Direct drive drawworks with bearingless motor

Patent metadata

Field	Value
Publication number	US-10150659-B2
Application number	US-201514815622-A
Country	US
Kind code	B2
Filing date	Jul 31, 2015
Priority date	Aug 4, 2014
Publication date	Dec 11, 2018
Grant date	Dec 11, 2018

Abstract

An electric motor for a direct drive drawworks may be supported by one or more motor mounts. The motor mounts may include adjusting assemblies adapted to increase or decrease the length of the motor mounts. The motor mounts may include damping assemblies adapted to allow damped motion between the electric motor and the surface. The length and damping coefficients of the motor mounts may be adjusted to align the electric motor with the drum or shaft to reduce vibration. The electric motor may be removable from the drawworks by, for example, a splined shaft, a flange coupled shaft, or the rotor being selectively removable from the interior of the motor.

First claim

The invention claimed is:

1. A direct drive hoist, comprising:
an electric motor,
a first motor mount, the first motor mount adapted to couple the electric motor to a surface, the first motor mount including a damping assembly adapted to allow damped movement between the electric motor and the surface, the first motor mount including an adjusting assembly adapted to extend or retract the first motor mount;
a shaft extending through electric motor wherein there is no bearing between the electric motor and the shaft, the shaft adapted to be rotated by the electric motor; and
a load connected to the shaft, the load adapted to be rotated by the shaft as the shaft is rotated by the electric motor.

2. The direct drive hoist of claim 1 , wherein the electric motor comprises:
a housing including a support point adapted to couple the electric motor to the first motor mount;
a stator coupled to the housing; and
a rotor coupled to the shaft.

3. The direct drive hoist of claim 2 , wherein the shaft further comprises a load shaft and a motor shaft, the load shaft coupled to the drum, the motor shaft coupled to the rotor, the load shaft and the motor shaft coupled by a fixed coupler.

4. The direct drive hoist of claim 3 , wherein the fixed coupling comprises a flange coupler.

5. The direct drive hoist of claim 2 , wherein the shaft comprises an externally splined end portion and the rotor comprises a corresponding internal spline, the shaft adapted to be inserted into or removed from the rotor.

6. The direct drive hoist of claim 2 , wherein the shaft and rotor are permanently coupled, the shaft and rotor adapted to be inserted into or removed from the stator of the electric motor.

7. The direct drive hoist of claim 6 , wherein the rotor is formed as a part of the shaft.

8. The direct drive hoist of claim 2 , wherein the support point is adapted to couple to the first motor mount by a pinned coupling.

9. The direct drive hoist of claim 2 , further comprising:
a second motor mount, the second motor mount adapted to couple the electric motor to the surface, the second motor mount including a second damping assembly adapted to allow damped movement between the electric motor and the surface, the second motor mount including a second adjusting assembly adapted to extend or retract the first motor mount, and
wherein the housing includes a second support point, the second motor mount coupled between the second support point and the surface, the first and second support points positioned diametrically opposed with respect to the shaft.

10. The direct drive hoist of claim 1 , wherein the damping assembly comprises a first damper element positioned between a surface mount coupled to the surface and a first bearing plate such that the damper element is compressed between the first bearing plate.

11. The direct drive hoist of claim 10 , wherein the damping assembly further comprises a second damper element positioned between the surface mount and a second bearing plate, the second bearing plate positioned on a side opposite the surface mount from the first bearing plate, the second bearing plate coupled to the first bearing plate such that compressive force between the first and second bearing plates compresses the first and second damper elements.

12. The direct drive hoist of claim 11 , wherein the first and second bearing plates are coupled by one or more threaded members, the threaded members adapted to allow adjustment of the compression of the damper elements.

13. The direct drive hoist of claim 12 , wherein the first and second damper elements have material properties corresponding to a spring coefficient and a damping coefficient, the spring coefficient, damping coefficient, and electric motor defining a spring-mass-damper system having a harmonic frequency; and the spring coefficient and damping coefficient are selected such that the harmonic frequency of the spring-mass-damper system does not correspond to an anticipated rotation rate of the load.

14. The direct drive hoist of claim 13 , wherein the harmonic frequency of the spring-mass-damper system is selected to be less than the anticipated rotation rate of the load.

15. The direct drive hoist of claim 14 , wherein the harmonic frequency of the spring-mass-damper system is selected to be less than ⅓ the anticipated rotation rate of the load.

16. The direct drive hoist of claim 13 , wherein adjustment of the threaded members allows the harmonic frequency to be adjusted.

17. The direct drive hoist of claim 1 , wherein the adjusting assembly comprises a screw jack assembly, the screw jack assembly including at least one threaded rod and a correspondingly threaded body nut, the threaded rod adapted to be extended or retracted from the threaded nut as the threaded nut is rotated.

18. The direct drive hoist of claim 17 , wherein the screw jack assembly comprises a first threaded rod having a right-handed thread and a second threaded rod having a left-handed thread, and the body nut includes a first portion of internal threading having a right-handed thread engaged with the first threaded rod and a second portion of internal threading having a left-handed thread engaged with the second threaded rod, such that rotation of the body nut causes the first and second threaded rods to move towards or away from each other depending on the direction of rotation of the body nut.

19. The direct drive hoist of claim 1 , further comprising a load cell coupled to the first motor mount adapted to measure one or more of loading, compression, vibration, or deflection of one or more of the first motor mount, the electric motor, or the shaft.

20. The direct drive hoist of claim 19 , wherein the load cell is adapted to measure the torsional loading on the electric motor.

21. The direct drive hoist of claim 1 , wherein the hoist comprises a drawworks.

22. The direct drive hoist of claim 1 , wherein the motor is coupled to the surface by at least one of a cable or chain.

23. A method comprising:
providing a direct drive hoist, the direct drive hoist including:
an electric motor,
a first motor mount, the first motor mount adapted to couple the electric motor to a surface, the first motor mount including a damping assembly adapted to allow damped movement between the electric motor and the surface, the first motor mount including an adjusting assembly adapted to extend or retract the first motor mount;
a shaft extending through the electric motor wherein there is no bearing between the electric motor and the shaft, the shaft adapted to be rotated by the electric motor; and
a load connected to the shaft, the load adapted to be rotated by the shaft as the shaft is rotated by the electric motor; and

adjusting one or more of the damping assembly and the adjusting assembly in response to one or more of radial displacement of the shaft; misalignment between the electric motor and the shaft, load, or rotor; observed vibration; cogging; or bearing tolerances.

Assignees

• Canrig Drilling Tech Ltd
• Nabors Drilling Tech Usa Inc

Inventors

• Kuttel Beat
• Williams Kevin R
• Ellis Brian
• Yousef Faisal

Classifications

• B66D1/82 Primary

  for slewing and hoisting by means of derricks · CPC title

• H02K5/24

  specially adapted for suppression or reduction of noise or vibrations · CPC title

• F16M1/04

  for rotary engines or similar machines · CPC title

• H02K5/26

  Means for adjusting casings relative to their supports · CPC title

• F16M7/00

  Details of attaching or adjusting engine beds, frames, or supporting-legs on foundation or base; Attaching non-moving engine parts, e.g. cylinder blocks (elastic or equivalent mounting for absorbing vibrations F16F, especially F16F15/04) · CPC title