Reinforced rotor for an electric machine

Abstract

A rotor for an electric machine includes a rotor body formed from a plurality of rotor laminations defining a first axial end and a second axial end. Each of the plurality of rotor laminations includes a plurality of openings aligned so as to define a plurality of channels through the rotor body. A plurality of reinforcement elements extend through the plurality of laminations. Each of the plurality of reinforcement elements is disposed in a corresponding one of the plurality of channels and includes a first end portion and a second end portion. The first end portion and the second end portion of selected ones of the plurality of reinforcement elements extend outwardly from the first axial end and the second axial end. An end ring is positioned at the first axial end. The end ring is integrally formed with the selected ones of the plurality of reinforcement elements.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of electric machines, and more specifically, to a reinforced rotor for an electric machine. BACKGROUND

[0002] The rotor is typically formed of a plurality of stacked laminations that support a central hub and a plurality of magnets. Typically, each lamination includes a plurality of openings that form webs and serve as cooling channels, magnet mounting locations, etc. The openings are also positioned or located to reduce the weight of the rotor. The webs serve as a flux leakage path, which can reduce the performance of the electric machine or increase the operating cost of the electric machine.

[0003] The magnets are typically inserted into the openings and held in place with an adhesive, such as epoxy. In this case, the openings typically include a wave edge that holds the magnets and enhances the retention of the epoxy. In many cases, the epoxy does not bond to the magnets and simply serves as a wedge, for example, to prevent movement of the magnets. Magnet retention, flux leakage, and structural support are issues that can limit the overall operating speed of the rotor. Accordingly, it is desirable to provide a rotor with structural supports that can stabilize the magnets, reduce flux leakage, and enhance stiffness so that the rotor can accommodate high speed operation. SUMMARY

[0004] A rotor for an electric machine is disclosed that includes a rotor body formed of a plurality of stacked laminations that define a first axial end and an opposite second axial end. Each of the plurality of stacked laminations includes a plurality of openings that are aligned so as to define a plurality of channels through the rotor body. A plurality of reinforcing elements extend through the plurality of stacked laminations. Each of the plurality of reinforcing elements is disposed in a corresponding one of the plurality of channels and includes a first end portion and a second end portion. The first end portion and the second end portion of selected ones of the plurality of reinforcing elements extend outwardly from the first axial end and the second axial end. An end ring is positioned at the first axial end. The end ring is integrally formed with the selected ones of the plurality of reinforcing elements.

[0005] In addition to one or more features described herein, another end ring is positioned at the second axial end, the other end ring being integrally formed with the selected ones of the plurality of reinforcing elements.

[0006] In addition to one or more features described herein, the end ring, the other end ring, and the plurality of reinforcing elements are formed of a polymer composite material.

[0007] In addition to one or more of the features described herein, the polymer composite includes at least one of an epoxy resin, a polymer, a polyimide, an acrylate, a silicone, a polyether ether ketone (PEEK), a polyether ketone (PEK), a polyamide, and a bismaleimide.

[0008] In addition to one or more of the features described herein, the first reinforcement member is mounted to the end ring.

[0009] In addition to one or more of the features described herein, the second reinforcement member is mounted to the other end ring.

[0010] In addition to one or more of the features described herein, the first and second reinforcement elements are formed of metal.

[0011] In addition to one or more of the features described herein, the plurality of reinforcement elements includes a first plurality of reinforcement elements extending from the first axial end to a center of the rotor body and a second plurality of reinforcement elements extending from the second axial end toward the center of the rotor body.

[0012] In addition to one or more of the features described herein, each of the first plurality of reinforcement elements includes a first end section extending outward from the first axial end and a second end section terminating in the rotor body.

[0013] In addition to one or more of the features described herein, each of the second plurality of reinforcement elements includes a third end section extending outward from the second axial end and a fourth end section terminating in the rotor body, the second end section spaced apart from the fourth end section within the rotor body.

[0014] In addition to one or more of the features described herein, a selected reinforcement element of the plurality of reinforcement elements includes all of the reinforcement elements.

[0015] A method of forming a reinforced rotor is also disclosed, including molding a rotor end ring and a plurality of reinforcement elements into an integral component, supporting a plurality of rotor laminations forming a rotor body at a first axial end with the rotor end ring, and internally supporting the plurality of rotor laminations with the plurality of reinforcement elements.

[0016] In addition to one or more of the features described herein, molding the plurality of reinforcement elements includes introducing a reinforcement element medium into a plurality of channels formed in the rotor body.

[0017] In addition to one or more of the features described herein, another rotor end ring is also molded into an integral component with the rotor end ring and the plurality of reinforcement elements.

[0018] In addition to one or more of the features described herein, the molded rotor end ring and the other rotor end ring include molding the rotor end ring and the other rotor end ring directly on the rotor body.

[0019] In addition to one or more of the features described herein, the internal support of the plurality of rotor laminations includes inserting the plurality of reinforcement elements into the channels formed in the rotor body at the first axial end.

[0020] In addition to one or more of the features described herein, the internal support of the plurality of rotor laminations includes inserting the plurality of reinforcement elements into the channels formed in the rotor body at the first axial end.

[0021] In addition to one or more of the features described herein, the rotor end ring reinforcement member is mounted to the rotor end ring.

[0022] The above features and advantages of the present disclosure, and other features and advantages, are readily apparent from the following detailed description, when taken in connection with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0023] Other features, aspects, and details are described below with reference to the drawings. The sum of all these detailed descriptions and specific examples merely illustrate the application and do not restrict it.

[0024] Figure 1 is a cross-sectional side view of a rotor including reinforcement elements and a rotor end ring taken along line 1-1 in Figure 2

[0025] Figure 2 is an axial end view of a rotor of Figure 1

[0026] Figure 3 depicts a perspective view of a first rotor end ring and a second rotor end ring formed with a plurality of reinforcement elements without rotor laminations according to a non-limiting example;

[0027] Figure 4 depicts a cross-sectional side view of a motor including a rotor of Figure 1

[0028] Figure 5 depicts an integrated rotor end ring and reinforcement according to a non-limiting example. DETAILED DESCRIPTION

[0029] The rotor according to a non-limiting example is in Figure 1 and Figure 2 ​​​A rotor 10 is shown. The rotor 10 is indicated generally at 10. The rotor 10 includes a main body 12 formed from a plurality of stacked laminations 14 defining a central opening 17. The central opening 17 supports a shaft and / or bearings (not shown) that facilitate rotation of the rotor 10 within a stator (also not shown). The main body 12 includes a first axial end 20 and an opposite second axial end 22. A plurality of openings are formed in each of the plurality of stacked laminations 14, one of which is indicated at 28. The openings 28 are aligned with one another to define a plurality of magnet receiving channels 31 and a plurality of reinforcement element channels 33. Selected ones of the openings 28 are connected by bridges 36 so as to provide structural support for the rotor 10.

[0030] According to non-limiting examples, a plurality of reinforcement elements, one of which is indicated at 40, extend through corresponding ones of the plurality of reinforcement element channels 33. Each of the plurality of reinforcement elements 40 includes a first end portion 44 and a second end portion 46. In non-limiting examples, a first rotor end ring 52 is disposed at the first axial end 20 and a second rotor end ring 56 is disposed at the second axial end 22. The first rotor end ring 52 and the second rotor end ring 56 are integrally formed with the reinforcement elements 40. In non-limiting examples, the first rotor end ring 52 and the second rotor end ring 56 are molded with the first end portions 44 and the second end portions 46 of the plurality of reinforcement elements 40. Figure 3 In the illustrated non-limiting examples, the first rotor end ring 52 is molded with the first end portions 44 of the plurality of reinforcement elements 40 and the second rotor end ring 56 is molded with the second end portions 46 of the plurality of reinforcement elements 40.

[0031] In non-limiting examples, the first rotor end ring 52, the second rotor end ring 56, and the plurality of reinforcement elements 40 can be formed from a variety of materials. According to non-limiting examples, the first rotor end ring 52, the second rotor end ring 56, and the plurality of reinforcement elements 40 can be made from a non-magnetic, non-conductive material that can be molded, such as various polymers and polymer composites. According to another non-limiting example, the first rotor end ring 52, the second rotor end ring 56, and the plurality of reinforcement elements 40 can be formed from one of an epoxy, a polymer, a polyimide, an acrylate, a silicone, a polyether ether ketone (PEEK), a polyether ketone (PEK), a polyamide, and a bismaleimide.

[0032] In non-limiting examples, a first reinforcement member 70 can be mounted on the first rotor end ring 52 and a second reinforcement member 72 can be mounted on the second rotor end ring 56. The first reinforcement member 70 and the second reinforcement member 72 can be added so as to provide additional structural support and to facilitate balancing of the rotor 10. In non-limiting examples, the first reinforcement member 70 and the second reinforcement member 72 can be formed from one of steel, aluminum, or other materials, including metallic and non-metallic materials and alloys.

[0033] In non-limiting examples, the reinforcement elements 40, the first rotor end ring 52, and the second rotor end ring 56 can be formed using various processes. For example, the reinforcement elements 40, the first rotor end ring 52, and the second rotor end ring 56 can be formed directly in the main body 12. In non-limiting examples, the reinforcement element channels 33 can be used as a mold to receive material to form the reinforcement elements 40. Material can be introduced into each of the reinforcement element channels 33, and a first mold (not shown) can be disposed at the first axial end 20, and a second mold (also not shown) can be disposed at the second axial end 22. The material can be introduced into the first mold, flow through the reinforcement element channels 33 to the second mold and allowed to cool. During cooling, a compressive force can be applied to the plurality of rotor laminations 14. In another non-limiting example, the reinforcement elements 40, the first rotor end ring 52, and the second rotor end ring 56 can be formed external to the main body 12 and installed.

[0034] In non-limiting examples, a first number of the plurality of laminations 14 can be aligned and formed into a first stack (not individually labeled). A first plurality of magnets (also not individually labeled) can then be inserted into corresponding ones of the magnet receiving channels 31. A second number of the plurality of laminations 14 can be aligned and formed into a second stack (not individually labeled). A second plurality of magnets (not individually labeled) can be inserted into corresponding ones of the magnet receiving channels in the second stack. The second stack can then be positioned on and aligned with the first stack. The number of stacks can vary.

[0035] At this point, the plurality of reinforcement elements 40 can be installed through the first and second stacks. Once all of the stacks are formed, aligned, and the reinforcement elements 40 added, the first and second end rings 52, 56 can be installed as described herein. Referring to Figure 4 The rotor 10 can then receive a shaft 65 and be balanced as needed prior to installation within a stator 68 of a motor 70.

[0036] Figure 5A rotor 10 is depicted in accordance with another non-limiting example that includes a first plurality of reinforcement elements 120 extending into the main body 12 from a first rotor end ring 122 positioned at the first axial end 20 and a second plurality of reinforcement elements 124 extending into the main body 12 from a second rotor end ring 126 positioned at the second axial end 22. The first plurality of reinforcement elements 120 includes a first end section 130 extending from and formed with the first rotor end ring 52 and a second end section 134 terminating within the main body 12. Similarly, the second plurality of reinforcement elements 124 includes a third end section 140 extending from and formed with the second rotor end ring 56 and a fourth end section 142 terminating within the main body 12. The second end section 134 of the first plurality of reinforcement elements 120 can be spaced apart from the fourth end section 142 of the second plurality of reinforcement elements 124 by a gap 144 defined by the laminations 14.

[0037] In non-limiting examples, the first plurality of reinforcement elements 120 includes a tapered profile 147. Similarly, the plurality of rotor laminations 14 includes channels (not individually labeled) having a taper. In non-limiting examples, the first end section 130 can have a greater dimension than the second end section 134. The second plurality of reinforcement elements 124 can be formed substantially similarly. In this manner, additional reinforcement can be provided at the first axial end 20 and the second axial end 22, respectively. Further, the taper allows the laminations to have a first thickness web and bridge portion toward the center portion (not individually labeled) of the main body 12 and further axially outwardly have a thinner web and bridge portion.

[0038] In this regard, it should be appreciated that the non-limiting examples described herein provide internal reinforcement elements formed with first and second rotor end rings in a rotor that increase structural support, allow for removal of and / or reduction of bridges from rotor laminations and reduce internal magnetic flux leakage sources. The internal reinforcement also supports the rotor magnets to reduce strain on the epoxy and / or other adhesive used for attachment. In this manner, the rotor can be operated at higher speeds without experiencing magnet failure or requiring large magnet support bridges in each lamination. Further, the rotor end rings can be configured to provide support for the reinforcement elements while also providing mass reduction without loss of rotor balancing capability.

[0039] While the foregoing disclosure has been described in reference to illustrative embodiments, those skilled in the art will appreciate that various changes can be made and equivalents can be substituted without departing from the scope of the disclosure. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the disclosure without departing from the central scope thereof. Therefore, the disclosure is not intended to be limited to the particular embodiments disclosed, but can include all embodiments falling within the scope of the disclosure.

Claims

1. A rotor for an electric motor, comprising: A rotor body formed of a plurality of stacked laminations defining a first axial end and an opposing second axial end, each of the plurality of stacked laminations including a plurality of openings aligned to define a plurality of channels through the rotor body; A plurality of reinforcing elements extending through the plurality of stacked laminations, each of the plurality of reinforcing elements being disposed in a corresponding channel of the plurality of channels, and including a first end portion and a second end portion; A first rotor end ring is positioned at the first axial end of the rotor body and is formed together with a selected reinforcing element of a plurality of reinforcing elements that are circumferentially spaced from each other around the rotor body and radially spaced from each other across the rotor body. and The second rotor end ring is located at the second axial end of the rotor body. The second rotor end ring is formed together with other selected reinforcing elements among the plurality of reinforcing elements, wherein the first rotor end ring forms an integral structure with the selected reinforcing elements among the plurality of reinforcing elements, and the second rotor end ring forms another integral structure with the other selected reinforcing elements among the plurality of reinforcing elements.

2. The rotor according to claim 1, wherein, The first rotor end ring, the second rotor end ring, and the plurality of reinforcing elements are formed of polymer composite material.

3. The rotor according to claim 2, wherein, The polymer composite material includes at least one of epoxy resin, polymer, polyimide, acrylate, silicone resin, polyether ether ketone (PEEK), polyether ketone (PEK), polyamide, and bismaleimide.

4. The rotor according to claim 1, further comprising: The first reinforcing member is installed on the first rotor end ring.

5. The rotor according to claim 4, further comprising: The second reinforcing member is installed on the end ring of the second rotor.

6. The rotor according to claim 5, wherein, The first and second reinforcing members are made of metal.

7. The rotor according to claim 1, wherein, The selected reinforcing element among the plurality of reinforcing elements includes a first plurality of reinforcing elements extending from the first rotor end ring into the rotor body, and the other selected reinforcing elements among the plurality of reinforcing elements include a second plurality of reinforcing elements extending from the second rotor end ring into the rotor body.

8. The rotor according to claim 7, wherein, Each of the first plurality of reinforcing elements includes a first end segment and a second end segment, the first end segment being formed together with the first rotor end ring at the first axial end, and the second end segment terminating within the rotor body.

9. The rotor according to claim 8, wherein, Each of the second plurality of reinforcing elements includes a third end segment formed together with a second rotor end ring at the second axial end and a fourth end segment terminating within the rotor body, the second end segment being spaced apart from the fourth end segment within the rotor body.

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