Induction rotor assembly

Abstract

An induction rotor assembly includes a stack of laminations, a conductor bar, a first end ring, and a second end ring. The stack includes a body having a first end, an opposing second end, and a peripheral surface extending along a longitudinal axis from the first end to the second end. The conductor bar is disposed within a groove in the outer peripheral surface. Each conductor bar includes a first conductor end and a second conductor end that extend beyond an end of the stack. The first and second conductor ends of each conductor bar include serrated surfaces having serrations. The first end ring and the second end ring are interlocked with the serrated surface of the conductor end. The conductor bar extends between the first end ring and the second end ring.

Description

Technical Field

[0001] The present disclosure relates to induction rotor assemblies, and more particularly, to systems and methods of manufacturing cast induction rotor assemblies having conductor bars. Background Art

[0002] An induction motor generally comprises a stator and a rotor. The stator is stationary, while the rotor rotates and comprises conductor bars arranged around the rotor body. The rotor contains a series of conductor bars arranged in a circular pattern around the rotor. When current is applied to the stator, a magnetic field is generated that interacts with the rotor and the conductor bars. This interaction causes the rotor to rotate, which in turn generates mechanical energy. As the rotor rotates, centrifugal forces are exerted on the conductor bars within the rotor.

[0003] While the current induction rotor assembly achieves its intended purpose, a need remains for a system and method of manufacturing an induction rotor having conductor bars with a stronger mechanical connection to the rotor body and improved electrical connection between each conductor bar and the end rings of the rotor. Summary of the invention

[0004] According to several aspects of the present disclosure, an induction rotor assembly having a conductor bar with a serrated surface is provided. The induction rotor assembly includes a lamination stack, a plurality of conductor bars, a first end ring, and a second end ring. The lamination stack includes a body having a first end arranged along a longitudinal axis and an opposite second end. In addition, the body has an outer peripheral surface extending from the first end to the second end along the longitudinal axis. The outer peripheral surface has a plurality of grooves extending from the first end through the second end. Each conductor bar of the plurality of conductor bars is disposed in each groove. Each conductor bar of the plurality of conductor bars includes a first conductor end extending axially beyond the first end of the lamination stack, and the first conductor end of each conductor bar of the plurality of conductor bars includes a serrated surface having a plurality of serrations. Each conductor bar of the plurality of conductor bars includes a second conductor end extending axially beyond the second end of the lamination stack, and the second conductor end includes a serrated surface having a plurality of serrations. The first end ring has a plurality of serrated surfaces opposite to and matching the serrated surface of each first conductor end to interlock each conductor bar of the plurality of conductor bars to the first end ring. The second end ring has a plurality of serrated surfaces that oppose and cooperate with the serrated surfaces of each second conductor end to interlock each conductor bar of the plurality of conductor bars to the second end ring. The plurality of conductor bars extend between the first end ring and the second end ring.

[0005] According to another aspect of the present disclosure, the induction rotor assembly includes a plurality of laminated steel plates.

[0006] According to another aspect of the present disclosure, the inductive rotor assembly includes a plurality of conductor bars formed of at least one of copper or aluminum.

[0007] According to another aspect of the present disclosure, the induction rotor assembly includes a conductor bar having an interlocking feature disposed as a portion of at least one of the first conductor end or the second conductor end. The interlocking feature is configured to provide a mechanical bond to at least one of the first end ring or the second end ring.

[0008] According to another aspect of the present disclosure, the induction rotor assembly includes a first end ring and a second end ring, which are cast in place over a first conductor end and a second conductor end of each conductor bar of a plurality of conductor bars, respectively.

[0009] According to another aspect of the present disclosure, the induction rotor assembly includes a first end ring and a second end ring, the first end ring and the second end ring including and formed of aluminum.

[0010] According to another aspect of the present disclosure, the induction rotor assembly includes serrations on the serrated surface, the serrations on the serrated surface having a tooth depth between 0.1 mm and 0.5 mm.

[0011] According to another aspect of the present disclosure, the induction rotor assembly includes serrations on the serrated surface, the serrations on the serrated surface having a pitch between 0.5 mm and 1.5 mm.

[0012] According to another aspect of the present disclosure, the induction rotor assembly includes serrations on the serrated surface extending parallel to the longitudinal axis.

[0013] According to another aspect of the present disclosure, the induction rotor assembly includes serrations extending the entire longitudinal length of each of the plurality of conductor bars. At least two surfaces of each of the plurality of conductor bars include serrated surfaces.

[0014] According to another aspect of the present disclosure, the induction rotor assembly includes serrations on the serrated surface extending perpendicular to the longitudinal axis.

[0015] According to another aspect of the present disclosure, the induction rotor assembly has serrations with a series of repeating semicircular indentations.

[0016] According to another aspect of the present disclosure, a vehicle motor includes a stator and an induction rotor assembly. The induction rotor assembly includes a lamination stack, a plurality of conductor bars, a first end ring, and a second end ring. The lamination stack includes a body having a first end arranged along a longitudinal axis and an opposite second end. In addition, the body has an outer peripheral surface extending from the first end to the second end along the longitudinal axis. The outer peripheral surface has a plurality of grooves extending from the first end to the second end. Each of the plurality of conductor bars is disposed in each groove. Each of the plurality of conductor bars includes a first conductor end extending axially beyond the first end of the lamination stack and a second conductor end extending axially beyond the second end of the lamination stack. The first conductor end and the second conductor end of each of the plurality of conductor bars include a serrated surface having a plurality of serrations. The first end ring has a plurality of serrated surfaces opposite to and matching the serrated surface of each first conductor end to interlock each of the plurality of conductor bars to the first end ring. The second end ring has a plurality of serrated surfaces opposite to and matching the serrated surface of each second conductor end to interlock each of the plurality of conductor bars to the second end ring. The conductor bar extends between the first end ring and the second end ring.

[0017] According to another aspect of the present disclosure, a vehicle electric motor has an induction rotor assembly having a plurality of conductor bars formed of copper or aluminum.

[0018] According to another aspect of the present disclosure, a vehicle electric motor has an induction rotor assembly having an interlocking feature on at least one of a first conductor end or a second conductor end, wherein the interlocking feature is configured to provide a mechanical bond to at least one of a first end ring or a second end ring.

[0019] According to another aspect of the present disclosure, a method of manufacturing an induction rotor assembly is disclosed. The method includes forming a conductor bar to define a serrated surface having serrations on a first conductor end of each conductor bar in a plurality of conductor bars. The method includes laminating a plurality of steel sheets to form a lamination stack. The lamination stack includes a first end and an opposite second end axially spaced apart along a longitudinal axis. A plurality of grooves are disposed on an outer peripheral surface of the lamination stack. The plurality of grooves extend from the first end of the lamination stack to the second end. In addition, the method includes positioning the conductor bar in each groove such that the first conductor end extends beyond the first end of the lamination stack. In addition, the method includes casting a first end ring around each first conductor end and the serrated surface of the first conductor end, and casting a second end ring around each second conductor end and the serrated surface of the second conductor end of each conductor bar. The first end ring at least partially surrounds the first conductor end and the second conductor end of each conductor bar in the plurality of conductor bars and is electrically connected to the first conductor end and the second conductor end of each conductor bar in the plurality of conductor bars. The serrated surface provides a mechanical bond between the first end ring and the plurality of conductor bars.

[0020] According to another aspect of the present disclosure, the method includes placing a lamination stack having a plurality of conductor bars positioned therein into a mold. Then, molten material is injected into the mold and surrounds the serrations on the serrated surface of the first conductor end of each of the plurality of conductor bars.

[0021] According to another aspect of the present disclosure, the method includes positioning at least one conductor bar having an interlocking feature disposed as a portion of at least one of the first conductor end or the second conductor end. The interlocking feature is configured to provide a mechanical bond to at least one of the first end ring or the second end ring.

[0022] According to another aspect of the present disclosure, the method includes positioning at least one conductor bar having a plurality of teeth extending parallel to a longitudinal axis.

[0023] According to another aspect of the present disclosure, the method includes a first end ring having a plurality of serrated surfaces that are opposite and matched to the serrated surface of each first conductor end. The method also includes a second end ring having a plurality of serrated surfaces that are opposite and matched to the serrated surface of each second conductor end. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

[0025] Figure 1 is a perspective view showing a vehicle having an electric motor with an induction rotor assembly according to the present disclosure.

[0026] Figure 2 It is shown that according to the present disclosure Figure 1 A schematic exploded view of an induction rotor assembly is shown, wherein the induction rotor assembly includes a plurality of conductor bars.

[0027] Figure 3A is a side perspective view showing a conductor bar having a first conductor end with a serrated surface having teeth oriented perpendicular to the length of the conductor bar in accordance with the present disclosure.

[0028] Figure 3B is a side perspective view showing an alternative conductor bar having a first conductor end with a serrated surface having serrations oriented parallel to the length of the conductor bar in accordance with the present disclosure.

[0029] Figure 3C is a diagram depicting the sawtooth edges of a sawtooth surface according to the present disclosure. Figure 3B An enlarged cross-sectional view of line 3C-3C is shown.

[0030] Figure 4is a diagram depicting a conductor bar having a first serrated surface, a second serrated surface opposite the first serrated surface, and a fin according to the present disclosure. Figure 3B A cross-sectional top view along line 4-4 is shown.

[0031] Figure 5 is a partial cross-sectional view of an alternative conductor bar showing first and second serrated surfaces having teeth in a serrated configuration in accordance with the present disclosure.

[0032] Figure 6 According to the present disclosure Figure 2 A partial side perspective view of an induction rotor assembly is shown depicting a cross-sectional view of a cast-in-place first end ring about a first conductor end of a conductor bar, the first conductor end having a serrated surface with serrations.

[0033] Figure 7 It is shown that according to the present disclosure Figure 2 A flow chart of a method for manufacturing an induction rotor assembly having a conductor bar with a serrated surface is shown. DETAILED DESCRIPTION

[0034] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.

[0035] refer to Figure 1 , a vehicle 10 having a vehicle motor 12 or inverter according to the principles of the present disclosure is shown. The vehicle motor 12 provides power to the vehicle 10 and receives power from at least one battery (not shown). The vehicle motor 12 is shown with an exemplary vehicle 10, and the vehicle 10 is an electric vehicle or a hybrid vehicle having wheels 14 driven by the vehicle motor 12. The vehicle motor 12 includes an induction motor. Although the vehicle 10 is shown as a passenger road vehicle, it should be understood that the vehicle motor 12 can be used with various other types of vehicles. For example, the vehicle motor 12 can be used in a marine vehicle (such as a ship) or an aerial vehicle (such as a drone or a passenger plane). In addition, the vehicle motor 12 can be used as a stationary power source separate and independent from the vehicle.

[0036] Figure 1 1 is a cross-sectional view of the vehicle motor 12, showing the stator 16 and the induction rotor assembly 18. The stator 16 is a fixed part of the rotating system within the vehicle motor 12, and the stator 16 is formed of steel. Electric power is supplied to the stator 16 and is converted into a rotating magnetic field. The induction rotor assembly 18 rotates due to the rotating magnetic field and provides torque for powering the vehicle 10.

[0037] Figure 2A schematic exploded perspective view of the induction rotor assembly 18 is shown. The induction rotor assembly 18 includes a lamination stack 20, a plurality of conductor bars 22, a first end ring 24, and a second end ring 26.

[0038] The lamination stack 20 includes a body 28 having a first end 30 and an opposite second end 32 to define a longitudinal axis A. The body 28 is formed of a plurality of laminated steel sheets stacked in an axial direction. In one example, the body 28 is steel or a steel alloy. The body 28 has an outer peripheral surface 34 extending from the first end 30 to the second end 32 coaxially with the longitudinal axis A. Figure 2 As shown, the outer peripheral surface 34 has a plurality of longitudinal walls 36 that define a plurality of open longitudinal grooves 38 formed therethrough from the first end 30 to the second end 32. The longitudinal grooves 38 may extend along the length L of the lamination stack 20. L Slightly inclined relative to the longitudinal axis A. Alternatively, the longitudinal groove 38 may be parallel to the longitudinal axis A.

[0039] Still refer to Figure 2 Each of the plurality of conductor bars 22 is disposed in each of the longitudinal grooves 38. For convenience, Figure 2 One conductor bar 22 is shown removed to show one longitudinal groove 38 defined by the longitudinal wall 36. The conductor bar 22 carries an induction current in the induction rotor assembly 18, which interacts with the magnetic field generated by the stator 16 and generates torque. Each conductor bar of the plurality of conductor bars 22 has a first conductor end 40. The first conductor end 40 extends axially beyond the first end 30 of the lamination stack 20. Each conductor bar of the plurality of conductor bars 22 also has a second conductor end 42. The second conductor end 42 extends axially beyond the second end 32 of the lamination stack 20. Each conductor bar 22 has a conductor length L extending parallel to the longitudinal axis A. C The conductor bar 22 may be made of aluminum or copper.

[0040] Reference now Figure 3A , a side view of the conductor bar 22 is shown. The first end 30 and the second end 32 of the conductor bar 22 are shown as having a serrated surface 44 at the first conductor end 40 and the second conductor end 42, the serrated surface 44 having a plurality of serrations 46. The serrations 46 include parallel alternating valleys and ridges and / or grooves extending along the serrated surface 44. The spaced grooves of the serrations 46 extend perpendicular to the longitudinal axis B of the conductor bar 22. Optionally, the first end 30 and the second end 32 may include an interlocking feature 48. The interlocking feature 48 includes a hole or other opening at the first end 30 and / or the second end 32 that is stamped into the conductor bar 22 and extends through the conductor bar 22.

[0041] Figure 3B2 is an alternative conductor bar 22' having serrations 46' extending parallel to the longitudinal axis B'. It should be understood that the serrations 46, 46' may take other configurations and may be located at locations other than the first end 30, 30' and / or the second end 32, 32' on each conductor bar 22, 22'. For example, the serrations 46, 46' may be disposed at the first end 30, 30', the second end 32, 32', and may also extend parallel to the longitudinal axis B, B' for the entire length L of each conductor bar 22, 22'. C In another example, the serrations 46 may be oriented on the serration surface 44 at an angle (eg, 45°) to the longitudinal axis B, B′.

[0042] Figure 3C is along Figure 3B 3C-3C in FIG. 4 shows an enlarged cross-sectional view of the serrated surface 44 and the serrations 46. The serrations 46 are grooves spaced apart from each other. In this particular example, the serrations 46 have a pitch P of 1 mm and a groove depth D of 0.25 mm. It should be understood that the serrations 46 can have a variety of pitches (e.g., between 0.5 mm and 1.5 mm) and a variety of depths (e.g., between 0.1 mm and 0.5 mm).

[0043] refer to Figure 4 , showing the Figure 3B 4-4 of the conductor bar 22'. The conductor bar 22 includes a first side 50A having a first serrated surface 44A, a second side 50B having a second serrated surface 44B, a third side 50C, a fourth side 50D opposite to the third side 50C, and a fin 52. The first side 50A is opposite to the second side 50B. Figure 4 As shown, the plane P1 of the first side 50A may not be parallel to the center plane P extending from the third side 50C through the conductor bar 22 to the fourth side 50D. C and with the center plane P C The plane P2 of the second side 50B may not be parallel to the central plane P C and with the center plane P C The first and second sides 50A and 50B are not parallel, and the first and second sides 50A and 50B are not parallel, so that a greater number of conductor bars 22 can be arranged circumferentially around the body 28 of the lamination stack 20 in the longitudinal grooves 38 than conductor bars having parallel sides. However, it is also within the scope of the present disclosure to have conductor bars with first sides 50A that are parallel to the second sides 50B. The fins 52 are disposed on the third sides 50C of the conductor bars 22 and extend beyond the outer peripheral surface 34 of the body 28 of the lamination stack 20. In addition, Figure 4A second serrated surface 44B is shown having serrations 46 having a pitch P of between 1 mm and 1.2 mm and a depth of between 0.25 mm and 0.3 mm.

[0044] refer to Figure 5 , a partial cross-sectional top view shows a first side 50A and a second side 50B of a conductor bar 22 having a first serrated surface 44A and a second serrated surface 44B with serrated teeth 46. The serrated teeth 46 include a serrated or uneven profile, such as saw teeth. Figure 5 In the embodiment, the serrated teeth 46 include offset semicircles, but the serrated teeth 46 may include other configurations, such as a series of protruding points or toothed surfaces. In some cases, the conductor bar 22 may have a third side 50C having a third serrated surface 44C that is perpendicular to at least one of the first serrated surface 44A or the second serrated surface 44B. The third serrated surface 44C includes at least one serration 46C.

[0045] refer to Figure 6 And refer again Figure 2 , the first end ring 24 is adjacent to and fixed to each first conductor end 40 of each conductor bar 22 in the plurality of conductor bars 22 at the first end 30 of the lamination stack 20, and the first end ring 26 is adjacent to and fixed to each second conductor end 42 of each conductor bar 22 in the plurality of conductor bars 22 at the second end 32 of the lamination stack 20. The first end ring 24 at least partially surrounds the first end 30 and electrically couples the first end 30 to the conductor bar 22. The second end ring 26 at least partially surrounds the second end 32 and electrically couples the second end 32 to the conductor bar 22. The first end ring 24 and the second end ring 26 are preferably cast in place from aluminum or a cast aluminum alloy. However, it should be understood that the first end ring 24 and the second end ring 26 can be cast in place from other conductive materials.

[0046] The cast-in-place first end ring 24 includes a plurality of serrated surfaces 27 that oppose and cooperate with the serrated surface 44 of each first conductor end 40 to interlock each of the plurality of conductor bars 22 to the first end ring 24. Similarly, the cast-in-place second end ring 26 includes a plurality of serrated surfaces 27 that oppose and cooperate with the serrated surface 44 of each second conductor end 42 to interlock each of the plurality of conductor bars 22 to the second end ring 26. When the first end 30 and / or the second end 32 include the interlocking feature 48, the cast-in-place first end ring 24 and / or the second end ring 26 are also mechanically interlocked with the interlocking feature 48.

[0047] The serrations 46 of each serrated surface 44 allow the material of the cast-in-place first and second end rings 24, 26 to flow into the grooves 38 and mechanically interlock with the serrated surface 44, thereby improving the mechanical and electrical bonding between the conductor bar 22 and the first or second end ring 24, 26. As the material flows into the grooves 38, a plurality of serrated surfaces are formed in the first and second end rings 24, 26, which interlock with the serrated surfaces 44 on the first and second conductor ends 40, 42, respectively, to interlock each of the plurality of conductor bars 22 to the first and second end rings 24, 26. In addition, the serrations 46 improve wetting and intermetallic compound formation between each conductor bar 22 and the first or second end ring 24, 26. In addition, during the casting process, the serrations 46 increase the surface reaction area between the conductor bar 22 and the first or second end ring 24, 26.

[0048] Reference now Figure 7 , a flow chart of a method 100 for manufacturing an induction rotor assembly 18 according to the present disclosure is shown. The method begins at box 102 where a conductor bar 22 is formed. The conductor bar 22 is formed to include a length L greater than the lamination stack length L. L Long conductor length L C , so that the first conductor end 40 and the second conductor end 42 extend outwardly beyond the first end 30 and the second end 32 of the lamination stack 20, respectively. The conductor bar 22 is also formed to define a serrated surface 44 having serrations 46 on the first conductor end 40 and the second conductor end 42. The serrations 46 are formed in a variety of ways, including using a mold to produce a wavy profile on the first conductor end 40 and the second conductor end 42, using a water jet cutting process, or a mechanical polishing process. Before the first end ring 24 and the second end ring 26 are cast on the first conductor end 40 and the second conductor end 42 of each conductor bar 22, the conductor bar 22, particularly the serrations 46, are pre-formed.

[0049] The method then moves to box 104. Box 104 depicts laminating a plurality of steel sheets to define a lamination stack 20. The lamination stack 20 includes a first end 30 and a second end 32. The second end 32 is axially spaced from the first end 30 along the longitudinal axis A. The steel sheets are laminated together such that the grooves in each steel sheet cooperate to define a groove 38 extending along the longitudinal axis A. The grooves 38 are angularly spaced about the longitudinal axis A and are equidistant from the longitudinal axis A.

[0050] Next, block 106 depicts positioning one of the conductor bars 22 in each longitudinal groove 38. The conductor bars 22 are positioned such that the first and second conductor ends 40, 42 of each of the plurality of conductor bars 22 extend axially outwardly beyond the first and second ends 30, 32 of the lamination stack 20, respectively.

[0051] Then, block 108 depicts casting a first end ring around the first conductor end 40. The method 100 may also include casting a second end ring 26 around the second conductor end 42. Casting the first end ring 24 and the second end ring 26 may include placing the lamination stack 20 with the plurality of conductor bars 22 positioned therein into a mold. The mold defines the first end ring 24 and / or the second end ring 26 and may be any suitable shape and size for casting the first end ring 24 and / or the second end ring 26. The first end ring 24 is cast around the serrated surface 44 and the serrations of the first conductor end 40 on each conductor bar 22. The first end ring 24 is cast to at least partially surround the first conductor end 40 of each conductor bar 22 in the plurality of conductor bars 22 and electrically connect the first conductor end 40 of each conductor bar 22 to the first end ring 24. Additionally, the second end ring 26 is cast around the serrated surface 44 and the serrations of the second conductor end 42 on each conductor bar 22. The second end ring 26 is cast to at least partially surround the second conductor end 42 of each conductor bar 22 of the plurality of conductor bars 22 and electrically connect the second conductor end 42 of each conductor bar 22 to the second end ring 26. In addition, casting the first end ring 24 and the second end ring 26 includes injecting molten material into the mold and surrounding the serrations 46 in the serrated surface 44 of the first conductor end 40 and the second conductor end 42 of each conductor bar 22. The first end ring 24 and the second end ring 26 are preferably cast from aluminum or an aluminum alloy. It should be understood that the first end ring 24 and the second end ring 26 can be cast using some other conductive materials. Casting the first end ring 24 and / or the second end ring 26 includes flowing the molten material in and around the serrations 46 so that the molten material and, when solidified, mechanically interlock with the serrated surface 44 of the first conductor end 40 and the serrated surface 44 of the second conductor end 42 of each conductor bar 22. Casting processes that may be used to cast the first end ring 24 and the second end ring 26 include a high pressure die casting process, a low pressure die casting process, a sand casting process, or a squeeze casting process.

[0052] Casting the first and second end rings 24, 26 may also include compressing the molten material as it solidifies. Compressing the molten material as it solidifies during the casting process reduces the porosity of the finished cast-in-place product and improves the mechanical properties of the finished product.

[0053] The method 100 may further include vibrating each conductor bar 22 at an ultrasonic frequency for a predetermined period of time during the solidification of the molten material of the cast-in-place first end ring 24 and / or the second end ring 26. Preferably, the ultrasonic frequency is 20 kHz or higher. The conductor bar 22 may be vibrated for a period of less than 20 seconds. Vibrating the conductor bar 22 during the solidification of the molten material in the casting process may break up the aluminum oxide disposed on the outer surface of the first conductor end 40 and / or the second conductor end 42 of the conductor bar 22. Vibrating the conductor bar 22 also improves wettability between the molten material and the conductor bar 22.

[0054] The present disclosure has many advantages and benefits over the prior art induction rotor assemblies. For example, forming serrations 46 on the serrated surface 44 of the first conductor end 40 and / or the second conductor end 42 and casting the first end ring 24 and the second end ring 26 in situ around each first conductor end 40 and / or the second conductor end 40 facilitates improving the mechanical connection and structural integrity of the metallurgical joint between the conductor bar 22 and the first end ring 24 and the second end ring 26. In addition, including the serrations 46 improves wettability, removes melt-front surface oxides, improves intermetallic compound (IMC) formation, and increases the surface reaction area between the conductor bar 22 and the first end ring 24 and the second end ring 26. Using a conductor bar 22 with a serrated surface 44 having serrations 46 instead of a conventional conductor bar increases the mechanical and electrical connection and integrity of the induction rotor assembly while providing a lightweight induction rotor assembly.

[0055] This description is merely illustrative in nature and is in no way intended to limit the present disclosure, its application or use. The broad teachings of the present disclosure can be implemented in many forms. Therefore, although the present disclosure includes specific examples, the true scope of the present disclosure should not be so limited, as other modifications will become apparent after studying the drawings, description and appended claims.

Claims

1. An induction rotor assembly, comprising: a lamination stack, the lamination stack comprising a body having a first end disposed along a longitudinal axis and an opposite second end, wherein the body has an outer peripheral surface extending from the first end to the second end along the longitudinal axis, wherein the outer peripheral surface has a plurality of grooves extending from the first end to the second end; a plurality of conductor bars, wherein each conductor bar of the plurality of conductor bars is disposed within each of the grooves, and wherein each conductor bar of the plurality of conductor bars includes a first conductor end extending axially beyond the first end of the lamination stack and a second conductor end extending axially beyond the second end of the lamination stack, and wherein the first conductor end and the second conductor end of each conductor bar of the plurality of conductor bars include a serrated surface having a plurality of serrations; a first end ring having a plurality of serrated surfaces that oppose and cooperate with the serrated surface of each first conductor end to interlock each conductor bar of the plurality of conductor bars to the first end ring; and a second end ring having a plurality of serrated surfaces opposing and cooperating with the serrated surface of each second conductor end to interlock each of the plurality of conductor bars to the second end ring, and wherein the plurality of conductor bars extend between the first end ring and the second end ring.

2. The induction rotor assembly according to claim 1, wherein: The body includes a plurality of laminated steel sheets.

3. The induction rotor assembly according to claim 1, wherein: The plurality of conductor bars are formed of at least one of copper or aluminum.

4. The induction rotor assembly according to claim 1, wherein: At least one conductor bar of the plurality of conductor bars includes an interlocking feature disposed as a portion of at least one of the first conductor end or the second conductor end, wherein the interlocking feature is configured to provide a mechanical bond to at least one of the first end ring or the second end ring.

5. The induction rotor assembly according to claim 1, wherein: The first end ring and the second end ring are each cast in place over the first conductor end and the second conductor end of each conductor bar of the plurality of conductor bars, respectively.

6. The induction rotor assembly according to claim 5, wherein: The first end ring and the second end ring include and are formed of aluminum.

7. The induction rotor assembly according to claim 1, wherein: The tooth depth of each saw tooth on the serrated surface is between 0.1 mm and 0.5 mm.

8. The induction rotor assembly of claim 1, wherein: The pitch of the saw teeth on the serrated surface is between 0.5 mm and 1.5 mm.

9. The induction rotor assembly of claim 1, wherein: A plurality of teeth on the serrated surface extend parallel to the longitudinal axis.

10. The induction rotor assembly according to claim 9, wherein: The plurality of serrations extend an entire longitudinal length of each of the plurality of conductor bars, and at least two surfaces of each of the plurality of conductor bars include the serrated surfaces.

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