Rotor and method of manufacturing a rotor

Abstract

The present application relates to a rotor and a manufacturing method of the rotor. A first shaft member of a shaft body of the rotor has a first large-diameter portion arranged at a radially inner side of a rotor core, and a first small-diameter portion arranged at an axially one side of the rotor core. A driving force transmission portion for transmitting a driving force transmitted from the rotor core to a driving force transmission member is provided at the first small-diameter portion. A portion of the first shaft member at an axially other side is engaged with a second shaft member of the shaft body.

Description

Technical Field

[0001] This invention relates to rotors and methods for manufacturing rotors. Background Technology

[0002] Previously, rotors having a shaft body composed of multiple shaft components and methods for manufacturing such rotors were known. Such rotors and methods for manufacturing such rotors were disclosed, for example, in Patent No. 6162020.

[0003] Patent No. 6162020 discloses a motor shaft that forms a rotor together with a motor core. This motor shaft consists of a first component and a second component. The first component is fixed to the motor core. The first component includes a hollow portion and a solid portion. Furthermore, the end face of the hollow portion of the first component is in contact with the end face of the second component, and the end face of the hollow portion engages with the end face of the second component. Additionally, a spline groove is formed in the second component. Moreover, the driving force from the motor core is transmitted to the driving force transmission member via the first component, the engagement portion between the first and second components, and the second component.

[0004] Patent Document 1: Patent No. 6162020

[0005] However, in the aforementioned Patent No. 6162020, the driving force (torque) from the motor core is transmitted to the driving force transmission component via the first component, the joint between the first and second components, and the second component. Therefore, it is argued that stress concentration sometimes occurs at the joint because the driving force transmission path (torque transmission path) includes the joint. That is, it is argued that the shape becomes complex due to welding, etc., causing stress concentration at the joint where stress is more likely to concentrate. As a result, to ensure the mechanical strength of the joint (motor shaft), it is necessary to enlarge the first component, the second component, and the joint. Therefore, in the motor shaft (rotor) of the aforementioned Patent No. 6162020, there is a problem that the first component (first shaft component), the second component (second shaft component), and the joint between the first and second components become larger due to the joining of the first and second components. Furthermore, "enlargement" is described, for example, as including not only increasing the outer diameter but also increasing the thickness (thickening the wall). Summary of the Invention

[0006] The present invention was made to solve the problems mentioned above. One object of the present invention is to provide a rotor that can ensure the mechanical strength of the shaft and prevent the first shaft component, the second shaft component, and the joint from becoming too large when the first shaft component and the second shaft component are joined at the joint to form a shaft.

[0007] To achieve the above objectives, the rotor of the first aspect of the present invention comprises: a cylindrical rotor core having a first end face on one axial side and a second end face on the other axial side; and a shaft integrally rotating with the rotor core, the shaft comprising: a first shaft member having an integrally formed hollow first large-diameter portion disposed radially inside the rotor core and a first small-diameter portion disposed axially adjacent to the first end face of the rotor core and continuously formed with the first large-diameter portion; and a second shaft member having a second small-diameter portion disposed axially adjacent to the second end face of the rotor core, at least a partial outer diameter of the first small-diameter portion of the first shaft member and the second shaft... The outer diameter of at least a portion of the second minor diameter portion of each component is smaller than the inner diameter of the rotor core. The first major diameter portion of the first shaft component has a driving force transmission outer peripheral surface that abuts against the inner peripheral surface of the rotor core and is transmitted with driving force from the rotor core. A driving force transmission section is provided in the first minor diameter portion of the first shaft component for transmitting the driving force transmitted from the rotor core via the driving force transmission outer peripheral surface to the driving force transmission component. A joint portion for engaging with the second shaft component is provided on the axially opposite side of the first shaft component, and the joint portion is located on the axially opposite side of the end of the driving force transmission outer peripheral surface. Furthermore, in this application specification, "joining" refers to a broad concept that includes not only connections by welding and riveting, but also connections by thermal expansion fitting or cold contraction fitting.

[0008] In the rotor of the first aspect of the present invention, as described above, the shaft body is constructed including a first shaft member and a second shaft member, and a drive force transmission portion for transmitting driving force from the rotor core to a drive force transmission member is provided in the first minor diameter portion of the first shaft member. Furthermore, a joint portion for engaging with another shaft member is provided on the axially opposite side of the first shaft member, and the joint portion is located on the axially opposite side of the end on the axially opposite side of the drive force transmission outer peripheral surface. Therefore, the joint portion is provided on the second shaft member not along the drive force transmission path from the rotor core to the drive force transmission portion of the first shaft member, thus preventing stress concentration at the joint portion. Therefore, compared to the case where the joint portion is provided along the drive force transmission path, it is not necessary to increase the size of the first shaft member, the second shaft member, and the joint portion. As a result, even when the first shaft member and the second shaft member are joined at the joint portion to form the shaft body, the mechanical strength of the shaft body can be ensured, and the enlargement of the first shaft member, the second shaft member, and the joint portion can be prevented.

[0009] The rotor manufacturing method of the second aspect of the present invention comprises: a first shaft component preparation step, wherein a first shaft component of a shaft body is prepared, the first shaft component of the shaft body integrally having a hollow first large-diameter portion disposed radially inside a cylindrical rotor core and a first small-diameter portion disposed on an axial side closer to a first end face of the rotor core and continuously formed with the first large-diameter portion and having an outer diameter at least partially smaller than the inner diameter of the rotor core, the shaft body rotating integrally with the rotor core; and a second shaft component preparation step, wherein a second shaft component of the shaft body is prepared, the second shaft component having a second small-diameter portion disposed on an axial side closer to a first end face of the rotor core. The second end face of the second shaft member is located on the other side of the axial direction, and at least a portion of the outer diameter of the second minor diameter portion is smaller than the inner diameter of the rotor core. The driving force transmission part forming process is to form a driving force transmission part for transmitting the driving force from the rotor core to the driving force transmission member via the driving force transmission outer surface of the first major diameter portion that abuts against the inner circumferential surface of the rotor core in the first minor diameter portion of the first shaft member. The joining process is to join the portion of the first shaft member on the other side of the axial direction to the second shaft member by welding at the end on the other side of the axial direction of the driving force transmission outer circumferential surface of the first major diameter portion. The fixing process is to fix the shaft body on the rotor core.

[0010] In the rotor manufacturing method of the second aspect of the present invention, as described above, a method for forming a drive force transmission portion for transmitting drive force from the rotor core to a drive force transmission member is provided in a first minor diameter portion of the first shaft member, and a joining step is provided in which a portion of the first shaft member on the axially opposite side of the drive force transmission outer peripheral surface of the first major diameter portion is joined to a second shaft member. Thus, the joining portion is provided on the second shaft member not along the drive force transmission path from the rotor core to the drive force transmission portion of the first shaft member, thereby preventing stress concentration at the joining portion. Therefore, compared to the case where the joining portion is provided along the drive force transmission path, it is not necessary to enlarge the first shaft member, the second shaft member, and the joining portion. As a result, a rotor manufacturing method is provided that ensures the mechanical strength of the shaft and prevents the enlargement of the first shaft member, the second shaft member, and the joining portion when the first shaft member and the second shaft member are joined at the joining portion to form a shaft body.

[0011] Furthermore, since the first shaft component and the second shaft component are joined by welding, the number of rotor components can be reduced compared to the case where the first shaft component and the second shaft component are connected by fastening components or the like.

[0012] According to the present invention, as described above, when the first shaft component and the second shaft component are joined at the joint to form a shaft body, the mechanical strength of the shaft body can be ensured and the enlargement of the first shaft component, the second shaft component, and the joint can be prevented. Attached Figure Description

[0013] Figure 1 This is a top view of a rotor (rotary motor) according to one implementation method.

[0014] Figure 2 This is a cross-sectional view along the axial direction showing the structure of a rotor according to one embodiment.

[0015] Figure 3 This is a schematic diagram illustrating the spraying of cooling oil in one embodiment.

[0016] Figure 4 This is a diagram showing the rotor viewed axially to illustrate the structure of the joint in one embodiment.

[0017] Figure 5 This is a cross-sectional view of the rotor of a first variation of one embodiment.

[0018] Figure 6 This is a cross-sectional view of the rotor of a second variation of one embodiment.

[0019] Figure 7 This is a cross-sectional view of the rotor of a third variation of one embodiment.

[0020] Figure 8 This is a flowchart illustrating a method for manufacturing a rotor according to one embodiment. Detailed Implementation

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0022] [Overall structure of the rotor]

[0023] Reference Figures 1-4 The structure of the rotor 100 in this embodiment will be described. The rotor 100 and the stator 101 together constitute a rotary electric motor 102. Furthermore, between the rotary electric motor 102 and the load, the rotor 100 is connected to a drive force transmission member 103 provided on the drive force transmission path (transmission system) for transmitting drive force. The stator 101 includes a stator core 101a and a coil 101b. The stator core 101a has an annular shape. The coil 101b is disposed on the stator core 101a.

[0024] In this application specification, "axial" refers to the direction along the rotation axis C1 of the rotor 100 (Z1 direction or Z2 direction). "Circumferential" refers to the circumferential direction of the rotor 100 (A1 direction or A2 direction). "Radial" refers to the radial direction of the rotor 100. Furthermore, "inner radial side" refers to the R1 direction side in the figure. "Outer radial side" refers to the R2 direction side in the figure. "One side of the axial direction" refers to the Z1 direction side in the figure. "The other side of the axial direction" refers to the Z2 direction side in the figure.

[0025] like Figure 2 As shown, the rotor 100 includes a rotor core 1, a shaft 2, end plates 3a and 3b, bearing components 4a and 4b, a rotational position detection unit 5, and an oil supply unit 6 (see reference). Figure 3 Furthermore, bearing component 4a is an example of the "first bearing component" in the claims. Additionally, bearing component 4b is an example of the "second bearing component" in the claims.

[0026] (Structure of the rotor core)

[0027] like Figure 1 As shown, the rotor core 1 is formed in an annular (cylindrical) shape. Furthermore, the rotor core 1 is disposed radially inside the stator core 101a. Figure 2 As shown, the rotor core 1 is formed by stacking multiple electromagnetic steel plates 1a along the axial direction. Furthermore, a permanent magnet (not shown) is disposed inside the rotor core 1. The stacking length of the rotor core 1 is L1. The stacking length L1 is the distance between the Z-direction position P1 of the Z1-direction side end face 11 of the rotor core 1 and the Z-direction position P2 of the Z2-direction side end face 12 of the rotor core 1. End face 11 and end face 12 are examples of the "first end face" and "second end face" as described in the claims.

[0028] Furthermore, the rotor core 1 is configured to generate driving force (torque) by interacting with the magnetic field generated by the current flowing in the coil 101b of the stator 101. That is, the rotor core 1 generates rotational force.

[0029] (Structure of the shaft)

[0030] Shaft 2 is a component that rotates about the rotation axis C1. Specifically, shaft 2 is configured to rotate integrally with rotor core 1, end plates 3a and 3b, and rotation position detection unit 5 relative to stator 101. Shaft 2 is formed by joining one shaft component 20 and another shaft component 30 using a joint 40. That is, shaft 2 is formed from multiple components. Furthermore, one shaft component 20 and the other shaft component 30 are examples of the "first shaft component" and "second shaft component" of the claims, respectively.

[0031] <Structure of a shaft component>

[0032] like Figure 2 As shown, a shaft member 20 is configured to extend radially inward and axially towards one side of the rotor core 1. Specifically, a shaft member 20 (the large-diameter portion 22 described later) has a hollow shape. For example, a shaft member 20 is formed as a cylinder extending along the rotation axis C1. Furthermore, a shaft member 20 is made of, for example, carbon steel. Additionally, a shaft member 20 is configured to extend from a position closer to the axial center C2 of the rotor core 1 in the Z1 direction to a position closer to the Z1 direction of the rotor core 1. The axial length of a shaft member 20 is L2, which is greater than the length L1.

[0033] Furthermore, a shaft component 20 is fixed to the inner circumferential surface 13 of the rotor core 1. For example, with a shaft component 20 disposed on the inner circumferential surface 13 of the rotor core 1, the shaft component 20 is expanded in diameter, thereby reducing the gap between the shaft component 20 and the rotor core 1, resulting in a state where the shaft component 20 is embedded into the rotor core 1 (press-fit state). Specifically, with a shaft component 20 disposed on the inner circumferential surface 13 of the rotor core 1, a shaft component 20 is press-fitted to the inner circumferential surface 13 using a hydroforming method. Furthermore, "expansion in diameter" refers to the change in outer diameter due to radial expansion of the component.

[0034] Furthermore, a shaft component 20 includes a small-diameter portion 21 and a large-diameter portion 22 integrally (continuously) formed together. That is, the small-diameter portion 21 and the large-diameter portion 22 are continuously formed. The large-diameter portion 22 is disposed radially inside the rotor core 1. The small-diameter portion 21 is disposed on the axial side (Z1 direction side) of the end face 11 of the rotor core 1. Moreover, the inner diameter of the small-diameter portion 21 is d11, and the outer diameter of the small-diameter portion 21 is d12. In addition, the inner diameter d11 and the outer diameter d12 of the small-diameter portion 21 refer to the inner diameter and outer diameter of the portions of the inner circumferential surface 21a and the outer circumferential surface 21b of the small-diameter portion 21 that correspond to the axial position P3 where the bearing component 4a is disposed, respectively. In addition, the small-diameter portion 21 is an example of the "first small-diameter portion" in the claims. In addition, the large-diameter portion 22 is an example of the "first large-diameter portion" in the claims.

[0035] Furthermore, the inner diameter of the large-diameter portion 22 is d21, which is larger than the inner diameter d11 of the small-diameter portion 21. The outer diameter of the large-diameter portion 22 is d22, which is larger than the outer diameter d12 of the small-diameter portion 21. Moreover, the inner diameter d21 and outer diameter d22 of the large-diameter portion 22 refer to the inner and outer diameters of the portions of the inner circumferential surface 22a and outer circumferential surface 22b of the large-diameter portion 22 corresponding to the region from the axial position P1 to P2 where the rotor core 1 is disposed. Furthermore, the outer diameter d12 of the small-diameter portion 21 is smaller than the inner diameter d51 of the rotor core 1. Furthermore, the outer circumferential surface 22b is configured to abut against the inner circumferential surface 13 of the rotor core 1 and is transmitted the driving force from the rotor core 1. Furthermore, the outer circumferential surface 22b is an example of the "driving force transmission outer circumferential surface" in the claims.

[0036] In addition, the outer diameter of the front end portion 23 on the other side of the axial direction (Z2 direction side) of the large diameter portion 22 is d23.

[0037] In this embodiment, a drive force transmission section 21c is provided in the small-diameter portion 21 to transmit the driving force from the rotor core 1 via the outer peripheral surface 22b of the large-diameter portion 22 to the drive force transmission member 103. Specifically, the drive force transmission section 21c is configured as a spline (tooth or groove) formed on the inner peripheral surface 21a of the small-diameter portion 21. Furthermore, a shaft member 20 is configured such that, by rotating together with the drive force transmission member 103 in a state where the drive force transmission member 103 is inserted into the drive force transmission section 21c, the driving force from the rotor core 1 is transmitted to the drive force transmission member 103 (load side). In addition, a shaft member 20 is configured to transmit the rotational force from the drive force transmission member 103 to the rotor core 1 during energy regeneration from the load side.

[0038] The large-diameter portion 22 is integrally formed on the Z2 direction side of the small-diameter portion 21. Furthermore, a flange 22d is provided on the large-diameter portion 22. The flange 22d is formed to protrude radially outward from the outer peripheral surface 22b of the large-diameter portion 22. Moreover, the Z2 direction side surface of the flange 22d is axially opposed to the Z1 direction side surface of the end plate 3a.

[0039] Furthermore, a through hole 22e is provided in the large-diameter portion 22. The through hole 22e is disposed in a portion of a shaft member 20 that is closer to the rotor core 1 in the Z1 direction. Specifically, the through hole 22e is located at a position closer to the Z1 direction side of the end face 11 on the Z1 direction side of the rotor core 1. In addition, the through hole 22e is formed as a portion of a radially penetrating flange 22d.

[0040] like Figure 3As shown, the through hole 22e functions to allow the cooling oil E to flow radially. The cooling oil E is, for example, ATF (Automatic Transmission Fluid). Specifically, the cooling oil E is sprayed into the shaft 2 from the oil supply section 6 located inside the shaft 2. Furthermore, as the shaft 2 rotates, centrifugal force acts on the cooling oil E, causing a portion of the cooling oil E to be sprayed out from the through hole 31c (described later) of another shaft component 30. The sprayed cooling oil E reaches the portion of the stator 101 in the Z2 direction (the coil end of the coil 101b). Thus, the portion of the stator 101 in the Z2 direction is cooled by the cooling oil E. Furthermore, in Figure 3 The image shows the state of cooling oil E being sprayed onto the coil 101b on the right side of the paper, but as the rotor 100 rotates, cooling oil E is also sprayed onto the coil 101b on the left side of the paper.

[0041] Additionally, cooling oil E flows along the inner circumferential surface 22a of a shaft component 20, thereby cooling the rotor core 1. Furthermore, cooling oil E is ejected from a through hole 22e of a shaft component 20, and the ejected cooling oil E reaches the portion of the stator 101 in the Z1 direction (the coil end of the coil 101b). Thus, the portion of the stator 101 in the Z1 direction is cooled by cooling oil E.

[0042] In addition, the rotor core 1 is fixed to the outer peripheral surface 22b of the large-diameter portion 22. That is, when manufacturing the rotor 100, the large-diameter portion 22 of a shaft component 20 is expanded by hydroforming, thereby fixing the rotor core 1 and the shaft body 2 to each other.

[0043] Furthermore, in this embodiment, a joint portion 40 is provided on the Z2 direction side of the large diameter portion 22 to engage with another shaft component 30. Specifically, the joint portion 40 is provided on the Z2 direction side of the large diameter portion 22 at position P2, which is closer to the Z2 direction side than the end face 12 on the Z2 direction side of the rotor core 1. In addition, the joint portion 40 is located on the axial side of the end on the other side (Z2 direction side) of the outer peripheral surface 22b of the large diameter portion 22.

[0044] <Structure of another shaft component>

[0045] like Figure 2As shown, another shaft component 30 is formed independently of one shaft component 20 and is disposed on the Z2 direction side of the rotor core 1. Specifically, the other shaft component 30 (the minor diameter portion 31 and the major diameter portion 32 described later) is disposed on the Z2 direction side closer to the end face 12 (position P2) of the rotor core 1 than on the Z2 direction side. Furthermore, the other shaft component 30 is configured to extend further towards the Z2 direction side from a position closer to the Z2 direction side than the rotor core 1. The axial length of the other shaft component 30 is L3, which is smaller than length L1 and smaller than length L2.

[0046] Here, in this embodiment, the other shaft component 30 is made of a material with lower rigidity than the shaft component 20. For example, the other shaft component 30 is made of carbon steel in the same way as the shaft component 20, but the carbon content of the other shaft component 30 is less than that of the shaft component 20.

[0047] Additionally, another shaft component 30 has a hollow shape. Furthermore, the other shaft component 30 includes a small-diameter portion 31 and a large-diameter portion 32 integrally formed with each other. That is, the small-diameter portion 31 and the large-diameter portion 32 are continuously formed. The large-diameter portion 32 is disposed on the axial side (Z1 direction side) of the small-diameter portion 31. Moreover, the inner diameter of the small-diameter portion 31 is d31, and the outer diameter of the small-diameter portion 31 is d32. Furthermore, it is stated that the inner diameter d31 and outer diameter d32 of the small-diameter portion 31 refer to the inner diameter and outer diameter of the portions of the inner circumferential surface 31a and outer circumferential surface 31b of the small-diameter portion 31 corresponding to the axial position P4 where the bearing component 4b is disposed, respectively. Additionally, the small-diameter portion 31 is an example of the "second small-diameter portion" in the claims. Additionally, the large-diameter portion 32 is an example of the "second large-diameter portion" in the claims.

[0048] Furthermore, the inner diameter of the large-diameter portion 32 is d41, which is larger than the inner diameter d31 of the small-diameter portion 31. Additionally, the outer diameter of the large-diameter portion 32 is d42, which is larger than the outer diameter d32 of the small-diameter portion 31. Moreover, the inner diameter d41 of the large-diameter portion 32 refers to the inner diameter of the end (or near the end) on the Z1 direction side of the large-diameter portion 32. Additionally, it is described that the outer diameter d42 of the large-diameter portion 32 refers to the outer diameter of the portion of the large-diameter portion 22 corresponding to the axial position P5 where the joint 40 is provided (the front end portion 33 on the Z1 direction side of the large-diameter portion 32). The outer diameter d42 of the front end portion 33 on the axial side (Z1 direction side) of the large-diameter portion 32 is larger than the outer diameter d32 of the small-diameter portion 31, and smaller than the outer diameter d23 of the front end portion 23 on the other axial side (Z2 direction side) of the large-diameter portion 22. Furthermore, the outer diameter d32 of the small-diameter portion 31 is smaller than the inner diameter d51 of the rotor core 1.

[0049] In this embodiment, a through hole 31c is provided in the portion of another shaft component 30 that is closer to the rotor core 1 in the Z2 direction, i.e., the smaller diameter portion 31, to allow cooling oil E to flow radially. Specifically, the through hole 31c is formed on the Z2 direction side closer to the axial position P5 of the joint portion 40.

[0050] Furthermore, the outer peripheral surface 32a of the large-diameter portion 32 is radially opposed to the inner peripheral surface 22a of the large-diameter portion 22 of one shaft member 20. Additionally, at least a portion of the outer peripheral surface 32a and at least a portion of the inner peripheral surface 22a are joined (e.g., welded) at a joint 40. Furthermore, the inner peripheral surface 32b of the large-diameter portion 32 of another shaft member 30 is connected to the inner peripheral surface 22a of the large-diameter portion 22 of one shaft member 20, thus forming the shaft 2 such that cooling oil E flows from the side of the other shaft member 30 to the side of one shaft member 20.

[0051] <Structure of the joint>

[0052] like Figure 2 As shown, the joint 40 is formed by welding the inner peripheral surface 22a of one shaft member 20 to the outer peripheral surface 32a of another shaft member 30. Specifically, the outer peripheral surface 32a of the front end portion 33 on one axial side (Z1 direction side) of the large-diameter portion 32 is joined to the inner peripheral surface 22a of the front end portion 23 on the other axial side (Z2 direction side) of the large-diameter portion 22 by welding. More specifically, one shaft member 20 and another shaft member 30 are positioned at an axial position P5 that overlaps radially. For example... Figure 4 As shown, when viewed along the Z1 direction, the joints 40 are arranged intermittently in a circumferential pattern. For example, when viewed along the Z1 direction, multiple joints 40 are arranged at equal angular intervals. Furthermore, in Figure 4 The illustration of bearing component 4b is omitted.

[0053] Furthermore, the joint 40 is formed by heating a portion of one shaft component 20 and a portion of another shaft component 30 together, causing them to fuse and solidify. For example, the joint 40 can be formed by various welding methods such as laser welding, electron beam welding, arc welding, and resistance welding.

[0054] (Structure of the end plate)

[0055] like Figure 2 As shown, end plate 3a is disposed on the end face 11 of the rotor core 1 on one axial side (Z1 direction side). End plate 3b is disposed on the end face 12 of the rotor core 1 on the other axial side (Z2 direction side). That is, end plates 3a and 3b are configured to clamp the rotor core 1 from both axial sides. Furthermore, end plates 3a and 3b are respectively fixed to the shaft 2 (a shaft component 20). For example, end plates 3a and 3b are riveted to a shaft component 20.

[0056] Furthermore, the end plate 3b is located at a position different from the axial position P5 of the joint 40. Specifically, the end plate 3b is positioned closer to the Z2 direction side than the axial position P2 of the end face 11 on the Z2 direction side of the rotor core 1 and closer to the Z1 direction side than the axial position P5 of the joint 40.

[0057] (Structure of bearing components and rotational position detection unit)

[0058] like Figure 2 As shown, bearing component 4a and rotational position detection unit 5 are disposed on the small-diameter portion 21 of one shaft component 20. Bearing component 4b is disposed on the small-diameter portion 31 of another shaft component 30. Bearing components 4a and 4b are configured to support the shaft 2 so that it can rotate about the rotation axis C1. Bearing component 4a is disposed on the outer peripheral surface 21b of one shaft component 20, and is positioned at a location that at least partially overlaps with the driving force transmission unit 21c when viewed radially. Bearing component 4a is disposed at an axial position P3 on the outer peripheral surface 21b of the small-diameter portion 21. Bearing component 4b is formed in the small-diameter portion 31 on the Z2 direction side relative to the axial position P5 of the joint portion 40.

[0059] Furthermore, a rotational position detection unit 5 is provided on the outer peripheral surface 21b of the minor diameter portion 21, closer to the rotor core 1 (Z2 direction side) than the axial position P3. The rotational position detection unit 5 is disposed in a shaft member 20 at a position closer to the Z1 direction than the axial position P1 of the end face 11 of the rotor core 1. Specifically, the rotational position detection unit 5 is provided on the outer peripheral surface 21b of the shaft member 20, and is positioned to at least partially overlap with the driving force transmission unit 21c when viewed radially. Moreover, the rotational position detection unit 5 is configured to detect the rotational position of the rotor core 1.

[0060] The rotational position detection unit 5 is configured as a resolver, for example. Specifically, the rotational position detection unit 5 is fixed to the shaft 2 as the rotor of the resolver. Moreover, it is configured to transmit rotational position information (signals) from the stator of the resolver to the outside in accordance with the relative position of the stator of the resolver (not shown) arranged radially outside the rotor of the resolver.

[0061] <Rotor Manufacturing Method>

[0062] like Figure 8As shown, the manufacturing method of the rotor 100 includes a manufacturing step of the shaft body 2, which includes: a shaft component preparation step (S1) for preparing a shaft component 20; a shaft component preparation step (S2) for preparing another shaft component 30; a driving force transmission part forming step (S3) for forming a driving force transmission part 21c in the small diameter portion 21 of a shaft component 20; and a joining step (S4) for joining a portion of the shaft component 20 on the other axial side (Z2 direction side) to the other shaft component 30. Additionally, the manufacturing method of the rotor 100 includes a fixing step (S5) for fixing the shaft body 2 onto the rotor core 1. Furthermore, the shaft component preparation step and the other shaft component preparation step are examples of the "first shaft component preparation step" and "second shaft component preparation step" of the claims, respectively.

[0063] In the manufacturing process of shaft 2, for example, it is manufactured in the following order: one shaft component preparation process, another shaft component preparation process, a drive force transmission part forming process, and a joining process. However, the order of the processes is not limited to the above. For example, the drive force transmission part forming process may be performed before one shaft component preparation process and another shaft component preparation process, or it may be performed after the joining process. Furthermore, one shaft component preparation process may be performed after another shaft component preparation process, or it may be performed simultaneously with another shaft component preparation process.

[0064] Furthermore, the fixing process (S5) is performed after the manufacturing process (S1 to S4) of the shaft 2. For example, the shaft 2 is fixed to the rotor core 1 by hydroforming.

[0065] [Effects of this implementation method]

[0066] In this embodiment, the following effects can be achieved.

[0067] In this embodiment, as described above, the first major diameter portion (22) of the first shaft member (20) has a driving force transmission outer peripheral surface (22b) that abuts against the inner peripheral surface (13) of the rotor core (1) and transmits the driving force from the rotor core (1). Furthermore, a driving force transmission portion (21c) is provided on the first minor diameter portion (21) of the first shaft member (20) for transmitting the driving force transmitted from the rotor core (1) via the driving force transmission outer peripheral surface (22b) to the driving force transmission member (103). Additionally, a joint portion (40) is provided on the axially opposite side of the first shaft member (20) to engage with the second shaft member (30). Moreover, the joint portion (40) is located on the axially opposite side of the end of the first shaft member (20) from the end of the first shaft member (20) from the axially opposite side. Therefore, instead of providing the driving force transmission path from the rotor core (1) to the driving force transmission section (21c) of the first shaft member (20), the joint (40) is provided on the second shaft member (30), thus preventing stress concentration at the joint (40). Therefore, compared to providing the joint (40) on the driving force transmission path, it is not necessary to enlarge the first shaft member (20), the second shaft member (30), and the joint (40). As a result, even when the first shaft member (20) and the second shaft member (30) are joined at the joint (40) to form the shaft body (2), the mechanical strength of the shaft body (2) can be ensured, and the enlargement of the first shaft member (20), the second shaft member (30), and the joint (40) can be prevented.

[0068] Furthermore, in this embodiment, as described above, the joint (40) is positioned on the axial side opposite to the second end face (12) of the rotor core (1). With this configuration, the driving force from the rotor core (1) is transmitted not entirely to the second shaft member (30) where the joint (40) is located, but rather to the first shaft member (20) where the driving force transmission part (21c) is located. As a result, the transmission of driving force (torque) at the joint (40) is further prevented, thus ensuring the mechanical strength of the shaft (2) and further preventing the first shaft member (20), the second shaft member (30), and the joint (40) from becoming too large.

[0069] Furthermore, in this embodiment, as described above, a first bearing member (4a) supporting the first shaft member (20) is disposed on the first minor diameter portion (21) of the first shaft member (20). Moreover, a second bearing member (4b) supporting the second shaft member (30) is disposed on the second minor diameter portion (31) of the second shaft member (30). With this configuration, the first bearing member (4a) is disposed on the first minor diameter portion (21) and the second bearing member (4b) is disposed on the second minor diameter portion (31), thus eliminating the need to increase the diameters of both the first bearing member (4a) and the second bearing member (4b). As a result, it is possible to prevent the first bearing member (4a) and the second bearing member (4b) from becoming too large.

[0070] Furthermore, in this embodiment, as described above, the second shaft component (30) has a second major diameter portion (32), which is disposed on the axial side of the second minor diameter portion (31) and is continuously formed with the second minor diameter portion (31). Additionally, the outer diameter (d42) of the front end portion (33) on the axial side of the second major diameter portion (32) is larger than at least a portion of the outer diameter (d32) of the second minor diameter portion (31), and smaller than the outer diameter (d23) of the front end portion (23) on the other axial side of the first major diameter portion (22). Moreover, the outer peripheral surface (32a) of the front end portion (33) on the axial side of the second major diameter portion (32) is joined to the inner peripheral surface (22a) of the front end portion (23) on the other axial side of the first major diameter portion (22) by welding. Here, when welding the end face of the other side of the first shaft member (20) to the end face of one side of the second shaft member (30), and when the thickness of the hollow first shaft member (20) and the thickness of the hollow second shaft member (30) are relatively small, the welding depth is considered to be relatively small. In this case, the mechanical strength of the joint (40) is considered to be reduced. In contrast, as in the above embodiment, if the joint (40) is formed by welding the inner peripheral surface (22a) of the front end portion (23) of the first major diameter portion (22) of the first shaft member (20) to the outer peripheral surface (32a) of the front end portion (33) of the second major diameter portion (32) of the second shaft member (30), the direction of the welding depth becomes the direction along the axial direction of the first shaft member (20) and the second shaft member (30). Therefore, even when the thickness of the first shaft member (20) and the thickness of the second shaft member (30) are relatively small, the welding depth can be sufficiently ensured. As a result, the mechanical strength of the joint (40) can be sufficiently ensured. Moreover, unlike the case where the outer peripheral surface (22b) of the first shaft component (20) is welded to the inner peripheral surface (31a) of the second shaft component (30), mechanical interference between the second shaft component (30) and the rotor core (1) disposed radially outside the first shaft component (20) can be prevented.

[0071] Furthermore, in this embodiment, as described above, the manufacturing method of the rotor (100) includes a joining process in which a portion of the first shaft member (20) on the axially opposite side of the end of the outer peripheral surface (22b) that transmits the driving force of the first large-diameter portion (22) is joined to the second shaft member (30) by welding. Therefore, instead of providing the joint portion (40) along the driving force transmission path from the rotor core (1) to the driving force transmission section (21c) of the first shaft member (20), the joint portion (40) is provided on the second shaft member (30), thus preventing stress concentration at the joint portion (40). Therefore, compared to providing the joint portion (40) along the driving force transmission path, it is not necessary to increase the size of the first shaft member (20), the second shaft member (30), and the joint portion (40). As a result, a method for manufacturing a rotor (100) is provided that can ensure the mechanical strength of the shaft body (2) and prevent the first shaft part (20), the second shaft part (30) and the joint (40) from becoming too large when the first shaft part (20) and the second shaft part (30) are joined at the joint (40) to form the shaft body (2).

[0072] In addition, the first shaft component (20) and the second shaft component (30) are joined by welding, so the number of components of the rotor (100) can be reduced compared with the case where the first shaft component (20) and the second shaft component (30) are connected by fastening components or the like.

[0073] [Variation Example]

[0074] Furthermore, the embodiments disclosed herein are illustrative in all respects and should not be considered as limiting statements. The scope of the invention is not shown by the description of the above embodiments, but by the claims. In addition, the scope of the invention includes all variations (modifications) within the scope of the claims.

[0075] (First variation)

[0076] For example, in the above embodiment, an example is shown where only one shaft component 20 of the shaft body 2 is fixed to the inner circumferential surface 13 of the rotor core 1, but the present invention is not limited thereto. For example Figure 5 As with the rotor 200 of the first modified example shown, not only is a shaft member 220 fixed to the inner circumferential surface 213 of the rotor core 201, but another shaft member 230 is also fixed thereto. In this case, a portion of the other shaft member 230 is arranged to overlap with a portion of the rotor core 201 when viewed radially. Furthermore, one shaft member 220 and the other shaft member 230 are examples of the "first shaft member" and "second shaft member" of the claims, respectively.

[0077] Furthermore, in the above embodiment, an example is shown where the joint 40 is located closer to the Z2 direction side of the end face 12 on the Z2 direction side than the rotor core 1, but the present invention is not limited to this. For example Figure 5 As shown in the rotor 200 of the first modified example, the joint 240 is provided on the Z1 direction side of the end face 212 of the rotor core 201.

[0078] Furthermore, the above embodiment illustrates an example of engaging the inner peripheral surface 22a of one shaft component 20 with the outer peripheral surface 32a of another shaft component 30, but the present invention is not limited thereto. For example... Figure 5 As with the rotor 200 of the first modified example shown, the end face 220a of one shaft member 220 in the Z2 direction can also be engaged with the end face 230a of another shaft member 230 in the Z1 direction.

[0079] (Second variation)

[0080] Furthermore, the above embodiments illustrate an example of engaging the large-diameter portion 22 of one shaft component 20 with the large-diameter portion 32 of another shaft component 30, but the present invention is not limited thereto. For example... Figure 6 As with the rotor 300 in the second modified example shown, the minor diameter portion 322 on the Z2 direction side of one shaft member 320 may engage with the minor diameter portion 332 of another shaft member 330. Furthermore, one shaft member 320 and the other shaft member 330 are examples of the "first shaft member" and "second shaft member" of the claims, respectively.

[0081] Furthermore, in the above embodiment, an example is shown where a through hole 22e is provided in a portion of a shaft component 20 on the axial side (Z1 direction side) of the rotor core 1, and a through hole 31c is provided in a portion of another shaft component 30 on the axial side (Z2 direction side) of the rotor core 1; however, the present invention is not limited to this. For example... Figure 6 As with the rotor 300 of the second modified example shown, a through hole 22e may be provided in a portion of a shaft member 320 that is axially closer to the rotor core 1 (Z1 direction side), and a through hole 331c may be provided in a portion of a shaft member 320 that is axially closer to the rotor core 1 (Z2 direction side).

[0082] (Third variation)

[0083] For example, in the above embodiment, an example is shown in which the inner peripheral surface 22a of the front end portion 23 on the other axial side (Z2 direction side) of a shaft member 20 (first shaft member) engages with the outer peripheral surface 32a of the front end portion 33 on one axial side (Z1 direction side) of another shaft member 30 (second shaft member), but the present invention is not limited thereto.

[0084] For example, in Figure 7 In the rotor 400 of the third modified example shown, the front end portion 433 of the axial side (Z1 direction side) of the large diameter portion 432 of another shaft member 430 is joined to the front end portion 423 of the axial side (Z2 direction side) of the large diameter portion 422 of one shaft member 420 by welding. In this case, as Figure 7 As shown, the Z1 direction end face 433a of the front end portion 433 of the large diameter portion 432 engages with the Z2 direction end face 423a of the front end portion 423 of the large diameter portion 422. That is, the outer diameter d433 of the front end portion 433 on the axial side of the large diameter portion 432 is larger than the outer diameter d431 of the small diameter portion 431 of the other shaft member 430, and equal to the outer diameter d423 of the front end portion 423 on the other axial side of the large diameter portion 422. In addition, the engagement portion 440 is provided on the other axial side of the end face 412 on the other axial side of the rotor core 1. In addition, the engagement portion 440 is provided on the other axial side of the through hole 431c of the rotor core 1. Furthermore, one shaft member 420 and the other shaft member 430 are examples of the "first shaft member" and "second shaft member" of the claims, respectively. Furthermore, the major diameter portions 422 and 432 are examples of the "first major diameter portion" and "second major diameter portion" in the claims, respectively. Additionally, the minor diameter portion 431 is an example of the "second minor diameter portion" in the claims. Furthermore, the end face 412 is an example of the "second end face" in the claims.

[0085] As described above, the front end portion 433 of the large diameter portion 432 of another shaft member 430 is axially joined to the front end portion 423 of the large diameter portion 422 of a shaft member 420 by welding. This allows for a reduction in the outer diameter of the shaft 402 at the joint 440 compared to the case where one shaft member 420 and another shaft member 430 are radially adjacent and joined at the joint 440. As a result, the rotor 400 can be further miniaturized.

[0086] (Other variations)

[0087] Furthermore, in the above embodiment, an example of shaft 2 being composed of two components (one shaft component 20 and another shaft component 30) is shown, but the present invention is not limited to this. That is, the shaft may also be composed of three or more components. In this case, the component located on the axially closest side among the three or more components is fixed with a rotor core and is provided with a drive force transmission part.

[0088] Furthermore, in the above embodiment, an example is shown in which the shaft body 2 is constructed in such a way that one shaft component 20 and the other shaft component 30 each have a hollow shape, but the present invention is not limited thereto. For example, the shaft body 2 may also be constructed in such a way that one or both of the shaft component 20 and the other shaft component 30 have a solid shape.

[0089] Furthermore, while the above embodiments illustrate an example of forming a joint through welding, the present invention is not limited thereto. For example, a joint may also be formed by pressing one shaft component 20 to another shaft component 30 together through thermal expansion or cold contraction.

[0090] Furthermore, in the above embodiment, an example is shown where the driving force transmission part 21c is disposed on the inner peripheral surface 21a, but the present invention is not limited thereto. That is, the driving force transmission part 21c may also be disposed on the outer peripheral surface 21b. In this case, the driving force transmission part 21c is disposed at an axial position different from the axial position of the bearing component 4a and the rotational position detection part 5.

[0091] Furthermore, in the above embodiments, an example is shown where a small-diameter portion 21 and a large-diameter portion 22 are provided in a shaft component 20, but the present invention is not limited thereto. That is, the shaft can also be constructed in a manner where a shaft component has a constant inner diameter and outer diameter.

[0092] Furthermore, in the above embodiment, an example is shown where the rotational position detection unit 5 is located on the Z2 direction side relative to the bearing component 4a, but the present invention is not limited to this. That is, the rotational position detection unit 5 may also be located on the Z1 direction side relative to the bearing component 4a.

[0093] Furthermore, in the above embodiment, an example of fixing end plates 3a and 3b to the shaft 2 is shown, but the present invention is not limited thereto. For example, end plates 3a and 3b can also be fixed to the rotor core 1 by welding or riveting.

[0094] Furthermore, in the above embodiment, an example is shown where through holes 22e and 31c are provided in the shaft body 2, but the present invention is not limited thereto. For example, only one of the through holes 22e and 31c may be provided in the shaft body 2, or neither may be provided.

[0095] Furthermore, in the above embodiments, an example is shown where one shaft component 20 and the other shaft component 30 are made of carbon steel, but the present invention is not limited thereto. That is, at least one of the shaft component 20 and the other shaft component 30 may also be made of components other than carbon steel (e.g., stainless steel or aluminum).

[0096] Furthermore, in the above embodiments, an example was shown where another shaft component 30 was constructed from a material having a lower rigidity than that of one shaft component 20, but the present invention is not limited thereto. That is, another shaft component 30 may also be constructed from a material having a rigidity greater than that of one shaft component 20.

[0097] Furthermore, in the above embodiment, an example is shown where the joint 40 is formed intermittently at equal angular intervals when viewed along the Z1 direction, but the present invention is not limited to this. That is, the joint 40 may also be continuously formed into an arc shape when viewed along the Z1 direction.

[0098] Furthermore, in the above embodiment, an example was illustrated in which the axial position of the end plate 3b and the axial position of the joint 40 are different from each other, but the present invention is not limited to this. That is, the shaft may also be constructed in a manner in which the axial position of the end plate and the axial position of the joint are the same (overlapping when viewed radially).

[0099] Explanation of reference numerals in the attached figures:

[0100] 1, 201…Rotor core; 2, 402…Shaft; 4a…Bearing component (first bearing component); 4b…Bearing component (second bearing component); 5…Rotational position detection unit; 11…End face (first end face); 12, 412…End face (second end face); 13, 213…Inner circumferential surface (inner circumferential surface of rotor core); 20, 220, 320, 420…One shaft component (first shaft component); 21…Small diameter section (first small diameter section); 21a, 22a…Inner circumferential surface (inner circumferential surface of one shaft component); 21b…Outer circumferential surface (outer circumferential surface of the first shaft component); 21c…Drive force transmission unit; 22, 422…Large diameter section (first large diameter section); 22b…Outer circumferential surface (outer circumferential surface of drive force transmission); 22e, 31c…Through hole; 23…Front end section ( The front end of the first major diameter section); 30, 230, 330, 430… another shaft component (second shaft component); 31, 431… minor diameter section (second minor diameter section); 32, 432… major diameter section (second major diameter section); 32a… outer peripheral surface (outer peripheral surface of the other shaft component); 33… front end section (front end of the second major diameter section); 40, 240, 440… joint; 100, 200, 300, 400… rotor; 103… driving force transmission component; d12… outer diameter (outer diameter of the first minor diameter section); d23… outer diameter (outer diameter of the front end of the first major diameter section); d32… outer diameter (outer diameter of the second minor diameter section); d42… outer diameter (outer diameter of the front end of the second major diameter section); d51… inner diameter (inner diameter of the rotor core).

Claims

1. A rotor, wherein, have: A cylindrical rotor core having a first end face on one axial side and a second end face on the other axial side; and The shaft body rotates integrally with the rotor core. The shaft includes: a first shaft component integrally having a hollow first large-diameter portion disposed radially inside the rotor core and a first small-diameter portion disposed on an axial side closer to the first end face of the rotor core and continuously formed with the first large-diameter portion, the inner diameter of the first large-diameter portion being larger than the inner diameter of the first small-diameter portion; and a second shaft component having a hollow shape and having a second small-diameter portion disposed on the axial side closer to the second end face of the rotor core. The inner circumferential surface of the second shaft component is connected to the inner circumferential surface of the first shaft component, forming a shaft body such that cooling oil flows from the second shaft component side to the first shaft component side. At least a portion of the outer diameter of the first minor diameter portion of the first shaft component and at least a portion of the outer diameter of the second minor diameter portion of the second shaft component are each smaller than the inner diameter of the rotor core. The first major diameter portion of the first shaft component has a driving force transmitting outer peripheral surface, which abuts against the inner peripheral surface of the rotor core and is subjected to driving force from the rotor core. A driving force transmission part is provided in the first minor diameter portion of the first shaft component. The driving force transmission part is used to transmit the driving force transmitted from the rotor core through the driving force transmission outer peripheral surface to the driving force transmission component. A joint portion for engaging with the second shaft component is provided on the portion on the other side of the axial direction of the first shaft component. The joint is located on the opposite side of the axial direction of the end of the outer peripheral surface on which the driving force is transmitted.

2. The rotor according to claim 1, wherein, The joint is located on the opposite side of the axial direction than the second end face of the rotor core.

3. The rotor according to claim 1 or 2, wherein, A first bearing component supporting the first shaft component is disposed on the first minor diameter portion of the first shaft component. A second bearing component supporting the second shaft component is disposed on the second minor diameter portion of the second shaft component.

4. The rotor according to any one of claims 1 to 3, wherein, The second shaft component has a second major diameter portion, which is disposed on the axial side of the second minor diameter portion and is continuously formed with the second minor diameter portion. The outer diameter of the front end portion on the axial side of the second major diameter portion is larger than at least a portion of the outer diameter of the second minor diameter portion, and is equal to the outer diameter of the front end portion on the other axial side of the first major diameter portion. The front end portion of the second large diameter portion on one axial side is joined to the front end portion of the first large diameter portion on the other axial side by welding.

5. The rotor according to any one of claims 1 to 3, wherein, The second shaft component has a second major diameter portion, which is disposed on the axial side of the second minor diameter portion and is continuously formed with the second minor diameter portion. The outer diameter of the front end portion on the axial side of the second large-diameter portion is larger than at least a portion of the outer diameter of the second small-diameter portion, and smaller than the outer diameter of the front end portion on the other axial side of the first large-diameter portion. The outer peripheral surface of the front end portion on one axial side of the second large diameter portion is joined to the inner peripheral surface of the front end portion on the other axial side of the first large diameter portion by welding.

6. A method for manufacturing a rotor, wherein, have: The first shaft component preparation process involves preparing a first shaft component for the shaft body. The first shaft component integrally has a hollow first large-diameter portion disposed on the radially inner side of a cylindrical rotor core and a first small-diameter portion disposed on a first end face closer to the axial side of the rotor core and continuously formed with the first large-diameter portion, and at least partially having an outer diameter smaller than the inner diameter of the rotor core. The inner diameter of the first large-diameter portion is larger than the inner diameter of the first small-diameter portion. The shaft body rotates integrally with the rotor core. The second shaft component preparation process involves preparing a second shaft component for the shaft body. The second shaft component has a hollow shape and a second minor diameter portion. The second minor diameter portion is disposed on a second end face that is closer to the other side of the axial direction than the rotor core. At least a portion of the outer diameter of the second minor diameter portion is smaller than the inner diameter of the rotor core. The inner circumferential surface of the second shaft component is connected to the inner circumferential surface of the first shaft component, and the shaft body is formed in such a way that cooling oil flows from the second shaft component side to the first shaft component side. In the process of forming a drive force transmission part, a drive force transmission part for transmitting the drive force from the rotor core to the drive force transmission member via the drive force transmitted from the first large-diameter portion abutting the inner peripheral surface of the rotor core to the drive force transmission member is formed in the first small-diameter portion of the first shaft member. In the joining process, at the end of the driving force transmission outer peripheral surface that is larger than the first large diameter portion, on the other side of the axial direction, the portion of the first shaft component on the other side of the axial direction is joined to the second shaft component by welding. as well as The fixing process involves fixing the shaft onto the rotor core.

Images