System and method for rotor sleeve mounting

Abstract

An assembly includes a rotor assembly having a rotor lamination stack with a rotor outer diameter and a rotor shaft extending along an axis of rotation of the rotor assembly. The mandrel includes a mandrel outer diameter extending between a proximal end and a distal end, and has a rotor engagement surface at the distal end of the mandrel. The mandrel outer diameter includes a first cylindrical portion adjacent the proximal end, a conical portion distal to the first cylindrical portion, and a first transition portion connecting the first cylindrical portion to the conical portion. The assembly also includes a sleeve having a sleeve inner diameter that is less than the rotor outer diameter when in the unexpanded state.

Description

Technical Field

[0001] The present disclosure relates to an electric machine, and more particularly to an electric machine including a rotor assembly having a press-fit sleeve. Background Art

[0002] Electric vehicles (EVs) such as battery electric vehicles (BEVs), hybrid vehicles, and / or fuel cell vehicles include one or more electric machines and battery systems. The battery system supplies power to one or more electric machines and receives power from one or more electric machines and / or utilities. The battery system includes one or more battery cells, modules, and / or battery packs. A power control system is used to control charging and / or discharging of the battery system during charging and / or driving.

[0003] An electric machine includes a rotor and a stator. During the manufacture of the electric machine, a reinforcing sleeve may be installed on the outer surface of the rotor to prevent the rotor assembly from expanding during operation. Summary of the Invention

[0004] Disclosed herein is an assembly. The assembly includes a rotor assembly having a rotor stack with a rotor outer diameter and a rotor shaft extending along a rotational axis of the rotor assembly. A mandrel includes a mandrel outer diameter extending between a proximal end and a distal end and has a rotor engagement surface at the distal end of the mandrel. The mandrel outer diameter includes a first cylindrical portion adjacent the proximal end, a conical portion distal to the first cylindrical portion, and a first transition portion connecting the first cylindrical portion to the conical portion. The assembly further includes a sleeve that has a sleeve inner diameter that is less than the rotor outer diameter when in an unexpanded state.

[0005] Another aspect of the present disclosure may be that an inner diameter of the mandrel engages an outer diameter of a bearing datum on the rotor assembly, and a fastener engages the bearing datum to fix the mandrel to the rotor assembly.

[0006] Another aspect of the present disclosure may be that the mandrel includes a second cylindrical portion distal to the conical portion, wherein the second cylindrical portion is connected to the conical portion by a second transition portion.

[0007] Another aspect of the present disclosure may be that at least one of the first transition portion or the second transition portion on the mandrel includes a radius of curvature.

[0008] Another aspect of the present disclosure may be that the radius of curvature is greater than twice the thickness of the sleeve divided by the maximum material strain of the sleeve material.

[0009] Another aspect of the present disclosure may include a polymer ring having a driver contact surface on a first axial face and a sleeve contact surface on a second axial face, the sleeve contact surface being configured to engage a proximal end of the sleeve.

[0010] Another aspect of the present disclosure may include a press having a sleeve driver with a body portion and a distal end, the body portion defining a central opening for surrounding a mandrel, the distal end having a ring engagement surface for engaging a driver contact surface on a polymer ring and a pressure relief hole extending through and defined by the body portion.

[0011] Another aspect of the present disclosure may include a fixed base having a cylindrical body defining a central opening for receiving a portion of a rotor shaft of a rotor assembly.

[0012] Another aspect of the present disclosure may include a flange located on an outer periphery of a distal end of a mandrel, wherein a radially inner side of the flange defines a portion of a circumferential channel recessed into the distal end of the mandrel.

[0013] Another aspect of the present disclosure may be that the rotor outer diameter and the mandrel outer diameter are each covered with a continuous material coating, and the continuous material coating includes a radially outer surface located radially outward from the rotor outer diameter and the mandrel outer diameter with respect to the axis of rotation.

[0014] Another aspect of the present disclosure may be that the distal end of the mandrel includes at least one protrusion configured to be received within a corresponding alignment opening defined by a portion of the rotor assembly.

[0015] A method of mounting a sleeve on a rotor assembly is disclosed herein. The method includes aligning a mandrel outer diameter of a mandrel with a rotor outer diameter of the rotor assembly. The mandrel outer diameter includes a first cylindrical portion adjacent a proximal end, a conical portion distal to the first cylindrical portion, and a first transition portion connecting the first cylindrical portion to the conical portion. The method further includes pressing the sleeve onto the mandrel outer diameter and onto the rotor assembly using a driver on a press, wherein the sleeve is configured to apply a compressive force to a portion of the rotor assembly surrounded by the sleeve.

[0016] Another aspect of the present disclosure may include positioning a polymer ring between a proximal end of the sleeve and a distal end of the driver.

[0017] Another aspect of the present disclosure may be that pressing the sleeve onto the mandrel outer diameter includes: expanding a radial dimension of the sleeve to align with a radial dimension of an outer surface of the rotor assembly.

[0018] Another aspect of the present disclosure may include attaching the mandrel to a bearing datum on a shaft of the rotor assembly to align the rotor outer diameter on the rotor lamination stack with the mandrel outer diameter. An inner diameter of the mandrel engages an outer diameter of the bearing datum on the rotor assembly.

[0019] Another aspect of the present disclosure may be that the mandrel includes a second cylindrical portion distal to the conical portion and connected to the conical portion by a second transition portion.

[0020] Another aspect of the present disclosure may be that the distal end of the mandrel includes a flexible flange around the outer periphery of the distal end, and the flexible flange deflects to align with the radially outer surface of the rotor assembly.

[0021] Another aspect of the present disclosure may include overmolding the mandrel and the rotor assembly with a polymeric coating of material and machining the polymeric layer across the mandrel and the rotor assembly to create a consistent transition for the sleeve in the radial direction between the mandrel and the rotor assembly.

[0022] Another aspect of the present disclosure may include applying a lubricant to the outer diameter of the mandrel and the outer diameter of the rotor and pressing the sleeve onto the mandrel and the rotor assembly at a speed equal to or greater than the hydrodynamic lubrication speed of the applied lubricant.

[0023] Disclosed herein is a press assembly for assembling a sleeve onto a rotor assembly. The press assembly includes a press having a drive and a fixture for supporting the rotor assembly. The rotor assembly includes a rotor stack having a rotor outer diameter and a rotor shaft extending along the axis of rotation of the rotor assembly. The press assembly further includes a mandrel having a mandrel outer diameter extending between a proximal end and a distal end and having a rotor engagement surface at the distal end of the mandrel. The mandrel outer diameter includes a first cylindrical portion adjacent the proximal end, a conical portion distal to the first cylindrical portion, and a first transition portion connecting the first cylindrical portion to the conical portion. When in an unexpanded state, the sleeve includes a sleeve inner diameter that is less than the rotor outer diameter.

[0024] The present invention provides the following technical solutions:

[0025] 1. An assembly, comprising:

[0026] A rotor assembly, the rotor assembly including a rotor stack having a rotor outer diameter and a rotor shaft extending along the axis of rotation of the rotor assembly;

[0027] A mandrel having a mandrel outer diameter extending between a proximal end and a distal end and having a rotor engagement surface at the distal end of the mandrel, wherein the mandrel outer diameter includes a first cylindrical portion adjacent the proximal end, a conical portion distal to the first cylindrical portion, and a first transition portion connecting the first cylindrical portion to the conical portion; and

[0028] A sleeve that, when in an unexpanded state, has a sleeve inner diameter that is less than the rotor outer diameter.

[0029] 2. The assembly according to aspect 1, wherein an inner diameter of the mandrel engages an outer diameter of a bearing datum on the rotor assembly, and a fastener engages the bearing datum to fix the mandrel to the rotor assembly.

[0030] 3. The component according to Solution 2, wherein the mandrel includes a second cylindrical portion distal to the conical portion, and the second cylindrical portion is connected to the conical portion through a second transition portion.

[0031] 4. The component according to Solution 3, wherein at least one of the first transition portion or the second transition portion on the mandrel includes a radius of curvature.

[0032] 5. The component according to Solution 4, wherein the radius of curvature is greater than twice the thickness of the sleeve divided by the maximum material strain of the material of the sleeve.

[0033] 6. The component according to Solution 1, including a polymer ring having a driver contact surface on a first axial face and a sleeve contact surface on a second axial face, and the sleeve contact surface is configured to engage the proximal end of the sleeve.

[0034] 7. The component according to Solution 6, including a press having a sleeve driver with a body portion and a distal end, the body portion defining a central opening for surrounding the mandrel, and the distal end having a ring engagement surface for engaging the driver contact surface on the polymer ring and a pressure relief hole extending through the body portion and defined by the body portion.

[0035] 8. The component according to Solution 1, including a fixed base having a cylindrical body defining a central opening for receiving a portion of the rotor shaft of the rotor assembly.

[0036] 9. The component according to Solution 1, including a flange on the outer periphery of the distal end of the mandrel, wherein the radially inner side of the flange defines a part of a circumferential channel recessed into the distal end of the mandrel.

[0037] 10. The component according to Solution 1, wherein the outer diameter of the rotor and the outer diameter of the mandrel are each covered with a continuous material coating, and the continuous material coating includes a radially outer surface located radially outward relative to the axis of rotation from the outer diameter of the rotor and the outer diameter of the mandrel.

[0038] 11. The component according to Solution 1, wherein the distal end of the mandrel includes at least one protrusion configured to be received within a corresponding alignment opening defined by a part of the rotor assembly.

[0039] 12. A method of installing a sleeve on a rotor assembly, the method comprising:

[0040] Align the mandrel outer diameter of the mandrel relative to the rotor outer diameter of the rotor assembly, the mandrel outer diameter including a first cylindrical portion adjacent the proximal end, a conical portion distal to the first cylindrical portion, and a first transition portion connecting the first cylindrical portion to the conical portion; and

[0041] Use a driver on a press to press a sleeve onto the mandrel outer diameter and onto the rotor assembly, wherein the sleeve is configured to apply a compressive force to a portion of the rotor assembly surrounded by the sleeve.

[0042] 13. The method according to claim 12, including positioning a polymer ring between the proximal end of the sleeve and the distal end of the driver.

[0043] 14. The method according to claim 12, wherein pressing the sleeve onto the mandrel outer diameter includes: expanding the radial dimension of the sleeve to align with the radial dimension of the outer surface of the rotor assembly.

[0044] 15. The method according to claim 12, including attaching the mandrel to a bearing datum on the shaft of the rotor assembly to align the rotor outer diameter on the rotor stack with the mandrel outer diameter, wherein the inner diameter of the mandrel engages the outer diameter of the bearing datum on the rotor assembly.

[0045] 16. The method according to claim 15, wherein the mandrel includes a second cylindrical portion distal to the conical portion and connected to the conical portion by a second transition portion.

[0046] 17. The method according to claim 12, wherein the distal end of the mandrel includes a flexible flange around the outer periphery of the distal end, the flexible flange deflecting to align with the radial outer surface of the rotor assembly.

[0047] 18. The method according to claim 12, including overmolding the mandrel and the rotor assembly with a polymer material layer, and machining the polymer material layer across the mandrel and the rotor assembly to create a consistent transition in the radial direction between the mandrel and the rotor assembly for the sleeve.

[0048] 19. The method according to claim 12, including applying a lubricant to the mandrel outer diameter and the rotor outer diameter, and pressing the sleeve onto the mandrel and the rotor assembly at a speed equal to or greater than the hydrodynamic lubrication speed of the applied lubricant.

[0049] 20. A press assembly for assembling a sleeve onto a rotor assembly, comprising:

[0050] A press having a driver;

[0051] A fixing device for supporting a rotor assembly, the rotor assembly including a rotor lamination stack having a rotor outer diameter and a rotor shaft extending along the axis of rotation of the rotor assembly;

[0052] A mandrel having a mandrel outer diameter extending between a proximal end and a distal end and having a rotor engagement surface at the distal end of the mandrel, the mandrel outer diameter including a first cylindrical portion adjacent the proximal end, a conical portion distal to the first cylindrical portion, and a first transition portion connecting the first cylindrical portion to the conical portion; and

[0053] When in an unexpanded state, the sleeve includes a sleeve inner diameter that is less than the rotor outer diameter. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 An example press assembly for assembling an example rotor assembly is shown.

[0055] Figure 2 Shows an enlarged view of a mandrel aligned with the Figure 1 rotor assembly.

[0056] Figure 3 Shows Figure 2 the mandrel of Figure 1 intersecting with the rotor assembly of

[0057] Figure 4 Shows an enlarged view of the intersection of another example mandrel and the Figure 1 rotor assembly.

[0058] Figure 5 Shows another example mandrel aligned with another example rotor assembly.

[0059] Figure 6 Shows a method of assembling a sleeve onto the Figure 1 rotor assembly or the Figure 5 rotor assembly.

[0060] The present disclosure may be modified or implemented in alternative forms, with representative embodiments shown in the drawings and described in detail below. The present disclosure is not limited to the disclosed embodiments. Instead, the present disclosure is intended to cover alternatives falling within the scope of the present disclosure as defined by the appended claims. DETAILED DESCRIPTION

[0061] Those of ordinary skill in the art will recognize that descriptive terms such as "above", "below", "upward", "downward", "top", "bottom", "left", "right", etc. used with respect to the figures do not represent a limitation on the scope of the present disclosure as defined by the appended claims. Additionally, the teachings herein may be described in terms of functional and / or logical block components and / or various processing steps. It should be recognized that such block components may include multiple hardware, software, and / or firmware components configured to perform the specified functions.

[0062] Reference is made to the accompanying drawings, in which like reference numerals refer to like parts throughout the several views, and in which like reference numerals refer to the same parts. Figure 1 A schematic illustration of a press assembly 20 for assembling a sleeve 50 onto a rotor assembly 40 by using a mandrel 46 is shown. In the illustrated example, the press assembly 20 includes an upper frame support 22 and a lower frame support 24. The upper frame support 22 at least partially supports a press arm 26, such as a servo press, and a sleeve driver 28 is attached to the distal end of the press arm 26 for moving the sleeve 50 relative to the rotor assembly 40.

[0063] In the illustrated example, the rotor assembly 40 includes a stack of laminations forming a rotor lamination stack 44 having a rotor outer diameter 56, and a rotor shaft 42 extends along the axis of rotation A ( Figure 2 ) of the rotor assembly 40. During assembly, the rotor assembly 40 is supported on a fixed base 32 disposed on top of the lower frame support 24. The fixed base 32 includes a cylindrical body having a central opening 34 for receiving a portion of the rotor assembly 40. In the illustrated example, the fixed base 32 receives a portion of the rotor shaft 42 within the central opening 34. The distal end of the fixed base 32 opposite the lower frame support 24 includes a protruding edge that engages the edge of the rotor lamination stack 44 to prevent longitudinal movement of the rotor assembly 40 relative to the axis of rotation A.

[0064] As Figure 1 and Figure 2 shown, the mandrel 46 is press-fitted onto the rotor assembly 40 and may be secured with or without fasteners 54 (such as bolts). In the illustrated example, the fasteners 54 threadedly engage a bearing datum 58 on one end of the rotor shaft 42, and the inner diameter 46D of the mandrel 46 engages the outer diameter of the bearing datum 58. One feature of this attachment arrangement is an improved alignment between the rotor outer diameter 56 on the rotor lamination stack 44 and the mandrel outer diameter 48 on the mandrel 46.

[0065] Additionally, a plurality of lifting screws 60 are located radially outward from the fasteners 54 and threadedly engage the mandrel 46 along the axis of the lifting screws 60. The lifting screws 60 assist in removing the mandrel by extending them to engage a portion of the rotor assembly 40 after the sleeve 50 has been installed.

[0066] The mandrel outer diameter 48 on the mandrel 46 extends between the proximal end 62 and the distal end 64 of the mandrel 46. The distal end 64 includes a rotor engagement surface that directly abuts a portion of the rotor assembly 40. As Figure 2 shown, the mandrel outer diameter 48 includes a first cylindrical portion 48A adjacent to the proximal end 62, a conical portion 48B distal to the first cylindrical portion 48A, and a second cylindrical portion 48C adjacent to the distal end 64. A first transition portion 48T connects the first cylindrical portion 48A to the conical portion 48B, and a second transition portion 48T connects the conical portion 48B to the second cylindrical portion 48C. The inner diameter of the sleeve 50 can have a sleeve inner diameter that is greater than or equal to the diameter of the first cylindrical portion 48A and less than the diameter of the conical portion 48B or the second cylindrical portion 48C. This allows the sleeve 50 to be easily placed on the proximal end 62 of the mandrel 46 during installation.

[0067] At least one of the first transition portion 48T or the second transition portion 48T in the mandrel 46 includes a radius of curvature that connects the first cylindrical portion 48A and the second cylindrical portion 48C to the conical portion 48B. One feature of the transition portion 48T is to prevent damage to the sleeve 50 when the sleeve 50 moves through portions of the mandrel 46 having different conical shapes during installation. In one example, the radius of curvature of the transition portion 48T is greater than or equal to twice the thickness of the sleeve 50 divided by the maximum material strain of the material of the sleeve 50.

[0068] As Figure 1 shown, a ring 52, such as a polymer ring made of nylon or torlon, is placed on the proximal end of the sleeve 50. The ring 52 includes a first axial face that defines a driver contact surface for engaging the distal end of the sleeve driver 28 and a second axial face that defines a sleeve contact surface for engaging the proximal end of the sleeve 50. One feature of the ring 52 is to reduce the lateral load on the sleeve 50 and apply pressure evenly to the sleeve 50 to reduce damage to the sleeve 50. Another feature of the ring 52 is that it expands with the sleeve 50 to allow an axial force to be applied to the sleeve 50 when the sleeve 50 expands. In particular, the sleeve 50 is configured to have significantly greater strength in the circumferential direction than in the longitudinal direction in order to apply compressive stress to the rotor stack 44 with less weight. In one example, the sleeve 50 is made of a carbon fiber material. Also, the distal end of the mandrel 46 and the proximal end of the rotor assembly 40 can have a chamfer or a radius of curvature along their outer diameters to facilitate the transition when the sleeve 50 passes between them, thereby preventing damage to the sleeve 50.

[0069] As Figure 1As shown, the pressing arm 26 includes a sleeve driver 28 at the distal end. The sleeve driver 28 has a body portion 29 for engaging the ring 52 and pressing the sleeve 50 onto the rotor assembly 40. The distal end 28D of the sleeve driver 28 defines a ring engagement surface surrounding an internal chamber 31 for receiving the mandrel 46 when pressing the sleeve 50 onto the mandrel 46 and onto the rotor assembly 40. The pressure relief hole 30 extends through a portion of the body portion 29 and is defined by a portion of the body portion 29 to relieve the pressure formed in the internal chamber 31.

[0070] As Figure 2 and Figure 3 As shown, a flange 66, such as a flexible flange, is located on the outer periphery of the distal end 64 of the mandrel 46. The radially inner side of the flange 66 defines a part of the circumferential channel 68 that is recessed into the distal end 64 of the mandrel 46. One feature of the flange 66 is that it can deflect radially inward relative to the longitudinal axis of the mandrel 46 to provide improved alignment between the mandrel 46 and the rotor assembly 40.

[0071] Due to manufacturing limitations, it may be difficult to machine and install the mandrel 46 such that there is a tolerance between the mandrel outer diameter 48 and the rotor outer diameter 56 that will not damage the sleeve 50 during installation. Since the circumferential strength of the sleeve 50 is much greater than the longitudinal strength of the sleeve 50, the sleeve 50 may be prone to failure during installation. The compressive force from the sleeve 50 can cause the flange 66 to deflect or bend radially inward during installation and align with the rotor outer diameter 56. Additionally, this allows the mandrel outer diameter 48 at the distal end 64 to be manufactured with a tolerance greater than the rotor outer diameter 56 to allow the flange 66 to accommodate diameter variations.

[0072] Figure 4 Another example mandrel 146 adjacent to the rotor assembly 40 is shown. The mandrel 146 is similar to the mandrel 46, except that the mandrel 146 does not include a flange 66 with an adjacent channel 68. Similar or identical components between the mandrel 46 and the mandrel 146 will include adding a leading "1".

[0073] In the example shown, both the mandrel outer diameter 148 of the mandrel 146 and the rotor outer diameter 56 of the rotor assembly 40 are covered with a continuous coating or layer of material 70. In one example, the material coating includes a polymeric material. The continuous coating of material 70 includes a radially outer surface that is radially outward of the rotor outer diameter 56 and the mandrel outer diameter 48 relative to the rotational axis A. The material coating 70 provides a continuous surface for the sleeve 50 to slide over. In one example, the material coating 70 can be machined after it has been applied to both the mandrel 146 and the rotor assembly 40. After the sleeve 50 has been installed, the mandrel 146 can be separated from the rotor assembly by rupturing the material coating 70. The material coating 70 can be removed from the mandrel 146 such that the mandrel 146 can be placed on another rotor assembly 40.

[0074] Figure 5 Another exemplary mandrel 246 and another exemplary rotor assembly 240 are shown. The mandrel 246 and the rotor assembly 240 are respectively similar to the mandrel 46 and the rotor assembly 40, except as described below or shown in the drawings. Similar or identical components between the mandrel 46 and the rotor assembly 40 and the mandrel 246 and the rotor assembly 240 will respectively include adding a leading "2".

[0075] The mandrel 246 includes a proximal end 262 and a distal end 264, and the distal end 264 is in abutting contact with the rotor stack 244 in the rotor assembly 240. The rotor assembly 240 includes a rotor shaft 242. The distal end 264 of the mandrel 246 includes at least one protrusion 265, such as a pin having a circular or oval cross-section, which mates with an alignment opening 245 or a groove in the rotor stack 244 in the rotor assembly 240. The interface between the at least one protrusion 265 and the alignment opening 245 provides improved alignment between the mandrel outer diameter 248 on the mandrel 246 and the radially outer surface 256 on the rotor stack 244 of the rotor assembly 240.

[0076] Figure 6 An exemplary method 300 for assembling the sleeve 50 onto the rotor assembly 40 is shown. The method 300 will also be applied to assembling the sleeve 50 onto the rotor assembly 240, with the differences described below. The method 300 begins at block 302, where one of the rotor assemblies 40 is placed into the fixed base 32. This allows the rotor assembly 40 to float laterally in the fixed base 32 to allow for improved alignment while pressing the sleeve 50, as further explained below.

[0077] At block 304, the mandrel 46 is aligned with the rotor assembly 40. The mandrel 46 is aligned with the rotor assembly 40 by aligning the mandrel outer diameter with the rotor outer diameter. This alignment can be performed by aligning the central longitudinal axis of the mandrel 46 with the rotational axis A of the rotor assembly 40. This ensures that the variation between the mandrel outer diameter and the rotor outer diameter is minimized to reduce damage to the sleeve 50 during installation. In the case of the rotor assembly 240 and the mandrel 246, the protrusion 265 on the mandrel 246 is placed into the alignment opening 245 on the rotor assembly 240.

[0078] The mandrel 46 can be attached to the rotor assembly 40 by a fastener 54 that engages a bearing datum 58 on the rotor assembly 40. Although Figure 1 、 2 the illustrated example in 5 shows two lifting screws 60, four or more lifting screws 60 can be circumferentially arranged around the bearing datum 58 and can be used to remove the mandrel 46 from the rotor assembly 40 after the sleeve has been installed.

[0079] In yet another example, the alignment of the mandrel 46 with the rotor assembly 40 includes overmolding the mandrel 46 and the rotor assembly 40 with a material coating 70. The material coating 70 can be machined to create a consistent transition for the sleeve 50 in the radial direction between the mandrel 46 and the rotor assembly 40.

[0080] At block 306, the sleeve 50 is placed around the proximal end of the mandrel 46. Since the mandrel 46 includes a first cylindrical portion 48A having a diameter less than or equal to the inner diameter of the sleeve 50, the sleeve 50 can be relatively easily placed on the mandrel 46 and the ring 52 can be placed on the sleeve 50.

[0081] At block 308, the sleeve 50 is pressed onto the mandrel 46 and onto the rotor assembly 40 using the sleeve driver 28 on the pressing arm 26. The sleeve driver 28 engages the ring 52 to provide uniform pressure to the sleeve 50 when pressed to reduce the likelihood of damage to the sleeve 50 during installation. Since the mandrel 46 includes a cylindrical portion and a conical portion, the sleeve 50 expands in radial dimension as it moves over the transition portion along the outer diameter of the conical portion. When the sleeve 50 is pressed onto the mandrel 46, pressurized air can accumulate within the internal chamber 31. The pressure can be released through the pressure relief holes 30 in the sleeve driver 28.

[0082] When the sleeve 50 is pressed onto the mandrel 46 and the rotor assembly 40, lubrication can be applied to at least one of the mandrel outer diameter 48 or the rotor outer diameter 56. As Figure 1 shown, the nozzles 80 can be used to apply the lubricant 82 to the outer diameters 48, 56. Although two nozzles 80 are shown in the example illustrated, additional nozzles 80 can be circumferentially positioned around the mandrel 46 and the rotor assembly 40 to provide additional lubrication when pressed. In another example, at least one of the rotor assembly 40 and the mandrel 46 includes internal channels 84 ( Figure 1 ) for dispensing the lubricant along the outer diameters 48, 56.

[0083] In addition, the sleeve 50 is pressed onto the mandrel 46 and the rotor assembly 40 at a speed sufficient to achieve a hydrodynamic lubrication speed in the lubricant 82. In one example, for a 30 MPa sleeve pressure, the speed is greater than 0.5 to 1 meter per second.

[0084] At block 310, the sleeve driver 28 is retracted from the mandrel 46 and the ring 52 is removed from its position surrounding the rotor assembly 40 and the mandrel 46. Then, at block 312, the mandrel 46 can be separated from the rotor assembly 40, leaving the sleeve 50 around the rotor outer diameter 56 and applying a compressive force to the rotor assembly 40.

[0085] The terms "a" and "an" do not denote a limitation of quantity, but rather denote the presence of at least one of the items recited. The term "or" means "and / or" unless the context clearly dictates otherwise. References throughout the specification to "one aspect" mean that a particular element (e.g., a feature, a structure, a step, or a representation) described in connection with that aspect is included in at least one aspect described herein and may or may not be present in other aspects. Additionally, it should be understood that the elements described may be combined in a suitable manner in the various aspects.

[0086] When an element such as a layer, a film, a region, or a substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements.

[0087] Unless otherwise specified herein, the test standards are the latest standards in effect as of the filing date of this application, or, if priority is claimed, the filing date of the earliest priority application in which the test standards appear.

[0088] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0089] Although the foregoing disclosure has been described with reference to exemplary embodiments, those of ordinary skill in the art will understand that various changes can be made and equivalents can be substituted for its elements without departing from its scope. Additionally, many modifications can be made to adapt a particular situation or material to the teachings of the disclosure without departing from its scope. Accordingly, it is intended that the disclosure not be limited to the particular embodiments disclosed, but include embodiments falling within its scope.

Claims

1. A component comprising: a rotor assembly including a rotor lamination stack having a rotor outer diameter and a rotor shaft extending along a rotational axis of the rotor assembly; a mandrel having a mandrel outer diameter extending between a proximal end and a distal end and having a rotor engagement surface at the distal end of the mandrel, wherein the mandrel outer diameter includes a first cylindrical portion adjacent the proximal end, a conical portion distal to the first cylindrical portion, and a first transition portion connecting the first cylindrical portion to the conical portion; and The sleeve, when in an unexpanded state, has an inner diameter of the sleeve that is smaller than an outer diameter of the rotor.

2. The assembly of claim 1 wherein an inner diameter of the spindle engages an outer diameter of a bearing datum on the rotor assembly and a fastener engages the bearing datum to secure the spindle to the rotor assembly.

3. The assembly of claim 2, wherein the mandrel includes a second cylindrical portion distal to the conical portion, the second cylindrical portion being connected to the conical portion by a second transition portion.

4. The assembly of claim 3, wherein at least one of the first transition portion or the second transition portion on the mandrel includes a radius of curvature.

5. The assembly of claim 4, wherein the radius of curvature is greater than the thickness of the sleeve divided by twice the maximum material strain of the material of the sleeve.

6. The assembly of claim 1, comprising a polymer ring having a driver contact surface on a first axial face and a sleeve contact surface on a second axial face, the sleeve contact surface configured to engage a proximal end of the sleeve.

7. The assembly of claim 6 comprising a press having a sleeve driver having a body portion defining a central opening for surrounding the mandrel and a distal end having a ring engaging surface for engaging a driver contact surface on the polymer ring and a pressure relief hole extending through the body portion and defined by the body portion.

8. The assembly of claim 1 including a stationary base having a cylindrical body defining a central opening for receiving a portion of a rotor shaft of the rotor assembly.

9. The assembly of claim 1, comprising a flange on an outer periphery of the distal end of the mandrel, wherein a radially inner side of the flange defines a portion of a circumferential channel recessed into the distal end of the mandrel.

10. The assembly of claim 1, wherein: The rotor outer diameter and the spindle outer diameter are each covered with a continuous coating of material, and the continuous coating of material includes a radially outer surface located radially outward from the rotor outer diameter and the spindle outer diameter relative to the axis of rotation.

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