Industrial robot having direct coaxial motor drive

• US 4,552,505 A
• Filed: 08/19/1983
• Issued: 11/12/1985
• Est. Priority Date: 11/19/1982
• Status: Expired due to Fees

• Current Assignee: American Robot Corporation
• Original Assignee: American Robot Corporation
• Inventors: Gorman, Robert H.
• Primary Examiner(s): Spar, Robert J.
• Assistant Examiner(s): Underwood, Donald W.
• Application Number:
  US06/524,839
• Time in Patent Office: 816 Days
• Field of Search: 414/1, 414/4, 414/7, 414/735, 901/14, 901/15, 901/21-24, 74/665 A, 74/665 D, 74/469, 318/568
• US Class Current: 414/735
• CPC Class Codes: B25J 17/0241 One-dimensional joints
• CPC Class Codes: B25J 9/046 Revolute coordinate type
• CPC Class Codes: B25J 9/08 characterised by modular constructions
• CPC Class Codes: B25J 9/126 Rotary actuators
• CPC Class Codes: H02K 37/00 Motors with rotor rotating step by step and without interrupter or commutator driven by the rotor, e.g. stepping motors
• CPC Class Codes: Y10T 74/19065 Aligned

Abstract

An industrial robot is disclosed which includes three primary drive units defining three separately controlled axes of movement, and an outer arm assembly having three additional axes of movement. The three primary drive units are interconnected so that a first drive unit defines a vertical axis of movement, and the second and third drive units define horizontal axes of movement which are coaxial. Also, the three primary drive units each include an electrical stepping motor which has its rotor and stator coaxially disposed about the axis of movement, with the rotor and stator being respectively fixed to the output components, to thereby eliminate the need for any torque converting drive train between the motor and output components.

Claims

1. An industrial robot having at least three controlled axes of movement, and characterized by the absence of a torque converting drive train in the drive units of three primary axes of movement, and comprising

a support member,

a first drive unit having a base component fixedly mounted to said support member, a secondary component rotatably mounted with respect to said base component to define a first axis, and drive means for relatively rotating said base component and secondary component about said first axis,

a second drive unit having a base component, a secondary component rotatably mounted with respect to its base component to define a second axis, means fixedly mounting said secondary component of said second drive unit to said secondary component of said first drive unit such that the second axis is non parallel to said first axis, output means fixed to said base component of said second drive unit and aligned coaxially with said second axis, and drive means for relatively rotating said base component and secondary component of said second drive unit about said second axis,

a third drive unit having a base component, a secondary component rotatably mounted with respect to its base component to define a further axis, means fixedly mounting said secondary component of said third drive unit to the secondary component of said first drive unit such that said further axis is coaxial with said second axis, output means fixed to said base component of said third drive unit and aligned coaxially with said second axis, and drive means for relatively rotating said base component and secondary component of said third drive unit about said second axis, and

said drive means of each of said first, second, and third drive units comprising an electrical motor having a rotor disposed coaxially about the associated rotational axis and being fixed to one of either said base component or said secondary component thereof, and a stator disposed coaxially about the associated rotational axis and being fixed to the other of said base component or said secondary component thereof.

2. The industrial robot as defined in claim 1 wherein said first and second axes perpendicularly intersect.

3. The industrial robot as defined in claim 2 wherein said base component and output means of said third drive unit are tubular, and said output means of said second drive unit includes a shaft extending coaxially through said base component and output means of said third drive unit.

4. The industrial robot as defined in claim 3 wherein said robot further comprises

an inner arm,

means interconnecting said inner arm to said output means of said third drive unit,

an outer arm,

means pivotally connecting said outer arm to said inner arm for relative rotation about a third axis disposed parallel to and laterally spaced from said second axis, and torque transmission means operatively connecting said output means of said second drive unit to said outer arm,

whereby said inner arm may be pivoted about said second axis by said third drive unit, and said outer arm may be pivoted about said third axis by said second drive unit.

5. The industrial robot as defined in claim 4 wherein said electrical motor of each of said first, second, and third drive units comprises a stepping motor and means for sensing the angular position of each such motor.

6. An industrial robot having a plurality of controlled axes of movement, and comprising

a support member (26),

a first drive unit (22) having a base component (22a) and a secondary component (22b), said base component being rotatably mounted with respect to said secondary component to define a central axis (B), means fixedly mounting said secondary component of said first drive unit to said support member, output shaft means (38) fixed to said base component and aligned coaxially with said central axis, and drive means (40, 42) for rotating said base component about said central axis, and

a second drive unit (23) having a tubular base component (23a) and a secondary component (23b), said base component being rotatably mounted with respect to its secondary component for rotation about said central axis and being coaxially disposed about said output shaft means, means fixedly mounting said secondary component of said second drive unit to said support member, tubular output means fixed to said base component of said second drive unit and aligned coaxially about said output shaft means of said first drive unit, and drive means for rotating said base component of said second drive unit about said central axis.

7. The industrial robot as defined in claim 6 wherein said drive means of each of said first and second drive units comprises an electrical motor having a rotor (40) disposed coaxially about the central axis and being fixed to said base component thereof, and a stator (42) disposed coaxially about the central axis and being fixed to said secondary component thereof.

8. The industrial robot as defined in claim 6 wherein said robot further comprises

an inner arm (15),

means (32) interconnecting said inner arm to said output means of said second drive unit,

an outer arm (16),

means (55) pivotally connecting said outer arm to said inner arm for relative rotation about a second axis (C) disposed parallel to and laterally spaced from said central axis, and torque transmission means (62) operatively connecting said output shaft means of said first drive unit to said outer arm,

whereby said inner arm may be pivoted about said central axis by said second drive unit, and said outer arm may be pivoted about said second axis by said first drive unit.

9. The industrial robot as defined in claim 8 wherein said drive means of each of said first and second drive units comprises an electrical motor having a rotor (40) disposed coaxially about the central axis and being fixed to said base component thereof, and a stator (42) disposed coaxially about the central axis and being fixed to said secondary component thereof, and means (44) for sensing the angular position of said rotor relative to said stator.