Electric motor powered actuator

• US 4,393,319 A
• Filed: 12/08/1980
• Issued: 07/12/1983
• Est. Priority Date: 12/08/1980
• Status: Expired due to Term

• Current Assignee: ITT Automotive Electrical Systems, Inc. (ITT, Inc.)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Bock, Gustavus P.
• Primary Examiner(s): Duggan, Donovan F.
• Application Number:
  US06/214,199
• Time in Patent Office: 946 Days
• Field of Search: 310/80, 310/83, 310/49, 310/112, 310/257, 310/156
• US Class Current: 310/80
• CPC Class Codes: F16K 31/048 with torque limiters F16K31/041 takes precedence
• CPC Class Codes: H02K 7/06 Means for converting reciprocating motion into rotary motion or vice versa

Abstract

An electric motor powered actuator in which a shaft has a threaded connection with the rotor of an electric motor whereby rotation of the rotor causes axial translation of the shaft. The shaft is urged in one direction by a compression spring and the compression spring is interposed between the shaft and a spacer ring that engages one of the thrust bearings for the motor rotor. The compression spring has nonrotatable connections with the shaft and motor housing such that the torsional force of the spring prevents rotation of the shaft relative to the motor housing when the motor rotor is rotated.

Claims

1. An electric motor powered actuator comprising in combination;

a shaft axially movable between an extended and stopped position and varying retracted positions,

a motor rotor telescoped on said shaft and in threaded relation therewith to position the shaft in accord with rotation of the rotor,

a first thrust bearing effective to oppose movement of the rotor in the retraction direction when the shaft is in extended and stopped position,

a second thrust bearing, one side of which engages said rotor, effective to oppose movement of the rotor in the extended direction, and

resilient means effective to exert a resilient expanding force between the shaft and an opposite side of said second thrust bearing to aid the motor in moving the shaft in the extended direction and to take up any last motion between the second thrust bearing and the rotor.

2. A stepper motor powered actuator comprising in combination;

a shaft axially movable between an extended and stopped position and varying retracted positions,

an electric stepper motor comprising housing means and a rotor telescoped on said shaft in threaded relation therewith to position the shaft in accord with rotation of the rotor,

a first thrust bearing effective to oppose movement of the rotor in the retraction direction when the shaft is in extended and stopped position,

a second thrust bearing, one side of which engages said rotor, effective to oppose movement of the rotor in the extended direction,

a force transmitting element slidably supported by said housing means engaging an opposite side of said second thrust bearing, and

resilient means interposed between said force transmitting element and said shaft effective to exert a resilient expanding force between the shaft and said opposite side of said second thrust bearing to aid the motor in moving the shaft in the extended direction and to take up any last motion between the second thrust bearing and the rotor.

3. An electric motor operated actuator comprising;

a motor housing having an end wall, a shaft extending through said end wall,

an electric motor comprising a stator and a rotor supported by said housing,

first and second thrust bearings engaging, respectively, opposite ends of said rotor,

means providing a threaded connection between said rotor and shaft whereby rotary movement of said rotor causes axial movement of said shaft,

a spacer having a wall portion located at the exterior of said motor housing end wall and having portions extending through openings formed in said end wall that engage said first thrust bearing, and

resilient means interposed between said shaft and said wall portion of said spacer operative to urge said shaft in a direction away from said spacer to thereby aid the motor in moving the shaft in that direction and effective to take up any end play in said first thrust bearing.

4. An electric motor operated actuator comprising;

a motor housing having an end wall, a shaft extending through said end wall having an abutment,

an electric motor comprising a stator and a rotor supported by said housing,

first and second thrust bearings engaging, respectively, opposite ends of said rotor,

means providing a threaded connection between said rotor and shaft whereby selective rotary movement of said rotor causes axial movement of said shaft in retracted or extended directions,

a spacer having a wall portion located at the exterior of said motor housing end wall having portions extending through openings formed in said end wall that engage said first thrust bearing, and

resilient means interposed between said shaft abutment and said wall portion of said spacer operative to urge said shaft in an extended direction away from said spacer to thereby aid the motor in moving the shaft in that direction and effective to take up any end play in said first thrust bearing,

the axial length of said spacer being such that said shaft abutment engages the end of said spacer when said shaft is moved in a retracted direction prior to engagement with said motor housing.

5. An electric motor operated actuator for translating rotary movement of the rotor of the motor into axial movement of a shaft comprising;

a motor housing having an end wall,

an electric motor comprising a stator and a rotor supported by said motor housing,

a shaft extending through said end wall,

means providing a threaded connection between said rotor and shaft whereby rotary movement of said rotor causes axial movement of said shaft,

thrust bearings engaging, respectively, opposite ends of said rotor,

a spacer ring disposed about said shaft having axially projecting portions extending through openings formed in said motor housing end wall the ends of which engage one of said thrust bearings, and

a compression spring interposed between said spacer ring and said shaft for urging said shaft in a direction away from motor housing to thereby aid the motor in moving the shaft in that direction,

said spring having axially spaced nonrotatable connections to said shaft and motor housing to prevent, by torsional force of the spring, relative rotation between said shaft and motor housing when said rotor rotates.

6. An electric motor operated actuator for translating rotary movement of the rotor of the motor into axial movement of a shaft comprising;

motor housing means,

an electric motor comprising a stator and a rotor supported by said housing means,

a shaft having a threaded connection with said rotor operative to move the shaft axially when the rotor is rotated, and

a coil spring disposed about said shaft arranged to urge said shaft in a direction away from said motor housing, said coil spring having axially spaced portions that are nonrotatably connected, respectively, to said shaft and housing means to thereby prevent, by the torsional force of the spring, relative rotation between said shaft and housing means when said rotor rotates relative to said housing means.

7. An electric motor operated actuator for translating rotary movement of the rotor of the motor into axial movement of a shaft comprising;

a motor housing having an end wall,

an electric motor comprising a stator and a rotor supported by said motor housing,

a shaft extending through said end wall,

means providing a threaded connection between said rotor and shaft whereby rotary movement of said rotor causes axial movement of said shaft,

thrust bearings engaging, respectively, opposite ends of said rotor,

a spacer having an annular portion disposed about said shaft and having axially projecting portions extending through openings formed in said motor housing end wall the ends of which engage one of said thrust bearings,

retainer means fixed to said motor housing engaging said spacer for preventing axial movement of said spacer relative to said motor housing,

said spacer being axially positioned to prevent end play of said rotor and thrust bearings, and

a compression spring interposed between said spacer ring and said shaft for urging said shaft in a direction away from motor housing to thereby aid the motor in moving the shaft in that direction.

8. An electric motor operated actuator for translating rotary movement of the rotor of the motor into axial movement of a shaft comprising;

a motor housing having an end wall,

an electric motor comprising a stator and a rotor supported by said motor housing,

a shaft extending through said end wall,

means providing a threaded connection between said rotor and shaft whereby rotary movement of said rotor causes axial movement of said shaft,

thrust bearings engaging, respectively, opposite ends of said rotor,

a spacer ring having an annular portion disposed about said shaft and having axially projecting portions extending through openings formed in said motor housing end wall the ends of which engage one of said thrust bearings,

an annular retainer fixed to said motor housing engaging the annular portion of said spacer ring for preventing axial movement of said spacer relative to said motor housing,

said spacer and retainer being axially positioned to prevent end play of said rotor and thrust bearings, and

a compression spring interposed between said retainer ring and said shaft for urging said shaft in a direction away from motor housing to thereby aid the motor in moving the shaft in that direction.