# US 10,767,652 B2 · Permanent magnet submersible motor with a one-piece rotor/yoke configuration and resin embedded magnets

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- Number: US 10,767,652 B2
- Document ID: US10767652B2
- Status: Granted
- Kind: B2
- Application number: 16/060,749
- Filed: 2016-12-14
- Published: 2018-12-20
- Granted: 2020-09-08
- Earliest claimed: 2015-12-14
- Assignees: Flowserve Management Company
- Applicants: Flowserve Management Company
- Inventors: Michael Klahn
- Web page: https://patentgrep.com/patent/US10767652B2

## CPC

- F04D 13/10: adapted for use in mining bore holes
- F04B 17/03: driven by electric motors
- F04B 47/06: having motor-pump units situated at great depth
- H02K 1/278: Surface mounted magnets; Inset magnets
- H02K 1/28: Means for mounting or fastening rotating magnetic parts on to, or to, the rotor structures
- H02K 5/128: using air-gap sleeves or air-gap discs
- F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02)
- F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F)
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})

## Abstract

A permanent magnet submersible motor for electric submersible pump systems and a method of making the rotor of such a motor. The unitary construction of the rotor shaft and the yoke provides improved protection of the damage-prone magnets, while the larger effective shaft diameter also improves shaft bending resistance. Shaped form closures on the yoke promote secure magnet retention, even under highly centrifugal loads, while an exterior cladding tube and a cast resin filler material are used to further secure the magnets around the yoke periphery while also providing hermetic sealing against a working fluid.

## Claims

### Claim 1

A rotor for use in an electric submersible pump, the rotor comprising:
a shaft in rigid communication with and configured to rotate one or more pump impellers, said shaft comprising a concentric yoke integrally-formed therewith, the yoke comprising a fore end and an aft end;
one or more permanent magnets disposed about the circumference of the yoke, the one or more permanent magnets positioned to axially coincide with the yoke and form an interface with the yoke to comprise an outer dimension form closure on the circumference of the yoke such that form closed torque transmission is present between the one or more permanent magnets and the yoke;
a cladding tube disposed around the circumference of the permanent magnets to secure the one or more permanent magnets to the shaft through the yoke; and
a stepped collar located on each of the fore end and the aft end of the yoke, wherein the one or more permanent magnets are sealed between the yoke and the cladding tube by the stepped collar.

### Claim 2 (depends on 1)

The rotor of claim 1, wherein the wherein the stepped collar is a balancing ring.

### Claim 3 (depends on 1)

The rotor of claim 1, wherein the one or more permanent magnets are hermetically sealed to the yoke by a castable resin and one or more gaps around the one or more permanent magnets are filled by the castable resin.

### Claim 4 (depends on 1)

The rotor of claim 1, wherein the one or more permanent magnets are composed of high-capacity rare-earth materials, comprising at least one of Nd, Dy, and Tb.

### Claim 5 (depends on 1)

The rotor of claim 1, wherein the yoke pole-pitch factor is maximized with the placement of the one or more permanent magnets on the surface of the yoke.

### Claim 6 (depends on 1)

The rotor of claim 1, wherein the yoke interface with the one or more permanent magnets comprises a substantially constant axial profile.

### Claim 7 (depends on 1)

The rotor of claim 1, wherein one or more of the permanent magnets comprise a planar lower surface which aligns with a portion of the form closure.

### Claim 8 (depends on 1)

The rotor of claim 1, wherein the form closure is defined by a faceted spot for each respective permanent magnet around the circumference of the yoke.

### Claim 9

A method of constructing a rotor for an electric submersible pump, the method comprising the assembly of a yoke, a stepped collar, and a cladding tube to define a magnet channel sized to accept one or more permanent magnets, the method further comprising:
placing a shaft in rigid communication with and configuring to rotate one or more pump impellers, said shaft comprising a concentric yoke integrally-formed therewith, the yoke comprising a fore end and an aft end;
disposing the one or more permanent magnets about the circumference of the yoke to form an interface with the yoke that comprises an outer dimension form closure on the circumference of the yoke in order to enhance torque transmission between the one or more permanent magnets and the yoke;
further positioning the one or more permanent magnets to axially coincide with the yoke;
positioning a stepped collar on each of the fore end and the aft end of the yoke; and
disposing a cladding tube around the circumference of the one or more permanent magnets, the cladding tube securing the one or more permanent magnets to the shaft through the yoke.

### Claim 10 (depends on 9)

The method of claim 9, the method further comprising injecting a castable resin into the magnet channel prior to the introduction of the one or more magnets to the magnet channel.

### Claim 11

An electric submersible pump comprising a motor section, a pump section, a fluid inlet section disposed axially between the motor section and the pump section, and a fluid outlet section disposed at the top of the pump section; wherein
the motor section comprises a synchronous motor, an outer casing enclosing the motor assembly, and a thermal transfer solution maintained within the outer casing and in fluidic contact with the synchronous motor, wherein the synchronous motor further comprises a rotor and a stator, the rotor comprising:
a shaft which extends over the length of the motor section in rigid communication with and configured to rotate one or more pump impellers, said shaft comprising a concentric yoke integrally-formed with the shaft, the yoke comprising a fore end and an aft end;
one or more permanent magnets disposed about the circumference of the yoke to form an interface with the yoke to comprise an outer dimension form closure on the circumference of the yoke such that form closed torque transmission is present between the one or more permanent magnets and the yoke, the one or more permanent magnets positioned to axially coincide with the yoke;
a cladding tube disposed around the circumference of the permanent magnets, the cladding tube secures the one or more permanent magnets to the shaft through the yoke; and
a stepped collar located on each of the fore end and the aft end of the yoke, wherein the one or more permanent magnets are sealed between the yoke and the cladding tube by the stepped collar; and
the pump section disposed above the motor section comprises one or more pump bowls, the pump bowls comprising centrifugal impellers, wherein the centrifugal impellers are rotated by the turning of the shaft, the centrifugal impellers receive an extracted fluid through the fluid inlet and expel the extracted fluid through the fluid outlet.

### Claim 12 (depends on 11)

The electric submersible pump of claim 11, wherein the motor section and the pump section may be comprised of serially-arranged modular subsections.

### Claim 13 (depends on 12)

The electrical submersible pump of claim 12, wherein the serially-arranged modular subsections are pump bowls housing a centrifugal impeller.

### Claim 14 (depends on 11)

The electric submersible pump of claim 11, wherein the shaft is fluidically isolated between the motor section and the pump section.

### Claim 15 (depends on 11)

The electric submersible pump of claim 11, wherein the thermal transfer solution is in thermal communication with the extracted fluid, wherein the heat generated from the motor assembly is transferred from the motor assembly to the extracted fluid.

### Claim 16 (depends on 11)

The electric submersible pump of claim 11, wherein the shaft extends over the length of the electric submersible pump.

### Claim 17 (depends on 11)

The electric submersible pump of claim 11, wherein the thermal transfer solution is selected from the group consisting of water, antifreeze, or combinations thereof.

### Claim 18 (depends on 11)

The electric submersible pump of claim 11, wherein the electric submersible pump is disposed within a well piping, the motor section further comprising a circumferential channel formed by the exterior of the outer casing and the interior of a well piping, and the circumferential channel provides a path for the extracted fluid around the outer casing and into the fluid inlet.

### Claim 19 (depends on 11)

The electric submersible pump of claim 11, wherein the motor section and the pump section each further comprise seals disposed between the respective adjoining ends along the shaft.