Multi-joint type industrial robot

• US 6,781,337 B2
• Filed: 10/09/2002
• Issued: 08/24/2004
• Est. Priority Date: 10/17/2001
• Status: Expired due to Fees

• Current Assignee: Japan Servo Co., Ltd. (Nidec Corporation), Tazmo Co., Ltd.
• Original Assignee: Japan Servo Co., Ltd. (Nidec Corporation), Tazmo Co., Ltd.
• Inventors: Kobiki, Takahiro, Yamazoe, Katsuhiro, Sakamoto, Masafumi, Endo, Kaoru
• Primary Examiner(s): DUDA, RINA I
• Application Number:
  US10/269,020
• Publication Number:
  US 20030085681A1
• Time in Patent Office: 685 Days
• Field of Search: 318/567, 318/568.12, 318/568.16, 318/568.18, 318/568.2, 318/568.21, 318/656, 318/647
• US Class Current: 318/567
• CPC Class Codes: B25J 19/0025 Means for supplying energy to the end effector
• CPC Class Codes: B25J 9/042 comprising an articulated arm
• CPC Class Codes: H01R 39/64 Devices for uninterrupted current collection

Abstract

In an industrial robot having a plurality of arms, each arm is coupled with other elements, such as a mounting base, another arm, a robotic hand, and revolved by a motion of the revolvable joint. The revolvable joint has a rotary electric connecting structure such as a slip ring or a rotary transformer which can be rotated endlessly. Electric powers for driving motors by which the arms are revolved and control signals for controlling the driving of the motors are supplied or transmitted through the rotary electric connecting structure, so that the arms can be rotated endlessly without twisting or breaking of electric cables.

Claims

1. An industrial robot, comprising:

a plurality of arms coupled by a plurality of revolvable joints which are endlessly rotatable;

motors, each being provided respectively at each of the revolvable joints, said motors each having a hollow drive shaft, each of the arms being movable by a driving force of a respective one of the motors;

each of the revolvable joints including a rotary electric connecting structure which can be rotated endlessly at least for supplying an electric power from a control circuit to an associated one of the motors, each of the revolvable joints further including an encoder being coupled with a rotation shaft of the rotary electric connecting structure; and

electric cables being directed through an inside of the hollow drive shaft of at least one of the motors.

2. The industrial robot in accordance with claim 1, wherein:

the rotary electric connecting structure is a slip ring structure including at least one conductive rotary member which can be rotated in correspondence with revolution of a corresponding one of the arms and at least one conductive stationary member which is not rotated in correspondence with the revolution of the corresponding one of the arms; and

electric connection is realized by slipping contact of the at least one rotary member and the at least one stationary member.

3. The industrial robot in accordance with claim 2, wherein the slip ring structure is further used for transmitting a sensing signal from the encoder to the control circuit.

4. The industrial robot in accordance with claim 1, wherein:

the rotary electric connecting structure includes a rotary transformer having a rotary secondary coil which can be rotated in correspondence with revolution of a corresponding one of the arms, and a stationary primary coil which is not rotated in correspondence with the revolution of the corresponding one of the arms; and

electric connection is realized by electromagnetic interactive induction between the stationary primary coil and the rotary secondary coil.

5. The industrial robot in accordance with claim 4, wherein the rotary transformer is further used for transmitting a sensing signal from the encoder to the control circuit.

6. The industrial robot in accordance with claim 2, wherein:

said at least one conductive rotary member includes axially spaced rotary members each having an outer electrical contact surface coaxial with a rational axis thereof; and

said at least one stationary member includes stationary members each with contact the outer electrical contact surface of a respective one of said axially spaced rotary members.

7. The industrial robot in accordance with claim 6, wherein said stationary members are each generally Y-shaped having a base portion connected to a terminal and two arm portions serving as bushes, each of said arm portions extending divergently from the base portion and tangentially contacting the outer electrical contact surface of the respective one of said axially spaced rotary members.

8. An industrial robot, comprising:

a plurality of arms coupled by a plurality of revolvable joints, each of the arms being movable by a driving force of a motor which drives each of the revolvable joints, each of the revolvable joints being endlessly rotatable, and having a rotary electric connecting structure which can be rotated endlessly at least for supplying an electric power from a control circuit to the motor, the rotary electric connecting structure being a rotary transformer having a rotary secondary coil which can be rotated in correspondence with revolution of a corresponding one of the arms, and a stationary primary coil which is not rotated in correspondence with the revolution of the corresponding one of the arms, and electric connection being realized by electromagnetic interactive induction between the stationary primary coil and the rotary secondary coil, the rotary transformer being further used for transmitting a sensing signal from the encoder to the control circuit; and

a plurality of modulator/demodulator units for modulating the electric power supplied from the control circuit and control signals transmitted from the control circuit to other signals which can be electrically connected by the electromagnetic interactive induction of the rotary transformer, and for demodulating modulated other signals to the electric power and the control signals.