Rotor end flange for an electric motor

Abstract

A rotor end flange for cooling coil conductors includes multiple magnetic poles, pole shoes, slots, an outer surface, an inner surface, multiple outlet holes, and multiple grooves. Adjacent magnetic poles and pole shoes define slots. The outer surface is located on the outer diameter in contact with the magnetic poles. Oil enters the inner surface through the multiple outlet holes, which are located radially inward of the inner surface. The inner surface has a radius of curvature (ROC). The ROC directs the oil along the inner surface to the multiple grooves. The multiple grooves are located on the outer surface and extend through the inner surface. The oil flows along the inner surface and is released from the rotor end flange through the multiple grooves, thereby coating and cooling the coil conductors.

Description

Technical Field

[0001] This disclosure relates to a rotor end flange for an electric motor. More specifically, this disclosure relates to a rotor end flange for a separately excited rotor in an electric motor to guide oil diffusion onto the coil windings, thereby cooling the coil windings. Background Technology

[0002] A separately excited synchronous motor (SESM) typically consists of a stator and a rotor. Instead of permanent magnets in the rotor, the SESM uses coil windings to generate the rotor's magnetic field. Therefore, the rotor's magnetic field can be adjusted by the level of current applied to the coil windings.

[0003] The rotor comprises a laminated iron core with magnetic poles and pole shoes defining slots. Coil windings are disposed within the slots and wound around the magnetic poles. As current is applied to the coil windings, the rotor begins to rotate at high speed. During rotation, the coil windings begin to heat up and face the risk of overheating. Overheating of the coil windings may impair their conductivity, causing the rotor to stop rotating.

[0004] One solution is to attach a rotor-end flange to the laminations. The rotor-end flange directs oil to the coil windings, thereby cooling them. The high rotor speed causes oil to pool at the corners of the rotor-end flange. Additionally, the high speed can cause oil to leave the rotor-end flange at a high axial velocity relative to the radial velocity, thus missing the coil windings. Therefore, there is a need in the art for an improved rotor-end flange design to achieve better oil diffusion and more uniform oil coverage across the entire coil winding. Summary of the Invention

[0005] According to several aspects, a rotor end flange for cooling coil conductors is provided. The rotor end flange defines a central axis of magnetic poles. The rotor end flange includes multiple magnetic poles. The multiple magnetic poles extend radially away from the axis of rotation. The rotor end flange also includes pole shoes. The pole shoes are located at the radially distal ends of the magnetic poles. The rotor end flange also includes slots. Adjacent magnetic poles and adjacent pole shoes define slots. The rotor end flange also includes an outer surface. The outer surface is located on the outer diameter of the rotor end flange. The outer diameter of the rotor end flange contacts the magnetic poles of the rotor. The rotor end flange also includes an inner surface. A portion of the inner surface is curved and has a radius of curvature (ROC). The ROC directs oil to multiple grooves. The rotor end flange also includes multiple outlet holes radially inward on the inner surface. Oil is released from the rotor into the rotor end flange through the multiple outlet holes. Multiple grooves are located on the outer surface and extend through the inner surface to allow oil to flow from the inner surface to the outer surface. The multiple grooves extend axially to allow oil to diffuse throughout the coil winding.

[0006] In another aspect of this disclosure, multiple outlet holes are aligned with the central axis of the magnetic poles.

[0007] In another aspect of this disclosure, the ROC of the inner surface increases from the central axis of the magnetic pole towards the front side. The ROC of the inner surface increases at different rates from the central axis of the magnetic pole towards the rear side. The front side is opposite to the rear side and is closer to the groove facing the direction of rotation. The rear side is closer to the groove opposite to the direction of rotation.

[0008] In another aspect of this disclosure, multiple outlet holes are located at a certain distance from the central axis of the magnetic poles.

[0009] In another aspect of this disclosure, the inner surface is curved, and the curve increases from the central axis of the magnetic pole towards the front side. The curve decreases from the central axis of the magnetic pole towards the rear side. The front side is opposite to the rear side and is closer to the slot facing the direction of rotation. The rear side is closer to the slot opposite to the direction of rotation.

[0010] In another aspect of this disclosure, the inner surface is curved, and the curve increases from the front to the rear. The front side is opposite to the rear side and closer to the groove facing the direction of rotation. The rear side is closer to the groove opposite to the direction of rotation.

[0011] In another aspect of this disclosure, the ROC of the inner surface begins from a plurality of outlet holes located on the front side and gradually decreases as it moves toward the rear side. The front side is opposite to the rear side and is closer to the groove facing the direction of rotation. The rear side is closer to the groove opposite to the direction of rotation.

[0012] In another aspect of this disclosure, the plurality of grooves also include a central groove. The central groove is aligned with the central axis of the magnetic pole.

[0013] In another aspect of this disclosure, the central groove is V-shaped. The width of the central groove increases as it moves radially outward toward the outer diameter of the rotor end flange.

[0014] In another aspect of this disclosure, the plurality of grooves also include an outlet hole groove. The outlet hole groove is aligned with the plurality of outlet holes.

[0015] In another aspect of this disclosure, the outlet hole groove is V-shaped. The width of the outlet hole groove increases as it moves radially outward toward the outer diameter of the rotor end flange.

[0016] In another aspect of this disclosure, the plurality of grooves also include corner grooves. The corner grooves are positioned at a distance from the central axis of the magnetic poles and between adjacent magnetic poles.

[0017] In another aspect of this disclosure, the plurality of grooves have an axial depth and the axial depths of the plurality of grooves are different.

[0018] In another aspect of this disclosure, the plurality of grooves have lengths and the lengths of the plurality of grooves are different.

[0019] In another aspect of this disclosure, the plurality of grooves also include an inner edge. The inner edge matches the profile of the coil winding.

[0020] In another aspect of this disclosure, the plurality of grooves also include an inner edge. The inner edge is perpendicular to the plurality of magnetic poles and proximates the coil winding.

[0021] In another aspect of this disclosure, a portion of the inner edge contacts the coil winding.

[0022] According to several aspects, a cooling system for cooling coil windings in a rotor is provided. The cooling system includes oil. The oil is injected into the center of the rotor. The cooling system also includes a rotor end flange. The rotor end flange defines a magnetic pole central axis. The rotor end flange includes a plurality of magnetic poles. The plurality of magnetic poles extend radially away from the rotation axis. The rotor end flange also includes pole shoes. The pole shoes are disposed at the radially distal ends of the magnetic poles. The rotor end flange also includes slots. Adjacent magnetic poles and adjacent pole shoes define slots. The rotor end flange also includes an outer surface. The outer surface is disposed on the outer diameter of the rotor end flange. The outer diameter of the rotor end flange contacts the magnetic poles of the rotor. The rotor end flange also includes an inner surface. A portion of the inner surface is curved and has a radius of curvature (ROC). The ROC directs the oil to a plurality of recesses. The rotor end flange also includes a plurality of outlet holes radially inward on the inner surface and positioned rearwardly at a distance from the magnetic pole central axis. The rearward side is adjacent to the slots opposite to the direction of rotation. Oil is released from the rotor into the rotor end flange through the plurality of outlet holes. The plurality of recesses are disposed on the outer surface and extend through the inner surface to allow oil to flow from the inner surface to the outer surface. Multiple grooves extend axially, allowing oil to diffuse throughout the coil winding. Oil is released from the rotor end flange through these grooves and diffuses throughout the coil winding.

[0023] In another aspect of this disclosure, the cooling system also includes external oil injectors. The external oil injectors release oil from the outside of the rotor and coat the coil windings with oil.

[0024] According to several aspects, a rotor end flange for cooling coil windings in a rotor is provided. The rotor end flange defines a magnetic pole central axis. The rotor end flange includes multiple magnetic poles. The multiple magnetic poles extend radially away from the rotation axis. The rotor end flange also includes pole shoes. The pole shoes are located at the radially distal ends of the magnetic poles. The rotor end flange also includes slots. Adjacent magnetic poles and adjacent pole shoes define slots. The rotor end flange also includes an outer surface. The outer surface is located on the outer diameter of the rotor end flange. The outer diameter of the rotor end flange contacts the magnetic poles of the rotor. The rotor end flange also includes an inner surface. A portion of the inner surface is curved and has a radius of curvature (ROC). The ROC directs oil to multiple grooves. The ROC of the inner surface increases from the magnetic pole central axis towards the front side. The ROC of the inner surface increases at different rates from the magnetic pole central axis towards the rear side. The front side is opposite to the rear side and closer to the groove facing the rotation direction. The rear side is closer to the groove opposite to the rotation direction. The rotor end flange also includes multiple outlet holes radially inward on the inner surface. Oil is released from the rotor into the rotor end flange through the multiple outlet holes. Multiple outlet holes are aligned with the central axis of the magnetic poles. Multiple grooves are formed on the outer surface and extend through the inner surface to allow oil to flow from the inner surface to the outer surface. Multiple grooves extend axially to allow oil to diffuse throughout the coil winding.

[0025] Further applicability will become apparent from the description provided herein. It should be understood that the specification and specific examples are for illustrative purposes only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0026] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of this disclosure in any way.

[0027] Figure 1 This is an isometric view of the rotor of a separately excited synchronous motor (SESM) with rotor end flanges according to an exemplary embodiment.

[0028] Figure 2 This is an isometric view of a rotor end flange according to an exemplary embodiment;

[0029] Figure 3 This is an enlarged view of the rotor end flange according to an exemplary embodiment;

[0030] Figure 4 This is a top view of a rotor end flange according to an exemplary embodiment;

[0031] Figure 5 This is a top view of a rotor end flange according to an exemplary embodiment;

[0032] Figure 6 This is a top view of a rotor end flange according to an exemplary embodiment;

[0033] Figure 7This is an enlarged view of an alternative embodiment of the rotor end flange according to an exemplary embodiment; and

[0034] Figure 8 This is a top view of an alternative embodiment of a rotor end flange according to an exemplary embodiment. Detailed Implementation

[0035] The following description is merely exemplary in nature and is not intended to limit this disclosure, its application, or its uses.

[0036] refer to Figure 1 The diagram illustrates a rotor end flange 10 and an exemplary rotor 12 according to the principles of this disclosure. The rotor 12 is part of a separately excited synchronous motor (SESM) (not shown). When current is applied to the rotor 12, the SESM converts electrical energy into mechanical energy. The rotor 12 includes a laminated iron core 14 and coil windings 16. The coil windings 16 are wires wound around the laminated iron core 14.

[0037] The laminated core 14 supports the coil winding 16 and is composed of multiple laminations 18. The laminations 18 are stacked together to form the laminated core 14. The laminated core 14 is connected to the output shaft 20 of the rotor 12. The output shaft 20 defines the rotation axis 22 of the rotor 12 about which the rotor 12 rotates.

[0038] refer to Figure 2 The rotor end flange 10 is shown. The rotor end flange 10 is attached to the laminated iron core 14. The rotor end flange 10 includes a plurality of magnetic poles 24 extending radially away from the axis of rotation 22. Each of the plurality of magnetic poles 24 has a curved exterior 26 and each includes a pole shoe 28. The pole shoe 28 is disposed at the radially distal end 30 of the plurality of magnetic poles 24 and extends circumferentially away from the plurality of magnetic poles 24. Adjacent magnetic poles 24 and adjacent pole shoes 28 define a groove 32 within the rotor end flange 10.

[0039] The rotor end flange 10 also includes a top 34 and a bottom 36. The top 34 is made of plastic, which electrically insulates the coil winding 16 and maintains the distance between the coil winding 16 and the bottom 36. The bottom 36 is made of steel.

[0040] The top 34 of the rotor end flange 10 includes a plurality of outlet holes 38, an inner surface 40, an outer surface 42, and a plurality of grooves 44. The plurality of outlet holes 38 are located radially inward of the inner surface 40. Oil is released through the plurality of outlet holes 38 and flows along the inner surface 40. The inner surface 40 is curved and has a radius of curvature (ROC), wherein the ROC and the curve of the inner surface guide the oil to the plurality of grooves 44, as will be described in more detail below. The plurality of grooves 44 are disposed on the edge 46 of the outer surface 42 and extend through the inner surface 40. The outer surface 42 is disposed on the outer diameter of the rotor end flange 10 and contacts a plurality of magnetic poles 24. Oil is released from the rotor end flange 10 through the plurality of grooves 44, coating the coil windings 16 (e.g., ...). Figure 1 (As shown).

[0041] refer to Figure 3 An enlarged view of the rotor end flange 10 is shown. A portion of the coil winding 16 is wound around multiple magnetic poles 24 and disposed within a slot 32 of the rotor end flange 10. When current is applied to the coil winding 16, the rotor 12 (as shown)... Figure 1 As shown, the rotor (e.g., the coil winding 16) begins to rotate at high speed, thus generating heat. To cool the coil winding 16 and prevent it from overheating, oil is supplied to the rotor (e.g., the rotor is rotating at high speed). Figure 1 (As shown). Oil exits the rotor 12 through the outlet hole 38 of the rotor end flange 10 at high speed. Multiple outlet holes 38 are arranged radially inside the inner surface 40 and positioned along the magnetic pole center axis 48.

[0042] Once the oil is released from the outlet port 38, it flows along the inner surface 40. The inner surface 40 is curved and has a ROC 41. The oil flows towards the location with the highest ROC 41. ROC 41 is defined as the radius from the rotation axis 22 to the inner surface 40. The direction and rate of oil flow vary depending on ROC 41. ROC 41 changes as it passes through the inner surface 40 of the rotor end flange 10. The ROC 41 of the inner surface 40 is lowest at the pole center axis 48. ROC 41 increases as it moves away from the pole center axis 48 towards the front 50 and towards the rear 52. ROC 41 increases at a different rate when moving towards the front 50 than when it increases towards the rear 52. The increase in ROC 41 away from the pole center axis 48 causes the inner surface 40 to guide the oil to the front 50 and rear 52 of the pole 24. The front side 50 is opposite to the rear side 52 and is close to the groove 32 facing the rotation direction 53. The rear side 52 is close to the groove 32 opposite to the rotation direction 53.

[0043] The curve of the inner surface 40 further guides the oil flow along the inner surface 40. This curve can gradually increase from the multiple outlet holes 38 located on the central axis 48 of the magnetic pole towards the front side 50. This directs the oil towards the front side 50. Alternatively, the curve of the inner surface 40 can increase from the multiple outlet holes 38 towards the rear side 52. This directs the oil towards the rear side 52.

[0044] As the oil flows along the inner surface 40, it exits the rotor end flange 10 to cover the coil winding 16 through a plurality of grooves 44. The plurality of grooves 44 are located on the outer surface 42 and extend through the inner surface 40 of the rotor end flange 10. The position of the plurality of grooves 44 along the outer surface 42 and the inner surface 40 determines the distance the oil must flow before being released from the rotor end flange 10 to coat the coil winding 16. The oil exits the plurality of grooves 44 at a certain velocity in the flow direction 57. The flow direction 57 is opposite to the rotation direction 53. For example, if the rotation direction 53 is counterclockwise, the flow direction 57 is clockwise. The shape and size of the plurality of grooves 44 can vary. One of the plurality of grooves 44 is a central groove 54. The central groove 54 is located along the central axis 48 of the magnetic pole. The central groove 54 is V-shaped, wherein the width of the central groove 54 increases as it moves radially outward toward the outer diameter of the rotor end flange 10. The plurality of grooves 44 also includes corner grooves 55. These corner grooves 55 are provided on the outer surface 42 and positioned between adjacent magnetic poles 24. Multiple grooves 44 may also have one or more sets of grooves at a certain distance from the central axis 48 of the magnetic poles.

[0045] refer to Figure 4 The image shows an enlarged top view of the rotor end flange 10. Multiple grooves 44 are provided on the outer surface 42 and extend to the inner surface 40. Some of the grooves 44 contact the coil winding 16. Corner grooves 55 do not contact the coil winding 16. The inner edges 56 of the grooves 44 that contact the coil winding 16 are curved to match the contour of the coil winding 16. The curved contour of the inner edges 56 allows the entire inner edge 56 to contact the coil winding 16. The contact between the inner edges 56 and the coil winding 16 allows oil to diffuse evenly and cover the coil winding 16. Furthermore, the curved inner edges 56 further allow oil to be released from the rotor end flange 10 without missing the coil winding 16.

[0046] refer to Figure 5An enlarged top view of the rotor end flange 10 is shown, in which alternative embodiments of the plurality of grooves 44 are indicated by reference numeral 100. The plurality of grooves 100 are provided on the outer surface 42. The plurality of grooves 100 include corner grooves 102 located between adjacent magnetic poles 24. The inner edges 108 of the plurality of grooves 100 (excluding the corner grooves 102) are curved to match the contour of the coil winding 16. The plurality of grooves 100 have different axial depths. For example, the plurality of grooves 100 may include a front groove 104 and a rear groove 106. The rear groove 106 has an inner edge 108 extending to and contacting the coil winding 16. The front groove 104 has an inner edge 108 that does not contact the coil winding 16. In other words, the rear groove 106 has a greater axial depth than the front groove 104. The different axial depths of the plurality of grooves 100 change the location of oil release. The axial depth of the plurality of grooves 100 can be varied depending on the rotation direction 53 of the rotor 12. For example, if the rotation direction 53 is counterclockwise, the axial depth of the plurality of grooves 100 near the front side 50 from the central axis 48 of the magnetic pole can be greater than the axial depth of the plurality of grooves 100 near the rear side 52 from the central axis 48 of the magnetic pole. This will guide oil to the front side 50. The axial depth of each of the plurality of grooves 100 can also be changed to optimize oil coverage at a given rotational speed.

[0047] refer to Figure 6 The figure shows an enlarged top view of the rotor end flange 10, wherein another alternative embodiment of the plurality of grooves 44 is indicated by reference numeral 200. The plurality of grooves 200 are disposed on the outer surface 42 of the rotor end flange 10. The plurality of grooves 200 includes corner grooves 202 located between adjacent magnetic poles 24. The inner edges 204 of the plurality of grooves 200 (excluding the corner grooves 202) are curved to match the profile of the coil winding 16. The inner edges 204 of the plurality of grooves 200 contact the coil winding 16. The plurality of grooves 200 have a length extending radially along the outer surface 42. The lengths of the plurality of grooves 200 may be different. For example, the plurality of grooves 200 may include a front groove 206 and a rear groove 208. The rear groove 208 has a length extending along the outer surface 42, and the front groove 206 has different lengths extending along the outer surface 42. The length of the rear groove 208 is greater than the different lengths of the front groove 206. The varying lengths of the plurality of grooves 200 change the amount of oil released from one of the grooves 200. For example, one of the plurality of grooves 200 with a longer length will allow more oil to be released from that one groove, thereby directing more oil flow in the direction of that one groove. The varying length also determines the distance the oil will flow before being released onto the coil winding 16. A longer length can be set closer to the plurality of outlet holes 38, resulting in a shorter distance the oil flows before being released onto the coil winding 16.

[0048] refer to Figure 7 An enlarged view of an alternative embodiment of the rotor end flange 300 is shown. The rotor end flange 300 is similar to the rotor end flange 10, and therefore the same parts are indicated by the same reference numerals. However, the rotor end flange 300 includes a portion located at the outlet port 38 ( Figure 3 Multiple outlet holes 302 at different locations. Additionally, the rotor end flange 300 includes a flange having a surface 40 (...). Figure 3 The inner surface 304 has a different profile. The rotor end flange 300 guides oil to cool the coil winding 16. The rotor end flange 300 includes multiple outlet holes 302, an inner surface 304, an outer surface 42, and multiple grooves 44.

[0049] Oil from rotor 12 (e.g.) Figure 1 (As shown) The material is released and enters the rotor end flange 300 through multiple outlet holes 302. The multiple outlet holes 302 are radially inward of the inner surface 304. The multiple outlet holes 302 are positioned at a certain distance from the magnetic pole center axis 48. One of the multiple outlet holes 302 may be positioned at the same distance as a different one of the multiple outlet holes 302, but in the opposite direction to the magnetic pole center axis 48. Additionally, one of the multiple outlet holes 302 may be positioned at a first distance from the magnetic pole center axis 48, and a different one of the multiple outlet holes 302 may be positioned at a second distance from the magnetic pole center axis 48. The first distance and the second distance are in opposite directions and are not equal.

[0050] By positioning the multiple outlet holes 302 at a distance from the magnetic pole center axis 48, oil is guided to coat the coil winding 16 where the multiple outlet holes 302 are located. For example, if one of the multiple outlet holes 302 is positioned at a distance from the magnetic pole center axis 48 towards the front 50, oil will be guided to cool the front 50 of the coil winding 16. Conversely, if one of the multiple outlet holes 302 is positioned at a distance from the magnetic pole center axis 48 towards the rear 52, oil is guided to cool the rear 52 of the coil winding 16. The front 50 is opposite to the rear 52 and closer to the slot 32 facing the rotation direction 53. The rear 52 is closer to the slot 32 opposite to the rotation direction 53.

[0051] Before the oil is coated on the coil winding 16, oil flows along the inner surface 304. The inner surface 304 has a radius of curvature (ROC) 306, which directs the oil to a plurality of grooves 44. The ROC 306 is defined as the radius from the axis of rotation 22 to the inner surface 304. The ROC 306 of the inner surface 304 increases as it moves away from the magnetic pole center axis 48 toward the front side 50 and as it moves toward the rear side 52. The oil flows toward the front side 50 and the rear side 52, where the ROC 306 is maximum. Alternatively, when the inner surface 40 also includes a lip 310, the front side 50 and / or the rear side 52 do not have the highest ROC 306.

[0052] The lip 310 is a radially inward extension of the inner surface 304. The lip 310 is located near and towards the front side 50 of the plurality of outlet holes 302. This further directs oil to the plurality of outlet holes 302 and the plurality of recesses 44. The lip 310 guides oil to be released from the rotor end flange 300 and coats the coil winding 16, which is wound around one of the plurality of magnetic poles 24 near the plurality of outlet holes 302.

[0053] The inner surface 304 can also be curved. The curve of the inner surface 304 further guides the oil to the plurality of grooves 44. This curve can begin from one of the plurality of outlet holes 302 located on the front side 50 and gradually decrease as it moves toward the rear side 52. This directs the oil toward the front side 50. The oil can also be directed toward the front side 50 by having a high curve in the front side 50 that gradually decreases toward the pole center axis 48 and reaches a point of no curvature. In other words, the curve of the inner surface 304 is flat at the pole center axis 48 and remains flat as it moves toward the rear side 52.

[0054] Multiple grooves 44 are provided on the edge 46 of the outer surface 42 and extend to the inner surface 304. As oil flows along the inner surface 304, it exits the rotor end flange 300 through the multiple grooves 44 and covers the coil winding 16. The oil is directed to the position at the highest ROC 306. One of the multiple grooves 44 is aligned with the highest ROC 306 of the inner surface 304. The oil exits the multiple grooves 44 at a certain speed in the flow direction 57. The flow direction 57 of the oil is opposite to the rotation direction 53. For example, if the rotation direction 53 is counterclockwise, the flow direction 57 is clockwise. The shape and size of the multiple grooves 44 can be different. The multiple grooves 44 include a central groove 54 and an outlet orifice groove 312.

[0055] The central groove 54 is disposed along the central axis 48 of the magnetic pole. The central groove 54 is V-shaped, wherein the width of the central groove 54 increases as it moves radially outward toward the outer diameter of the rotor end flange 300. The plurality of grooves 44 may also have one or more grooves disposed on the outer surface 42 of the rotor end flange 300 and at a certain distance from the central axis 48 of the magnetic pole.

[0056] An outlet recess 312 is provided on the outer surface 42 and extends to the inner surface 304. The outlet recess 312 is aligned with a plurality of outlet holes 302. The outlet recess 312 is V-shaped, wherein the width of the outlet recess 312 increases as it moves radially outward toward the outer diameter of the rotor end flange 300. The outlet recess 312 forms a direct path for releasing oil from the plurality of outlet holes 302 to the coil winding 16.

[0057] In addition to rotor 12 ( Figure 1In addition to the oil released internally (as shown), an external oil injector (not shown) can also diffuse oil across the entire coil winding 16. The external oil injector covers the front side 50 of the coil winding 16 with oil. When an external jet is present, the outlet orifice 302 is positioned a distance 52 rearward from the magnetic pole center axis 48. Oil released from the rotor end flange 300 is directed to the rear side 52 of the coil winding 16. This allows the oil to diffuse across the entire coil winding 16, thereby cooling the coil winding 16 and reducing its peak temperature.

[0058] refer to Figure 8 The image shows an enlarged top view of the rotor end flange 300. A plurality of grooves 44 are provided on the outer surface 42. The plurality of grooves 44 extend axially toward the coil winding 16 to form a depth. The plurality of grooves includes corner grooves 314. Each of the plurality of grooves 44 has an equal axial depth, excluding the corner grooves 314. The plurality of grooves 44 includes an inner edge 316 adjacent to the coil winding 16. The inner edge 316 is perpendicular to the plurality of magnetic poles 24. A portion of the inner edge 316 of the plurality of grooves 44, excluding the corner grooves 314, contacts the coil winding 16. The plurality of grooves 44 also includes a length extending radially along the outer surface 42. The length of each of the plurality of grooves 44 may be different.

[0059] The design of the rotor end flanges 10 and 300 disclosed herein offers several advantages. These include increased oil diffusion on the coil winding 16 and increased heat transfer coefficient (HTC). The increased HTC helps reduce the peak temperature of the coil winding 16. Furthermore, the arrangement of the multiple outlet holes 38 and 302, ROC 41 and 306, and the arrangement of the multiple grooves 44, 100, and 200 control the diffusion of oil to specific locations on the coil winding 16, thereby allowing for more uniform oil diffusion throughout the coil winding 16.

[0060] The description in this disclosure is merely exemplary in nature, and variations thereof without departing from the spirit and scope of this disclosure are intended to fall within its scope. Such variations should not be considered as departing from the spirit and scope of this disclosure.

Claims

1. A rotor end flange for cooling coil windings in a rotor, the rotor end flange defining a magnetic pole center axis and comprising: Multiple magnetic poles, wherein the multiple magnetic poles extend radially away from the axis of rotation; Pole shoe, wherein the pole shoe is disposed at the radial distal end of the magnetic pole; A slot, wherein adjacent magnetic poles and adjacent pole shoes define the slot; outer surface, The outer surface is disposed on the outer diameter of the rotor end flange, and The outer diameter of the rotor end flange is in contact with the magnetic pole of the rotor; An inner surface, wherein a portion of the inner surface is curved and has a radius of curvature (ROC), wherein the ROC guides oil into a plurality of grooves; as well as The inner surface has a plurality of radially inwardly oriented outlet holes through which oil is released from the rotor into the rotor end flange. The plurality of grooves are provided on the outer surface and extend through the inner surface to allow the oil to flow from the inner surface to the outer surface, and The plurality of grooves extend axially, allowing the oil to diffuse throughout the coil winding.

2. The rotor end flange according to claim 1, wherein, The plurality of outlet holes are aligned with the central axis of the magnetic pole.

3. The rotor end flange according to claim 2, wherein, The ROC of the inner surface increases from the central axis of the magnetic pole to the front side, wherein the ROC of the inner surface increases at a different rate from the central axis of the magnetic pole to the rear side, wherein the front side is opposite to the rear side and close to the groove facing the direction of rotation, and wherein the rear side is close to the groove opposite to the direction of rotation.

4. The rotor end flange according to claim 1, wherein, The plurality of outlet holes are at a certain distance from the central axis of the magnetic pole.

5. The rotor end flange according to claim 4, wherein, The inner surface is curved and the degree of curvature increases from the central axis of the magnetic pole to the front side, wherein the degree of curvature decreases from the central axis of the magnetic pole to the rear side, wherein the front side is opposite to the rear side and close to the groove facing the direction of rotation, and wherein the rear side is close to the groove opposite to the direction of rotation.

6. The rotor end flange according to claim 4, wherein, The inner surface is curved and the degree of curvature increases from the front side to the rear side, wherein the front side is opposite to the rear side and close to the groove facing the direction of rotation, and wherein the rear side is close to the groove opposite to the direction of rotation.

7. The rotor end flange according to claim 4, wherein, The ROC of the inner surface begins from the plurality of outlet holes located on the front side and gradually decreases as it moves toward the rear side, wherein the front side is opposite to the rear side and is close to the groove facing the direction of rotation, and wherein the rear side is close to the groove opposite to the direction of rotation.

8. The rotor end flange according to claim 1, wherein, The plurality of grooves also includes a central groove, wherein the central groove is aligned with the central axis of the magnetic pole.

9. The rotor end flange according to claim 8, wherein, The central groove is V-shaped, and the width of the central groove increases as it moves radially outward toward the outer diameter of the rotor end flange.

10. The rotor end flange according to claim 1, wherein, The plurality of grooves also include an outlet hole groove, wherein the outlet hole groove is aligned with the plurality of outlet holes.

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