Synchronized Actuator Having Multiple Motors for Downhole Well Tool

Abstract

A downhole tool, such an interval control valve, for use in a well has multiple motors and two drive assemblies to displace a yoke. A member, such as a sliding sleeve, of the downhole tool is connected to the yoke and can be actuated in response to the displacement of the yoke. The drive assemblies include first and second rotatable screws, and the yoke is disposed on the screws. Each motor can produce drive to rotate a respective screw. A respective gear is rotatable in association with at least the rotation of its associated screw. An intermediate gear is engaged between these two gears. The intermediate gear interconnects the rotation of the two screws, forcing them to rotate at the same speed. Likewise, the intermediate gear balances the drive of the motors, forcing the two screws to rotate at the same speed.

What is claimed is: 
     
         1 . A downhole tool for use in a well, the downhole tool comprising:
 an actuator comprising:
 a first motor configured to produce a first drive; 
 a second motor configured to produce a second drive; 
 a first gear being rotatable in association with first drive; 
 a second gear being rotatable in association with second drive; 
 a screw being rotatable and having a proximal end; 
 an intermediate gear engaged between the first and second gears and being configured to synchronize first and second rotations of the first and second gears as a synchronized rotation produced by at least one of the first and second drives, the intermediate gear having an inline connection to the proximal end of the screw and transferring the synchronized rotation to the screw; and 
 a yoke disposed on the screw and being displaceable thereon by the synchronized rotation; and 
   an actuatable member of the downhole tool connected to the yoke of the actuator and being actuatable in response to the displacement of the yoke.   
     
     
         2 . The downhole tool of  claim 1 , wherein the screw comprises a worm gear feed screw, and the yoke comprises a nut disposed on the worm gear feed screw; or wherein the screw is a rotatable screw of a ball screw assembly, and the yoke comprises a ball nut of the ball screw assembly disposed on the rotatable screw. 
     
     
         3 . The downhole tool of  claim 1 , comprising:
 a first mount having a first bearing supporting the proximal end of the screw on the first mount; and   a motor mount having the first and second motors mounted thereon, wherein the first gear, the second gear, and the intermediate gear are disposed between the first mount and the motor mount.   
     
     
         4 . The downhole tool of  claim 3 , comprising a second mount having a second bearing supporting a distal end of the screw on the second mount. 
     
     
         5 . The downhole tool of  claim 1 , wherein the yoke is displaceable in a first linear direction in response to the first drive of the first motor alone in a first rotational direction, the second drive of the second motor alone in the first rotational direction, or the first and second drive of the first and second motors both in the first rotational direction; and wherein the yoke is displaceable in a second linear direction opposite to the first linear direction in response to the first drive of the first motor alone in a second rotational direction opposite to the first rotational direction, the second drive of the second motor alone in the second rotational direction, or the first and second drives of the first and second motors both in the second rotational direction. 
     
     
         6 . The downhole tool of  claim 1 , wherein the intermediate gear is disposed on the proximal end of the screw, and wherein the inline connection comprises a spline connection of the intermediate gear to the proximal end of the screw. 
     
     
         7 . The downhole tool of  claim 1 , wherein the downhole tool is an interval control valve comprising a housing having a bore and at least one side port; and wherein the actuatable member comprises a sliding sleeve disposed in the bore and connected to the yoke, the sliding sleeve being movable relative to the at least one side port in response to the displacement of the yoke. 
     
     
         8 . A downhole tool for use in a well, the downhole tool comprising:
 an actuator comprising:
 a screw being rotatable and having a proximal end; 
 a first motor being configured to produce a first drive; 
 a first gear being rotatable in association with first drive; 
 a second motor configured to produce a second drive; 
 a second gear having an inline connection to a drive shaft of the second motor and to the proximal end of the screw; 
 an intermediate gear engaged between the first and second gears and being configured to synchronize first and second rotations of the first and second gears as a synchronized rotation produced by at least one of the first and second drives; and 
 a yoke disposed on the screw and being displaceable thereon by the synchronized rotation; and 
   an actuatable member of the downhole tool connected to the yoke of the actuator and being actuatable in response to the displacement of the yoke.   
     
     
         9 . The downhole tool of  claim 8 , wherein the screw comprises a worm gear feed screw, and the yoke comprises a nut disposed on the worm gear feed screw; or wherein the screw is a rotatable screw of a ball screw assembly, and the yoke comprises a ball nut of the ball screw assembly disposed on the rotatable screw. 
     
     
         10 . The downhole tool of  claim 8 , comprising:
 a first mount having a first bearing supporting the proximal end of the screw on the first mount; and   a motor mount having the first and second motors mounted thereon,   wherein the first gear and the second gear are disposed between the first mount and the motor mount; and   wherein the intermediate gear is disposed on an intermediate shaft connected between the first mount and the motor mount.   
     
     
         11 . The downhole tool of  claim 10 , comprising a second mount having a second bearing supporting a distal end of the screw on the second mount. 
     
     
         12 . The downhole tool of  claim 10 , wherein the intermediate gear is rotatable relative to the intermediate shaft, the intermediate shaft is rotatable relative to the first mount and the motor mount, or both. 
     
     
         13 . The downhole tool of  claim 8 , wherein the yoke is displaceable in a first linear direction in response to the first drive of the first motor alone in a first rotational direction, the second drive of the second motor alone in the first rotational direction, or the first and second drive of the first and second motors both in the first rotational direction; and wherein the yoke is displaceable in a second linear direction opposite to the first linear direction in response to the first drive of the first motor alone in a second rotational direction opposite to the first rotational direction, the second drive of the second motor alone in the second rotational direction, or the first and second drives of the first and second motors both in the second rotational direction. 
     
     
         14 . The downhole tool of  claim 8 , wherein the second gear is disposed on the drive shaft of the second motor and the proximal end of the screw, and wherein the inline connection comprises a spline connection of the second gear to the drive shaft and the proximal end. 
     
     
         15 . The downhole tool of  claim 8 , wherein the downhole tool is an interval control valve comprising a housing having a bore and at least one side port; and wherein the actuatable member comprises a sliding sleeve disposed in the bore and connected to the yoke, the sliding sleeve being movable relative to the at least one side port in response to the displacement of the yoke. 
     
     
         16 . A downhole tool for use in a well, the downhole tool comprising:
 an actuator comprising:
 a first motor being configured to produce a first drive; 
 a first gear being rotatable in association with the first drive; 
 a second motor configured to produce a second drive; 
 a second gear being rotatable in association with second drive; 
 a roto-linear drive having a third gear; 
 an intermediate gear being rotatable and having first and second portions, the first portion of the intermediate gear engaged between the first and second gears and being configured to synchronize the first and second drives as a synchronized drive, the second portion of the intermediate gear engaged with the third gear and being configured to transfer the synchronized drive to a synchronized rotation for the roto-linear drive; and 
 a yoke disposed on the roto-linear drive and being displaceable thereon by the synchronized rotation; and 
   an actuatable member of the downhole tool connected to the yoke of the actuator and being actuatable in response to the displacement of the yoke.   
     
     
         17 . The downhole tool of  claim 16 , comprising:
 a first mount having a bearing supporting a proximal end of the roto-linear drive on the first mount; and   a motor mount having the first and second motors mounted thereon,   wherein the first gear, the second gear, and the third gear are disposed between the first and second mounts; and   wherein the intermediate gear is disposed on an intermediate shaft connected between the first mount and the motor mount.   
     
     
         18 . The downhole tool of  claim 17 , wherein the intermediate gear is rotatable relative to the intermediate shaft, the intermediate shaft is rotatable relative to the first mount and the motor mount, or both. 
     
     
         19 . The downhole tool of  claim 16 , wherein the roto-linear drive comprises a worm gear feed screw, and the yoke comprises a nut disposed on the worm gear feed screw; or wherein the roto-linear drive is a rotatable screw of a ball screw assembly, and the yoke comprises a ball nut of the ball screw assembly disposed on the rotatable screw. 
     
     
         20 . The downhole tool of  claim 16 , wherein the downhole tool is an interval control valve comprising a housing having a bore and at least one side port; and wherein the actuatable member comprises a sliding sleeve disposed in the bore and connected to the yoke, the sliding sleeve being movable relative to the at least one side port in response to the displacement of the yoke.