fitting portion 41a and the second press-fitting portion 41b is a part of the large-diameter portion 41 in the axial direction. As will be described later, a first protrusion 42 extending in the axial direction is formed on the outer peripheral surface of the large-diameter portion 41.

[0031] The rotor core 10 has a structure in which a plurality of electromagnetic steel sheets 11 are laminated. The rotor core 10 has a cylindrical shape as a whole. A through-hole 12 penetrating in the axial direction is formed in the central portion of the rotor core 10. The large-diameter portion 41 of the shaft 40 is installed in the through-hole 12 of the rotor core 10 by press-fitting or shrink-fitting. Thereby, the rotor core 10 is fixed relative to the shaft 40. At positions in the rotor core 10 on the outer peripheral side of the through-hole 12, a plurality of magnet insertion holes 13 penetrating in the axial direction are formed respectively. A permanent magnet 14 is inserted into each of the magnet insertion holes 13. One axial end portion of each of the magnet insertion holes 13 is closed by the first end plate 20. The other axial end portion of each of the magnet insertion holes 13 is closed by the second end plate 30.

[0032] Each of the first end plate 20 and the second end plate 30 has a disc shape. The first end plate 20 and the second end plate 30 are formed of a non-magnetic material such as SUS304. The first end plate 20 and the second end plate 30 are formed of a non-magnetic material to prevent the magnetic flux of the permanent magnet 14 from leaking to the first end plate 20 or the second end plate 30 and causing a decrease in magnetic force.

[0033] A first through-hole 21 penetrating in the axial direction is formed in the central portion of the first end plate 20. The first press-fitting portion 41a of the shaft 40 is press-fitted into the first through-hole 21. Thereby, the first end plate 20 is fixed relative to the shaft 40.

[0034] The first end plate 20 has a flat plate portion 22 that contacts the end face 10a on the axial one-end side of the rotor core 10. The flat plate portion 22 has an annular shape. The flat plate portion 22 is of course provided on the outer peripheral side of the first press-fitting portion 41a of the shaft 40. The flat plate portion 22 is provided over the entire circumference in the circumferential direction centered on the first press-fitting portion 41a. The surface of the flat plate portion 22 is in surface contact with the end face 10a of the rotor core 10 without a gap. When viewed in the axial direction, the outer peripheral side end portion of the flat plate portion 22, that is, the outer peripheral side end portion 20a of the first end plate 20, is located on the inner peripheral side of the outer peripheral surface of the rotor core 10.

[0035] In addition, the first end plate 20 has a warped portion 23, and the warped portion 23 is provided on the inner peripheral side of the flat plate portion 22 and on the outer peripheral side of the first press-fitting portion 41a of the shaft 40. The inner peripheral side end portion of the warped portion 23, that is, the inner peripheral side end portion 20b of the first end plate 20, contacts the outer peripheral surface of the first press-fitting portion 41a. The warped portion 23 is provided over the entire circumference in the circumferential direction centered on the first press-fitting portion 41a. The warped portion 23 warps in the radial cross-section of the first end plate 20 shown in Figure 1 and Figure 2 such that the farther away from the flat plate portion 22, that is, the closer to the shaft 40, the farther away from the end face 10a of the rotor core 10. In addition, the warped portion 23 is continuously and smoothly connected to the flat plate portion 22 in the radial cross-section and is bent so as to protrude toward the rotor core 10 side. The width of the warped portion 23, that is, the radial dimension of the warped portion 23, is smaller than the width of the flat plate portion 22, that is, the radial dimension of the flat plate portion 22.

[0036] By providing the warped portion 23, the flat plate portion 22 is pressed against the end face 10a of the rotor core 10 by the elastic force of the first end plate 20 itself with the inner peripheral side end portion 20b of the first end plate 20 as a fulcrum. Therefore, the flat plate portion 22 is in close contact with the end face 10a of the rotor core 10 without a gap.

[0037] Similarly to the first end plate 20, a second through-hole 31 penetrating in the axial direction is formed in the center portion of the second end plate 30. The second press-fitting portion 41b of the shaft 40 is press-fitted into the second through-hole 31. Thus, the second end plate 30 is fixed relative to the shaft 40.

[0038] The second end plate 30 has a flat plate portion 32 that contacts the end face 10b on the other axial end side of the rotor core 10. The flat plate portion 32 has an annular shape. The flat plate portion 32 is of course provided on the outer peripheral side of the second press-fitting portion 41b of the shaft 40. The flat plate portion 32 is provided over the entire circumference in the circumferential direction centered on the second press-fitting portion 41b. The surface of the flat plate portion 32 is in surface contact with the end face 10b of the rotor core 10 without a gap. When observed in the axial direction, the outer peripheral side end portion of the flat plate portion 32, that is, the outer peripheral side end portion 30a of the second end plate 30, is located on the inner peripheral side of the outer peripheral surface of the rotor core 10.

[0039] In addition, the second end plate 30 has a warped portion 33, and the warped portion 33 is provided on the inner peripheral side of the flat plate portion 32 and on the outer peripheral side of the second press-fitting portion 41b of the shaft 40. The inner peripheral side end portion of the warped portion 33, that is, the inner peripheral side end portion 30b of the second end plate 30, contacts the outer peripheral surface of the second press-fitting portion 41b. The warped portion 33 is provided over the entire circumference in the circumferential direction centered on the second press-fitting portion 41b. The warped portion 33 is in Figure 1In the radial cross-section of the second end plate 30 shown, it warps in such a way that the farther away from the flat portion 32, that is, the closer to the shaft 40, the farther away from the end face 10b of the rotor core 10. Further, the warped portion 33 is continuously and smoothly connected to the flat portion 32 in the above-mentioned radial cross-section, and bends in a manner protruding toward the rotor core 10 side. The width of the warped portion 33, that is, the radial dimension of the warped portion 33, is smaller than the width of the flat portion 32, that is, the radial dimension of the flat portion 32.

[0040] By providing the warped portion 33, the flat portion 32 is pressed against the end face 10b of the rotor core 10 by using the elastic force of the second end plate 30 itself with the inner peripheral side end portion 30b of the second end plate 30 as a fulcrum. Therefore, the flat portion 32 is in close contact with the end face 10b of the rotor core 10 without a gap.

[0041] In this way, the flat portion 22 of the first end plate 20 is in close contact with the end face 10a of the rotor core 10, and the flat portion 32 of the second end plate 30 is in close contact with the end face 10b of the rotor core 10. That is, the rotor core 10 is pressed from both axial ends by the first end plate 20 and the second end plate 30. Thereby, during the operation of the rotating electric machine, it is possible to suppress the vibration of the electromagnetic steel sheets 11 located at both axial ends of the rotor core 10 due to electromagnetic force. In addition, the axial position of the permanent magnet 14 can be restricted thereby. Thus, it is possible to suppress the noise generated during the operation of the rotating electric machine.

[0042] Here, a comparative example is used to illustrate the state where neither the first end plate 20 nor the second end plate 30 is in close contact with the rotor core 10. Figure 3 It is a cross-sectional view showing the structure of the rotor 200 of the rotating electric machine of the comparative example of the present embodiment. In Figure 3 In the structure of the comparative example shown, the first end plate 20 and the second end plate 30 are also each fixed to the shaft 40 by press-fitting. However, in the structure of the comparative example, the outer peripheral sides of the first end plate 20 and the second end plate 30 are each in a warped state toward the direction away from the rotor core 10. As a result, a gap 201 is formed between the first end plate 20 and the end face 10a of the rotor core 10, and a gap 202 is formed between the second end plate 30 and the end face 10b of the rotor core 10. This is because the first end plate 20 and the second end plate 30, which are each formed in a flat plate shape before press-fitting, are deformed due to the stress generated during press-fitting. It is known that when a force is locally applied around the central hole of a flat plate-shaped member such as the first end plate 20 and the second end plate 30, and the flat plate-shaped member is press-fitted into a cylindrical member such as the shaft 40, warping occurs on the outer peripheral side of the flat plate-shaped member in the direction opposite to the direction of the force applied to the flat plate-shaped member. If it is in the state shown in Figure 3 In the state shown, during the operation of the rotating electric machine, in addition to the electromagnetic steel sheets 11 located at both axial ends of the rotor core 10 vibrating due to electromagnetic force, the axial position of the permanent magnet 14 cannot be restricted.

[0043] Next, the manufacturing method of the rotor of the rotating electric machine according to the present embodiment will be described using Figures 4 to 13 . Figure 4 FIG. is a plan view showing the structure of the first end plate 20 used in the manufacturing method of the rotor of the rotating electric machine according to the present embodiment. In Figure 4 , the structure of the first end plate 20 as a component before assembling the rotor 100 is shown.

[0044] As Figure 4 shown, the first end plate 20 has a circular plate-like and flat plate-like shape. A first through hole 21 into which the first press-fitting portion 41a of the shaft 40 is press-fitted is formed at the center portion of the first end plate 20. The first through hole 21 has a circular cross-sectional shape. That is, no protrusion protruding inward in the radial direction and no recess recessed outward in the radial direction are formed on the inner peripheral surface of the first through hole 21.

[0045] Figure 5 FIG. is a cross-sectional view showing the structure of the first press-fitting portion 41a of the shaft 40 used in the manufacturing method of the rotor of the rotating electric machine according to the present embodiment. In Figure 5 , the structure of the shaft 40 as a component before assembling the rotor 100 after being cut by a plane perpendicular to the axial direction is shown. Figure 6 FIG. is a cross-sectional view showing an enlarged view of part VI of Figure 5 .

[0046] As Figure 5 and Figure 6 shown, a plurality of first protrusions 42 protruding outward in the radial direction are formed on the outer peripheral surface of the first press-fitting portion 41a of the shaft 40. As Figure 1 shown, each of the first protrusions 42 extends in the axial direction up to the portion of the large-diameter portion 41 of the shaft 40 that is press-fitted into the rotor core 10. The first protrusions 42 function to ensure the fixing force when the shaft 40 is press-fitted into the rotor core 10 and the fixing force when the shaft 40 is press-fitted into the first end plate 20. A recess 43 is formed between two adjacent first protrusions 42, and the recess 43 can accommodate the fragments of the rotor core 10 cut off by the first protrusions 42 during press-fitting. On the outer peripheral surface of the large-diameter portion 41, multiple sets of a group of two first protrusions 42 and one recess 43 are provided at equal intervals in the circumferential direction.

[0047] Here, Figure 4The diameter of the first through hole 21 of the first end plate 20 shown is set to D1. The diameter of the cylindrical portion of the first press-fit portion 41a where neither the first protrusion 42 nor the recess 43 is formed is set to D2. The diameter of the circumscribed circle centered on the central axis of the shaft 40 and circumscribed to the plurality of first protrusions 42 is set to D3. At this time, the diameter D1, the diameter D2, and the diameter D3 satisfy the relationship of D2≤D1<D3. Since the above relationship is satisfied, the fixing force when the first press-fit portion 41a of the shaft 40 is pressed into the first end plate 20 can be ensured by the first protrusion 42.

[0048] Figure 7 FIG. 2 is a plan view showing the structure of the second end plate 30 used in the method for manufacturing the rotor of the rotating electrical machine according to the present embodiment. Figure 7 , the structure of the second end plate 30 as a component before the rotor 100 is assembled is shown. Figure 8 Yes Figure 7 Part VIII is an enlarged top view.

[0049] like Figure 7 and Figure 8 As shown, the second end plate 30 has a disc-like and flat plate-like shape. A second through hole 31 into which the large diameter portion 41 of the shaft 40 is pressed is formed at the center of the second end plate 30. A plurality of second protrusions 34 are formed on the inner circumferential surface of the second through hole 31, each protruding radially inward.

[0050] Figure 9 4 is a cross-sectional view showing the structure of the second press-fit portion 41b of the shaft 40 used in the method for manufacturing the rotor of the rotating electrical machine according to the present embodiment. Figure 9 , a structure obtained by cutting the shaft 40 , which is a component before assembling the rotor 100 , along a plane perpendicular to the axial direction is shown.

[0051] like Figure 9 As shown in FIG. 1 , the second press-fit portion 41 b of the shaft 40 has a perfect circular cross-sectional shape. That is, no protrusions protruding outward in the radial direction and no recesses recessed inward in the radial direction are formed on the outer peripheral surface of the second press-fit portion 41 b.

[0052] Here, Figure 7The diameter of the cylindrical portion of the second through hole 31 of the second end plate 30 shown in the figure, where the second protrusion 34 is not formed, is set to D4. The diameter of the inscribed circle centered on the central axis of the second through hole 31 and inscribed in the plurality of second protrusions 34 is set to D5. The diameter of the second press-fit portion 41b is set to D6. At this time, the diameter D4, the diameter D5, and the diameter D6 satisfy the relationship of D5<D6≤D4. Since the above relationship is satisfied, the fixing force when the shaft 40 is pressed into the second end plate 30 can be ensured by the second protrusion 34. The diameter D6 of the second press-fit portion 41b may also be the same as the diameter D2 of the first press-fit portion 41a. The diameter D4 of the second through hole 31 may also be the same as the diameter D1 of the first through hole 21.

[0053] In this embodiment, the structure of the first press-fit portion 41a and the first end plate 20 is different from the structure of the second press-fit portion 41b and the second end plate 30. That is, a plurality of first protrusions 42 are formed on the outer circumferential surface of the first press-fit portion 41a, while no protrusions and recesses are formed on the outer circumferential surface of the second press-fit portion 41b. In addition, no protrusions and recesses are formed on the inner circumferential surface of the first through hole 21 of the first end plate 20, while a plurality of second protrusions 34 are formed on the inner circumferential surface of the second through hole 31 of the second end plate 30. This is because in the axial direction, the plurality of first protrusions 42 are not provided in the entire portion of the large diameter portion 41 that is pressed into the rotor core 10, and do not reach the second press-fit portion 41b. When the shaft 40 is pressed into the rotor core 10, the inner circumferential surface of the rotor core 10 is scraped off by the first protrusions 42. By forming the first protrusions 42 so as not to reach the second press-fit portion 41b, the scraped pieces of the rotor core 10 can be left inside the rotor core 10.

[0054] However, the structures of the second press-fit portion 41b and the second end plate 30 may be the same as the structures of the first press-fit portion 41a and the first end plate 20. That is, the first protrusion 42 is formed on the outer peripheral surface of the second press-fit portion 41b similarly to the first press-fit portion 41a, and the second through hole 31 has a perfect circular cross-sectional shape similarly to the first through hole 21. Alternatively, the second protrusion 34 is formed on the inner peripheral surface of the first through hole 21 similarly to the second through hole 31, and the first press-fit portion 41a has a perfect circular cross-sectional shape similarly to the second press-fit portion 41b.

[0055] Next, a manufacturing process of the rotor 100 of the rotating electrical machine according to the present embodiment will be described. Figure 10 , Figure 11 and Figure 13 It is a cross-sectional view showing a manufacturing process of the rotor 100 of the rotating electrical machine according to the present embodiment. Figure 12 Yes Figure 11 This is an enlarged cross-sectional view of part XII. Figures 10 to 13In the figure, as part of the manufacturing process of the rotor 100, a process of pressing the first press-fitting portion 41a of the shaft 40 into the first end plate 20 is shown. In Figures 10 to 13 In the shown process, the second end plate 30 has been press-fitted and installed in the second press-fitting portion 41b. However, the process of pressing the second press-fitting portion 41b into the second end plate 30 can also be carried out after the process of pressing the first press-fitting portion 41a into the first end plate 20. The process of pressing the second press-fitting portion 41b into the second end plate 30 can be carried out in the same manner as the process of pressing the first press-fitting portion 41a into the first end plate 20.

[0056] Figure 10 A state before the shaft 40 is press-fitted into the first end plate 20 is shown. As Figure 10 shown, in the process of pressing the first press-fitting portion 41a of the shaft 40 into the first end plate 20, first, the flat first end plate 20 is supported by the jig 50. The jig 50 has: a planar portion 51 for supporting the first end plate 20; and a cylindrical hole portion 52 formed at a position surrounded by the planar portion 51 and extending in a direction perpendicular to the planar portion 51. If the diameter of the hole 52 is set as D7, the diameter D7 satisfies the relationships of D7 > D1 and D7 > D2. A tapered surface 53 is formed over the entire circumference at the corner between the planar portion 51 and the inner peripheral surface of the hole portion 52. The first end plate 20 is positioned such that the center of the hole portion 52 coincides with the center of the first through hole 21 when viewed in a direction perpendicular to the planar portion 51.

[0057] Figure 11 and Figure 12 A state in the middle of the shaft 40 being press-fitted into the first end plate 20 is shown. As Figure 11 and Figure 12 shown, the first press-fitting portion 41a of the shaft 40 is gradually press-fitted into the first through hole 21 of the first end plate 20. At this time, the inner peripheral side end portion 20b of the first end plate 20 deforms under the action of the stress generated by the press-fitting of the shaft 40. That is, the inner peripheral side end portion 20b of the first end plate 20 deforms along the tapered surface 53 with the inner peripheral edge portion 51a of the planar portion 51 as a fulcrum. As a result, warping in the press-fitting direction of the shaft 40 is generated in the inner peripheral side end portion 20b of the first end plate 20. Therefore, a warped portion 23 is formed on the inner peripheral side of the first end plate 20. On the other hand, the outer peripheral side end portion 20a of the first end plate 20 floats from the planar portion 51 with the inner peripheral edge portion 51a as a fulcrum. A gap 54 is formed between the outer peripheral side end portion 20a and the planar portion 51. As a result, the first end plate 20 as a whole deforms into a disc spring-like shape protruding in a direction away from the rotor core 10.

[0058] Figure 13 A state after the press-fitting of the shaft 40 into the first end plate 20 is completed is shown. As Figure 13As shown, the portion of the first end plate 20 on the outer peripheral side of the warping portion 23 is sandwiched between the end face 10a of the rotor core 10 and the flat portion 51 of the jig 50 and deformed into a flat plate shape. As a result, a flat plate portion 22 is formed in the first end plate 20. The flat plate portion 22 is pressed against the end face 10b of the rotor core 10 with the inner peripheral side end portion 20b as a fulcrum by the elastic force of the first end plate 20 itself. Therefore, the flat plate portion 22 is in close contact with the end face 10a of the rotor core 10 without a gap. Here, the elastic force of the first end plate 20 is obtained by the first end plate 20 itself being deformed into a disc spring shape along with the press-fitting of the shaft 40. The first end plate 20 is deformed into a disc spring shape mainly due to the action of the tapered surface 53 provided on the jig 50.

[0059] In the method for manufacturing a motor rotor described in Patent Document 1, in order to make the rotor core and the end plate in close contact, an end plate preformed into a disc spring shape before press-fitting is used. However, in this manufacturing method, when the end plate is press-fitted onto the shaft, the end plate may warp toward the side opposite to the rotor core. Therefore, the shape deviation of the end plate becomes large, and sometimes the desired elastic force cannot be obtained in the end plate. As a result, there is a problem that a gap may be generated between the end plate and the rotor core. In addition, since an additional process of forming the end plate into a disc spring shape is required, there is also a problem that the manufacturing cost of the rotor increases due to the increase in the manufacturing process.

[0060] In addition, generally, in order to make the flat end plate in a rotating electrical machine in close contact with the rotor core, other components such as rivets and bushings are required. Therefore, there is a problem that the manufacturing cost of the rotor increases due to the increase in the number of components and the manufacturing process.

[0061] In contrast, in the present embodiment, the first end plate 20 and the second end plate 30 are each in close contact with the rotor core 10 without a gap by their own elastic forces. As a result, during the operation of the rotating electrical machine, vibration of the electromagnetic steel sheets 11 located at the axial both ends of the rotor core 10 due to electromagnetic force can be suppressed. In addition, thereby, the axial position of the permanent magnet 14 can be restricted. Therefore, noise generated during the operation of the rotating electrical machine can be suppressed. In addition, in the present embodiment, a flat plate-shaped component can be used for each of the first end plate 20 and the second end plate 30, and no additional components such as rivets and bushings are required. Thus, simplification of the manufacturing process of the rotor 100 and reduction of the manufacturing cost of the rotor 100 can be achieved.

[0062] As described above, the rotor 100 of the rotating electric machine according to the present embodiment includes a rotor core 10, a first end plate 20, and a shaft 40. The first end plate 20 is provided at an end of the rotor core 10 in the axial direction of the rotor core 10. The shaft 40 axially penetrates each of the rotor core 10 and the first end plate 20. The first end plate 20 has: an annular flat plate portion 22 that contacts the rotor core 10; and a warped portion 23 that is provided on the inner peripheral side of the flat plate portion 22 and contacts the shaft 40. In the radial cross section of the first end plate 20, the warped portion 23 warps in such a manner that it moves away from the rotor core 10 as it moves away from the flat plate portion 22. Here, the first end plate 20 is an example of an end plate.

[0063] According to this structure, the flat plate portion 22 of the first end plate 20 is pressed against the rotor core 10 by the elastic force of the first end plate 20 itself. Therefore, according to the above structure, the first end plate 20 can be more reliably brought into close contact with the rotor core 10.

[0064] The manufacturing method of the rotor 100 of the rotating electric machine according to the present embodiment includes a step of pressing a first press-fitting portion 41a on one end side of the shaft 40 on which the rotor core 10 is mounted into a first through hole 21 of a flat plate-shaped first end plate 20 supported by a jig 50. The jig 50 has a flat surface portion 51, a hole portion 52, and a tapered surface 53. The flat surface portion 51 is configured to support the first end plate 20. The hole portion 52 is formed at a position surrounded by the flat surface portion 51, has a diameter D7 that is larger than either the diameter D1 of the first through hole 21 or the diameter D2 of the first press-fitting portion 41a, and extends in a direction perpendicular to the flat surface portion 51. The tapered surface 53 is formed between the inner peripheral surface of the hole 52 and the flat surface portion 51.

[0065] According to this structure, in the step of pressing the first press-fitting portion 41a into the first through hole 21, the inner peripheral side end portion of the first end plate 20 deforms along the tapered surface 53. As a result, the first end plate 20 is deformed into a shape like a disc spring as a whole. When the pressing of the first press-fitting portion 41a into the first through hole 21 is completed, the first end plate 20 is pressed against the rotor core 10 by the elastic force of the first end plate 20 itself. Therefore, the first end plate 20 and the rotor core 10 can be more reliably brought into close contact.

[0066] In addition, in the manufacturing method of the rotor 100 of the rotating electric machine according to the present embodiment, a first protrusion 42 is formed on the outer peripheral surface of the first press-fitting portion 41a, and the cross section of the first through hole 21 is formed in a perfect circular shape. According to this structure, the fixing force between the first end plate 20 and the shaft 40 can be ensured by the first protrusion 42.

[0067] In addition, in the method for manufacturing the rotor 100 of the rotating electric machine according to the present embodiment, the cross-section of the first press-fitting portion 41a is formed in a perfect circle shape, and the second protrusion 34 is formed on the inner peripheral surface of the first through-hole 21. According to this structure, the fixing force between the first end plate 20 and the shaft 40 can be ensured by the second protrusion 34.

[0068] In addition, the method for manufacturing the rotor 100 of the rotating electric machine according to the present embodiment further includes a step of press-fitting the second press-fitting portion 41b of the shaft 40, which is located on the other end side of the rotor core 10, into the second through-hole 31 of the flat second end plate 30 supported by the jig 50. The first protrusion 42 is formed on the outer peripheral surface of the first press-fitting portion 41a. The cross-section of the first through-hole 21 is formed in a perfect circle shape. The cross-section of the second press-fitting portion 41b is formed in a perfect circle shape. The second protrusion 34 is formed on the inner peripheral surface of the second through-hole 31. According to this structure, the fixing force between the first end plate 20 and the shaft 40 can be ensured by the first protrusion 42, and the fixing force between the second end plate 30 and the shaft 40 can be ensured by the second protrusion 34.

[0069] The present invention is not limited to the above-described embodiments and can be variously modified. For example, in the above-described embodiment, an example of the IPM type rotor 100 is given, but the present invention can be applied to various types of rotors such as SPM (Surface Permanent Magnet) type, intermediate pole type, and inserted type.

[0070] (Reference Signs)

[0071] 10 Rotor core; 10a, 10b End faces; 11 Electromagnetic steel sheet; 12 Through-hole; 13 Magnet insertion hole; 14 Permanent magnet; 20 First end plate; 20a Outer peripheral side end; 20b Inner peripheral side end; 21 First through-hole; 22 Flat plate portion; 23 Warped portion; 30 Second end plate; 30a Outer peripheral side end; 30b Inner peripheral side end; 31 Second through-hole; 32 Flat plate portion; 33 Warped portion; 34 Second protrusion; 40 Shaft; 41 Large diameter portion; 41a First press-fitting portion; 41b Second press-fitting portion; 42 First protrusion; 43 Concave portion; 50 Jig; 51 Flat surface portion; 51a Inner peripheral edge portion; 52 Hole portion; 53 Tapered surface; 54 Gap; 100, 200 Rotors; 201, 202 Gaps.

Claims

1. A rotor of a rotating electrical machine, comprising: a rotor core; a first end plate disposed at one end of the rotor core in the axial direction of the rotor core; a second end plate disposed at the other end of the rotor core in the axial direction of the rotor core; and a shaft extending axially through each of the rotor core, the first end plate, and the second end plate, wherein each of the first end plate and the second end plate has: an annular flat portion in contact with the rotor core; and a warped portion disposed on the inner circumferential side of the flat portion and in contact with the shaft, wherein the warped portion warps in a radial cross-section of the first end plate and the second end plate such that it moves away from the rotor core as it moves away from the flat portion, the shaft has a first press-fitting portion press-fitted into the first end plate and a second press-fitting portion press-fitted into the second end plate, wherein a plurality of first protrusions are formed on an outer circumferential surface of the first press-fitting portion, wherein a recess is formed between two adjacent first protrusions among the plurality of first protrusions, wherein each of the plurality of first protrusions extends along the axial direction, and each of the plurality of first protrusions does not reach an outer circumferential surface of the second press-fitting portion.

2. A method for manufacturing a rotor of a rotating electrical machine, comprising: a step of press-fitting a first press-fitting portion on one end side of the rotor core in a shaft on which the rotor core is mounted into a first through-hole of a flat first end plate supported by a jig, wherein the jig has: a flat portion for supporting the first end plate; a hole portion formed at a position surrounded by the flat portion, having a diameter larger than either the diameter of the first through-hole or the diameter of the first press-fitting portion, and extending in a direction perpendicular to the flat portion; and a tapered surface formed between an inner circumferential surface of the hole portion and the flat portion.

3. The method for manufacturing a rotor of a rotating electrical machine according to claim 2, characterized in that a first protrusion is formed on an outer circumferential surface of the first press-fitting portion, and a cross-section of the first through-hole is formed in a circular shape.

4. The method for manufacturing a rotor of a rotating electrical machine according to claim 2, characterized in that a cross-section of the first press-fitting portion is formed in a circular shape, and a second protrusion is formed on an inner circumferential surface of the first through-hole.

5. The method for manufacturing a rotor of a rotating electrical machine according to claim 2, characterized in that it further has a step of press-fitting a second press-fitting portion on the other end side of the rotor core in the shaft into a second through-hole of a flat second end plate supported by the jig, a first protrusion is formed on an outer circumferential surface of the first press-fitting portion, a cross-section of the first through-hole is formed in a circular shape, a cross-section of the second press-fitting portion is formed in a circular shape, and a second protrusion is formed on an inner circumferential surface of the second through-hole.

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