1. Technical Field
The present disclosure relates to robotic technologies, and particularly, to a robot arm assembly.
2. Description of the Related Art
Industrial robots generally include robot arm assemblies pivotally connected in sequence. Each arm assembly can rotate relative to the others when driven by a motor. Performance parameters such as precision, loading ability, and stability are determined by the position relationships and the driving relationships among the components arranged at a plurality of pivotal portions of the robot arm assemblies.
A commonly used robot arm assembly includes a first joint, a second joint, a flange, and a rotary bearing. The first joint is substantially cylindrical and rotatably connected to the second joint. The second joint and the flange are received in the first joint. The rotary bearing is sleeved on the second joint. The flange is fixed on an open end of the second joint, such that the rotary bearing is limited in the first joint. The robot arm assembly provides a plurality of electrical circuit cables and an airflow duct located between the first joint and the second joint. However, when the second joint rotates relative to the first joint at an angle less than 360°, the electrical circuit cables and the airflow duct are easily damaged due to excessive distortion thereof.
Therefore, there is room for improvement within the art.
The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout several views, and all the views are schematic.
Referring to
The first joint 10 includes a main body 11, a rotary connecting portion 12, and a limiting portion 13. The rotary connecting portion 12 is substantially ring-shaped, and located on an end of the main body 11. The limiting portion 13 is located adjacent to the rotary connecting portion 12. The first joint 10 further defines a fixing hole 15 in the end of the first joint 10. In the illustrated embodiment, the limiting portion 13 is a threaded member received in the fixing hole 15.
The second joint 20 includes a mounting portion 21, a receiving portion 23, a stepped hole 25, and a driving member 27. The receiving portion 23 is defined in a middle portion of the second joint 20. The stepped hole 25 is defined in the mounting portion 21 communicating with the receiving portion 23. The rotary member 30 and the bearing 40 are received in the receiving portion 23. A larger end of the stepped hole 25 is defined in a side surface of the second joint 20. The driving member 27 drives the rotary member 30 to rotate. In the illustrated embodiment, the driving member 27 is a stepper motor.
The rotary member 30 includes an axial portion 31, a first connecting portion 32, a second connecting portion 35, and a resisting portion 37. The first connecting portion 32 and the second connecting portion 35 are located on opposite ends of the axial portion 31, respectively. The first connecting portion 32 is connected to the first joint 10. The second connecting portion 35 is connected to the driving member 27. The resisting portion 37 is positioned at an end of the first connecting portion 32 adjacent to the axial portion 31.
The bearing 40 is substantially circular, and a cross-section of the bearing 40 is substantially rectangular. A diameter of the bearing 40 is less than the maximum diameter of the stepped hole 25 of the second joint 20, and exceeds the minimum diameter of the stepped hole 25, such that the bearing 40 is prevented from detaching from the stepped hole 25.
Referring to
The limiting member 60 is substantially ring shaped. A diameter of the limiting member 60 is less than that of the through hole 54. The limiting member 60 is received in the through hole 54, and resists the ring protrusion 55.
The robot arm assembly 100 further includes a plurality of electrical circuit cables and an airflow duct (not shown). The airflow duct passes through the rotary member 30, the first joint 10 and the second joint 20.
Referring to
When the first joint 10 is rotated relative to the second joint 20, the limiting portion 13 of the first joint 10 slides in the open ring groove 56, and is stopped at the end of the open ring groove 56, such that a rotation angle of the first joint 10 is less than 360°. Thereby, the robot arm assembly 100 can protect the electrical circuit cables and the airflow from being damaged due to excessive distortion.
Finally, while the present disclosure has been described with reference to particular embodiments, the description is illustrative of the disclosure and is not to be construed as limiting the disclosure. Therefore, various modifications can be made to the embodiments by those of ordinary skill in the art without departing from the true spirit and scope of the disclosure as defined by the appended claims.
Number | Date | Country | Kind |
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200910312664.0 | Dec 2009 | CN | national |