KR20180003246U - Motor rotor - Google Patents

Abstract

A motor rotor and method are disclosed. The motor rotor includes a magnet carrier, a magnet supported by the magnet carrier, a sleeve surrounding the magnet, and first and second circumferential seals positioned to seal the magnet within the cavity between the magnet carrier and the sleeve. In this manner, the magnets are encapsulated by reusing the magnets carriers and sleeves with the seals, so that the magnets are fluidically isolated or protected from chemicals in the environment in which they operate. This helps to prevent damage to the magnet caused by harmful chemicals in the environment.

Description

MOTOR ROTOR

The present invention relates to a motor rotor and method.

The motor is known. In an electric motor, there is provided a rotor assembly that rotates about a non-rotating portion or a stator. In one configuration of the motor, the stator includes one or more coils surrounding a rotor assembly having one or more magnets. Activation of the coil causes the rotor assembly to rotate within the stator.

A motor is useful, but its operation can lead to unexpected results. Therefore, it is desirable to provide an improved rotor.

According to a first aspect there is provided a magnet comprising a magnet carrier, a magnet supported by the magnet carrier, a sleeve surrounding the magnet, and a sleeve positioned to seal the magnet within the void between the magnet carrier and the sleeve. A motor rotor comprising first and second circumferential seals is provided. The first aspect is that when operating a motor in a challenging environment, such as occurs when chemicals in the environment are operating in an aggressive chemical environment that can attack the rotor or degrade the performance of the rotor, It is recognized that it may be desirable to seal the magnet from such an environment to maintain its performance.

Thus, a rotor is provided. The rotor may be for an electric motor. The rotor may include a magnetic carrier or holder. The rotor may also include one or more magnets supported by or attached to the magnet carrier. The rotor may also include a sleeve or housing enclosing or accommodating a magnet therein. The rotor may also include at least one, preferably a pair of circumferential or annular seals. The seal may be positioned to seal the magnet within a cavity or opening created between the magnet carrier and the sleeve. In this way, the magnet is encapsulated by reusing the magnet carrier and sleeve with the seal, and is fluidically isolated or protected from the chemicals in the operating environment. This helps to prevent damage to the magnet caused by harmful chemicals in the environment.

In one embodiment, the first and second circumferential seals are located at the axial ends of the magnets. Thus, the seal can be located or disposed at both ends of the magnet.

In one embodiment, the magnet extends axially between the first and second circumferential seals. Thus, a magnet can be provided between the seals.

In one embodiment, the magnet carrier and the sleeve extend axially beyond the first and second circumferential seals. Thus, the magnet carrier and / or sleeve may extend axially beyond the seal to maintain the seal.

In one embodiment, the magnet carrier has an annular shoulder arranged to position the magnet in an axial position on the magnet carrier. Thus, the magnet carrier may have a radially upstanding shoulder or protrusion from its outer side, and the magnet abuts the shoulder or protrusion to position the magnet at a selected location in the axial direction on the magnet carrier. This helps align the magnet with the coil.

In one embodiment, the first circumferential seal is located proximate the annular shoulder. Thus, the annular shoulder may be disposed adjacent the first seal to help position the first seal.

In one embodiment, the annular shoulder defines a first circumferential recess dimensioned to receive the first circumferential seal. Thus, the annular shoulder may at least partially define or provide a portion of the circumferential groove on the outer surface of the magnet carrier on which the circumferential seal may rest.

In one embodiment, the magnet carrier defines a second circumferential recess dimensioned to receive a second circumferential seal. Providing additional circumferential grooves on the outer side of the magnet carrier helps keep the seal in place.

In one embodiment, the sleeve is held by the first and second circumferential seals. Thus, the sleeve may be located on the circumferential seal or held in place by the circumferential seal to maintain the sleeve, magnet and seal in place.

In one embodiment, the sleeve and the magnet carrier are dimensioned to compress the first and second circumferential seals. Thus, the seal can be compressed or squeezed between the sleeve and the magnet carrier to keep them in place and improve the seal of the magnet.

In one embodiment, the first and second circumferential seals comprise at least one of a potting compound seal and an O-ring seal.

In one embodiment, the first and second circumferential seals comprise synthetic rubber and a fluoropolymer elastomer compound.

In one embodiment, the magnet comprises a ring magnet.

In one embodiment, the ring magnet comprises a plurality of C-shaped magnet segments.

In one embodiment, the rotor includes a fixing operable to secure the magnet to the magnet carrier.

In one embodiment, the magnet comprises a rare earth magnet.

In one embodiment, the magnet comprises one of the group comprising iron boron and samarium cobalt.

In one embodiment, the first and second circumferential seals are positioned to airtightly seal the magnets within the cavity between the magnet carrier and the sleeve.

According to a second aspect, there is provided a vacuum pump including the motor rotor of the first aspect.

According to a third aspect, there is provided a method of manufacturing a magnet, comprising the steps of providing a magnet carrier, providing a magnet supported by the magnet carrier, providing a sleeve surrounding the magnet, and sealing the magnet within the cavity between the magnet carrier and the sleeve. A method is provided that includes positioning the first and second circumferential seals.

In one embodiment, the method includes positioning the first and second circumferential seals at the axial end of the magnet.

In one embodiment, the magnet extends axially between the first and second circumferential seals.

In one embodiment, the magnet carrier and the sleeve extend axially beyond the first and second circumferential seals.

In one embodiment, the method includes positioning the magnet with respect to the annular shoulder on the magnet carrier to position the magnet in an axial position on the magnet carrier.

In one embodiment, the method includes positioning the first circumferential seal proximate the annular shoulder.

In one embodiment, the method includes receiving a first circumferential seal within a first circumferential recess dimensioned to receive a first circumferential seal and defined by an annular shoulder.

In one embodiment, the method includes receiving a second circumferential seal within a second circumferential recess defined by the magnet carrier.

In one embodiment, the method includes maintaining the sleeve in first and second circumferential seals.

In one embodiment, the method includes dimensioning the sleeve and the magnet carrier to compress the first and second circumferential seals.

In one embodiment, the first and second circumferential seals comprise one of a potting compound seal and an O-ring seal.

In one embodiment, the first and second circumferential seals comprise synthetic rubber and a fluoropolymer elastomeric compound.

In one embodiment, the magnet comprises a ring magnet.

In one embodiment, the ring magnet comprises a plurality of C-shaped magnet segments.

In one embodiment, the method includes securing the magnet to the magnet carrier.

In one embodiment, the magnet comprises a rare earth magnet.

In one embodiment, the magnet comprises one of the group comprising iron boron and samarium cobalt.

In one embodiment, the first and second circumferential seals are positioned to airtightly seal the magnets within the cavity between the magnet carrier and the sleeve.

Additional specific and preferred aspects are set forth in the appended independent and dependent claims. The characteristics of the dependent claims can be combined with the features of the independent claims as appropriate and suitably other than those explicitly set forth in the claims.

When a device feature is described as being operational to provide this functionality, it will be understood to include device features that are adapted or configured to provide such functionality or provide such functionality.

Embodiments of the present invention will now be further described with reference to the accompanying drawings, in which:
Figures 1A-1D illustrate a motor rotor (collectively, 10) according to one embodiment.

Prior to discussing the embodiments in more detail, a brief overview is provided. Embodiments provide an electric motor rotor assembly that is less susceptible to chemical attack in harsh chemical environments. In particular, the embodiment provides a magnet which is hermetically sealed against the magnet of the motor rotor and any chemical used to fix the magnet to the magnet carrier, in the environment in which the motor operates. The magnet typically comprises a surface ring permanent magnet that can be formed as an integral or C-shaped component and is received on a magnet carrier. The magnet carrier forms part of a hermetically sealing enclosure to protect the magnet from chemical attack from chemicals present in the environment in which the motor rotor is located. In some embodiments, the magnets are secured to the magnet carrier using an adhesive. The cylindrical sleeve is coaxially positioned to surround the magnet to help protect the radially outer side of the magnet from mechanical damage during assembly, to help keep the magnet in place under strong centrifugal forces, and to provide a portion of the hermetically sealed enclosure . Both ends of the magnet are also provided with a portion of a hermetically sealed enclosure, sealing each axial end of the magnet and providing a circumferential seal that completely seals the magnet within the annular cavity defined by the magnet carrier, sleeve and circumferential seal itself / RTI > Such a hermetic seal protects the ring permanent magnets from chemical attack during operation of the motor rotor and protects any adhesive if present.

Rotor  Assembly

IA is a side view showing a motor rotor (generally, 10) according to one embodiment. 1B is a side cross-sectional view of the motor rotor 10. Fig. 1C is a perspective view of the motor rotor 10. Fig. 1D is another perspective view of the motor rotor 10. The motor rotor 10 includes a magnet carrier 20. In this example, the magnet carrier 20 is formed of C45E carbon steel to provide a good magnetic circuit for the magnet. The magnet carrier is an elongated cylinder having profiled inner and outer surfaces, as will now be described. The magnet carrier 20 defines a radially inner bore 25 configured to receive a rotor shaft (not shown). The magnet carrier (20) has a profiled radially outer surface (27). The first portion 27A of the outer surface 27 is cylindrical and extends from the axial end 30 to the first shoulder 27B that rises radially from the first portion 27A. The second shoulder 27D is radially upright from the first portion 27A and is located axially away from the first shoulder 27B and defines a circumferential groove 27C with the first shoulder 27B do. The second shoulder 27D is upright in the radial direction by a height higher than the height of the first shoulder 27B.

The motor rotor 10 also includes a surface ring permanent magnet 40 that is an annular ring having a radially inner surface 43, a radially outer surface 47 and an annular end 41, In the present embodiment, the surface ring permanent magnet 40 is made of neodymium iron boron or samarium cobalt.

The motor rotor 10 also includes O-ring seals 52, 50 positioned proximate the axial end 30 and within the groove 27C, respectively. In this embodiment, the O-ring seal is made of Viton (trademark). The first portion 27A may be provided with a shallow groove proximate to the axial end 30 to aid in the retention of the O-ring seal 52, optionally.

The motor rotor 10 also includes a sleeve 60 coaxially positioned with the surface ring permanent magnets 40 and the O-ring seals 50, 52 and circumferentially surrounding them. In this embodiment, the sleeve 60 is a grade 303 stainless steel formed as a cylinder having an inner side 63 and an outer side 65.

Now, the assembly of the motor rotor 10 will be described. A magnet carrier 20 is provided and the surface ring permanent magnet 40 is moved along the axial length of the first portion 27A from the axial end 30 until it abuts against the first shoulder 27B. Any adhesive disposed between the outer surface 27 and the inner surface 43 may adhere the surface ring permanent magnet 40 to the magnet carrier 20 such that the surface ring permanent magnets 20 are attached to the peripheral coils of the motor (Not shown) to cause the magnet carrier 20 to rotate.

The O-ring 50 is received in the groove 27C and the O-ring 52 is moved over the axial end 30 and abuts the axial end of the surface ring permanent magnet 40, ) Axial end 30, as shown in Fig.

The sleeve 60 is then moved from the axial end 30 over the O-ring 52 (held in place by the surface ring permanent magnet 40) to the surface ring permanent magnet 40 (Held in place by the second shoulder 27B) and onto the O-ring 50 (held in place by the second shoulder 27D).

The relative dimensions of the magnet carrier 20, the sleeve 60 and the O-rings 50, 52 are determined by the O-rings 50, 52 to form an airtight circumferential seal at both axial ends of the surface ring permanent magnets 40 , 52).

The surface ring permanent magnet 40 is therefore made by the surface ring permanent magnet 40 itself or by a chemical capable of deteriorating any adhesive used to secure the surface ring permanent magnet 40 on the magnet carrier 20. [ It can be seen that it is hermetically sealed from the intrusion.

It will be appreciated that although the above-described embodiment uses an O-ring seal, a potting compound may also be used, thereby changing the profile of the outer surface 27. It will also be appreciated that the application of such a potting compound typically occurs under vacuum conditions.

Previously, permanent magnet motor solutions tended to be for mild / light-duty vacuum applications. Such permanent magnet motor solutions have been dominated by surface ring permanent magnet motor designs due to their low cost and simple construction. However, as noted above, both magnets and adhesives in this design are particularly vulnerable to chemical attack in harsh duty vacuum applications.

Examples include the robustness of surface ring permanent magnet motor designs by hermetically sealed carriers designed to extend the application suitability of surface ring permanent magnet motors from light-duty load-lock applications to intermediate harsh vacuum applications And reliability.

The use of rare earth magnets and adhesives, especially neodymium iron boron, is vulnerable to long term chemical attack during certain vacuum applications, such as high concentrations of hydrogen and fluorine. Over time, the adhesive and magnet assemblies may be weakened, resulting in poor performance and ultimately motor failure. As a result of this failure mode, induction motor technology is typically used for medium harsh vacuum applications, and surface ring permanent magnet motor technology has been used only for light load lock applications, especially in semiconductor processing applications.

The embodiment provides a hermetically sealed magnet construction that protects both the rare earth magnet and the adhesive from chemical attack. This provides a more reliable motor structure for intermediate severe vacuum applications and thus enables the use of high efficiency synchronous motors in more semiconductor processing applications.

Embodiments include the following components:

1. C45E Carbon Steel Magnet Carrier - This provides a good magnetic circuit for the magnet;

2. Two O-ring grooves machined on the carrier - this provides a reliable position for the two sealing O-rings;

3. Two VITON® O-ring-BITONS® are proven materials for medium to severe vacuum applications;

4. Neodymium iron boron (Nd Fe B) magnet ring - This provides a cost-effective magnet solution with excellent magnet strength;

5. Grade 303 stainless steel protective sleeve.

The use of the Vantage O-ring provides a hermetic seal for magnets and adhesives. O-ring compression also keeps the protective stainless steel sleeve in place and thus eliminates the need for adhesion on the outer sealing surface.

Embodiments enable the use of surface ring permanent magnet motors in semiconductor vacuum applications. However, this approach can be used in other industrial applications.

Although an exemplary embodiment of the present invention has been disclosed in detail herein with reference to the accompanying drawings, it is to be understood that the present invention is not limited to the precise embodiment, and that the scope of the present invention, as defined by the appended claims and their equivalents, It will be understood that various changes and modifications may be made by one skilled in the art without departing from the invention.

10: Motor rotor 20: Magnet carrier
25: inner bore 27: outer surface
27A: first portion 27B: first shoulder
27C: groove 27D: second shoulder
30: axial end 40: permanent magnet
43: inner side 47: outer side
41, 49: annular end 52, 50: O-ring seal
60: Sleeve 63: My side
65: Outer side

Claims (18)

In the motor rotor,
A magnet carrier,
A magnet supported by the magnet carrier;
A sleeve surrounding the magnet,
And a first and a second circumferential seal positioned to seal the magnet within a cavity between the magnet carrier and the sleeve
Motor rotor. The method according to claim 1,
Wherein the first and second circumferential seals are located at the axial ends of the magnets
Motor rotor. 3. The method according to claim 1 or 2,
The magnet extends axially between the first and second circumferential seals
Motor rotor. 4. The method according to any one of claims 1 to 3,
Wherein the magnet carrier and the sleeve extend axially beyond the first and second circumferential seals
Motor rotor. 5. The method according to any one of claims 1 to 4,
The magnet carrier having an annular shoulder arranged to position the magnet in an axial position on the magnet carrier
Motor rotor. 6. The method of claim 5,
The first circumferential seal is located proximate the annular shoulder
Motor rotor. The method according to claim 5 or 6,
The annular shoulder defines a first circumferential recess dimensioned to receive the first circumferential seal
Motor rotor. 8. The method according to any one of claims 1 to 7,
The magnet carrier defines a second circumferential recess dimensioned to receive the second circumferential seal
Motor rotor. 9. The method according to any one of claims 1 to 8,
The sleeve is held by the first and second circumferential seals
Motor rotor. 10. The method according to any one of claims 1 to 9,
The sleeve and the magnet carrier are dimensioned to compress the first and second circumferential seals
Motor rotor. 11. The method according to any one of claims 1 to 10,
Wherein the first and second circumferential seals comprise one of a potting compound seal and an O-ring seal
Motor rotor. 12. The method according to any one of claims 1 to 11,
Wherein the first and second circumferential seals comprise synthetic rubber and a fluoropolymer elastomeric compound
Motor rotor. 13. The method according to any one of claims 1 to 12,
The magnet includes a ring magnet
Motor rotor. 14. The method of claim 13,
Wherein the ring magnet comprises a plurality of C-shaped magnet segments
Motor rotor. 15. The method according to any one of claims 1 to 14,
The magnet comprises a rare earth magnet
Motor rotor. 16. The method according to any one of claims 1 to 15,
Wherein the magnet comprises one of the group comprising iron boron and samarium cobalt
Motor rotor. 17. The method according to any one of claims 1 to 16,
The first and second circumferential seals are positioned to seal the magnet hermetically within the cavity between the magnet carrier and the sleeve
Motor rotor. A motor comprising the motor rotor according to any one of claims 1 to 17
Vacuum pump.

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