Rotor with self-securing end plates

Abstract

The invention provides a rotor with a self-fixing end plate. A permanent magnet synchronous motor includes a rotor. The rotor is formed by sliding rotor plates and end plates onto a rotor shaft. At least one of the end plates is axially secured to the rotor shaft by rotating the at least one of the end plates such that a key engages a circumferential keyway in the shaft. An axial keyway allows the end plate to slide to the circumferential keyway. The axial keyways may also be used to rotationally secure the rotor plate to the shaft. The second end plate may be axially fixed in a similar manner, or may be axially fixed by a shoulder.

Description

Technical Field

[0001] This disclosure relates to electric motors. More specifically, this disclosure relates to a permanent magnet motor having at least one end plate fixed by a circumferential keyway. Background Technology

[0002] Many electrified vehicles utilize permanent magnet synchronous traction motors. One type of permanent magnet synchronous traction motor includes a rotor having multiple rotor plates fixed to a rotor shaft. The rotor plates are made of a magnetically conductive material and have recesses in which permanent magnets are mounted to establish an alternating pattern of north and south magnetic fields around a circumference. These magnetic fields interact with a magnetic field generated by current in the motor stator to produce torque on the rotor shaft. The rotor may also include end plates, which are not necessarily made of a magnetically conductive material. The end plates can be axially positioned by a combination of clasps and bolts extending through the rotor plates. Summary of the Invention

[0003] A rotor includes a shaft, a first end plate, and at least one rotor plate. The shaft defines a first circumferential keyway and a first axial keyway. The first axial keyway extends at least from a first step in the shaft to the first circumferential keyway. The first circumferential keyway may extend only partially around the shaft. The first circumferential keyway may define a notch in the shaft facing the first step. The first end plate has a first internal key located in the first circumferential keyway to prevent axial movement of the first end plate. The first internal key may be located in the notch. The rotor plate is rotatably fixed to the shaft on a side of the first end plate opposite to the step in the shaft. Each of the rotor plates may have a third internal key located in the first axial keyway. A second end plate having a second internal key may be located in a second circumferential keyway. The first end plate and the second end plate may be on opposite sides of the rotor plate. The first axial keyway may extend at least from a first step in the shaft to the second circumferential keyway. Alternatively, the shaft may define a second axial keyway extending at least from a second step in the shaft to the second circumferential keyway. In another alternative, the second end plate may be adjacent to the shoulder of the shaft. The end plate may be made of a different material than the rotor plate.

[0004] A method of assembling a rotor includes sliding a rotor plate and a first end plate onto a shaft. The shaft has a first axial keyway and a first circumferential keyway. The first end plate has a first key that slides within the first axial keyway. After sliding the first end plate onto the shaft, the first end plate is rotated such that the first key engages the first circumferential keyway. The rotor plate may also have a key that engages the first axial keyway. The method may further include sliding a second end plate onto the shaft. The second end plate may have a second key that slides within the first axial keyway. After sliding the second end plate onto the shaft, the second end plate is rotated such that the second key engages a second circumferential keyway in the shaft. The first end plate, the second end plate, and the rotor plate can all slide onto the shaft from a first end of the shaft. Alternatively, the first end plate and the second end plate can slide onto the shaft from opposite ends of the shaft. Alternatively, the second key can slide within a second axial keyway in the shaft. In yet another alternative, the second end plate may abut a shoulder in the shaft.

[0005] A motor includes a stator, a rotor shaft, a plurality of rotor plates, and a first end plate and a second end plate. The rotor shaft is supported for rotation relative to the stator. Each of the rotor plates has a permanent magnet. The rotor plates are fixed to the rotor shaft and axially compressed between the first end plate and the second end plate. The first end plate has a first key that engages a first circumferential keyway in the rotor shaft. The second end plate may abut a shoulder in the rotor shaft. The rotor shaft may define a second circumferential keyway. The second end plate may have a second key that engages a second axial keyway. The rotor shaft may define an axial keyway extending from a first step in the shaft, through the first circumferential keyway, and at least to the second circumferential keyway. Alternatively, the rotor shaft may define a first axial keyway extending from a first step in the shaft at least to the first circumferential keyway, and a second axial keyway extending from a second step in the shaft at least to the second circumferential keyway. Attached Figure Description

[0006] Figure 1 This is a block diagram of an electric vehicle.

[0007] Figure 2 This is a schematic cross-sectional view of an electric motor.

[0008] Figure 3 This is a three-dimensional view of the rotor of a permanent magnet electric motor.

[0009] Figure 4 It is suitable for Figure 3 A perspective view of the first rotor shaft used in the rotor.

[0010] Figure 5 yes Figure 4 A perspective view of a rotor shaft with two end plates.

[0011] Figure 6 yes Figure 4 The installation includes a three-dimensional view of a rotor shaft with an end plate and a rotor plate.

[0012] Figure 7 yes Figure 3 A cross-sectional view of the rotor.

[0013] Figure 8 It is suitable for Figure 3 A perspective view of the second rotor shaft used in the rotor.

[0014] Figure 9 It is suitable for Figure 3 A perspective view of the third rotor shaft used in the rotor. Detailed Implementation

[0015] Detailed embodiments of the invention are disclosed herein as needed; however, it should be understood that the disclosed embodiments are merely examples of the invention that can be embodied in various forms and alternative forms. The drawings are not necessarily drawn to scale; some features may be enlarged or minimized to show details of specific components. Therefore, the specific structural and functional details disclosed herein should not be construed as limiting, but only as representative bases for teaching those skilled in the art to utilize the invention in various forms.

[0016] Now for reference Figure 1 A block diagram of an exemplary electric vehicle (“EV”) 12 is shown. In this example, EV 12 is a plug-in hybrid electric vehicle (PHEV). EV 12 includes one or more motors 14 (“e-machines”) mechanically connected to a transmission 16. The motors 14 are capable of operating as both motors and generators. The transmission 16 is mechanically connected to an engine 18 and a drive shaft 20 mechanically connected to wheels 22. When the engine 18 is on or off, the motors 14 provide propulsion and deceleration capabilities. The motors 14 reduce vehicle emissions by allowing the engine 18 to operate at more efficient speeds and by allowing the EV 12 to operate in electric mode when the engine 18 is off under certain conditions.

[0017] Traction battery 24 (“battery”) stores energy that can be used by motor 14 to propel EV 12. Battery 24 typically provides a high-voltage (HV) direct current (DC) output. Battery 24 is electrically connected to power electronics module 26. Power electronics module 26 is electrically connected to motor 14 and provides the ability to transfer energy bidirectionally between battery 24 and motor. For example, battery 24 may provide DC voltage, while motor 14 may require three-phase alternating current (AC) voltage to operate. Power electronics module 26 can convert DC voltage to three-phase AC voltage to operate motor 14. In regenerative mode, power electronics module 26 can convert three-phase AC voltage from motor 14, which acts as a generator, to DC voltage compatible with battery 24.

[0018] Battery 24 can be recharged by an external power source 36 (e.g., the power grid). An Electric Vehicle Power Supply Equipment (EVSE) 38 is connected to the external power source 36. EVSE 38 provides circuitry and controls to manage the energy transfer between the external power source 36 and EV 12. The external power source 36 can supply DC or AC power to EVSE 38. EVSE 38 may have a charging connector 40 for insertion into a charging port 34 of EV 12. Charging port 34 can be any type of port configured to transfer power from EVSE 38 to EV 12. EV 12's power conversion module 32 can regulate the power supplied from EVSE 38 to provide appropriate voltage and current levels to battery 24. Power conversion module 32 can interface with EVSE 38 to coordinate power delivery to battery 24. Alternatively, various components described as electrically connected may use wireless inductive coupling to transfer power.

[0019] The various components discussed may have one or more associated controllers to control and monitor the operation of the components. The controllers may be microprocessor-based devices. The controllers may communicate via a serial bus (e.g., a Controller Area Network (CAN)) or via discrete conductors. For example, there is a system controller 48 (i.e., a vehicle controller) to coordinate the operation of the various components.

[0020] As described, EV 12 in this example is a PHEV with an engine 18 and a battery 24. In other embodiments, EV 12 is a battery electric vehicle (BEV). In a BEV configuration, EV 12 does not include an engine.

[0021] Figure 2An electric motor is shown. A stator 52 is fixed to the vehicle structure. A set of electrical windings is mounted on the stator 52 to generate a magnetic field by adjusting the current level in the wires. A rotor shaft 54 ​​is supported to rotate relative to the stator and adapted for rotatable connection to powertrain components. A set of rotor plates 56 are rotatably coupled to the rotor shaft 54. End plates 58 may be attached to the rotor shaft at each axial end of the set of rotor plates. The end plates may be made of a different material than the rotor plates. Each rotor plate has a set of permanent magnets mounted with alternating polarities. The magnetic field of the permanent magnets interacts with the magnetic field generated by the stator windings to produce torque, which is transmitted to the rotor shaft.

[0022] Figure 3 yes Figure 2 A perspective view of the rotor assembly of the motor. In this example, there are two rotor plates 56A and 56B between the left end plate 58A and the right end plate 58B. The rotor plates are made of a magnetically conductive material and hold a set of permanent magnets in a defined pattern to generate a series of alternating north and south magnetic poles around their perimeter. The end plates 58A and 58B may be made of a different material than the rotor plates (such as aluminum).

[0023] Figure 4 This is a perspective view of a rotor shaft 54 ​​according to a first embodiment. The rotor shaft 54 ​​defines an axial keyway 60. A keyway is a groove designed to engage with a key on a mating component to prevent relative movement of the mating components. The axial keyway extends parallel to the axis of the shaft. The interaction between the key and the axial keyway prevents rotation relative to the shaft. The axial keyway 60 extends between a left step 62A and a right step 62B in the shaft. A step in the shaft is the axial location where the shaft diameter changes. (The ends of the shaft are steps, but the shaft may also have other steps.) When the mating component slides over a step, the key can begin to engage the keyway that begins at that step. The rotor shaft 54 ​​also defines two circumferential keyways 64A and 64B. The circumferential keyways extend along an arc substantially perpendicular to the axis of the shaft. The circumferential keyways 64A and 64B intersect the axial keyway 60. In the illustrated embodiment, the circumferential keyways extend approximately 90 degrees around the shaft, but this may differ in other embodiments. The circumferential keyway 66A has a notch 68A at which the circumferential keyway is slightly wider in the direction toward the left end of the shaft. Similarly, the circumferential keyway 66B has a notch 66B at which the circumferential keyway is slightly wider in the direction toward the right end of the shaft.

[0024] Figure 5This is a perspective view of the rotor shaft 54 ​​with end plates 58A and 58B in place. Rotor plates 56A and 56B are not shown, so the connection between the shaft and the end plates is visible. End plate 58A has an inner key 68A that engages a circumferential keyway 64A. More specifically, an axial separating force applied to end plate 58A by the rotor plates locks the key 68A in a recess 66A, thereby preventing rotation of end plate 58A relative to shaft 54. Similarly, end plate 58B has an inner key 68B that rests in a recess 66B of the circumferential keyway 64B. The end plates are installed by sliding the key along the axial keyway 60 from one of the steps to the point where the axial keyway 60 intersects with the appropriate circumferential keyway. The end plates are then rotated relative to rotor shaft 54, with the key sliding within the circumferential keyway. In the illustrated embodiment, the first of the two end plates to be installed can be installed from either end. In an alternative embodiment, the axial keyway may not extend to the second stage, thus requiring both end plates to be mounted from the same end of the rotor shaft. The rotor plate is mounted on the shaft prior to the installation of the second end plate, as discussed below. In the mounted state, the end plates compress the rotor plate.

[0025] Figure 6 After one of the end plates 58B and one of the rotor plates 56B have been installed on the rotor shaft 54 Figure 2 A perspective view of the motor. Rotor plate 56B includes a set of permanent magnets 70 mounted in a slot. The rotor plate also has an internal key 72. The internal key 72 engages an axial keyway 60 to prevent relative rotation between the rotor plate and the rotor shaft. Torque generated by the motor can be transmitted to the rotor shaft via the key 72. The key in the rotor plate ensures that the magnetic fields of the various rotor plates are aligned with each other (or, if skew is desired, they are slightly offset from each other). Rotor plate 56B is mounted on the shaft by sliding from one end, where the key 72 slides in the axial keyway 60. If the rotor plate is mounted before either end plate, it can slide onto the shaft from either end.

[0026] Figure 7 This is a cross-sectional view of the assembled rotor. Rotor plates 56A and 56B are axially held in place by end plates 58A and 58B. The end plates are then axially held in place by keys 68A and 68B in circumferential keyways 64A and 64B.

[0027] Figure 8 The rotor shaft according to the second embodiment Rotor shaft A left-hand axial keyway 60A is defined, extending from a left step 62A to a left circumferential keyway 64A. Similarly, a right-hand axial keyway 60B extends from a right step 62B to a right circumferential keyway 64B. In this embodiment, the end plate 58A extends from the rotor shaft... The left end slides up, and end plate 58B slides up from the right end. Before the second of end plates 58A and 58B slides onto the shaft, rotor plates 56A and 56B are slid onto the rotor shaft. Above. Some other measures were taken to rotatably secure the rotor plate to the rotor shaft. For example, a separate axial keyway could be used. Figure 8 On the opposite side of the axis outside the view in the image.

[0028] Figure 9 The rotor shaft according to the third embodiment Rotor shaft A shoulder 74 is defined near the right end of the shaft. An axial keyway 60 extends from the left step 62A, through the circumferential keyway 64, and extends to the shoulder 74. In some embodiments, the axial keyway 60 may not extend so far to the right. In a third embodiment, the two end plates and the rotor plate slide onto the rotor shaft from the left end in a specific order. First, end plate 58B slides up such that it abuts the shoulder 74. Then, rotor plate 56B slides up such that it abuts the end plate 58B. Rotor plate 56A slides up such that it abuts the rotor plate 56B. The key of the rotor plate slides in the axial keyway 60. Finally, end plate 58A slides up until the key 68A is axially aligned with the circumferential keyway 64. From there, end plate 58A is positioned relative to the rotor shaft. Rotation causes the end plate 58A to be axially locked into place via the circumferential keyway 64.

[0029] While exemplary embodiments have been described above, these embodiments are not intended to describe all possible forms covered by the claims. Features of the first, second, and third embodiments can be combined in various ways to produce other embodiments. The terms used in this specification are descriptive rather than restrictive, and it should be understood that various changes may be made without departing from the spirit and scope of this disclosure.

[0030] As previously described, features of various embodiments can be combined to form other embodiments of the invention that may not be explicitly described or shown. While various embodiments may have been described as offering advantages or preferences over other embodiments or prior art implementations in terms of one or more desired characteristics, those skilled in the art will recognize that one or more features or characteristics may be compromised to achieve desired overall system properties, depending on the specific application and implementation. These properties may include, but are not limited to, strength, durability, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. Therefore, embodiments described as less desirable than other embodiments or prior art implementations in terms of one or more characteristics are within the scope of this disclosure and may be desirable for a particular application.

[0031] According to the present invention, a rotor is provided having: a shaft defining a first circumferential keyway and a first axial keyway, the first axial keyway extending at least from a first step in the shaft to the first circumferential keyway; a first end plate having a first internal key located in the first circumferential keyway to prevent axial movement of the first end plate; and at least one rotor plate rotatably fixed to the shaft on a side of the first end plate opposite to the first step in the shaft.

[0032] According to an embodiment, the first circumferential keyway extends only partially around the shaft.

[0033] According to an embodiment, the first circumferential keyway defines a notch in the shaft with its surface facing the first step; and the first inner key is located in the notch.

[0034] According to an embodiment, the invention is further characterized by a second end plate having a second internal key located in a second circumferential keyway, wherein the first end plate and the second end plate are on opposite sides of the at least one rotor plate.

[0035] According to an embodiment, the first axial keyway extends at least from the first step in the shaft to the second circumferential keyway.

[0036] According to an embodiment, each of the at least one rotor plate has a third inner key located in the first axial keyway.

[0037] According to an embodiment, the shaft defines a second axial keyway extending at least from a second step in the shaft to the second circumferential keyway, wherein the first step in the shaft and the second step in the shaft are located at opposite ends of the shaft relative to the at least one rotor plate.

[0038] According to an embodiment, the invention is further characterized by a second end plate, which is adjacent to the shoulder of the shaft, and wherein the first end plate and the second end plate are on opposite sides of the at least one rotor plate.

[0039] According to an embodiment, the first end plate is made of a different material than the at least one rotor plate.

[0040] According to the present invention, a method of assembling a rotor includes: sliding at least one rotor plate onto a shaft having a first axial keyway and a first circumferential keyway; sliding a first end plate onto the shaft having a first key that slides within the first axial keyway; and after sliding the first end plate onto the shaft, rotating the first end plate such that the first key engages the first circumferential keyway.

[0041] According to an embodiment, the invention is further characterized by: sliding a second end plate onto the shaft, the second end plate having a second key that slides within the first axial keyway; and after sliding the second end plate onto the shaft, rotating the second end plate such that the second key engages a second circumferential keyway in the shaft.

[0042] According to an embodiment, the first end plate, the second end plate, and the at least one rotor plate are all slid onto the shaft from the first end of the shaft.

[0043] According to an embodiment, the invention is further characterized by: sliding a second end plate onto the shaft, the second end plate having a second key that slides within a second axial keyway in the shaft; and after sliding the second end plate onto the shaft, rotating the second end plate such that the second key engages a second circumferential keyway in the shaft.

[0044] According to an embodiment, the first end plate is slid from a first end of the shaft onto the shaft, and the second end plate is slid from a second end of the shaft opposite to the first end of the shaft onto the shaft.

[0045] According to an embodiment, the invention is further characterized in that: before sliding the first end plate and the at least one rotor plate onto the shaft, the second end plate is slid onto the shaft such that the second end plate abuts a shoulder in the shaft.

[0046] According to an embodiment, the at least one rotor plate has a third key that engages the first axial keyway.

[0047] According to the present invention, a motor is provided having: a stator; a rotor shaft supported for rotation relative to the stator; and a plurality of rotor plates, each rotor plate having a permanent magnet, the plurality of rotor plates being fixed to the rotor shaft and axially compressed between a first end plate and a second end plate; wherein the first end plate has a first key engaging a first circumferential keyway in the rotor shaft.

[0048] According to an embodiment, the rotor shaft defines a shoulder; and the second end plate is adjacent to the shoulder.

[0049] According to an embodiment, the rotor shaft defines a second circumferential keyway; the second end plate has a second key that engages the second circumferential keyway; and the rotor shaft defines an axial keyway that extends from a first step in the shaft, through the first circumferential keyway, and at least to the second circumferential keyway.

[0050] According to an embodiment, the rotor shaft defines a second circumferential keyway; the second end plate has a second key that engages the second circumferential keyway; the rotor shaft defines a first axial keyway extending from a first step in the shaft to at least the first circumferential keyway; and the rotor shaft defines a second axial keyway extending from a second step in the shaft to at least the second circumferential keyway.

Claims

1. A rotor comprising: A shaft defining a first circumferential keyway and a first axial keyway, the first axial keyway extending at least from a first step in the shaft to the first circumferential keyway; A first end plate, the first end plate having a first internal key, the first internal key being located in the first circumferential keyway to prevent axial movement of the first end plate; as well as At least one rotor plate, the at least one rotor plate being rotatably fixed to the shaft on the side of the first end plate opposite to the step in the shaft.

2. The rotor as claimed in claim 1, wherein: The first circumferential keyway defines a notch in the shaft with its surface facing the first step; and The first internal key is located in the notch.

3. The rotor of claim 1, further comprising a second end plate having a second internal key located in a second circumferential keyway, wherein the first end plate and the second end plate are on opposite sides of the at least one rotor plate.

4. The rotor as claimed in claim 3, wherein: The first axial keyway extends at least from the first step in the shaft to the second circumferential keyway; and Each of the at least one rotor plate has a third inner key located in the first axial keyway.

5. The rotor of claim 3, wherein the shaft defines a second axial keyway extending at least from a second step in the shaft to the second circumferential keyway, the first step in the shaft and the second step in the shaft being located at opposite ends of the shaft relative to the at least one rotor plate.

6. The rotor of claim 1, further comprising a second end plate adjacent to a shoulder in the shaft, wherein the first end plate and the second end plate are on opposite sides of the at least one rotor plate.

7. The rotor of claim 1, wherein the first end plate is made of a material different from that of the at least one rotor plate.

8. A method for assembling a rotor, comprising: At least one rotor plate is slid onto a shaft having a first axial keyway and a first circumferential keyway; The first end plate is slid onto the shaft, the first end plate having a first key that slides within the first axial keyway; as well as After sliding the first end plate onto the shaft, the first end plate is rotated so that the first key engages the first circumferential keyway.

9. The method of claim 8, further comprising: The second end plate is slid onto the shaft, and the second end plate has a second key that slides within the first axial keyway; as well as After sliding the second end plate onto the shaft, the second end plate is rotated so that the second key engages the second circumferential keyway in the shaft.

10. The method of claim 8, further comprising: The second end plate is slid onto the shaft, the second end plate having a second key that slides within a second axial keyway in the shaft; as well as After sliding the second end plate onto the shaft, the second end plate is rotated so that the second key engages the second circumferential keyway in the shaft.

11. The method of claim 8, further comprising: Before sliding the first end plate and the at least one rotor plate onto the shaft, the second end plate is slid onto the shaft such that the second end plate abuts a shoulder in the shaft.

12. A motor comprising: stator; A rotor shaft, which is supported to rotate relative to the stator; as well as Multiple rotor plates, each rotor plate having a permanent magnet, the multiple rotor plates being fixed to the rotor shaft and axially compressed between a first end plate and a second end plate; in The first end plate has a first key that engages a first circumferential keyway in the rotor shaft.

13. The motor of claim 12, wherein: The rotor shaft defines a shoulder; and The second end plate is adjacent to the shoulder.

14. The motor of claim 12, wherein: The rotor shaft defines a second circumferential keyway; The second end plate has a second key, which engages the second circumferential keyway; and The rotor shaft defines an axial keyway that extends from a first step in the shaft, through the first circumferential keyway, and at least to the second circumferential keyway.

15. The motor as claimed in claim 12, wherein: The rotor shaft defines a second circumferential keyway; The second end plate has a second key, which engages the second circumferential keyway; The rotor shaft defines a first axial keyway, which extends at least from a first step in the shaft to the first circumferential keyway. and The rotor shaft defines a second axial keyway that extends at least from a second step in the shaft to a second circumferential keyway.

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